New upstream version 0.32.1upstream/0.32.1

12 files changed, 1982 insertions, 0 deletions

diff --git a/src/video-support/AVIChunk.vala b/src/video-support/AVIChunk.vala
new file mode 100644
index 0000000..970f443
--- /dev/null
+++ b/src/video-support/AVIChunk.vala
@@ -0,0 +1,121 @@
+private class AVIChunk {
+    private GLib.File file = null;
+    private string section_name = "";
+    private uint64 section_size = 0;
+    private uint64 section_offset = 0;
+    private GLib.DataInputStream input = null;
+    private AVIChunk? parent = null;
+    private const int MAX_STRING_TO_SECTION_LENGTH = 1024;
+
+    public AVIChunk(GLib.File file) {
+        this.file = file;
+    }
+
+    private AVIChunk.with_input_stream(GLib.DataInputStream input, AVIChunk parent) {
+        this.input = input;
+        this.parent = parent;
+    }
+
+    public void open_file() throws GLib.Error {
+        close_file();
+        input = new GLib.DataInputStream(file.read());
+        input.set_byte_order(DataStreamByteOrder.LITTLE_ENDIAN);
+        section_size = 0;
+        section_offset = 0;
+        section_name = "";
+    }
+
+    public void close_file() throws GLib.Error {
+        if (null != input) {
+            input.close();
+            input = null;
+        }
+    }
+
+    public void nonsection_skip(uint64 skip_amount) throws GLib.Error {
+        skip_uint64(input, skip_amount);
+    }
+
+    public void skip(uint64 skip_amount) throws GLib.Error {
+        advance_section_offset(skip_amount);
+        skip_uint64(input, skip_amount);
+    }
+
+    public AVIChunk get_first_child_chunk() {
+        return new AVIChunk.with_input_stream(input, this);
+    }
+
+    private void advance_section_offset(uint64 amount) {
+        if ((section_offset + amount) > section_size)
+            amount = section_size - section_offset;
+
+        section_offset += amount;
+        if (null != parent) {
+            parent.advance_section_offset(amount);
+        }
+    }
+
+    public uchar read_byte() throws GLib.Error {
+        advance_section_offset(1);
+        return input.read_byte();
+    }
+
+    public uint16 read_uint16() throws GLib.Error {
+       advance_section_offset(2);
+       return input.read_uint16();
+    }
+
+    public void read_chunk() throws GLib.Error {
+        // don't use checked reads here because they advance the section offset, which we're trying
+        // to determine here
+        GLib.StringBuilder sb = new GLib.StringBuilder();
+        sb.append_c((char) input.read_byte());
+        sb.append_c((char) input.read_byte());
+        sb.append_c((char) input.read_byte());
+        sb.append_c((char) input.read_byte());
+        section_name = sb.str;
+        section_size = input.read_uint32();
+        section_offset = 0;
+    }
+
+    public string read_name() throws GLib.Error {
+        GLib.StringBuilder sb = new GLib.StringBuilder();
+        sb.append_c((char) read_byte());
+        sb.append_c((char) read_byte());
+        sb.append_c((char) read_byte());
+        sb.append_c((char) read_byte());
+        return sb.str;
+    }
+
+    public void next_chunk() throws GLib.Error {
+        skip(section_size_remaining());
+        section_size = 0;
+        section_offset = 0;
+    }
+
+    public string get_current_chunk_name() {
+        return section_name;
+    }
+
+    public bool is_last_chunk() {
+        return section_size == 0;
+    }
+
+    public uint64 section_size_remaining() {
+        assert(section_size >= section_offset);
+        return section_size - section_offset;
+    }
+
+    // Reads section contents into a string.
+    public string section_to_string() throws GLib.Error {
+        GLib.StringBuilder sb = new GLib.StringBuilder();
+        while (section_offset < section_size) {
+            sb.append_c((char) read_byte());
+            if (sb.len > MAX_STRING_TO_SECTION_LENGTH) {
+                return sb.str;
+            }
+        }
+        return sb.str;
+    }
+
+}
diff --git a/src/video-support/AVIMetadataLoader.vala b/src/video-support/AVIMetadataLoader.vala
new file mode 100644
index 0000000..2b507e2
--- /dev/null
+++ b/src/video-support/AVIMetadataLoader.vala
@@ -0,0 +1,227 @@
+public class AVIMetadataLoader {
+
+    private File file = null;
+
+    // A numerical date string, i.e 2010:01:28 14:54:25
+    private const int NUMERICAL_DATE_LENGTH = 19;
+
+    // Marker for timestamp section in a Nikon nctg blob.
+    private const uint16 NIKON_NCTG_TIMESTAMP_MARKER = 0x13;
+
+    // Size limit to ensure we don't parse forever on a bad file.
+    private const int MAX_STRD_LENGTH = 100;
+
+    public AVIMetadataLoader(File file) {
+        this.file = file;
+    }
+
+    public MetadataDateTime? get_creation_date_time() {
+        return new MetadataDateTime(get_creation_date_time_for_avi());
+    }
+
+    public string? get_title() {
+        // Not supported.
+        return null;
+    }
+
+    // Checks if the given file is an AVI file.
+    public bool is_supported() {
+        AVIChunk chunk = new AVIChunk(file);
+        bool ret = false;
+        try {
+            chunk.open_file();
+            chunk.read_chunk();
+            // Look for the header and identifier.
+            if ("RIFF" == chunk.get_current_chunk_name() &&
+                "AVI " == chunk.read_name()) {
+                ret = true;
+            }
+        } catch (GLib.Error e) {
+            debug("Error while testing for AVI file: %s", e.message);
+        }
+
+        try {
+            chunk.close_file();
+        } catch (GLib.Error e) {
+            debug("Error while closing AVI file: %s", e.message);
+        }
+        return ret;
+    }
+
+    // Parses a Nikon nctg tag.  Based losely on avi_read_nikon() in FFmpeg.
+    private string read_nikon_nctg_tag(AVIChunk chunk) throws GLib.Error {
+        bool found_date = false;
+        while (chunk.section_size_remaining() > sizeof(uint16)*2) {
+            uint16 tag = chunk.read_uint16();
+            uint16 size = chunk.read_uint16();
+            if (NIKON_NCTG_TIMESTAMP_MARKER == tag) {
+                found_date = true;
+                break;
+            }
+            chunk.skip(size);
+        }
+
+        if (found_date) {
+            // Read numerical date string, example: 2010:01:28 14:54:25
+            GLib.StringBuilder sb = new GLib.StringBuilder();
+            for (int i = 0; i < NUMERICAL_DATE_LENGTH; i++) {
+                sb.append_c((char) chunk.read_byte());
+            }
+            return sb.str;
+        }
+        return "";
+    }
+
+    // Parses a Fujifilm strd tag. Based on information from:
+    // http://www.eden-foundation.org/products/code/film_date_stamp/index.html
+    private string read_fuji_strd_tag(AVIChunk chunk) throws GLib.Error {
+        chunk.skip(98); // Ignore 98-byte binary blob.
+        chunk.skip(8); // Ignore the string "FUJIFILM"
+        // Read until we find four colons, then two more chars.
+        int colons = 0;
+        int post_colons = 0;
+        GLib.StringBuilder sb = new GLib.StringBuilder();
+        // End of date is two chars past the fourth colon.
+        while (colons <= 4 && post_colons < 2) {
+            char c = (char) chunk.read_byte();
+            if (4 == colons) {
+                post_colons++;
+            }
+            if (':' == c) {
+                colons++;
+            }
+            if (c.isprint()) {
+                sb.append_c(c);
+            }
+            if (sb.len > MAX_STRD_LENGTH) {
+                return ""; // Give up searching.
+            }
+        }
+
+        if (sb.str.length < NUMERICAL_DATE_LENGTH) {
+            return "";
+        }
+        // Date is now at the end of the string.
+        return sb.str.substring(sb.str.length - NUMERICAL_DATE_LENGTH);
+    }
+
+    // Recursively read file until the section is found.
