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• avcodec/mpegvideo_dec : Don't use MotionEstContext as scratch space

  30 octobre 2022, par Andreas Rheinhardt

  avcodec/mpegvideo_dec : Don't use MotionEstContext as scratch space
  Decoders that might use quarter pixel motion estimation
  
  (namely MPEG-4 as well as the VC-1 family) currently
  
  use MpegEncContext.me.qpel_(put|avg) as scratch space
  
  for pointers to arrays of function pointers.
  
  (MotionEstContext contains such pointers as it supports
  
  quarter pixel motion estimation.) The MotionEstContext
  
  is unused apart from this for the decoding part of
  
  mpegvideo.
  Using the context at all is for decoding is actually
  
  unnecessary and easily avoided : All codecs with
  
  quarter pixels set me.qpel_avg to qdsp.avg_qpel_pixels_tab,
  
  so one can just unconditionally use this in ff_mpv_reconstruct_mb().
  
  MPEG-4 sets qpel_put to qdsp.put_qpel_pixels_tab
  
  or to qdsp.put_no_rnd_qpel_pixels_tab based upon
  
  whether the current frame is a b-frame with no_rounding
  
  or not, while the VC-1-based decoders set it to
  
  qdsp.put_qpel_pixels_tab unconditionally. Given
  
  that no_rounding is always zero for VC-1, using
  
  the same check for VC-1 as well as for MPEG-4 would work.
  
  Since ff_mpv_reconstruct_mb() already has exactly
  
  the right check (for hpeldsp), it can simply be reused.
  (This change will result in ff_mpv_motion() receiving
  
  a pointer to an array of NULL function pointers instead
  
  of a NULL pointer for codecs without qpeldsp (like MPEG-1/2).
  
  It doesn't matter.)
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/h263dec.c
  • [DH] libavcodec/mpv_reconstruct_mb_template.c
  • [DH] libavcodec/mss2.c
  • [DH] libavcodec/vc1dec.c

• Damaged h264 stream not working with ffmpeg but working with vlc or mplayer

  15 avril 2013, par gregoiregentil

  I have a h264 file, coming from an rtsp stream, that is slightly damaged. Some frames are altered.

  ffmpeg reports :

  ffmpeg -i stream.mpg 
  
  ffmpeg version 0.8.6-4:0.8.6-0ubuntu0.12.04.1, Copyright (c) 2000-2013 the Libav developers
  
    built on Apr  2 2013 17:00:59 with gcc 4.6.3
  
  *** THIS PROGRAM IS DEPRECATED ***
  
  This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.
  
  
  
  Seems stream 0 codec frame rate differs from container frame rate: 180000.00 (180000/1) -> 90000.00 (180000/2)
  
  Input #0, mpegts, from 'a.mpg':
  
    Duration: 00:03:18.84, start: 93370.745522, bitrate: 2121 kb/s
  
    Program 1 
  
      Stream #0.0[0x44](): Video: h264 (Baseline), yuv420p, 640x480, 90k tbr, 90k tbn, 180k tbc
  
  At least one output file must be specified

  I can play the file with VLC or mplayer. Obviously, the damaged frames are "kind of blurred" but it's working. mplayer reports :

  mplayer stream.mpg
  
  MPlayer2 UNKNOWN (C) 2000-2011 MPlayer Team
  
  mplayer: could not connect to socket
  
  mplayer: No such file or directory
  
  Failed to open LIRC support. You will not be able to use your remote control.
  
  
  
  Playing stream.mpg.
  
  Detected file format: MPEG-2 transport stream format (libavformat)
  
  [lavf] stream 0: video (h264), -vid 0
  
  LAVF: Program 1 
  
  VIDEO:  [H264]  640x480  0bpp  90000.000 fps    0.0 kbps ( 0.0 kbyte/s)
  
  Load subtitles in .
  
  [ass] auto-open
  
  ==========================================================================
  
  Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
  
  Asking decoder to use 2 threads if supported.
  
  Selected video codec: [ffh264] vfm: ffmpeg (FFmpeg H.264)
  
  ==========================================================================
  
  Audio: no sound
  
  Starting playback...
  
  V:   0.0   0/  0 ??% ??% ??,?% 0 0 
  
  Movie-Aspect is undefined - no prescaling applied.
  
  VO: [xv] 640x480 => 640x480 Planar YV12 
  
  V:93370.7   0/  0 ??% ??% ??,?% 0 0 
  
  No pts value from demuxer to use for frame!
  
  Video pts after filters MISSING
  
  V:93370.7   0/  0 ??% ??% ??,?% 0 0 
  
  No pts value from demuxer to use for frame!
  
  Video pts after filters MISSING
  
  V:93370.7   0/  0 ??% ??% ??,?% 0 0 
  
  No pts value from demuxer to use for frame!
  
  Video pts after filters MISSING
  
  V:93370.7   0/  0 ??% ??% ??,?% 0 0 
  
  No pts value from demuxer to use for frame!
  
  Video pts after filters MISSING
  
  V:93370.7   0/  0 ??% ??% ??,?% 0 0 
  
  No pts value from demuxer to use for frame!
  
  Video pts after filters MISSING
  
  V:93370.7   0/  0 ??% ??% ??,?% 0 0 
  
  No pts value from demuxer to use for frame!
  
  Video pts after filters MISSING
  
  V:93370.7   0/  0 ??% ??% ??,?% 0 0 
  
  No pts value from demuxer to use for frame!

  When I try to re-encode the file with :

  ffmpeg -i stream.mpg -fflags +genpts -an -vcodec mpeg4 -r 65535/2733 stream.mp4

  ffmpeg seems to jump over the altered frames. The length of stream.mp4 << length of stream.mpg

  How could I fix this problem, i.e. having ffmpeg to output something similar to what mplayer and vlc output ?

• fate : Prefix cllc tests with canopus

  9 avril 2015, par Vittorio Giovara

  fate : Prefix cllc tests with canopus
  They belong to the same family of codecs.
  

  • [DH] tests/fate/lossless-video.mak
  • [DH] tests/ref/fate/canopus-cllc-argb
  • [DH] tests/ref/fate/canopus-cllc-rgb
  • [DH] tests/ref/fate/canopus-cllc-yuy2-noblock