Merge commit 'b75a1f9892b5b715397edbf837e4d4cda337907b'

* commit 'b75a1f9892b5b715397edbf837e4d4cda337907b':
  matroska: Factor out write_track from mkv_write_tracks

Conflicts:
	libavformat/matroskaenc.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 275 insertions, 251 deletions

diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 1f634f5c71..599637c892 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -572,6 +572,45 @@ static void get_aac_sample_rates(AVFormatContext *s, AVCodecContext *codec,
     *output_sample_rate = mp4ac.ext_sample_rate;
 }
 
+static int mkv_write_native_codecprivate(AVFormatContext *s,
+                                         AVCodecContext *codec,
+                                         AVIOContext *dyn_cp)
+{
+    switch (codec->codec_id) {
+    case AV_CODEC_ID_VORBIS:
+    case AV_CODEC_ID_THEORA:
+        return put_xiph_codecpriv(s, dyn_cp, codec);
+    case AV_CODEC_ID_FLAC:
+        return put_flac_codecpriv(s, dyn_cp, codec);
+    case AV_CODEC_ID_WAVPACK:
+        return put_wv_codecpriv(dyn_cp, codec);
+    case AV_CODEC_ID_H264:
+        return ff_isom_write_avcc(dyn_cp, codec->extradata,
+                                  codec->extradata_size);
+    case AV_CODEC_ID_HEVC:
+        return ff_isom_write_hvcc(dyn_cp, codec->extradata,
+                                  codec->extradata_size, 0);
+    case AV_CODEC_ID_ALAC:
+        if (codec->extradata_size < 36) {
+            av_log(s, AV_LOG_ERROR,
+                   "Invalid extradata found, ALAC expects a 36-byte "
+                   "QuickTime atom.");
+            return AVERROR_INVALIDDATA;
+        } else
+            avio_write(dyn_cp, codec->extradata + 12,
+                       codec->extradata_size - 12);
+        break;
+    default:
+        if (codec->codec_id == AV_CODEC_ID_PRORES &&
+            ff_codec_get_id(ff_codec_movvideo_tags, codec->codec_tag) == AV_CODEC_ID_PRORES) {
+            avio_wl32(dyn_cp, codec->codec_tag);
+        } else if (codec->extradata_size && codec->codec_id != AV_CODEC_ID_TTA)
+            avio_write(dyn_cp, codec->extradata, codec->extradata_size);
+    }
+
+    return 0;
+}
+
 static int mkv_write_codecprivate(AVFormatContext *s, AVIOContext *pb,
                                   AVCodecContext *codec, int native_id,
                                   int qt_id)
@@ -585,33 +624,7 @@ static int mkv_write_codecprivate(AVFormatContext *s, AVIOContext *pb,
         return ret;
 
     if (native_id) {
-        if (codec->codec_id == AV_CODEC_ID_VORBIS ||
-            codec->codec_id == AV_CODEC_ID_THEORA)
-            ret = put_xiph_codecpriv(s, dyn_cp, codec);
-        else if (codec->codec_id == AV_CODEC_ID_FLAC)
-            ret = put_flac_codecpriv(s, dyn_cp, codec);
-        else if (codec->codec_id == AV_CODEC_ID_WAVPACK)
-            ret = put_wv_codecpriv(dyn_cp, codec);
-        else if (codec->codec_id == AV_CODEC_ID_H264)
-            ret = ff_isom_write_avcc(dyn_cp, codec->extradata,
-                                     codec->extradata_size);
-        else if (codec->codec_id == AV_CODEC_ID_HEVC)
-            ret = ff_isom_write_hvcc(dyn_cp, codec->extradata,
-                                     codec->extradata_size, 0);
-        else if (codec->codec_id == AV_CODEC_ID_ALAC) {
-            if (codec->extradata_size < 36) {
-                av_log(s, AV_LOG_ERROR,
-                       "Invalid extradata found, ALAC expects a 36-byte "
-                       "QuickTime atom.");
-                ret = AVERROR_INVALIDDATA;
-            } else
-                avio_write(dyn_cp, codec->extradata + 12,
-                           codec->extradata_size - 12);
-        } else if (codec->codec_id == AV_CODEC_ID_PRORES &&
-                   ff_codec_get_id(ff_codec_movvideo_tags, codec->codec_tag) == AV_CODEC_ID_PRORES) {
-            avio_wl32(dyn_cp, codec->codec_tag);
-        } else if (codec->extradata_size && codec->codec_id != AV_CODEC_ID_TTA)
-            avio_write(dyn_cp, codec->extradata, codec->extradata_size);
+        ret = mkv_write_native_codecprivate(s, codec, dyn_cp);
     } else if (codec->codec_type == AVMEDIA_TYPE_VIDEO) {
         if (qt_id) {
             if (!codec->codec_tag)
@@ -667,258 +680,269 @@ static int mkv_write_codecprivate(AVFormatContext *s, AVIOContext *pb,
     return ret;
 }
 