+    private string? read_section(AVIChunk chunk) throws GLib.Error {
+        while (true) {
+            chunk.read_chunk();
+            string name = chunk.get_current_chunk_name();
+            if ("IDIT" == name) {
+                return chunk.section_to_string();
+            } else if ("nctg" == name) {
+                return read_nikon_nctg_tag(chunk);
+            } else if ("strd" == name) {
+                return read_fuji_strd_tag(chunk);
+            }
+
+            if ("LIST" == name) {
+                chunk.read_name(); // Read past list name.
+                string result = read_section(chunk.get_first_child_chunk());
+                if (null != result) {
+                    return result;
+                }
+            }
+
+            if (chunk.is_last_chunk()) {
+                break;
+            }
+            chunk.next_chunk();
+        }
+        return null;
+    }
+
+    // Parses a date from a string.
+    // Largely based on GStreamer's avi/gstavidemux.c
+    // and the information here:
+    // http://www.eden-foundation.org/products/code/film_date_stamp/index.html
+    private DateTime? parse_date(string sdate) {
+        if (sdate.length == 0) {
+            return null;
+        }
+
+        int year, month, day, hour, min, sec;
+        char weekday[4];
+        char monthstr[4];
+        DateTime parsed_date;
+
+        if (sdate[0].isdigit()) {
+            // Format is: 2005:08:17 11:42:43
+            // Format is: 2010/11/30/ 19:42
+            // Format is: 2010/11/30 19:42
+            string tmp = sdate.dup();
+            tmp.canon("0123456789 ", ' '); // strip everything but numbers and spaces
+            sec = 0;
+            int result = tmp.scanf("%d %d %d %d %d %d", out year, out month, out day, out hour, out min, out sec);
+            if(result < 5) {
+                return null;
+            }
+
+            parsed_date = new DateTime.utc(year, month, day, hour, min, sec);
+        } else {
+            // Format is: Mon Mar  3 09:44:56 2008
+            if(7 != sdate.scanf("%3s %3s %d %d:%d:%d %d", weekday, monthstr, out day, out hour,
+                  out min, out sec, out year)) {
+                return null; // Error
+            }
+            parsed_date = new DateTime.local(year, month_from_string((string)monthstr), day, hour, min, sec);
+        }
+
+        return parsed_date;
+    }
+
+    private DateMonth month_from_string(string s) {
+        switch (s.down()) {
+        case "jan":
+            return DateMonth.JANUARY;
+        case "feb":
+            return DateMonth.FEBRUARY;
+        case "mar":
+            return DateMonth.MARCH;
+        case "apr":
+            return DateMonth.APRIL;
+        case "may":
+            return DateMonth.MAY;
+        case "jun":
+            return DateMonth.JUNE;
+        case "jul":
+            return DateMonth.JULY;
+        case "aug":
+            return DateMonth.AUGUST;
+        case "sep":
+            return DateMonth.SEPTEMBER;
+        case "oct":
+            return DateMonth.OCTOBER;
+        case "nov":
+            return DateMonth.NOVEMBER;
+        case "dec":
+            return DateMonth.DECEMBER;
+        }
+        return DateMonth.BAD_MONTH;
+    }
+
+    private DateTime? get_creation_date_time_for_avi() {
+        AVIChunk chunk = new AVIChunk(file);
+        DateTime? timestamp = null;
+        try {
+            chunk.open_file();
+            chunk.nonsection_skip(12); // Advance past 12 byte header.
+            string sdate = read_section(chunk);
+            if (null != sdate) {
+                timestamp = parse_date(sdate.strip());
+            }
+        } catch (GLib.Error e) {
+            debug("Error while reading AVI file: %s", e.message);
+        }
+
+        try {
+            chunk.close_file();
+        } catch (GLib.Error e) {
+            debug("Error while closing AVI file: %s", e.message);
+        }
+        return timestamp;
+    }
+}
diff --git a/src/video-support/QuickTimeAtom.vala b/src/video-support/QuickTimeAtom.vala
new file mode 100644
index 0000000..996046a
--- /dev/null
+++ b/src/video-support/QuickTimeAtom.vala
@@ -0,0 +1,118 @@
+private class QuickTimeAtom {
+    private GLib.File file = null;
+    private string section_name = "";
+    private uint64 section_size = 0;
+    private uint64 section_offset = 0;
+    private GLib.DataInputStream input = null;
+    private QuickTimeAtom? parent = null;
+
+    public QuickTimeAtom(GLib.File file) {
+        this.file = file;
+    }
+
+    private QuickTimeAtom.with_input_stream(GLib.DataInputStream input, QuickTimeAtom parent) {
+        this.input = input;
+        this.parent = parent;
+    }
+
+    public void open_file() throws GLib.Error {
+        close_file();
+        input = new GLib.DataInputStream(file.read());
+        input.set_byte_order(DataStreamByteOrder.BIG_ENDIAN);
+        section_size = 0;
+        section_offset = 0;
+        section_name = "";
+    }
+
+    public void close_file() throws GLib.Error {
+        if (null != input) {
+            input.close();
+            input = null;
+        }
+    }
+
+    private void advance_section_offset(uint64 amount) {
+        section_offset += amount;
+        if (null != parent) {
+            parent.advance_section_offset(amount);
+        }
+    }
+
+    public QuickTimeAtom get_first_child_atom() {
+        // Child will simply have the input stream
+        // but not the size/offset.  This works because
+        // child atoms follow immediately after a header,
+        // so no skipping is required to access the child
+        // from the current position.
+        return new QuickTimeAtom.with_input_stream(input, this);
+    }
+
+    public uchar read_byte() throws GLib.Error {
+        advance_section_offset(1);
+        return input.read_byte();
+    }
+
+    public uint32 read_uint32() throws GLib.Error {
+        advance_section_offset(4);
+        return input.read_uint32();
+    }
+
+    public uint64 read_uint64() throws GLib.Error {
+        advance_section_offset(8);
+        return input.read_uint64();
+    }
+
+    public void read_atom() throws GLib.Error {
+        // Read atom size.
+        section_size = read_uint32();
+
+        // Read atom name.
+        GLib.StringBuilder sb = new GLib.StringBuilder();
+        sb.append_c((char) read_byte());
+        sb.append_c((char) read_byte());
+        sb.append_c((char) read_byte());
+        sb.append_c((char) read_byte());
+        section_name = sb.str;
+
+        // Check string.
+        if (section_name.length != 4) {
+            throw new IOError.NOT_SUPPORTED("QuickTime atom name length is invalid for %s",
+                file.get_path());
+        }
+        for (int i = 0; i < section_name.length; i++) {
+            if (!section_name[i].isprint()) {
+                throw new IOError.NOT_SUPPORTED("Bad QuickTime atom in file %s", file.get_path());
+            }
+        }
+
+        if (1 == section_size) {
+            // This indicates the section size is a 64-bit
+            // value, specified below the atom name.
+            section_size = read_uint64();
+        }
+    }
+
+    private void skip(uint64 skip_amount) throws GLib.Error {
+        skip_uint64(input, skip_amount);
+    }
+
+    public uint64 section_size_remaining() {
+        assert(section_size >= section_offset);
+        return section_size - section_offset;
+    }
+
+    public void next_atom() throws GLib.Error {
+        skip(section_size_remaining());
+        section_size = 0;
+        section_offset = 0;
+    }
+
+    public string get_current_atom_name() {
+        return section_name;
+    }
+
+    public bool is_last_atom() {
+        return 0 == section_size;
+    }
+
+}
diff --git a/src/video-support/QuicktimeMetdataLoader.vala b/src/video-support/QuicktimeMetdataLoader.vala
new file mode 100644
index 0000000..0a831d2
--- /dev/null
+++ b/src/video-support/QuicktimeMetdataLoader.vala
@@ -0,0 +1,127 @@
+public class QuickTimeMetadataLoader {
+
+    // Quicktime calendar date/time format is number of seconds since January 1, 1904.
+    // This converts to UNIX time (66 years + 17 leap days).
+    public const int64 QUICKTIME_EPOCH_ADJUSTMENT = 2082844800;
+
+    private File file = null;
+
+    public QuickTimeMetadataLoader(File file) {
+        this.file = file;
+    }
+
+    public MetadataDateTime? get_creation_date_time() {
+        var dt = get_creation_date_time_for_quicktime();
+        if (dt == null) {
+            return null;
+        } else {
+            return new MetadataDateTime(dt);
+        }
+    }
+
+    public string? get_title() {
+        // Not supported.
