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shshankjain / webm

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vp8 encoder filter should provide a way to force keyframe immediately #103

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
Right now you can set the min and max keyframe intervals (to the same value, if 
desired), which will force keyframes to be generated at the given frequency.

What is desired is a way to explicitly request that a keyframe be generated 
now, on demand.

Original issue reported on code.google.com by matthewj...@google.com on 23 Jun 2010 at 12:47

GoogleCodeExporter commented 9 years ago 
It would seem to me that this is required for multi-bitrate streaming - 
keyframe alignment is necessary when switching between alternate streams, isn't 
it?

Now, most of the time, given the same source scaled to different resolutions, 
the encoder seems to automatically choose the same keyframes. But I don't think 
that behavior is guaranteed. Say I am encoding both a 720p and 360p version of 
the same content. If the scaled down version of the video loses enough fine 
detail that the differences between two frames falls below the automatic 
keyframe threshold, the keyframe intervals between the two streams could become 
misaligned, couldn't they?

This is also probably a requirement for chapter support too - you need to make 
sure your chapter seek point is a keyframe.

Original comment by malay...@gmail.com on 3 Dec 2010 at 4:03

GoogleCodeExporter commented 9 years ago 
This is already implemented: see IVP8Encoder::SetForceKeyFrame().

Original comment by matthewj...@google.com on 4 Dec 2010 at 12:21

GoogleCodeExporter commented 9 years ago 
This issue was closed by revision e4e3ec19adb6.

Original comment by jz...@google.com on 18 Jan 2012 at 10:00