-static int mkv_write_tracks(AVFormatContext *s)
+static int mkv_write_track(AVFormatContext *s, MatroskaMuxContext *mkv,
+                           int i, AVIOContext *pb, int default_stream_exists)
 {
-    MatroskaMuxContext *mkv = s->priv_data;
-    AVIOContext *pb = s->pb;
-    ebml_master tracks;
-    int i, j, ret, default_stream_exists = 0;
+    AVStream *st = s->streams[i];
+    AVCodecContext *codec = st->codec;
+    ebml_master subinfo, track;
+    int native_id = 0;
+    int qt_id = 0;
+    int bit_depth = av_get_bits_per_sample(codec->codec_id);
+    int sample_rate = codec->sample_rate;
+    int output_sample_rate = 0;
+    int display_width_div = 1;
+    int display_height_div = 1;
+    int j, ret;
+    AVDictionaryEntry *tag;
 
-    ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_TRACKS, avio_tell(pb));
-    if (ret < 0)
-        return ret;
+    // ms precision is the de-facto standard timescale for mkv files
+    avpriv_set_pts_info(st, 64, 1, 1000);
 
-    tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS, 0);
-    for (i = 0; i < s->nb_streams; i++) {
-        AVStream *st = s->streams[i];
-        default_stream_exists |= st->disposition & AV_DISPOSITION_DEFAULT;
+    if (codec->codec_type == AVMEDIA_TYPE_ATTACHMENT) {
+        mkv->have_attachments = 1;
+        return 0;
     }
-    for (i = 0; i < s->nb_streams; i++) {
-        AVStream *st = s->streams[i];
-        AVCodecContext *codec = st->codec;
-        ebml_master subinfo, track;
-        int native_id = 0;
-        int qt_id = 0;
-        int bit_depth = av_get_bits_per_sample(codec->codec_id);
-        int sample_rate = codec->sample_rate;
-        int output_sample_rate = 0;
-        int display_width_div = 1;
-        int display_height_div = 1;
-        AVDictionaryEntry *tag;
-
-        // ms precision is the de-facto standard timescale for mkv files
-        avpriv_set_pts_info(st, 64, 1, 1000);
-
-        if (codec->codec_type == AVMEDIA_TYPE_ATTACHMENT) {
-            mkv->have_attachments = 1;
-            continue;
-        }
 
-        if (!bit_depth && codec->codec_id != AV_CODEC_ID_ADPCM_G726)
-            bit_depth = av_get_bytes_per_sample(codec->sample_fmt) << 3;
-        if (!bit_depth)
-            bit_depth = codec->bits_per_coded_sample;
-
-        if (codec->codec_id == AV_CODEC_ID_AAC)
-            get_aac_sample_rates(s, codec, &sample_rate, &output_sample_rate);
-
-        track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY, 0);
-        put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER,
-                       mkv->is_dash ? mkv->dash_track_number : i + 1);
-        put_ebml_uint (pb, MATROSKA_ID_TRACKUID,
-                       mkv->is_dash ? mkv->dash_track_number : i + 1);
-        put_ebml_uint (pb, MATROSKA_ID_TRACKFLAGLACING , 0);    // no lacing (yet)
-
-        if ((tag = av_dict_get(st->metadata, "title", NULL, 0)))
-            put_ebml_string(pb, MATROSKA_ID_TRACKNAME, tag->value);
-        tag = av_dict_get(st->metadata, "language", NULL, 0);
-        if (mkv->mode != MODE_WEBM || codec->codec_id != AV_CODEC_ID_WEBVTT) {
-            put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, tag ? tag->value:"und");
-        } else if (tag && tag->value) {
-            put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, tag->value);
-        }
+    if (!bit_depth && codec->codec_id != AV_CODEC_ID_ADPCM_G726)
+        bit_depth = av_get_bytes_per_sample(codec->sample_fmt) << 3;
+    if (!bit_depth)
+        bit_depth = codec->bits_per_coded_sample;
+
+    if (codec->codec_id == AV_CODEC_ID_AAC)
+        get_aac_sample_rates(s, codec, &sample_rate, &output_sample_rate);
+
+    track = start_ebml_master(pb, MATROSKA_ID_TRACKENTRY, 0);
+    put_ebml_uint (pb, MATROSKA_ID_TRACKNUMBER,
+                   mkv->is_dash ? mkv->dash_track_number : i + 1);
+    put_ebml_uint (pb, MATROSKA_ID_TRACKUID,
+                   mkv->is_dash ? mkv->dash_track_number : i + 1);
+    put_ebml_uint (pb, MATROSKA_ID_TRACKFLAGLACING , 0);    // no lacing (yet)
+
+    if ((tag = av_dict_get(st->metadata, "title", NULL, 0)))
+        put_ebml_string(pb, MATROSKA_ID_TRACKNAME, tag->value);
+    tag = av_dict_get(st->metadata, "language", NULL, 0);
+    if (mkv->mode != MODE_WEBM || codec->codec_id != AV_CODEC_ID_WEBVTT) {
+        put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, tag ? tag->value:"und");
+    } else if (tag && tag->value) {
+        put_ebml_string(pb, MATROSKA_ID_TRACKLANGUAGE, tag->value);
+    }
 
