diff options
author | Vignesh Venkatasubramanian <vigneshv@google.com> | 2014-05-07 20:46:40 +0400 |
---|---|---|
committer | Michael Niedermayer <michaelni@gmx.at> | 2014-05-22 20:53:13 +0400 |
commit | 37cef8c77449a34a3e2f31d6fa209e769d45874c (patch) | |
tree | 7453c4fba5befe4a2c1a52289fcb9f340f9736a9 /libavformat/matroskaenc.c | |
parent | a996eacce269218178c9d8a5fdd507ae22c4b646 (diff) |
libavformat/matroskaenc: Add WebM DASH support
WebM DASH specification [1] requires the Clusters and Cues to be output in a
specific way. Adding a flag to matroskaenc that will enable support for
creating WebM/Mkv files conforming to the WebM DASH specification.
[1] http://wiki.webmproject.org/adaptive-streaming/webm-dash-specification
Signed-off-by: Vignesh Venkatasubramanian <vigneshv@google.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'libavformat/matroskaenc.c')
-rw-r--r-- | libavformat/matroskaenc.c | 68 |
1 files changed, 50 insertions, 18 deletions
diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c index 9ced57a9cf..980bf3a739 100644 --- a/libavformat/matroskaenc.c +++ b/libavformat/matroskaenc.c @@ -70,6 +70,7 @@ typedef struct mkv_seekhead { typedef struct { uint64_t pts; + int stream_idx; int tracknum; int64_t cluster_pos; ///< file offset of the cluster containing the block int64_t relative_pos; ///< relative offset from the position of the cluster containing the block @@ -114,6 +115,8 @@ typedef struct MatroskaMuxContext { int cluster_size_limit; int64_t cues_pos; int64_t cluster_time_limit; + int is_dash; + int dash_track_number; uint32_t chapter_id_offset; int wrote_chapters; @@ -399,8 +402,8 @@ static mkv_cues * mkv_start_cues(int64_t segment_offset) return cues; } -static int mkv_add_cuepoint(mkv_cues *cues, int stream, int64_t ts, int64_t cluster_pos, int64_t relative_pos, - int64_t duration) +static int mkv_add_cuepoint(mkv_cues *cues, int stream, int tracknum, int64_t ts, + int64_t cluster_pos, int64_t relative_pos, int64_t duration) { mkv_cuepoint *entries = cues->entries; @@ -413,7 +416,8 @@ static int mkv_add_cuepoint(mkv_cues *cues, int stream, int64_t ts, int64_t clus cues->entries = entries; cues->entries[cues->num_entries].pts = ts; - cues->entries[cues->num_entries].tracknum = stream + 1; + cues->entries[cues->num_entries].stream_idx = stream; + cues->entries[cues->num_entries].tracknum = tracknum; cues->entries[cues->num_entries].cluster_pos = cluster_pos - cues->segment_offset; cues->entries[cues->num_entries].relative_pos = relative_pos; cues->entries[cues->num_entries++].duration = duration; @@ -443,7 +447,7 @@ static int64_t mkv_write_cues(AVIOContext *pb, mkv_cues *cues, mkv_track *tracks for (j = 0; j < num_tracks; j++) tracks[j].has_cue = 0; for (j = 0; j < cues->num_entries - i && entry[j].pts == pts; j++) { - int tracknum = entry[j].tracknum - 1; + int tracknum = entry[j].stream_idx; av_assert0(tracknum>=0 && tracknum<num_tracks); if (tracks[tracknum].has_cue) continue; @@ -646,8 +650,10 @@ static int mkv_write_tracks(AVFormatContext *s) 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 , i + 1); - put_ebml_uint (pb, MATROSKA_ID_TRACKUID , i + 1); + 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))) @@ -1435,7 +1441,8 @@ static void mkv_write_block(AVFormatContext *s, AVIOContext *pb, put_ebml_id(pb, blockid); put_ebml_num(pb, size+4, 0); - avio_w8(pb, 0x80 | (pkt->stream_index + 1)); // this assumes stream_index is less than 126 + // this assumes stream_index is less than 126 + avio_w8(pb, 0x80 | (mkv->is_dash ? mkv->dash_track_number : (pkt->stream_index + 1))); avio_wb16(pb, ts - mkv->cluster_pts); avio_w8(pb, flags); avio_write(pb, data + offset, size); @@ -1549,7 +1556,7 @@ static void mkv_flush_dynbuf(AVFormatContext *s) mkv->dyn_bc = NULL; } -static int mkv_write_packet_internal(AVFormatContext *s, AVPacket *pkt) +static int mkv_write_packet_internal(AVFormatContext *s, AVPacket *pkt, int add_cue) { MatroskaMuxContext *mkv = s->priv_data; AVIOContext *pb = s->pb; @@ -1606,8 +1613,13 @@ static int mkv_write_packet_internal(AVFormatContext *s, AVPacket *pkt) end_ebml_master(pb, blockgroup); } - if ((codec->codec_type == AVMEDIA_TYPE_VIDEO && keyframe) || codec->codec_type == AVMEDIA_TYPE_SUBTITLE) { - ret = mkv_add_cuepoint(mkv->cues, pkt->stream_index, ts, mkv->cluster_pos, relative_packet_pos, + if ((codec->codec_type == AVMEDIA_TYPE_VIDEO && keyframe) || + codec->codec_type == AVMEDIA_TYPE_SUBTITLE || + add_cue) { + ret = mkv_add_cuepoint(mkv->cues, + pkt->stream_index, + mkv->is_dash ? mkv->dash_track_number : pkt->stream_index + 1, + ts, mkv->cluster_pos, relative_packet_pos, codec->codec_type == AVMEDIA_TYPE_SUBTITLE ? duration : -1); if (ret < 0) return ret; } @@ -1625,6 +1637,7 @@ static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt) int64_t cluster_time; AVIOContext *pb; int ret; + int start_new_cluster; if (mkv->tracks[pkt->stream_index].write_dts) cluster_time = pkt->dts - mkv->cluster_pts; @@ -1642,11 +1655,26 @@ static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt) cluster_size = avio_tell(pb); } - if (mkv->cluster_pos != -1 && - (cluster_size > mkv->cluster_size_limit || - cluster_time > mkv->cluster_time_limit || - (codec_type == AVMEDIA_TYPE_VIDEO && keyframe && - cluster_size > 4 * 1024))) { + if (mkv->is_dash && codec_type == AVMEDIA_TYPE_VIDEO) { + // WebM DASH specification states that the first block of every cluster + // has to be a key frame. So for DASH video, we only create a cluster + // on seeing key frames. + start_new_cluster = keyframe; + } else if (mkv->is_dash && codec_type == AVMEDIA_TYPE_AUDIO && + cluster_time > mkv->cluster_time_limit) { + // For DASH audio, we create a Cluster based on cluster_time_limit + start_new_cluster = 1; + } else if (!mkv->is_dash && + (cluster_size > mkv->cluster_size_limit || + cluster_time > mkv->cluster_time_limit || + (codec_type == AVMEDIA_TYPE_VIDEO && keyframe && + cluster_size > 4 * 1024))) { + start_new_cluster = 1; + } else { + start_new_cluster = 0; + } + + if (mkv->cluster_pos != -1 && start_new_cluster) { av_log(s, AV_LOG_DEBUG, "Starting new cluster at offset %" PRIu64 " bytes, pts %" PRIu64 "dts %" PRIu64 "\n", avio_tell(pb), pkt->pts, pkt->dts); @@ -1659,7 +1687,9 @@ static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt) // check if we have an audio packet cached if (mkv->cur_audio_pkt.size > 0) { - ret = mkv_write_packet_internal(s, &mkv->cur_audio_pkt); + // for DASH audio, a CuePoint has to be added when there is a new cluster. + ret = mkv_write_packet_internal(s, &mkv->cur_audio_pkt, + mkv->is_dash ? start_new_cluster : 0); av_free_packet(&mkv->cur_audio_pkt); if (ret < 0) { av_log(s, AV_LOG_ERROR, "Could not write cached audio packet ret:%d\n", ret); @@ -1680,7 +1710,7 @@ static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt) ret = av_copy_packet_side_data(&mkv->cur_audio_pkt, &mkv->cur_audio_pkt); } } else - ret = mkv_write_packet_internal(s, pkt); + ret = mkv_write_packet_internal(s, pkt, 0); return ret; } @@ -1716,7 +1746,7 @@ static int mkv_write_trailer(AVFormatContext *s) // check if we have an audio packet cached if (mkv->cur_audio_pkt.size > 0) { - ret = mkv_write_packet_internal(s, &mkv->cur_audio_pkt); + ret = mkv_write_packet_internal(s, &mkv->cur_audio_pkt, 0); av_free_packet(&mkv->cur_audio_pkt); if (ret < 0) { av_log(s, AV_LOG_ERROR, "Could not write cached audio packet ret:%d\n", ret); @@ -1831,6 +1861,8 @@ static const AVOption options[] = { { "reserve_index_space", "Reserve a given amount of space (in bytes) at the beginning of the file for the index (cues).", OFFSET(reserve_cues_space), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, FLAGS }, { "cluster_size_limit", "Store at most the provided amount of bytes in a cluster. ", OFFSET(cluster_size_limit), AV_OPT_TYPE_INT , { .i64 = -1 }, -1, INT_MAX, FLAGS }, { "cluster_time_limit", "Store at most the provided number of milliseconds in a cluster.", OFFSET(cluster_time_limit), AV_OPT_TYPE_INT64, { .i64 = -1 }, -1, INT64_MAX, FLAGS }, + { "dash", "Create a WebM file conforming to WebM DASH specification", OFFSET(is_dash), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, FLAGS }, + { "dash_track_number", "Track number for the DASH stream", OFFSET(dash_track_number), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 127, FLAGS }, { NULL }, }; |