+        return null;
+    }
+
+    // Checks if the given file is a QuickTime file.
+    public bool is_supported() {
+        QuickTimeAtom test = new QuickTimeAtom(file);
+
+        bool ret = false;
+        try {
+            test.open_file();
+            test.read_atom();
+
+            // Look for the header.
+            if ("ftyp" == test.get_current_atom_name()) {
+                ret = true;
+            } else {
+                // Some versions of QuickTime don't have
+                // an ftyp section, so we'll just look
+                // for the mandatory moov section.
+                while(true) {
+                    if ("moov" == test.get_current_atom_name()) {
+                        ret = true;
+                        break;
+                    }
+                    test.next_atom();
+                    test.read_atom();
+                    if (test.is_last_atom()) {
+                        break;
+                    }
+                }
+            }
+        } catch (GLib.Error e) {
+            debug("Error while testing for QuickTime file for %s: %s", file.get_path(), e.message);
+        }
+
+        try {
+            test.close_file();
+        } catch (GLib.Error e) {
+            debug("Error while closing Quicktime file: %s", e.message);
+        }
+        return ret;
+    }
+
+    private DateTime? get_creation_date_time_for_quicktime() {
+        QuickTimeAtom test = new QuickTimeAtom(file);
+        DateTime? timestamp = null;
+
+        try {
+            test.open_file();
+            bool done = false;
+            while(!done) {
+                // Look for "moov" section.
+                test.read_atom();
+                if (test.is_last_atom()) break;
+                if ("moov" == test.get_current_atom_name()) {
+                    QuickTimeAtom child = test.get_first_child_atom();
+                    while (!done) {
+                        // Look for "mvhd" section, or break if none is found.
+                        child.read_atom();
+                        if (child.is_last_atom() || 0 == child.section_size_remaining()) {
+                            done = true;
+                            break;
+                        }
+
+                        if ("mvhd" == child.get_current_atom_name()) {
+                            // Skip 4 bytes (version + flags)
+                            child.read_uint32();
+                            // Grab the timestamp.
+
+                            // Some Android phones package videos recorded with their internal cameras in a 3GP
+                            // container that looks suspiciously like a QuickTime container but really isn't -- for
+                            // the timestamps of these Android 3GP videos are relative to the UNIX epoch
+                            // (January 1, 1970) instead of the QuickTime epoch (January 1, 1904). So, if we detect a
+                            // QuickTime movie with a negative timestamp, we can be pretty sure it isn't a valid
+                            // QuickTime movie that was shot before 1904 but is instead a non-compliant 3GP video
+                            // file. If we detect such a video, we correct its time. See this Redmine ticket
+                            // (https://bugzilla.gnome.org/show_bug.cgi?id=717384) for more information.
+
+                            if ((child.read_uint32() - QUICKTIME_EPOCH_ADJUSTMENT) < 0) {
+                                timestamp = new DateTime.from_unix_utc(child.read_uint32());
+                            } else {
+                                timestamp = new DateTime.from_unix_utc(child.read_uint32() - QUICKTIME_EPOCH_ADJUSTMENT);
+                            }
+                            done = true;
+                            break;
+                        }
+                        child.next_atom();
+                    }
+                }
+                test.next_atom();
+            }
+        } catch (GLib.Error e) {
+            debug("Error while testing for QuickTime file: %s", e.message);
+        }
+
+        try {
+            test.close_file();
+        } catch (GLib.Error e) {
+            debug("Error while closing Quicktime file: %s", e.message);
+        }
+
+        return timestamp;
+    }
+}
diff --git a/src/video-support/Video.vala b/src/video-support/Video.vala
new file mode 100644
index 0000000..0238d7f
--- /dev/null
+++ b/src/video-support/Video.vala
@@ -0,0 +1,703 @@
+/* Copyright 2016 Software Freedom Conservancy Inc.
+ *
+ * This software is licensed under the GNU LGPL (version 2.1 or later).
+ * See the COPYING file in this distribution.
+ */
+
+public class Video : VideoSource, Flaggable, Monitorable, Dateable {
+    public const string TYPENAME = "video";
+
+    public const uint64 FLAG_TRASH =    0x0000000000000001;
+    public const uint64 FLAG_OFFLINE =  0x0000000000000002;
+    public const uint64 FLAG_FLAGGED =  0x0000000000000004;
+
+    public class InterpretableResults {
+        internal Video video;
+        internal bool update_interpretable = false;
+        internal bool is_interpretable = false;
+        internal Gdk.Pixbuf? new_thumbnail = null;
+
+        public InterpretableResults(Video video) {
+            this.video = video;
+        }
+
+        public void foreground_finish() {
+            if (update_interpretable)
+                video.set_is_interpretable(is_interpretable);
+
+            if (new_thumbnail != null) {
+                try {
+                    ThumbnailCache.replace(video, ThumbnailCache.Size.BIG, new_thumbnail);
+                    ThumbnailCache.replace(video, ThumbnailCache.Size.MEDIUM, new_thumbnail);
+
+                    video.notify_thumbnail_altered();
+                } catch (Error err) {
+                    message("Unable to update video thumbnails for %s: %s", video.to_string(),
+                        err.message);
+                }
+            }
+        }
+    }
+
+    private static bool normal_regen_complete;
+    private static bool offline_regen_complete;
+    public static VideoSourceCollection global;
+
+    private VideoRow backing_row;
+
+    public Video(VideoRow row) {
+        this.backing_row = row;
+
+        // normalize user text
+        this.backing_row.title = prep_title(this.backing_row.title);
+
+        if (((row.flags & FLAG_TRASH) != 0) || ((row.flags & FLAG_OFFLINE) != 0))
+            rehydrate_backlinks(global, row.backlinks);
+    }
+
+    public static void init(ProgressMonitor? monitor = null) {
+        // Must initialize static variables here.