-        // The default value for TRACKFLAGDEFAULT is 1, so add element
-        // if we need to clear it.
-        if (default_stream_exists && !(st->disposition & AV_DISPOSITION_DEFAULT))
-            put_ebml_uint(pb, MATROSKA_ID_TRACKFLAGDEFAULT, !!(st->disposition & AV_DISPOSITION_DEFAULT));
-
-        if (st->disposition & AV_DISPOSITION_FORCED)
-            put_ebml_uint(pb, MATROSKA_ID_TRACKFLAGFORCED, 1);
-
-        if (mkv->mode == MODE_WEBM && codec->codec_id == AV_CODEC_ID_WEBVTT) {
-            const char *codec_id;
-            if (st->disposition & AV_DISPOSITION_CAPTIONS) {
-                codec_id = "D_WEBVTT/CAPTIONS";
-                native_id = MATROSKA_TRACK_TYPE_SUBTITLE;
-            } else if (st->disposition & AV_DISPOSITION_DESCRIPTIONS) {
-                codec_id = "D_WEBVTT/DESCRIPTIONS";
-                native_id = MATROSKA_TRACK_TYPE_METADATA;
-            } else if (st->disposition & AV_DISPOSITION_METADATA) {
-                codec_id = "D_WEBVTT/METADATA";
-                native_id = MATROSKA_TRACK_TYPE_METADATA;
-            } else {
-                codec_id = "D_WEBVTT/SUBTITLES";
-                native_id = MATROSKA_TRACK_TYPE_SUBTITLE;
-            }
-            put_ebml_string(pb, MATROSKA_ID_CODECID, codec_id);
+    // The default value for TRACKFLAGDEFAULT is 1, so add element
+    // if we need to clear it.
+    if (default_stream_exists && !(st->disposition & AV_DISPOSITION_DEFAULT))
+        put_ebml_uint(pb, MATROSKA_ID_TRACKFLAGDEFAULT, !!(st->disposition & AV_DISPOSITION_DEFAULT));
+
+    if (st->disposition & AV_DISPOSITION_FORCED)
+        put_ebml_uint(pb, MATROSKA_ID_TRACKFLAGFORCED, 1);
+
+    if (mkv->mode == MODE_WEBM && codec->codec_id == AV_CODEC_ID_WEBVTT) {
+        const char *codec_id;
+        if (st->disposition & AV_DISPOSITION_CAPTIONS) {
+            codec_id = "D_WEBVTT/CAPTIONS";
+            native_id = MATROSKA_TRACK_TYPE_SUBTITLE;
+        } else if (st->disposition & AV_DISPOSITION_DESCRIPTIONS) {
+            codec_id = "D_WEBVTT/DESCRIPTIONS";
+            native_id = MATROSKA_TRACK_TYPE_METADATA;
+        } else if (st->disposition & AV_DISPOSITION_METADATA) {
+            codec_id = "D_WEBVTT/METADATA";
+            native_id = MATROSKA_TRACK_TYPE_METADATA;
         } else {
-            // look for a codec ID string specific to mkv to use,
-            // if none are found, use AVI codes
-            for (j = 0; ff_mkv_codec_tags[j].id != AV_CODEC_ID_NONE; j++) {
-                if (ff_mkv_codec_tags[j].id == codec->codec_id) {
-                    put_ebml_string(pb, MATROSKA_ID_CODECID, ff_mkv_codec_tags[j].str);
-                    native_id = 1;
-                    break;
-                }
+            codec_id = "D_WEBVTT/SUBTITLES";
+            native_id = MATROSKA_TRACK_TYPE_SUBTITLE;
+        }
+        put_ebml_string(pb, MATROSKA_ID_CODECID, codec_id);
+    } else {
+        // look for a codec ID string specific to mkv to use,
+        // if none are found, use AVI codes
+        for (j = 0; ff_mkv_codec_tags[j].id != AV_CODEC_ID_NONE; j++) {
+            if (ff_mkv_codec_tags[j].id == codec->codec_id) {
+                put_ebml_string(pb, MATROSKA_ID_CODECID, ff_mkv_codec_tags[j].str);
+                native_id = 1;
+                break;
             }
         }
+    }
 
