[FFmpeg-devel] [PATCH 6/6] ffplay: use AV_PKT_FLAG_DISPOSABLE in frame drop logic

[Marton Balint]

On Thu, 30 Nov 2017, John Stebbins wrote:

> ---
> fftools/ffplay.c | 21 ++++++++++++++++-----
> 1 file changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/fftools/ffplay.c b/fftools/ffplay.c
> index 10a917194d..152d220cdb 100644
> --- a/fftools/ffplay.c
> +++ b/fftools/ffplay.c
> @@ -198,6 +198,8 @@ typedef struct Decoder {
>     int64_t next_pts;
>     AVRational next_pts_tb;
>     SDL_Thread *decoder_tid;
> +    int drop_disposable;
> +    int frame_drops_disposable;
> } Decoder;
> 
> typedef struct VideoState {
> @@ -660,10 +662,16 @@ static int decoder_decode_frame(Decoder *d, AVFrame *frame, AVSubtitle *sub) {
>                     ret = got_frame ? 0 : (pkt.data ? AVERROR(EAGAIN) : AVERROR_EOF);
>                 }
>             } else {
> -                if (avcodec_send_packet(d->avctx, &pkt) == AVERROR(EAGAIN)) {
> -                    av_log(d->avctx, AV_LOG_ERROR, "Receive_frame and send_packet both returned EAGAIN, which is an API violation.\n");
> -                    d->packet_pending = 1;
> -                    av_packet_move_ref(&d->pkt, &pkt);
> +                if (d->avctx->codec_type == AVMEDIA_TYPE_VIDEO &&
> +                    d->drop_disposable &&
> +                    (pkt.flags & AV_PKT_FLAG_DISPOSABLE)) {
> +                    d->frame_drops_disposable++;
> +                } else {
> +                    if (avcodec_send_packet(d->avctx, &pkt) == AVERROR(EAGAIN)) {
> +                        av_log(d->avctx, AV_LOG_ERROR, "Receive_frame and send_packet both returned EAGAIN, which is an API violation.\n");
> +                        d->packet_pending = 1;
> +                        av_packet_move_ref(&d->pkt, &pkt);
> +                    }
>                 }
>             }
>             av_packet_unref(&pkt);
> @@ -1622,6 +1630,7 @@ retry:
>                     frame_queue_next(&is->pictq);
>                     goto retry;
>                 }
> +                is->viddec.drop_disposable = 0;
>             }
>
>             if (is->subtitle_st) {
> @@ -1699,7 +1708,8 @@ display:
>                    get_master_clock(is),
>                    (is->audio_st && is->video_st) ? "A-V" : (is->video_st ? "M-V" : (is->audio_st ? "M-A" : "   ")),
>                    av_diff,
> -                   is->frame_drops_early + is->frame_drops_late,
> +                   is->frame_drops_early + is->frame_drops_late +
> +                                           is->viddec.frame_drops_disposable,
>                    aqsize / 1024,
>                    vqsize / 1024,
>                    sqsize,
> @@ -1767,6 +1777,7 @@ static int get_video_frame(VideoState *is, AVFrame *frame)
>                     is->frame_drops_early++;
>                     av_frame_unref(frame);
>                     got_picture = 0;
> +                    is->viddec.drop_disposable = 1;
>                 }
>             }
>         }

The patch looks OK now, but as I mentioned earlier, please do not enable 
this kind of frame dropping by default, either introduce a separate option 
"hardframedrop", or make -framedrop an integer and use "2" for this kind 
of hard dropping.

Regards,
Marton