+        // TODO: set values at declaration time once the following Vala bug is fixed:
+        //       https://bugzilla.gnome.org/show_bug.cgi?id=655594
+        normal_regen_complete = false;
+        offline_regen_complete = false;
+
+        // initialize GStreamer, but don't pass it our actual command line arguments -- we don't
+        // want our end users to be able to parameterize the GStreamer configuration
+        unowned string[] args = null;
+        Gst.init(ref args);
+
+        var registry = Gst.Registry.@get ();
+
+        /* Update our local registr to not include vaapi stuff. This is basically to
+        * work-around concurrent access to VAAPI/X11 which it doesn't like, cf
+         * https://bugzilla.gnome.org/show_bug.cgi?id=762416
+         */
+
+        var features = registry.feature_filter ((f) => {
+            return f.get_name ().has_prefix ("vaapi");
+        }, false);
+
+        foreach (var feature in features) {
+            debug ("Removing registry feature %s", feature.get_name ());
+            registry.remove_feature (feature);
+        }
+
+        global = new VideoSourceCollection();
+
+        Gee.ArrayList<VideoRow?> all = VideoTable.get_instance().get_all();
+        Gee.ArrayList<Video> all_videos = new Gee.ArrayList<Video>();
+        Gee.ArrayList<Video> trashed_videos = new Gee.ArrayList<Video>();
+        Gee.ArrayList<Video> offline_videos = new Gee.ArrayList<Video>();
+        int count = all.size;
+        for (int ctr = 0; ctr < count; ctr++) {
+            Video video = new Video(all.get(ctr));
+
+            if (video.is_trashed())
+                trashed_videos.add(video);
+            else if (video.is_offline())
+                offline_videos.add(video);
+            else
+                all_videos.add(video);
+
+            if (monitor != null)
+                monitor(ctr, count);
+        }
+
+        global.add_many_to_trash(trashed_videos);
+        global.add_many_to_offline(offline_videos);
+        global.add_many(all_videos);
+    }
+
+    public static void notify_normal_thumbs_regenerated() {
+        if (normal_regen_complete)
+            return;
+
+        message("normal video thumbnail regeneration completed");
+
+        normal_regen_complete = true;
+    }
+
+    public static void notify_offline_thumbs_regenerated() {
+        if (offline_regen_complete)
+            return;
+
+        message("offline video thumbnail regeneration completed");
+
+        offline_regen_complete = true;
+    }
+
+    public static void terminate() {
+    }
+
+    public static ExporterUI? export_many(Gee.Collection<Video> videos, Exporter.CompletionCallback done,
+        bool export_in_place = false) {
+        if (videos.size == 0)
+            return null;
+
+        // in place export is relatively easy -- provide a fast, separate code path for it
+        if (export_in_place) {
+             ExporterUI temp_exporter = new ExporterUI(new Exporter.for_temp_file(videos,
+                Scaling.for_original(), ExportFormatParameters.unmodified()));
+             temp_exporter.export(done);
+             return temp_exporter;
+        }
+
+        // one video
+        if (videos.size == 1) {
+            Video video = null;
+            foreach (Video v in videos) {
+                video = v;
+                break;
+            }
+
+            File save_as = ExportUI.choose_file(video.get_basename());
+            if (save_as == null)
+                return null;
+
+            try {
+                AppWindow.get_instance().set_busy_cursor();
+                video.export(save_as);
+                AppWindow.get_instance().set_normal_cursor();
+            } catch (Error err) {
+                AppWindow.get_instance().set_normal_cursor();
+                export_error_dialog(save_as, false);
+            }
+
+            return null;
+        }
+
+        // multiple videos
+        File export_dir = ExportUI.choose_dir(_("Export Videos"));
+        if (export_dir == null)
+            return null;
+
+        ExporterUI exporter = new ExporterUI(new Exporter(videos, export_dir,
+            Scaling.for_original(), ExportFormatParameters.unmodified()));
+        exporter.export(done);
+
+        return exporter;
+    }
+
+    protected override void commit_backlinks(SourceCollection? sources, string? backlinks) {
+        try {
+            VideoTable.get_instance().update_backlinks(get_video_id(), backlinks);
+            lock (backing_row) {
+                backing_row.backlinks = backlinks;
+            }
+        } catch (DatabaseError err) {
+            warning("Unable to update link state for %s: %s", to_string(), err.message);
+        }
+    }
+
+    protected override bool set_event_id(EventID event_id) {
+        lock (backing_row) {
+            bool committed = VideoTable.get_instance().set_event(backing_row.video_id, event_id);
+
+            if (committed)
+                backing_row.event_id = event_id;
+
+            return committed;
+        }
+    }
+
+    public static bool is_duplicate(File? file, string? full_md5) {
+        assert(file != null || full_md5 != null);
+#if !NO_DUPE_DETECTION
+        return VideoTable.get_instance().has_duplicate(file, full_md5);
+#else
+        return false;
+#endif
+    }
+
+    public static ImportResult import_create(VideoImportParams params, out Video video) {
+        video = null;
+
+        // add to the database
+        try {
+            if (VideoTable.get_instance().add(params.row).is_invalid())
+                return ImportResult.DATABASE_ERROR;
+        } catch (DatabaseError err) {
+            return ImportResult.DATABASE_ERROR;
+        }
+
+        // create local object but don't add to global until thumbnails generated
+        video = new Video(params.row);
+
+        return ImportResult.SUCCESS;
+    }
+
+    public static void import_failed(Video video) {
+        try {
+            VideoTable.get_instance().remove(video.get_video_id());
+        } catch (DatabaseError err) {
+            AppWindow.database_error(err);
+        }
+    }
+
+    public override BackingFileState[] get_backing_files_state() {
+        BackingFileState[] backing = new BackingFileState[1];
+        lock (backing_row) {
+            backing[0] = new BackingFileState(backing_row.filepath, backing_row.filesize,
+                backing_row.timestamp, backing_row.md5);
+        }
+
+        return backing;
+    }
+
+    public override Gdk.Pixbuf? get_thumbnail(int scale) throws Error {
+        return ThumbnailCache.fetch(this, scale);
+    }
+
+    public override string get_master_md5() {
+        lock (backing_row) {
+            return backing_row.md5;
+        }
+    }
+
+    public override Gdk.Pixbuf get_preview_pixbuf(Scaling scaling) throws Error {
+        Gdk.Pixbuf pixbuf = get_thumbnail(ThumbnailCache.Size.BIG);
+
+        return scaling.perform_on_pixbuf(pixbuf, Gdk.InterpType.NEAREST, true);
+    }
+
+    public override Gdk.Pixbuf? create_thumbnail(int scale) throws Error {
+        VideoReader reader = new VideoReader(get_file());
+        Gdk.Pixbuf? frame = reader.read_preview_frame();
+
+        return (frame != null) ? frame : Resources.get_noninterpretable_badge_pixbuf().copy();
+    }
+
+    public override string get_typename() {
+        return TYPENAME;
+    }
+
+    public override int64 get_instance_id() {
+        return get_video_id().id;
+    }
+
+    public override ImportID get_import_id() {
+        lock (backing_row) {
+            return backing_row.import_id;
+        }
+    }
+
+    public override PhotoFileFormat get_preferred_thumbnail_format() {
+        return PhotoFileFormat.get_system_default_format();
+    }
+
+    public override string? get_title() {
+        lock (backing_row) {
+            return backing_row.title;
+        }
+    }
+
+    public override void set_title(string? title) {
+        string? new_title = prep_title(title);
+
+        lock (backing_row) {
+            if (backing_row.title == new_title)
+                return;
+
+            try {
+                VideoTable.get_instance().set_title(backing_row.video_id, new_title);
+            } catch (DatabaseError e) {
+                AppWindow.database_error(e);
+                return;
+            }
+            // if we didn't short-circuit return in the catch clause above, then the change was
+            // successfully committed to the database, so update it in the in-memory row cache
+            backing_row.title = new_title;
+        }
+
+        notify_altered(new Alteration("metadata", "name"));
+    }
+
+    public override string? get_comment() {
+        lock (backing_row) {
+            return backing_row.comment;
+        }
+    }
+
+    public override bool set_comment(string? comment) {
+        string? new_comment = prep_title(comment);
+
+        lock (backing_row) {
+            if (backing_row.comment == new_comment)
+                return true;
+
+            try {
+                VideoTable.get_instance().set_comment(backing_row.video_id, new_comment);
+            } catch (DatabaseError e) {
+                AppWindow.database_error(e);
+                return false;
+            }
+            // if we didn't short-circuit return in the catch clause above, then the change was
+            // successfully committed to the database, so update it in the in-memory row cache
+            backing_row.comment = new_comment;
+        }
+
+        notify_altered(new Alteration("metadata", "comment"));
+
+        return true;
+    }
+
+
+    public override Rating get_rating() {
+        lock (backing_row) {
+            return backing_row.rating;
+        }
+    }
+
+    public override void set_rating(Rating rating) {
+        lock (backing_row) {
+            if ((!rating.is_valid()) || (rating == backing_row.rating))
+                return;
+
+            try {
+                VideoTable.get_instance().set_rating(get_video_id(), rating);
+            } catch (DatabaseError e) {
+                AppWindow.database_error(e);
+                return;
+            }
+            // if we didn't short-circuit return in the catch clause above, then the change was
+            // successfully committed to the database, so update it in the in-memory row cache
+            backing_row.rating = rating;
+        }
+