-        if (codec->codec_type == AVMEDIA_TYPE_AUDIO && codec->delay && codec->codec_id == AV_CODEC_ID_OPUS) {
-//             mkv->tracks[i].ts_offset = av_rescale_q(codec->delay,
-//                                                     (AVRational){ 1, codec->sample_rate },
-//                                                     st->time_base);
+    if (codec->codec_type == AVMEDIA_TYPE_AUDIO && codec->delay && codec->codec_id == AV_CODEC_ID_OPUS) {
+//         mkv->tracks[i].ts_offset = av_rescale_q(codec->delay,
+//                                                 (AVRational){ 1, codec->sample_rate },
+//                                                 st->time_base);
 
-            put_ebml_uint(pb, MATROSKA_ID_CODECDELAY,
-                          av_rescale_q(codec->delay, (AVRational){ 1, codec->sample_rate },
-                                       (AVRational){ 1, 1000000000 }));
-        }
-        if (codec->codec_id == AV_CODEC_ID_OPUS) {
-            put_ebml_uint(pb, MATROSKA_ID_SEEKPREROLL, OPUS_SEEK_PREROLL);
-        }
+        put_ebml_uint(pb, MATROSKA_ID_CODECDELAY,
+                      av_rescale_q(codec->delay, (AVRational){ 1, codec->sample_rate },
+                                   (AVRational){ 1, 1000000000 }));
+    }
+    if (codec->codec_id == AV_CODEC_ID_OPUS) {
+        put_ebml_uint(pb, MATROSKA_ID_SEEKPREROLL, OPUS_SEEK_PREROLL);
+    }
 
-        if (mkv->mode == MODE_WEBM && !(codec->codec_id == AV_CODEC_ID_VP8 ||
-                                        codec->codec_id == AV_CODEC_ID_VP9 ||
-                                        codec->codec_id == AV_CODEC_ID_OPUS ||
-                                        codec->codec_id == AV_CODEC_ID_VORBIS ||
-                                        codec->codec_id == AV_CODEC_ID_WEBVTT)) {
-            av_log(s, AV_LOG_ERROR,
-                   "Only VP8 or VP9 video and Vorbis or Opus audio and WebVTT subtitles are supported for WebM.\n");
-            return AVERROR(EINVAL);
-        }
+    if (mkv->mode == MODE_WEBM && !(codec->codec_id == AV_CODEC_ID_VP8 ||
+                                    codec->codec_id == AV_CODEC_ID_VP9 ||
+                                    codec->codec_id == AV_CODEC_ID_OPUS ||
+                                    codec->codec_id == AV_CODEC_ID_VORBIS ||
+                                    codec->codec_id == AV_CODEC_ID_WEBVTT)) {
+        av_log(s, AV_LOG_ERROR,
+               "Only VP8 or VP9 video and Vorbis or Opus audio and WebVTT subtitles are supported for WebM.\n");
+        return AVERROR(EINVAL);
+    }
 
