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

[John Stebbins]

On 12/01/2017 08:25 AM, wm4 wrote:
> On Thu, 30 Nov 2017 16:27:01 -0800
> John Stebbins <jstebbins at jetheaddev.com> 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;
>>                  }
>>              }
>>          }
> Why not just make libavcodec drop disposable frames?
>

libavcodec doesn't know anything about the current playback timeline.  I.e. it doesn't know if a frame is late.

-- 
John      GnuPG fingerprint: D0EC B3DB C372 D1F1 0B01  83F0 49F1 D7B2 60D4 D0F7


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