+        notify_altered(new Alteration("metadata", "rating"));
+    }
+
+    public override void increase_rating() {
+        lock (backing_row) {
+            set_rating(backing_row.rating.increase());
+        }
+    }
+
+    public override void decrease_rating() {
+        lock (backing_row) {
+            set_rating(backing_row.rating.decrease());
+        }
+    }
+
+    public override bool is_trashed() {
+        return is_flag_set(FLAG_TRASH);
+    }
+
+    public override bool is_offline() {
+        return is_flag_set(FLAG_OFFLINE);
+    }
+
+    public override void mark_offline() {
+        add_flags(FLAG_OFFLINE);
+    }
+
+    public override void mark_online() {
+        remove_flags(FLAG_OFFLINE);
+
+        if ((!get_is_interpretable()))
+            check_is_interpretable().foreground_finish();
+    }
+
+    public override void trash() {
+        add_flags(FLAG_TRASH);
+    }
+
+    public override void untrash() {
+        remove_flags(FLAG_TRASH);
+    }
+
+    public bool is_flagged() {
+        return is_flag_set(FLAG_FLAGGED);
+    }
+
+    public void mark_flagged() {
+        add_flags(FLAG_FLAGGED, new Alteration("metadata", "flagged"));
+    }
+
+    public void mark_unflagged() {
+        remove_flags(FLAG_FLAGGED, new Alteration("metadata", "flagged"));
+    }
+
+    public override EventID get_event_id() {
+        lock (backing_row) {
+            return backing_row.event_id;
+        }
+    }
+
+    public override string to_string() {
+        lock (backing_row) {
+            return "[%s] %s".printf(backing_row.video_id.id.to_string(), backing_row.filepath);
+        }
+    }
+
+    public VideoID get_video_id() {
+        lock (backing_row) {
+            return backing_row.video_id;
+        }
+    }
+
+    public override DateTime? get_exposure_time() {
+        lock (backing_row) {
+            return backing_row.exposure_time;
+        }
+    }
+
+    public void set_exposure_time(DateTime time) {
+        lock (backing_row) {
+            try {
+                VideoTable.get_instance().set_exposure_time(backing_row.video_id, time);
+            } catch (Error e) {
+                debug("Warning - %s", e.message);
+            }
+            backing_row.exposure_time = time;
+        }
+
+        notify_altered(new Alteration("metadata", "exposure-time"));
+    }
+
+    public Dimensions get_frame_dimensions() {
+        lock (backing_row) {
+            return Dimensions(backing_row.width, backing_row.height);
+        }
+    }
+
+    public override Dimensions get_dimensions(Photo.Exception disallowed_steps = Photo.Exception.NONE) {
+        return get_frame_dimensions();
+    }
+
+    public override uint64 get_filesize() {
+        return get_master_filesize();
+    }
+
+    public override uint64 get_master_filesize() {
+        lock (backing_row) {
+            return backing_row.filesize;
+        }
+    }
+
+    public override DateTime? get_timestamp() {
+        lock (backing_row) {
+            return backing_row.timestamp;
+        }
+    }
+
+    public void set_master_timestamp(FileInfo info) {
+        var time_val = info.get_modification_date_time();
+
+        try {
+            lock (backing_row) {
+                if (backing_row.timestamp.equal(time_val))
+                    return;
+
+                VideoTable.get_instance().set_timestamp(backing_row.video_id, time_val);
+                backing_row.timestamp = time_val;
+            }
+        } catch (Error err) {
+            AppWindow.database_error(err);
+
+            return;
+        }
+
+        notify_altered(new Alteration("metadata", "master-timestamp"));
+    }
+
+    public string get_filename() {
+        lock (backing_row) {
+            return backing_row.filepath;
+        }
+    }
+
+    public override File get_file() {
+        return File.new_for_path(get_filename());
+    }
+
+    public override File get_master_file() {
+        return get_file();
+    }
+
+    public void export(File dest_file) throws Error {
+        File source_file = File.new_for_path(get_filename());
+        source_file.copy(dest_file, FileCopyFlags.OVERWRITE | FileCopyFlags.TARGET_DEFAULT_PERMS,
+            null, null);
+    }
+
+    public double get_clip_duration() {
+        lock (backing_row) {
+            return backing_row.clip_duration;
+        }
+    }
+
+    public bool get_is_interpretable() {
+        lock (backing_row) {
+            return backing_row.is_interpretable;
+        }
+    }
+
+    private void set_is_interpretable(bool is_interpretable) {
+        lock (backing_row) {
+            if (backing_row.is_interpretable == is_interpretable)
+                return;
+
+            backing_row.is_interpretable = is_interpretable;
+        }
+
+        try {
+            VideoTable.get_instance().update_is_interpretable(get_video_id(), is_interpretable);
+        } catch (DatabaseError e) {
+            AppWindow.database_error(e);
+        }
+    }
+
+    // Intended to be called from a background thread but can be called from foreground as well.
+    // Caller should call InterpretableResults.foreground_process() only from foreground thread,
+    // however
+    public InterpretableResults check_is_interpretable() {
+        InterpretableResults results = new InterpretableResults(this);
+
+        double clip_duration = -1.0;
+        Gdk.Pixbuf? preview_frame = null;
+
+        VideoReader backing_file_reader = new VideoReader(get_file());
+        try {
+            clip_duration = backing_file_reader.read_clip_duration();
+            preview_frame = backing_file_reader.read_preview_frame();
+        } catch (VideoError e) {
+            // if we catch an error on an interpretable video here, then this video is
+            // non-interpretable (e.g. its codec is not present on the users system).
+            results.update_interpretable = get_is_interpretable();
+            results.is_interpretable = false;
+
+            return results;
+        }
+
+        // if already marked interpretable, this is only confirming what we already knew
+        if (get_is_interpretable()) {
+            results.update_interpretable = false;
+            results.is_interpretable = true;
+
+            return results;
+        }
+
+        debug("video %s has become interpretable", get_file().get_basename());
+
+        // save this here, this can be done in background thread
+        lock (backing_row) {
+            backing_row.clip_duration = clip_duration;
+        }
+
+        results.update_interpretable = true;
+        results.is_interpretable = true;
+        results.new_thumbnail = preview_frame;
+
+        return results;
+    }
+
+    public override void destroy() {
+        VideoID video_id = get_video_id();
+
+        ThumbnailCache.remove(this);
+
+        try {
+            VideoTable.get_instance().remove(video_id);
+        } catch (DatabaseError err) {
+            error("failed to remove video %s from video table", to_string());
+        }
+
+        base.destroy();
+    }
+
+    protected override bool internal_delete_backing() throws Error {
+        bool ret = delete_original_file();
+
+        // Return false if parent method failed.
+        return base.internal_delete_backing() && ret;
+    }
+
+    private void notify_flags_altered(Alteration? additional_alteration) {
+        Alteration alteration = new Alteration("metadata", "flags");
+        if (additional_alteration != null)
+            alteration = alteration.compress(additional_alteration);
+
+        notify_altered(alteration);
+    }
+
+    public uint64 add_flags(uint64 flags_to_add, Alteration? additional_alteration = null) {
+        uint64 new_flags;
+        lock (backing_row) {
+            new_flags = internal_add_flags(backing_row.flags, flags_to_add);
+            if (backing_row.flags == new_flags)
+                return backing_row.flags;
+
+            try {
+                VideoTable.get_instance().set_flags(get_video_id(), new_flags);
+            } catch (DatabaseError e) {
+                AppWindow.database_error(e);
+                return backing_row.flags;
+            }
+
+            backing_row.flags = new_flags;
+        }
+
+        notify_flags_altered(additional_alteration);
+
+        return new_flags;
+    }
+
+    public uint64 remove_flags(uint64 flags_to_remove, Alteration? additional_alteration = null) {
+        uint64 new_flags;
+        lock (backing_row) {
+            new_flags = internal_remove_flags(backing_row.flags, flags_to_remove);
+            if (backing_row.flags == new_flags)
+                return backing_row.flags;
+
+            try {
+                VideoTable.get_instance().set_flags(get_video_id(), new_flags);
+            } catch (DatabaseError e) {
+                AppWindow.database_error(e);
+                return backing_row.flags;
+            }
+
+            backing_row.flags = new_flags;
+        }
+
+        notify_flags_altered(additional_alteration);
+
+        return new_flags;
+    }
+
+    public bool is_flag_set(uint64 flag) {
+        lock (backing_row) {
+            return internal_is_flag_set(backing_row.flags, flag);
+        }
+    }
+
+    public void set_master_file(File file) {
+        string new_filepath = file.get_path();
+        string? old_filepath = null;
+        try {
+            lock (backing_row) {
+                if (backing_row.filepath == new_filepath)
+                    return;
+
+                old_filepath = backing_row.filepath;
+
+                VideoTable.get_instance().set_filepath(backing_row.video_id, new_filepath);
+                backing_row.filepath = new_filepath;
+            }
+        } catch (Error err) {
+            AppWindow.database_error(err);
+
+            return;
+        }
+
+        assert(old_filepath != null);
+        notify_master_replaced(File.new_for_path(old_filepath), file);
+
+        notify_altered(new Alteration.from_list("backing:master,metadata:name"));
+    }
+
+    public VideoMetadata read_metadata() throws Error {
+        return (new VideoReader(get_file())).read_metadata();
+    }
+}
diff --git a/src/video-support/VideoImportParams.vala b/src/video-support/VideoImportParams.vala
new file mode 100644
index 0000000..6804c53
--- /dev/null
+++ b/src/video-support/VideoImportParams.vala
@@ -0,0 +1,28 @@
+/* Copyright 2016 Software Freedom Conservancy Inc.