-        switch (codec->codec_type) {
-        case AVMEDIA_TYPE_VIDEO:
-            put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
-
-            if(   st->avg_frame_rate.num > 0 && st->avg_frame_rate.den > 0
-               && 1.0/av_q2d(st->avg_frame_rate) > av_q2d(codec->time_base))
-                put_ebml_uint(pb, MATROSKA_ID_TRACKDEFAULTDURATION, 1E9 / av_q2d(st->avg_frame_rate));
-            else
-                put_ebml_uint(pb, MATROSKA_ID_TRACKDEFAULTDURATION, av_q2d(codec->time_base)*1E9);
-
-            if (!native_id &&
-                ff_codec_get_tag(ff_codec_movvideo_tags, codec->codec_id) &&
-                (!ff_codec_get_tag(ff_codec_bmp_tags,   codec->codec_id) ||
-                 codec->codec_id == AV_CODEC_ID_SVQ1 ||
-                 codec->codec_id == AV_CODEC_ID_SVQ3 ||
-                 codec->codec_id == AV_CODEC_ID_CINEPAK))
-                qt_id = 1;
-
-            if (qt_id)
-                put_ebml_string(pb, MATROSKA_ID_CODECID, "V_QUICKTIME");
-            else if (!native_id) {
-                // if there is no mkv-specific codec ID, use VFW mode
-                put_ebml_string(pb, MATROSKA_ID_CODECID, "V_MS/VFW/FOURCC");
-                mkv->tracks[i].write_dts = 1;
-            }
+    switch (codec->codec_type) {
+    case AVMEDIA_TYPE_VIDEO:
+        put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_VIDEO);
 
-            subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO, 0);
-            // XXX: interlace flag?
-            put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
-            put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
+        if(   st->avg_frame_rate.num > 0 && st->avg_frame_rate.den > 0
+           && 1.0/av_q2d(st->avg_frame_rate) > av_q2d(codec->time_base))
+            put_ebml_uint(pb, MATROSKA_ID_TRACKDEFAULTDURATION, 1E9 / av_q2d(st->avg_frame_rate));
+        else
+            put_ebml_uint(pb, MATROSKA_ID_TRACKDEFAULTDURATION, av_q2d(codec->time_base)*1E9);
+
+        if (!native_id &&
+            ff_codec_get_tag(ff_codec_movvideo_tags, codec->codec_id) &&
+            (!ff_codec_get_tag(ff_codec_bmp_tags,   codec->codec_id) ||
+             codec->codec_id == AV_CODEC_ID_SVQ1 ||
+             codec->codec_id == AV_CODEC_ID_SVQ3 ||
+             codec->codec_id == AV_CODEC_ID_CINEPAK))
+            qt_id = 1;
+
+        if (qt_id)
+            put_ebml_string(pb, MATROSKA_ID_CODECID, "V_QUICKTIME");
+        else if (!native_id) {
+            // if there is no mkv-specific codec ID, use VFW mode
+            put_ebml_string(pb, MATROSKA_ID_CODECID, "V_MS/VFW/FOURCC");
+            mkv->tracks[i].write_dts = 1;
+        }
 
-            if ((tag = av_dict_get(st->metadata, "stereo_mode", NULL, 0)) ||
-                (tag = av_dict_get( s->metadata, "stereo_mode", NULL, 0))) {
-                // save stereo mode flag
-                uint64_t st_mode = MATROSKA_VIDEO_STEREO_MODE_COUNT;
+        subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKVIDEO, 0);
+        // XXX: interlace flag?
+        put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
+        put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
 
-                for (j=0; j<MATROSKA_VIDEO_STEREO_MODE_COUNT; j++)
-                    if (!strcmp(tag->value, ff_matroska_video_stereo_mode[j])){
-                        st_mode = j;
-                        break;
-                    }
+        if ((tag = av_dict_get(st->metadata, "stereo_mode", NULL, 0)) ||
+            (tag = av_dict_get( s->metadata, "stereo_mode", NULL, 0))) {
+            // save stereo mode flag
+            uint64_t st_mode = MATROSKA_VIDEO_STEREO_MODE_COUNT;
 
-                if ((mkv->mode == MODE_WEBM && st_mode > 3 && st_mode != 11)
-                    || st_mode >= MATROSKA_VIDEO_STEREO_MODE_COUNT) {
-                    av_log(s, AV_LOG_ERROR,
-                           "The specified stereo mode is not valid.\n");
-                    return AVERROR(EINVAL);
-                } else
-                    put_ebml_uint(pb, MATROSKA_ID_VIDEOSTEREOMODE, st_mode);
-
-                switch (st_mode) {
-                case 1:
-                case 8:
-                case 9:
-                case 11:
-                    display_width_div = 2;
-                    break;
-                case 2:
-                case 3:
-                case 6:
-                case 7:
-                    display_height_div = 2;
+            for (j=0; j<MATROSKA_VIDEO_STEREO_MODE_COUNT; j++)
+                if (!strcmp(tag->value, ff_matroska_video_stereo_mode[j])){
+                    st_mode = j;
                     break;
                 }
-            }
 
