fftools/ffmpeg: propagate frame durations to packets when encoding

Remove now-obsolete code setting packet durations pre-muxing for CFR
encoded video.

Changes output in the following FATE tests:
* numerous adpcm tests
* ffmpeg-filter_complex_audio
* lavf-asf
* lavf-mkv
* lavf-mkv_attachment
* matroska-encoding-delay
  All of these change due to the fact that the output duration is now
  the actual input data duration and does not include padding added by
  the encoder.

* apng-osample: less wrong packet durations are now passed to the muxer.
  They are not entirely correct, because the first frame duration should
  be 3 rather than 2. This is caused by the vsync code and should be
  addressed later, but this change is a step in the right direction.
* tscc2-mov: last output frame has a duration of 11 rather than 1 - this
  corresponds to the duration actually returned by the demuxer.
* film-cvid: video frame durations are now 2 rather than 1 - this
  corresponds to durations actually returned by the demuxer and matches
  the timestamps.
* mpeg2-ticket6677: durations of some video frames are now 2 rather than
  1 - this matches the timestamps.

1 files changed, 0 insertions, 9 deletions

diff --git a/fftools/ffmpeg_mux.c b/fftools/ffmpeg_mux.c
index 7778510d2c..a2e8873ad2 100644
--- a/fftools/ffmpeg_mux.c
+++ b/fftools/ffmpeg_mux.c
@@ -76,15 +76,6 @@ static int write_packet(Muxer *mux, OutputStream *ost, AVPacket *pkt)
     if (ost->type == AVMEDIA_TYPE_VIDEO && ost->vsync_method == VSYNC_DROP)
         pkt->pts = pkt->dts = AV_NOPTS_VALUE;
 
-    if (ost->type == AVMEDIA_TYPE_VIDEO) {
-        if (ost->frame_rate.num && ost->is_cfr) {
-            if (pkt->duration > 0)
-                av_log(ost, AV_LOG_WARNING, "Overriding packet duration by frame rate, this should not happen\n");
-            pkt->duration = av_rescale_q(1, av_inv_q(ost->frame_rate),
-                                         pkt->time_base);
-        }
-    }
-
     av_packet_rescale_ts(pkt, pkt->time_base, ost->st->time_base);
     pkt->time_base = ost->st->time_base;