From ff55d1cc20780dc90457368cb4ccae2435a878b1 Mon Sep 17 00:00:00 2001 From: Anton Khirnov Date: Fri, 5 Jul 2024 12:19:35 +0200 Subject: [PATCH] fftools/ffmpeg_dec: improve detection of lavf-guessed durations Will be useful in following commit. --- fftools/ffmpeg_dec.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/fftools/ffmpeg_dec.c b/fftools/ffmpeg_dec.c index 70de151301..c2bcf784b0 100644 --- a/fftools/ffmpeg_dec.c +++ b/fftools/ffmpeg_dec.c @@ -260,6 +260,10 @@ static int64_t video_duration_estimate(const DecoderPriv *dp, const AVFrame *fra const int ts_unreliable = dp->flags & DECODER_FLAG_TS_UNRELIABLE; const int fr_forced = dp->flags & DECODER_FLAG_FRAMERATE_FORCED; int64_t codec_duration = 0; + // difference between this and last frame's timestamps + const int64_t ts_diff = + (frame->pts != AV_NOPTS_VALUE && dp->last_frame_pts != AV_NOPTS_VALUE) ? + frame->pts - dp->last_frame_pts : -1; // XXX lavf currently makes up frame durations when they are not provided by // the container. As there is no way to reliably distinguish real container @@ -267,8 +271,13 @@ static int64_t video_duration_estimate(const DecoderPriv *dp, const AVFrame *fra // the container has timestamps. Eventually lavf should stop making up // durations, then this should be simplified. + // frame duration is unreliable (typically guessed by lavf) when it is equal + // to 1 and the actual duration of the last frame is more than 2x larger + const int duration_unreliable = frame->duration == 1 && ts_diff > 2 * frame->duration; + // prefer frame duration for containers with timestamps - if (frame->duration > 0 && (!ts_unreliable || fr_forced)) + if (fr_forced || + (frame->duration > 0 && !ts_unreliable && !duration_unreliable)) return frame->duration; if (dp->dec_ctx->framerate.den && dp->dec_ctx->framerate.num) { @@ -285,9 +294,8 @@ static int64_t video_duration_estimate(const DecoderPriv *dp, const AVFrame *fra // when timestamps are available, repeat last frame's actual duration // (i.e. pts difference between this and last frame) - if (frame->pts != AV_NOPTS_VALUE && dp->last_frame_pts != AV_NOPTS_VALUE && - frame->pts > dp->last_frame_pts) - return frame->pts - dp->last_frame_pts; + if (ts_diff > 0) + return ts_diff; // try frame/codec duration if (frame->duration > 0)