-            if ((tag = av_dict_get(st->metadata, "alpha_mode", NULL, 0)) ||
-                (tag = av_dict_get( s->metadata, "alpha_mode", NULL, 0)) ||
-                (codec->pix_fmt == AV_PIX_FMT_YUVA420P)) {
-                put_ebml_uint(pb, MATROSKA_ID_VIDEOALPHAMODE, 1);
+            if ((mkv->mode == MODE_WEBM && st_mode > 3 && st_mode != 11)
+                || st_mode >= MATROSKA_VIDEO_STEREO_MODE_COUNT) {
+                av_log(s, AV_LOG_ERROR,
+                       "The specified stereo mode is not valid.\n");
+                return AVERROR(EINVAL);
+            } else
+                put_ebml_uint(pb, MATROSKA_ID_VIDEOSTEREOMODE, st_mode);
+
+            switch (st_mode) {
+            case 1:
+            case 8:
+            case 9:
+            case 11:
+                display_width_div = 2;
+                break;
+            case 2:
+            case 3:
+            case 6:
+            case 7:
+                display_height_div = 2;
+                break;
             }
+        }
 
-            if (st->sample_aspect_ratio.num) {
-                int64_t d_width = av_rescale(codec->width, st->sample_aspect_ratio.num, st->sample_aspect_ratio.den);
-                if (d_width > INT_MAX) {
-                    av_log(s, AV_LOG_ERROR, "Overflow in display width\n");
-                    return AVERROR(EINVAL);
-                }
-                put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , d_width / display_width_div);
-                put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, codec->height / display_height_div);
-            } else if (display_width_div != 1 || display_height_div != 1) {
-                put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , codec->width / display_width_div);
-                put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, codec->height / display_height_div);
-            }
+        if ((tag = av_dict_get(st->metadata, "alpha_mode", NULL, 0)) ||
+            (tag = av_dict_get( s->metadata, "alpha_mode", NULL, 0)) ||
+            (codec->pix_fmt == AV_PIX_FMT_YUVA420P)) {
+            put_ebml_uint(pb, MATROSKA_ID_VIDEOALPHAMODE, 1);
+        }
 
-            if (codec->codec_id == AV_CODEC_ID_RAWVIDEO) {
-                uint32_t color_space = av_le2ne32(codec->codec_tag);
-                put_ebml_binary(pb, MATROSKA_ID_VIDEOCOLORSPACE, &color_space, sizeof(color_space));
-            }
-            end_ebml_master(pb, subinfo);
-            break;
-
-        case AVMEDIA_TYPE_AUDIO:
-            put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
-
-            if (!native_id)
-                // no mkv-specific ID, use ACM mode
-                put_ebml_string(pb, MATROSKA_ID_CODECID, "A_MS/ACM");
-
-            subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO, 0);
-            put_ebml_uint  (pb, MATROSKA_ID_AUDIOCHANNELS    , codec->channels);
-            put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, sample_rate);
-            if (output_sample_rate)
-                put_ebml_float(pb, MATROSKA_ID_AUDIOOUTSAMPLINGFREQ, output_sample_rate);
-            if (bit_depth)
-                put_ebml_uint(pb, MATROSKA_ID_AUDIOBITDEPTH, bit_depth);
-            end_ebml_master(pb, subinfo);
-            break;
-
-        case AVMEDIA_TYPE_SUBTITLE:
-            if (!native_id) {
-                av_log(s, AV_LOG_ERROR, "Subtitle codec %d is not supported.\n", codec->codec_id);
-                return AVERROR(ENOSYS);
+        if (st->sample_aspect_ratio.num) {
+            int64_t d_width = av_rescale(codec->width, st->sample_aspect_ratio.num, st->sample_aspect_ratio.den);
+            if (d_width > INT_MAX) {
+                av_log(s, AV_LOG_ERROR, "Overflow in display width\n");
+                return AVERROR(EINVAL);
             }
-
-            if (mkv->mode != MODE_WEBM || codec->codec_id != AV_CODEC_ID_WEBVTT)
-                native_id = MATROSKA_TRACK_TYPE_SUBTITLE;
-
-            put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, native_id);
-            break;
-        default:
-            av_log(s, AV_LOG_ERROR, "Only audio, video, and subtitles are supported for Matroska.\n");
-            return AVERROR(EINVAL);
+            put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , d_width / display_width_div);
+            put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, codec->height / display_height_div);
+        } else if (display_width_div != 1 || display_height_div != 1) {
+            put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , codec->width / display_width_div);
+            put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYHEIGHT, codec->height / display_height_div);
         }
 
