[FFmpeg-devel] [PATCH 12/20] avformat/matroskaenc: Improve Cues in case of no video
Steve Lhomme
robux4 at ycbcr.xyz
Sun Apr 19 10:43:12 EEST 2020
> On April 5, 2020 5:59 PM Andreas Rheinhardt <andreas.rheinhardt at gmail.com> wrote:
>
>
> The Matroska muxer currently only adds CuePoints in three cases:
> a) For video keyframes. b) For the first audio frame in a new Cluster if
> in DASH-mode. c) For subtitles. This means that ordinary Matroska audio
> files won't have any Cues which impedes seeking.
>
> This commit changes this. For every track in a file without video track
> it is checked and tracked whether a Cue entry has already been added
> for said track for the current Cluster. This is used to add a Cue entry
> for each first packet of each track in each Cluster.
>
> Implements #3149.
>
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> ---
> libavformat/matroskaenc.c | 21 +++++++++++--------
> tests/ref/fate/aac-autobsf-adtstoasc | 4 ++--
> tests/ref/fate/matroska-flac-extradata-update | 4 ++--
> tests/ref/lavf/mka | 4 ++--
> 4 files changed, 18 insertions(+), 15 deletions(-)
>
> diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
> index b9bfd34756..a469d48cc0 100644
> --- a/libavformat/matroskaenc.c
> +++ b/libavformat/matroskaenc.c
> @@ -2120,6 +2120,10 @@ static void mkv_end_cluster(AVFormatContext *s)
> MatroskaMuxContext *mkv = s->priv_data;
>
> end_ebml_master_crc32(s->pb, &mkv->cluster_bc, mkv, MATROSKA_ID_CLUSTER, 0, 1);
> + if (!mkv->have_video) {
You could initialize it even for video. In case in the future you want a Cue only on the first video keyframe of the Cluster.
> + for (unsigned i = 0; i < s->nb_streams; i++)
> + mkv->tracks[i].has_cue = 0;
> + }
> mkv->cluster_pos = -1;
> avio_write_marker(s->pb, AV_NOPTS_VALUE, AVIO_DATA_MARKER_FLUSH_POINT);
> }
> @@ -2222,7 +2226,7 @@ static int mkv_check_new_extra_data(AVFormatContext *s, AVPacket *pkt)
> return 0;
> }
>
> -static int mkv_write_packet_internal(AVFormatContext *s, AVPacket *pkt, int add_cue)
> +static int mkv_write_packet_internal(AVFormatContext *s, AVPacket *pkt)
> {
> MatroskaMuxContext *mkv = s->priv_data;
> AVIOContext *pb;
> @@ -2268,10 +2272,12 @@ static int mkv_write_packet_internal(AVFormatContext *s, AVPacket *pkt, int add_
> ret = mkv_write_block(s, pb, MATROSKA_ID_SIMPLEBLOCK, pkt, keyframe);
> if (ret < 0)
> return ret;
> - if ((s->pb->seekable & AVIO_SEEKABLE_NORMAL) && (par->codec_type == AVMEDIA_TYPE_VIDEO && keyframe || add_cue)) {
> + if ((s->pb->seekable & AVIO_SEEKABLE_NORMAL) && keyframe &&
> + (par->codec_type == AVMEDIA_TYPE_VIDEO || !mkv->have_video && !track->has_cue)) {
You may restrict this to Audio/Subtitles. Other streams/tracks may not create a cue entry.
> ret = mkv_add_cuepoint(mkv, pkt->stream_index, ts,
> mkv->cluster_pos, relative_packet_pos, -1);
> if (ret < 0) return ret;
> + track->has_cue = 1;
> }
> } else {
> if (par->codec_id == AV_CODEC_ID_WEBVTT) {
> @@ -2336,8 +2342,7 @@ static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
> // on seeing key frames.
