[FFmpeg-devel] full support for PAFF (was - Decoding artifacts with some AVCHD files)

Gerald Dalley gerald.dalley
Fri Mar 21 15:42:30 CET 2008


2008/3/20 Loren Merritt <lorenm at u.washington.edu>:
> On Thu, 20 Mar 2008, Igor wrote:
>
>  >>  they are using field-based interlacing (aka PAFF) , with 2 bframes.
>  >>  Their top field for b-slice uses temporal bdirect mode, whereas
>  >>  their bottom field in b-slice uses spatial prediction bdirect mode.
>  >>  Support for this prediction is incomplete in ffmpeg, hence the artifacts
>  >>  you're seing.
>  >
>  > is there any palns about implementation of full PAFF support in ffmpeg ? Does somebody work under this point ?
>
>  Bad question. I don't think anyone will ever write a decoder that
>  suppports all the features of the standard. (No, the reference doesn't
>  either). Nor all the features that can conceivably be in the same stream
>  as PAFF.
>  Now, you can ask about some specific feature, like field deblocking, or
>  mixed direct mode.

Okay, here's a more direct question... Are there any plans on
implementing whatever is required to decode the following video?

http://people.csail.mit.edu/dalleyg/collaboration/avchd/hg10-pf24-clip2.mts

Currently some of the bottom fields decode improperly.  Starting at
about frame 26, there's a chunk of frames that show difficulties.  At

http://people.csail.mit.edu/dalleyg/collaboration/avchd/readme.html

search for "Frame Corruption" and you can see a figure illustrating the issue.

>  --Loren Merritt
>
>
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-- 
--Gerald Dalley
 dalleyg at mit.edu




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