[FFmpeg-trac] #7083(avcodec:new): Decoder playing out frames at double speed

FFmpeg trac at avcodec.org
Wed Mar 14 11:41:13 EET 2018

#7083: Decoder playing out frames at double speed
             Reporter:  baudouin0   |                    Owner:
                 Type:  defect      |                   Status:  new
             Priority:  normal      |                Component:  avcodec
              Version:  git-master  |               Resolution:
             Keywords:  h264        |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |

Comment (by baudouin0):

 Many thanks for the quick response.

 When we play a mpeg transport stream into the decoder (ffplay or VLC
 3.0.1) we see the I-frame (which has a PTS time stamp in the ts before the
 SPS) played out followed by the P-frames at double speed then a gap before
 the next I-frame (and PTS) comes along. This does not happen on VLC 2.2.8
 but I have not found which version of ffmpeg these are built with. In
 trying to find out the cause of this problem we discovered the bug that
 the h->x264_build becomes zero rather than -1. So I added printf into the
 code as I have shown into h264_slice_header_init(). You can then see this
 with the bitstream I have sent. We can also fix the issue be setting
 time_scale in the h264 bitstream to 25000 rather than 50000 but this is
 not correct as H264 ticks are always in fields regardless of the picture

Ticket URL: <https://trac.ffmpeg.org/ticket/7083#comment:3>
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