+ *
+ * This software is licensed under the GNU LGPL (version 2.1 or later).
+ * See the COPYING file in this distribution.
+ */
+
+public class VideoImportParams {
+    // IN:
+    public File file;
+    public ImportID import_id = ImportID();
+    public string? md5;
+    public DateTime? exposure_time_override;
+
+    // IN/OUT:
+    public Thumbnails? thumbnails;
+
+    // OUT:
+    public VideoRow row = new VideoRow();
+
+    public VideoImportParams(File file, ImportID import_id, string? md5,
+        Thumbnails? thumbnails = null, DateTime? exposure_time_override = null) {
+        this.file = file;
+        this.import_id = import_id;
+        this.md5 = md5;
+        this.thumbnails = thumbnails;
+        this.exposure_time_override = exposure_time_override;
+    }
+}
diff --git a/src/video-support/VideoMetadata.vala b/src/video-support/VideoMetadata.vala
new file mode 100644
index 0000000..02580f8
--- /dev/null
+++ b/src/video-support/VideoMetadata.vala
@@ -0,0 +1,51 @@
+/* Copyright 2016 Software Freedom Conservancy Inc.
+ *
+ * This software is licensed under the GNU Lesser General Public License
+ * (version 2.1 or later).  See the COPYING file in this distribution.
+ */
+
+public class VideoMetadata : MediaMetadata {
+
+    private MetadataDateTime timestamp = null;
+    private string title = null;
+    private string comment = null;
+
+    public VideoMetadata() {
+    }
+
+    ~VideoMetadata() {
+    }
+
+    public override void read_from_file(File file) throws Error {
+        QuickTimeMetadataLoader quicktime = new QuickTimeMetadataLoader(file);
+        if (quicktime.is_supported()) {
+            timestamp = quicktime.get_creation_date_time();
+            title = quicktime.get_title();
+	        // TODO: is there an quicktime.get_comment ??
+            comment = null;
+            return;
+        }
+        AVIMetadataLoader avi = new AVIMetadataLoader(file);
+        if (avi.is_supported()) {
+            timestamp = avi.get_creation_date_time();
+            title = avi.get_title();
+            comment = null;
+            return;
+        }
+
+        throw new IOError.NOT_SUPPORTED("File %s is not a supported video format", file.get_path());
+    }
+
+    public override MetadataDateTime? get_creation_date_time() {
+        return timestamp;
+    }
+
+    public override string? get_title() {
+        return title;
+    }
+
+    public override string? get_comment() {
+        return comment;
+    }
+
+}
diff --git a/src/video-support/VideoMetadataReaderProcess.vala b/src/video-support/VideoMetadataReaderProcess.vala
new file mode 100644
index 0000000..26d61a6
--- /dev/null
+++ b/src/video-support/VideoMetadataReaderProcess.vala
@@ -0,0 +1,66 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
+using Gst;
+using Gst.PbUtils;
+
+int main(string[] args) {
+    Intl.setlocale(GLib.LocaleCategory.NUMERIC, "C");
+
+    var option_context = new OptionContext("- shotwell video metadata reader helper binary");
+    option_context.set_help_enabled(true);
+    option_context.add_group(Gst.init_get_option_group());
+
+    double clip_duration;
+    GLib.DateTime timestamp = null;
+
+    try {
+        option_context.parse(ref args);
+
+        if (args.length < 2)
+            throw new IOError.INVALID_ARGUMENT("Missing URI");
+
+        var f = File.new_for_commandline_arg (args[1]);
+
+        Gst.PbUtils.Discoverer d = new Gst.PbUtils.Discoverer((Gst.ClockTime) (Gst.SECOND * 5));
+        Gst.PbUtils.DiscovererInfo info = d.discover_uri(f.get_uri());
+
+        clip_duration = ((double) info.get_duration()) / 1000000000.0;
+
+        // Get creation time.
+        // TODO: Note that TAG_DATE can be changed to TAG_DATE_TIME in the future
+        // (and the corresponding output struct) in order to implement #2836.
+        Gst.DateTime? video_date = null;
+
+        Gst.TagList? tags = null;
+
+        var stream_info = info.get_stream_info();
+        if (stream_info is Gst.PbUtils.DiscovererContainerInfo) {
+            tags = ((Gst.PbUtils.DiscovererContainerInfo)stream_info).get_tags();
+        }
+        else if (stream_info is Gst.PbUtils.DiscovererStreamInfo) {
+            tags = ((Gst.PbUtils.DiscovererStreamInfo)stream_info).get_tags();
+        }
+
+        if (tags != null && tags.get_date_time(Gst.Tags.DATE_TIME, out video_date)) {
+            // possible for get_date() to return true and a null Date
+            if (video_date != null) {
+                timestamp = video_date.to_g_date_time().to_local();
+            }
+        }
+
+        print("%.3f\n", clip_duration);
+        if (timestamp != null) {
+            print("%s\n", timestamp.format_iso8601());
+        } else {
+            print("none\n");
+        }
+    } catch (Error error) {
+        critical("Failed to parse options: %s", error.message);
+
+        return 1;
+    }
+
+    return 0;
+}
diff --git a/src/video-support/VideoReader.vala b/src/video-support/VideoReader.vala
new file mode 100644
index 0000000..11f11e1
--- /dev/null
+++ b/src/video-support/VideoReader.vala
@@ -0,0 +1,317 @@
+/* Copyright 2016 Software Freedom Conservancy Inc.
+ *
+ * This software is licensed under the GNU LGPL (version 2.1 or later).
+ * See the COPYING file in this distribution.
+ */
+
+public errordomain VideoError {
+    FILE,          // there's a problem reading the video container file (doesn't exist, no read
+                   // permission, etc.)
+
+    CONTENTS,      // we can read the container file but its contents are indecipherable (no codec,
+                   // malformed data, etc.)
+}
+
+public class VideoReader {
+    private const double UNKNOWN_CLIP_DURATION = -1.0;
+    private const uint THUMBNAILER_TIMEOUT = 10000; // In milliseconds.