> start_new_cluster = keyframe;
> } else if (mkv->is_dash && codec_type == AVMEDIA_TYPE_AUDIO &&
> - (mkv->cluster_pos == -1 ||
> - cluster_time > mkv->cluster_time_limit)) {
> + cluster_time > mkv->cluster_time_limit) {
Is this related to this patch ? It currently means that if the Cluster did not write any Block then a new cluster is not needed.
> // For DASH audio, we create a Cluster based on cluster_time_limit
> start_new_cluster = 1;
> } else if (!mkv->is_dash &&
> @@ -2361,9 +2366,7 @@ static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
>
> // check if we have an audio packet cached
> if (mkv->cur_audio_pkt.size > 0) {
> - // 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);
> + ret = mkv_write_packet_internal(s, &mkv->cur_audio_pkt);
> av_packet_unref(&mkv->cur_audio_pkt);
> if (ret < 0) {
> av_log(s, AV_LOG_ERROR,
> @@ -2378,7 +2381,7 @@ static int mkv_write_packet(AVFormatContext *s, AVPacket *pkt)
> if (pkt->size > 0)
> ret = av_packet_ref(&mkv->cur_audio_pkt, pkt);
> } else
> - ret = mkv_write_packet_internal(s, pkt, 0);
> + ret = mkv_write_packet_internal(s, pkt);
> return ret;
> }
>
> @@ -2406,7 +2409,7 @@ 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, 0);
> + ret = mkv_write_packet_internal(s, &mkv->cur_audio_pkt);
> if (ret < 0) {
> av_log(s, AV_LOG_ERROR,
> "Could not write cached audio packet ret:%d\n", ret);
> diff --git a/tests/ref/fate/aac-autobsf-adtstoasc b/tests/ref/fate/aac-autobsf-adtstoasc
> index f1c6f889d4..d9191fb37f 100644
> --- a/tests/ref/fate/aac-autobsf-adtstoasc
> +++ b/tests/ref/fate/aac-autobsf-adtstoasc
> @@ -1,5 +1,5 @@
> -9d0c81ce285a84c0137316004d091d95 *tests/data/fate/aac-autobsf-adtstoasc.matroska
> -6620 tests/data/fate/aac-autobsf-adtstoasc.matroska
> +76a14cc1b3292c7f724006d56b7e2eac *tests/data/fate/aac-autobsf-adtstoasc.matroska
> +6648 tests/data/fate/aac-autobsf-adtstoasc.matroska
> #extradata 0: 2, 0x0030001c
> #tb 0: 1/1000
> #media_type 0: audio
> diff --git a/tests/ref/fate/matroska-flac-extradata-update b/tests/ref/fate/matroska-flac-extradata-update
> index dfb2851b0f..16b268c4a8 100644
> --- a/tests/ref/fate/matroska-flac-extradata-update
> +++ b/tests/ref/fate/matroska-flac-extradata-update
> @@ -1,5 +1,5 @@
> -83aca2772c52f6f802cac288f889382b *tests/data/fate/matroska-flac-extradata-update.matroska
> -2019 tests/data/fate/matroska-flac-extradata-update.matroska
> +5f6a67a45906f1bc7dd11d840470b0e4 *tests/data/fate/matroska-flac-extradata-update.matroska
> +2071 tests/data/fate/matroska-flac-extradata-update.matroska
> #extradata 0: 34, 0x7acb09e7
> #extradata 1: 34, 0x7acb09e7
> #extradata 2: 34, 0x443402dd
> diff --git a/tests/ref/lavf/mka b/tests/ref/lavf/mka
> index b3c4117d92..24ccef51fd 100644
> --- a/tests/ref/lavf/mka
> +++ b/tests/ref/lavf/mka
> @@ -1,3 +1,3 @@
> -0d48d93057f14704f6b839bb15e7328a *tests/data/lavf/lavf.mka
> -43552 tests/data/lavf/lavf.mka
> +df7155d4333e9993c9ea2a9d53868881 *tests/data/lavf/lavf.mka
> +43580 tests/data/lavf/lavf.mka
> tests/data/lavf/lavf.mka CRC=0x3a1da17e
> --
> 2.20.1
>
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