-        if (mkv->mode != MODE_WEBM || codec->codec_id != AV_CODEC_ID_WEBVTT) {
-            ret = mkv_write_codecprivate(s, pb, codec, native_id, qt_id);
-            if (ret < 0)
-                return ret;
+        if (codec->codec_id == AV_CODEC_ID_RAWVIDEO) {
+            uint32_t color_space = av_le2ne32(codec->codec_tag);
+            put_ebml_binary(pb, MATROSKA_ID_VIDEOCOLORSPACE, &color_space, sizeof(color_space));
         }
+        end_ebml_master(pb, subinfo);
+        break;
+
+    case AVMEDIA_TYPE_AUDIO:
+        put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, MATROSKA_TRACK_TYPE_AUDIO);
+
+        if (!native_id)
+            // no mkv-specific ID, use ACM mode
+            put_ebml_string(pb, MATROSKA_ID_CODECID, "A_MS/ACM");
+
+        subinfo = start_ebml_master(pb, MATROSKA_ID_TRACKAUDIO, 0);
+        put_ebml_uint  (pb, MATROSKA_ID_AUDIOCHANNELS    , codec->channels);
+        put_ebml_float (pb, MATROSKA_ID_AUDIOSAMPLINGFREQ, sample_rate);
+        if (output_sample_rate)
+            put_ebml_float(pb, MATROSKA_ID_AUDIOOUTSAMPLINGFREQ, output_sample_rate);
+        if (bit_depth)
+            put_ebml_uint(pb, MATROSKA_ID_AUDIOBITDEPTH, bit_depth);
+        end_ebml_master(pb, subinfo);
+        break;
+
+    case AVMEDIA_TYPE_SUBTITLE:
+        if (!native_id) {
+            av_log(s, AV_LOG_ERROR, "Subtitle codec %d is not supported.\n", codec->codec_id);
+            return AVERROR(ENOSYS);
+        }
+
+        if (mkv->mode != MODE_WEBM || codec->codec_id != AV_CODEC_ID_WEBVTT)
+            native_id = MATROSKA_TRACK_TYPE_SUBTITLE;
+
+        put_ebml_uint(pb, MATROSKA_ID_TRACKTYPE, native_id);
+        break;
+    default:
+        av_log(s, AV_LOG_ERROR, "Only audio, video, and subtitles are supported for Matroska.\n");
+        return AVERROR(EINVAL);
+    }
 
-        end_ebml_master(pb, track);
+    if (mkv->mode != MODE_WEBM || codec->codec_id != AV_CODEC_ID_WEBVTT) {
+        ret = mkv_write_codecprivate(s, pb, codec, native_id, qt_id);
+        if (ret < 0)
+            return ret;
+    }
+
+    end_ebml_master(pb, track);
+
+    return 0;
+}
+
+static int mkv_write_tracks(AVFormatContext *s)
+{
+    MatroskaMuxContext *mkv = s->priv_data;
+    AVIOContext *pb = s->pb;
+    ebml_master tracks;
+    int i, ret, default_stream_exists = 0;
+
+    ret = mkv_add_seekhead_entry(mkv->main_seekhead, MATROSKA_ID_TRACKS, avio_tell(pb));
+    if (ret < 0)
+        return ret;
+
+    tracks = start_ebml_master(pb, MATROSKA_ID_TRACKS, 0);
+    for (i = 0; i < s->nb_streams; i++) {
+        AVStream *st = s->streams[i];
+        default_stream_exists |= st->disposition & AV_DISPOSITION_DEFAULT;
+    }
+    for (i = 0; i < s->nb_streams; i++) {
+        ret = mkv_write_track(s, mkv, i, pb, default_stream_exists);
+        if (ret < 0)
+            return ret;
     }
     end_ebml_master(pb, tracks);
     return 0;