+
+    // File extensions for video containers that pack only metadata as per the AVCHD spec
+    private const string[] METADATA_ONLY_FILE_EXTENSIONS = { "bdm", "bdmv", "cpi", "mpl" };
+
+    private double clip_duration = UNKNOWN_CLIP_DURATION;
+    private Gdk.Pixbuf preview_frame = null;
+    private File file = null;
+    private Subprocess thumbnailer_process = null;
+    public DateTime? timestamp { get; private set; default = null; }
+
+    public VideoReader(File file) {
+        this.file = file;
+     }
+
+    public static bool is_supported_video_file(File file) {
+        var mime_type = ContentType.guess(file.get_basename(), new uchar[0], null);
+        // special case: deep-check content-type of files ending with .ogg
+        if (mime_type == "audio/ogg" && file.has_uri_scheme("file")) {
+            try {
+                var info = file.query_info(FileAttribute.STANDARD_CONTENT_TYPE,
+                                           FileQueryInfoFlags.NONE);
+                var content_type = info.get_content_type();
+                if (content_type != null && content_type.has_prefix ("video/")) {
+                    return true;
+                }
+            } catch (Error error) {
+                debug("Failed to query content type: %s", error.message);
+            }
+        }
+
+        return is_supported_video_filename(file.get_basename());
+    }
+
+    public static bool is_supported_video_filename(string filename) {
+        string mime_type;
+        mime_type = ContentType.guess(filename, new uchar[0], null);
+        // Guessed mp4/mxf from filename has application/ as prefix, so check for mp4/mxf in the end
+        if (mime_type.has_prefix ("video/") ||
+            mime_type.has_suffix("mp4") ||
+            mime_type.has_suffix("mxf")) {
+            string? extension = null;
+            string? name = null;
+            disassemble_filename(filename, out name, out extension);
+
+            if (extension == null)
+                return true;
+
+            foreach (string s in METADATA_ONLY_FILE_EXTENSIONS) {
+                if (utf8_ci_compare(s, extension) == 0)
+                    return false;
+            }
+
+            return true;
+        } else {
+            debug("Skipping %s, unsupported mime type %s", filename, mime_type);
+            return false;
+        }
+    }
+
+    public static ImportResult prepare_for_import(VideoImportParams params) {
+#if MEASURE_IMPORT
+        Timer total_time = new Timer();
+#endif
+        File file = params.file;
+
+        FileInfo info = null;
+        try {
+            info = file.query_info(DirectoryMonitor.SUPPLIED_ATTRIBUTES,
+                FileQueryInfoFlags.NOFOLLOW_SYMLINKS, null);
+        } catch (Error err) {
+            return ImportResult.FILE_ERROR;
+        }
+
+        if (info.get_file_type() != FileType.REGULAR)
+            return ImportResult.NOT_A_FILE;
+
+        if (!is_supported_video_file(file)) {
+            message("Not importing %s: file is marked as a video file but doesn't have a" +
+                "supported extension", file.get_path());
+
+            return ImportResult.UNSUPPORTED_FORMAT;
+        }
+
+        var timestamp = info.get_modification_date_time();
+
+        // make sure params has a valid md5
+        assert(params.md5 != null);
+
+        DateTime exposure_time = params.exposure_time_override;
+        string title = "";
+        string comment = "";
+
+        VideoReader reader = new VideoReader(file);
+        bool is_interpretable = true;
+        double clip_duration = 0.0;
+        Gdk.Pixbuf preview_frame = reader.read_preview_frame();
+        try {
+            clip_duration = reader.read_clip_duration();
+        } catch (VideoError err) {
+            if (err is VideoError.FILE) {
+                return ImportResult.FILE_ERROR;
+            } else if (err is VideoError.CONTENTS) {
+                is_interpretable = false;
+                clip_duration = 0.0;
+            } else {
+                error("can't prepare video for import: an unknown kind of video error occurred");
+            }
+        }
+
+        try {
+            VideoMetadata metadata = reader.read_metadata();
+            MetadataDateTime? creation_date_time = metadata.get_creation_date_time();
+
+            if (creation_date_time != null && creation_date_time.get_timestamp() != null)
+                exposure_time = creation_date_time.get_timestamp();
+
+            string? video_title = metadata.get_title();
+            string? video_comment = metadata.get_comment();
+            if (video_title != null)
+                title = video_title;
+            if (video_comment != null)
+                comment = video_comment;
+        } catch (Error err) {
+            warning("Unable to read video metadata: %s", err.message);
+        }
+
+        if (exposure_time == null) {
+            // Use time reported by Gstreamer, if available.
+            exposure_time = reader.timestamp;
+        }
+
+        params.row.video_id = VideoID();
+        params.row.filepath = file.get_path();
+        params.row.filesize = info.get_size();
+        params.row.timestamp = timestamp;
+        params.row.width = preview_frame.width;
+        params.row.height = preview_frame.height;
+        params.row.clip_duration = clip_duration;
+        params.row.is_interpretable = is_interpretable;
+        params.row.exposure_time = exposure_time;
+        params.row.import_id = params.import_id;
+        params.row.event_id = EventID();
+        params.row.md5 = params.md5;
+        params.row.time_created = 0;
+        params.row.title = title;
+        params.row.comment = comment;
+        params.row.backlinks = "";
+        params.row.time_reimported = 0;
+        params.row.flags = 0;
+
+        if (params.thumbnails != null) {
+            params.thumbnails = new Thumbnails();
+            ThumbnailCache.generate_for_video_frame(params.thumbnails, preview_frame);
+        }
+
+#if MEASURE_IMPORT
+        debug("IMPORT: total time to import video = %lf", total_time.elapsed());
+#endif
+        return ImportResult.SUCCESS;
+    }
+
+    private void read_internal() throws VideoError {
+        if (!does_file_exist())
+            throw new VideoError.FILE("video file '%s' does not exist or is inaccessible".printf(
+                file.get_path()));
+
+        uint id = 0;
+        try {
+            var cancellable = new Cancellable();
+
+            id = Timeout.add_seconds(10, () => {
+                cancellable.cancel();
+                id = 0;
+
+                return false;
+            });
+
+            Bytes stdout_buf = null;
+            Bytes stderr_buf = null;
+
+            var process = new GLib.Subprocess(GLib.SubprocessFlags.STDOUT_PIPE, AppDirs.get_metadata_helper().get_path(), file.get_uri());
+            var result = process.communicate(null, cancellable, out stdout_buf, out stderr_buf);
+            if (result && process.get_if_exited() && process.get_exit_status () == 0 && stdout_buf != null && stdout_buf.get_size() > 0) {
+                string[] lines = ((string) stdout_buf.get_data()).split("\n");
+
+                var old = Intl.setlocale(GLib.LocaleCategory.NUMERIC, "C");
+                clip_duration = double.parse(lines[0]);
+                Intl.setlocale(GLib.LocaleCategory.NUMERIC, old);
+                if (lines[1] != "none")
+                    timestamp = new DateTime.from_iso8601(lines[1], null);
+            } else {
+                string message = "";
+                if (stderr_buf != null && stderr_buf.get_size() > 0) {
+                    message = (string) stderr_buf.get_data();
+                }
+                warning ("External Metadata helper failed");
+            }
+        } catch (Error e) {
+            debug("Video read error: %s", e.message);
+            throw new VideoError.CONTENTS("GStreamer couldn't extract clip information: %s"
+                .printf(e.message));
+        }
+
+        if (id != 0) {
+            Source.remove(id);
+        }
+    }
+
+    // Used by thumbnailer() to kill the external process if need be.
+    private bool on_thumbnailer_timer() {
+        debug("Thumbnailer timer called");
+        if (thumbnailer_process != null) {
+            thumbnailer_process.force_exit();
+        }
+        return false; // Don't call again.
+    }
+
+    // Performs video thumbnailing.
+    // Note: not thread-safe if called from the same instance of the class.
+    private Gdk.Pixbuf? thumbnailer(string video_file) {
+        // Use Shotwell's thumbnailer, redirect output to stdout.
+        debug("Launching thumbnailer process: %s", AppDirs.get_thumbnailer_bin().get_path());
+        FileIOStream stream;
+        File output_file;
+        try {
+            output_file = File.new_tmp(null, out stream);
+        } catch (Error e) {
+            debug("Failed to create temporary file: %s", e.message);
+            return null;
+        }
+
+        try {
+            thumbnailer_process = new Subprocess(SubprocessFlags.NONE,
+                AppDirs.get_thumbnailer_bin().get_path(), video_file, output_file.get_path());
+        } catch (Error e) {
+            debug("Error spawning process: %s", e.message);
+            return null;
+        }
+
+        // Start timer.
+        Timeout.add(THUMBNAILER_TIMEOUT, on_thumbnailer_timer);
+
+        // Make sure process exited properly.
+        try {
+            thumbnailer_process.wait_check();
+
+            // Read pixbuf from stream.
+            Gdk.Pixbuf? buf = null;
+            try {
+                buf = new Gdk.Pixbuf.from_stream(stream.get_input_stream(), null);
+                return buf;
+            } catch (Error e) {
+                debug("Error creating pixbuf: %s", e.message);
+            }
+        } catch (Error err) {
+            debug("Thumbnailer process exited with error: %s", err.message);
+        }
+
+        try {
+            output_file.delete(null);
+        } catch (Error err) {
+            debug("Failed to remove temporary file: %s", err.message);
+        }
+        
+        return null;
+    }
+
+    private bool does_file_exist() {
+        return FileUtils.test(file.get_path(), FileTest.EXISTS | FileTest.IS_REGULAR);
+    }
+
+    public Gdk.Pixbuf? read_preview_frame() {
+        if (preview_frame != null)
+            return preview_frame;
+
+        if (!does_file_exist())
+            return null;
+
+        // Get preview frame from thumbnailer.
