[FFmpeg-devel] [PATCH] avformat/dv: fix timestamps of audio packets in case of dropped corrupt audio frames
Dave Rice
dave at dericed.com
Sat Oct 31 20:42:41 EET 2020
Hi Marton,
> On Oct 31, 2020, at 12:56 PM, Marton Balint <cus at passwd.hu> wrote:
>
> Fixes out of sync timestamps in ticket #8762.
Although Michael’s recent patch does address the issue documented in 8762, I haven’t found this patch to fix the issue. I tried with -c:a copy and with -c:a pcm_s16le with some sample files that exhibit this issue but each output was out of sync. I put an output at https://gist.github.com/dericed/659bd843bd38b6f24a60198b5e345795. That output notes that 3597 packages of video are read and 3586 packets of audio. In the resulting file, at the end of the timeline the audio is 9 frames out of sync and my output video stream is 00:02:00.020 and output audio stream is 00:01:59.653.
Beyond copying or encoding the audio, are there other options I should use to test this?
> Signed-off-by: Marton Balint <cus at passwd.hu>
> ---
> libavformat/dv.c | 16 ++--------------
> tests/ref/seek/lavf-dv | 18 +++++++++---------
> 2 files changed, 11 insertions(+), 23 deletions(-)
>
> diff --git a/libavformat/dv.c b/libavformat/dv.c
> index 3e0d12c0e3..26a78139f5 100644
> --- a/libavformat/dv.c
> +++ b/libavformat/dv.c
> @@ -49,7 +49,6 @@ struct DVDemuxContext {
> uint8_t audio_buf[4][8192];
> int ach;
> int frames;
> - uint64_t abytes;
> };
>
> static inline uint16_t dv_audio_12to16(uint16_t sample)
> @@ -258,7 +257,7 @@ static int dv_extract_audio_info(DVDemuxContext *c, const uint8_t *frame)
> c->ast[i] = avformat_new_stream(c->fctx, NULL);
> if (!c->ast[i])
> break;
> - avpriv_set_pts_info(c->ast[i], 64, 1, 30000);
> + avpriv_set_pts_info(c->ast[i], 64, c->sys->time_base.num, c->sys->time_base.den);
> c->ast[i]->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
> c->ast[i]->codecpar->codec_id = AV_CODEC_ID_PCM_S16LE;
>
> @@ -387,8 +386,7 @@ int avpriv_dv_produce_packet(DVDemuxContext *c, AVPacket *pkt,
> for (i = 0; i < c->ach; i++) {
> c->audio_pkt[i].pos = pos;
> c->audio_pkt[i].size = size;
> - c->audio_pkt[i].pts = c->abytes * 30000 * 8 /
> - c->ast[i]->codecpar->bit_rate;
> + c->audio_pkt[i].pts = (c->sys->height == 720) ? (c->frames & ~1) : c->frames;
> ppcm[i] = c->audio_buf[i];
> }
> if (c->ach)
> @@ -401,10 +399,7 @@ int avpriv_dv_produce_packet(DVDemuxContext *c, AVPacket *pkt,
> c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
> } else {
> c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
> - c->abytes += size;
> }
> - } else {
> - c->abytes += size;
> }
>
> /* Now it's time to return video packet */
> @@ -444,13 +439,6 @@ static int64_t dv_frame_offset(AVFormatContext *s, DVDemuxContext *c,
> void ff_dv_offset_reset(DVDemuxContext *c, int64_t frame_offset)
> {
> c->frames = frame_offset;
> - if (c->ach) {
> - if (c->sys) {
> - c->abytes = av_rescale_q(c->frames, c->sys->time_base,
> - (AVRational) { 8, c->ast[0]->codecpar->bit_rate });
> - } else
> - av_log(c->fctx, AV_LOG_ERROR, "cannot adjust audio bytes\n");
> - }
> c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
> c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
> }
> diff --git a/tests/ref/seek/lavf-dv b/tests/ref/seek/lavf-dv
> index 0000ff5abe..f63e4460be 100644
> --- a/tests/ref/seek/lavf-dv
> +++ b/tests/ref/seek/lavf-dv
> @@ -7,9 +7,9 @@ ret: 0 st: 0 flags:0 ts: 0.800000
> ret: 0 st: 0 flags:1 dts: 0.800000 pts: 0.800000 pos:2880000 size:144000
> ret: 0 st: 0 flags:1 ts:-0.320000
> ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 0 size:144000
> -ret: 0 st: 1 flags:0 ts: 2.576667
> +ret: 0 st: 1 flags:0 ts: 2.560000
> ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos:3456000 size:144000
> -ret: 0 st: 1 flags:1 ts: 1.470833
> +ret: 0 st: 1 flags:1 ts: 1.480000
> ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos:3456000 size:144000
> ret: 0 st:-1 flags:0 ts: 0.365002
> ret: 0 st: 0 flags:1 dts: 0.360000 pts: 0.360000 pos:1296000 size:144000
> @@ -19,9 +19,9 @@ ret: 0 st: 0 flags:0 ts: 2.160000
> ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos:3456000 size:144000
> ret: 0 st: 0 flags:1 ts: 1.040000
> ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos:3456000 size:144000
> -ret: 0 st: 1 flags:0 ts:-0.058333
> +ret: 0 st: 1 flags:0 ts:-0.040000
> ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 0 size:144000
> -ret: 0 st: 1 flags:1 ts: 2.835833
> +ret: 0 st: 1 flags:1 ts: 2.840000
> ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos:3456000 size:144000
> ret: 0 st:-1 flags:0 ts: 1.730004
> ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos:3456000 size:144000
> @@ -31,10 +31,10 @@ ret: 0 st: 0 flags:0 ts:-0.480000
> ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 0 size:144000
> ret: 0 st: 0 flags:1 ts: 2.400000
> ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos:3456000 size:144000
> -ret: 0 st: 1 flags:0 ts: 1.306667
> -ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos:3456000 size:144000
> -ret: 0 st: 1 flags:1 ts: 0.200833
> +ret: 0 st: 1 flags:0 ts: 1.320000
> ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos:3456000 size:144000
> +ret: 0 st: 1 flags:1 ts: 0.200000
> +ret: 0 st: 0 flags:1 dts: 0.200000 pts: 0.200000 pos: 720000 size:144000
> ret: 0 st:-1 flags:0 ts:-0.904994
> ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 0 size:144000
> ret: 0 st:-1 flags:1 ts: 1.989173
> @@ -43,9 +43,9 @@ ret: 0 st: 0 flags:0 ts: 0.880000
> ret: 0 st: 0 flags:1 dts: 0.880000 pts: 0.880000 pos:3168000 size:144000
> ret: 0 st: 0 flags:1 ts:-0.240000
> ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 0 size:144000
> -ret: 0 st: 1 flags:0 ts: 2.671667
> +ret: 0 st: 1 flags:0 ts: 2.680000
> ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos:3456000 size:144000
> -ret: 0 st: 1 flags:1 ts: 1.565833
> +ret: 0 st: 1 flags:1 ts: 1.560000
> ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos:3456000 size:144000
> ret: 0 st:-1 flags:0 ts: 0.460008
> ret: 0 st: 0 flags:1 dts: 0.480000 pts: 0.480000 pos:1728000 size:144000
> —
> 2.26.2
Best Regards,
Dave Rice
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