[FFmpeg-devel] Decoding artifacts with some AVCHD files

[Gerald Dalley]

On Thu, Mar 20, 2008 at 9:43 AM, Pascal Massimino
<pascal.massimino at gmail.com> wrote:
>   Gerald,
>
>  On Thu, Mar 20, 2008 at 2:31 AM, Gerald Dalley <gerald.dalley at gmail.com>
>  wrote:
>
>  > I have a Canon HG10 camcorder and I'm attempting to decode their AVCHD
>  > content.  Unfortunately, some frames don't seem to be decoding
>  > properly.  As an example, at several points (e.g. starting at about
>  > frame 52) of
>  >
>  >
>  > http://people.csail.mit.edu/dalleyg/collaboration/avchd/hg10-pf24-clip2.mts
>  >
>
>   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.

Life just keeps getting stranger.  Do you have any idea when such
support might be completed in ffmpeg?  I'm trying to decide if it's
better to press hard on some commercial vendors for a short-term
solution or if I should just wait for ffmpeg.

>  > the bottom field image patches don't seem to be updated quite properly
>  > during a time when the camera moved quickly.  Using the InterVideo
>  > codec, the decoding seems to work fine (unless its always-on
>  > deinterlacer is erasing the mistakes) so I don't think it's a problem
>  > with the HG10's encoder.  Here's a direct link to a cutout frame
>  > demonstrating the problem:
>  >
>  >
>  > http://people.csail.mit.edu/dalleyg/collaboration/avchd/decoded/cropped0053bottom.png
>  >
>  > I see the problem using the latest clsid build of ffdshow on Windows
>  > from 17 March 2008 and using the latest SVN-built compilation
>  > of and ffmpeg on x64 Linux on 18 March 2008.
>  >
>  > I've written up an article that mostly discusses pulldown issues with
>  > the camera (which are not pertinent to this issue), but I also include
>  > this ffmpeg decoding issue.  Search for "Frame Corruption" in
>  >
>  >  http://people.csail.mit.edu/dalleyg/collaboration/avchd/readme.html
>
>
>   very interesting article. Hell will freeze before
>   we're rid of last millenium's interlacing.

:)

>  skal
>  _______________________________________________
>  ffmpeg-devel mailing list
>  ffmpeg-devel at mplayerhq.hu
>  https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-devel

-- 
--Gerald Dalley
 dalleyg at mit.edu