+        preview_frame = thumbnailer(file.get_path());
+        if (null == preview_frame)
+            preview_frame = Resources.get_noninterpretable_badge_pixbuf();
+
+        return preview_frame;
+    }
+
+    public double read_clip_duration() throws VideoError {
+        if (clip_duration == UNKNOWN_CLIP_DURATION)
+            read_internal();
+
+        return clip_duration;
+    }
+
+    public VideoMetadata read_metadata() throws Error {
+        VideoMetadata metadata = new VideoMetadata();
+        metadata.read_from_file(File.new_for_path(file.get_path()));
+
+        return metadata;
+    }
+}
diff --git a/src/video-support/VideoSourceCollection.vala b/src/video-support/VideoSourceCollection.vala
new file mode 100644
index 0000000..89daad3
--- /dev/null
+++ b/src/video-support/VideoSourceCollection.vala
@@ -0,0 +1,175 @@
+/* Copyright 2016 Software Freedom Conservancy Inc.
+ *
+ * This software is licensed under the GNU LGPL (version 2.1 or later).
+ * See the COPYING file in this distribution.
+ */
+
+public class VideoSourceCollection : MediaSourceCollection {
+    public enum State {
+        UNKNOWN,
+        ONLINE,
+        OFFLINE,
+        TRASH
+    }
+
+    public override TransactionController transaction_controller {
+        get {
+            if (_transaction_controller == null)
+                _transaction_controller = new MediaSourceTransactionController(this);
+
+            return _transaction_controller;
+        }
+    }
+
+    private TransactionController _transaction_controller = null;
+    private Gee.MultiMap<uint64?, Video> filesize_to_video =
+        new Gee.TreeMultiMap<uint64?, Video>(uint64_compare);
+
+    public VideoSourceCollection() {
+        base("VideoSourceCollection", get_video_key);
+
+        get_trashcan().contents_altered.connect(on_trashcan_contents_altered);
+        get_offline_bin().contents_altered.connect(on_offline_contents_altered);
+    }
+
+    protected override MediaSourceHoldingTank create_trashcan() {
+        return new MediaSourceHoldingTank(this, is_video_trashed, get_video_key);
+    }
+
+    protected override MediaSourceHoldingTank create_offline_bin() {
+        return new MediaSourceHoldingTank(this, is_video_offline, get_video_key);
+    }
+
+    public override MediaMonitor create_media_monitor(Workers workers, Cancellable cancellable) {
+        return new VideoMonitor(cancellable);
+    }
+
+    public override bool holds_type_of_source(DataSource source) {
+        return source is Video;
+    }
+
+    public override string get_typename() {
+        return Video.TYPENAME;
+    }
+
+    public override bool is_file_recognized(File file) {
+        return VideoReader.is_supported_video_file(file);
+    }
+
+    private void on_trashcan_contents_altered(Gee.Collection<DataSource>? added,
+        Gee.Collection<DataSource>? removed) {
+        trashcan_contents_altered((Gee.Collection<Video>?) added,
+            (Gee.Collection<Video>?) removed);
+    }
+
+    private void on_offline_contents_altered(Gee.Collection<DataSource>? added,
+        Gee.Collection<DataSource>? removed) {
+        offline_contents_altered((Gee.Collection<Video>?) added,
+            (Gee.Collection<Video>?) removed);
+    }
+
+    protected override MediaSource? fetch_by_numeric_id(int64 numeric_id) {
+        return fetch(VideoID(numeric_id));
+    }
+
+    public static int64 get_video_key(DataSource source) {
+        Video video = (Video) source;
+        VideoID video_id = video.get_video_id();
+
+        return video_id.id;
+    }
+
+    public static bool is_video_trashed(DataSource source) {
+        return ((Video) source).is_trashed();
+    }
+
+    public static bool is_video_offline(DataSource source) {
+        return ((Video) source).is_offline();
+    }
+
+    public Video fetch(VideoID video_id) {
+        return (Video) fetch_by_key(video_id.id);
+    }
+
+    public override Gee.Collection<string> get_event_source_ids(EventID event_id){
+        return VideoTable.get_instance().get_event_source_ids(event_id);
+    }
+
+    public Video? get_state_by_file(File file, out State state) {
+        Video? video = (Video?) fetch_by_master_file(file);
+        if (video != null) {
+            state = State.ONLINE;
+
+            return video;
+        }
+
+        video = (Video?) get_trashcan().fetch_by_master_file(file);
+        if (video != null) {
+            state = State.TRASH;
+
+            return video;
+        }
+
+        video = (Video?) get_offline_bin().fetch_by_master_file(file);
+        if (video != null) {
+            state = State.OFFLINE;
+
+            return video;
+        }
+
+        state = State.UNKNOWN;
+
+        return null;
+    }
+
+    private void compare_backing(Video video, FileInfo info, Gee.Collection<Video> matching_master) {
+        if (video.get_filesize() != info.get_size())
+            return;
+
+        if (video.get_timestamp().equal(info.get_modification_date_time()))
+            matching_master.add(video);
+    }
+
+    public void fetch_by_matching_backing(FileInfo info, Gee.Collection<Video> matching_master) {
+        foreach (DataObject object in get_all())
+            compare_backing((Video) object, info, matching_master);
+
+        foreach (MediaSource media in get_offline_bin_contents())
+            compare_backing((Video) media, info, matching_master);
+    }
+
+    protected override void notify_contents_altered(Gee.Iterable<DataObject>? added,
+        Gee.Iterable<DataObject>? removed) {
+        if (added != null) {
+            foreach (DataObject object in added) {
+                Video video = (Video) object;
+
+                filesize_to_video.set(video.get_master_filesize(), video);
+            }
+        }
+
+        if (removed != null) {
+            foreach (DataObject object in removed) {
+                Video video = (Video) object;
+
+                filesize_to_video.remove(video.get_master_filesize(), video);
+            }
+        }
+
+        base.notify_contents_altered(added, removed);
+    }
+
+    public VideoID get_basename_filesize_duplicate(string basename, uint64 filesize) {
+        foreach (Video video in filesize_to_video.get(filesize)) {
+            if (utf8_ci_compare(video.get_master_file().get_basename(), basename) == 0)
+                return video.get_video_id();
+        }
+
+        return VideoID(); // the default constructor of the VideoID struct creates an invalid
+                          // video id, which is just what we want in this case
+    }
+
+    public bool has_basename_filesize_duplicate(string basename, uint64 filesize) {
+        return get_basename_filesize_duplicate(basename, filesize).is_valid();
+    }
+}
diff --git a/src/video-support/meson.build b/src/video-support/meson.build
new file mode 100644
index 0000000..da3f9d7
--- /dev/null
+++ b/src/video-support/meson.build
@@ -0,0 +1,36 @@
+executable(
+    'shotwell-video-metadata-handler',
+    [
+        'VideoMetadataReaderProcess.vala'
+    ],
+    dependencies : [
+        gio,
+        gstreamer,
+        gstreamer_pbu
+    ],
+    c_args : '-DGST_PB_UTILS_IS_DISCOVERER_INFO=GST_IS_DISCOVERER_INFO'
+    # Work-around for wrong type-check macro generated by valac
+)
+
+libvideometadata_handling = static_library(
+    'video_metadata_handling',
+    [
+        'AVIChunk.vala',
+        'AVIMetadataLoader.vala',
+        'QuickTimeAtom.vala',
+        'QuicktimeMetdataLoader.vala',
+        'util.vala'
+    ],
+    vala_header : 'shotwell-internal-video-metadata-handling.h',
+    vala_vapi : 'shotwell-internal-video-metadata-handling.vapi',
+    include_directories : config_incdir,
+    dependencies : [
+        gio,
+        metadata
+    ]
+)
+
+metadata_handling = declare_dependency(
+    include_directories : include_directories('.'),
+    link_with : libvideometadata_handling
+)
diff --git a/src/video-support/util.vala b/src/video-support/util.vala
new file mode 100644
index 0000000..ad06680
--- /dev/null
+++ b/src/video-support/util.vala
@@ -0,0 +1,13 @@
+// Breaks a uint64 skip amount into several smaller skips.
+public void skip_uint64(InputStream input, uint64 skip_amount) throws GLib.Error {
+    while (skip_amount > 0) {
+        // skip() throws an error if the amount is too large, so check against ssize_t.MAX
+        if (skip_amount >= ssize_t.MAX) {
+            input.skip(ssize_t.MAX);
+            skip_amount -= ssize_t.MAX;
+        } else {
+            input.skip((size_t) skip_amount);
+            skip_amount = 0;
+        }
+    }
+}