[FFmpeg-trac] #1754(avformat:new): Error in Matroska Muxer

FFmpeg trac at avcodec.org
Wed Sep 19 21:15:28 CEST 2012

#1754: Error in Matroska Muxer
             Reporter:  Dan203       |                     Type:  defect
               Status:  new          |                 Priority:  important
            Component:  avformat     |                  Version:
             Keywords:  MKV,         |               Blocked By:
  Matroska                           |  Reproduced by developer:  0
             Blocking:               |
Analyzed by developer:  0            |
 On line 635 of matroskaenc.c there is an error. The line is currently...

 put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYUNIT, 3);

 it should either be deleted completely or set to 0 instead of 3. (0 is
 default so deleting it should be OK)

 According to the MKV specification...


 ...the DisplayUnit value should only be set to 3 if the DisplayHeight and
 DisplayWidth values are set to aspect ratio values. However the lines
 above that one clearly show that DisplayHeight and DisplayWidth are being
 set to pixel values that are adjusted for aspect.

 Most players ignore this value, but some hardware players have issues with
 files created with this incorrect DisplayUnit value.

Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1754>
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