[FFmpeg-trac] #472(undetermined:new): Initial gray frames when first frame is no keyframe

FFmpeg trac at avcodec.org
Thu Sep 15 11:21:15 CEST 2011

#472: Initial gray frames when first frame is no keyframe
             Reporter:  DonMoir      |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
 I think maybe this has been discussed before, but if there is no initial
 keyframe then gray frames are produced. This happens often enough that it
 needs a solution. What I currently do in my application is I don't display
 anything until I get one initial keyframe and this seems to fix it well
 and easy.

 A couple possible solutions for ffmpeg might be:

 o - Assume the first keyframe is all black if there is no initial keyframe

 o - In avcodec_decode_video2 maybe got_picture_ptr should not be set until
 a first keyframe is received.

 I believe a related discussion is here:


 This file is pretty bad and probably a worst case. I have a few others
 where is its much cleaner but still initially gray.

 http://sms.pangolin.com/temp/grayframes.ts (5 MB)

Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/472>
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