[FFmpeg-devel] [PATCH] avformat/fifo: Check for keyframe video type before stop dropping

[Arthur Grillo Queiroz Cabral]

On Wed Mar 12, 2025 at 3:45 PM -03, Arthur Grillo wrote:
> The current behavior when using restart_with_keyframe is that it will
> recover if it also encounters any audio packet, as they are flagged as a
> keyframe.
>
> The expectation is that packets are dropped until the next _video_
> keyframe.
>
> Fix that by checking the packet stream codec type, only letting it
> recover when it is a video one.
>
> Fixes ticket: #11467
>
> Signed-off-by: Arthur Grillo <arthurgrillo at riseup.net>

Gentle ping :-)

> ---
> Cc: lingjiujianke at gmail.com
> ---
>  libavformat/fifo.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/libavformat/fifo.c b/libavformat/fifo.c
> index 23e4149ad606b201aade77e28057afe8e5fe2b71..1ebfa1f38f3affec2d81b5a2bb9d69190a5aa63f 100644
> --- a/libavformat/fifo.c
> +++ b/libavformat/fifo.c
> @@ -185,14 +185,21 @@ static int fifo_thread_write_packet(FifoThreadContext *ctx, AVPacket *pkt)
>      AVRational src_tb, dst_tb;
>      int ret, s_idx;
>      int64_t orig_pts, orig_dts, orig_duration;
> +    enum AVMediaType stream_codec_type = avf->streams[pkt->stream_index]->codecpar->codec_type;
>  
>      if (fifo->timeshift && pkt->dts != AV_NOPTS_VALUE)
>          atomic_fetch_sub_explicit(&fifo->queue_duration, next_duration(avf, pkt, &ctx->last_received_dts), memory_order_relaxed);
>  
>      if (ctx->drop_until_keyframe) {
>          if (pkt->flags & AV_PKT_FLAG_KEY) {
> -            ctx->drop_until_keyframe = 0;
> -            av_log(avf, AV_LOG_VERBOSE, "Keyframe received, recovering...\n");
> +            if (stream_codec_type == AVMEDIA_TYPE_VIDEO) {
> +                ctx->drop_until_keyframe = 0;
> +                av_log(avf, AV_LOG_VERBOSE, "Video keyframe received, recovering...\n");
> +            } else {
> +                av_log(avf, AV_LOG_VERBOSE, "Dropping non-video keyframe\n");
> +                av_packet_unref(pkt);
> +                return 0;
> +            }
>          } else {
>              av_log(avf, AV_LOG_VERBOSE, "Dropping non-keyframe packet\n");
>              av_packet_unref(pkt);
>
> ---
> base-commit: 3165fe5ecf4917d9f7d7f27d4fa3af31bc604515
> change-id: 20250312-video-only-kf-recover-18816009f240
>
> Best regards,