[FFmpeg-trac] #11628(avformat:new): Ogg: Broken file, keyframe not correctly marked

[FFmpeg]

#11628: Ogg: Broken file, keyframe not correctly marked
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             Reporter:  Bernat    |                     Type:  defect
               Status:  new       |                 Priority:  normal
            Component:  avformat  |                  Version:  unspecified
             Keywords:            |               Blocked By:
             Blocking:            |  Reproduced by developer:  0
Analyzed by developer:  0         |
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 FFmpeg show this message whenever an Ogg page having a granulepos
 corresponding to a keyframe contains a non-keyframe, besides the mandatory
 keyframe. And viceversa.

 It seems FFmpeg expects pages to contain only non-keyframes or only
 keyframes, depending on the granulepos of the page, but never a mix of
 both.

 Ogv files produced by FFmpeg are like that, but other Ogv files aren't.
 And I think the Ogg specification doesn't require it.

 The `encoder_example` program in the Theora package doesn't follow this
 practice and mixes both. It does some things wrong too, so I don't know
 whether we can trust it.

 I don't know if it's an exclusive requirement in FFmpeg or if it's indeed
 written somewhere in the documentation.

 If it's not really a hard requirement, the message could be changed to
 something that doesn't say "broken file" to not scare users.

 Thanks!
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Ticket URL: <https://trac.ffmpeg.org/ticket/11628>
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