[mythtv] [PATCH] libpostprocess

[Kenneth Aafløy]

On Tue, 2003-10-28 at 00:00, Andrew Mahone wrote:
> I've been wanting this, and I believe others have mentioned interest in 
> deblocking and deringing filters as well.  Does your patch tell ffmpeg 
> to apply postproc filters, or did you port the filters themselves to the 
> MythTV filter API?

It only uses the postproc lib in the regular MythTV filter api, and as
far as I know, there is no method of telling ffmpeg (libavcodec) to use
the postprocess api automagically.

> My understanding is that most of these need information that's only
> available from the decoder, although being able to deblock RTjpeg
> would be helpful - I see blocks even at the highest quality settings,
> sometimes, because q=255 is still only 75% JPEG quality.

This would be what is called qscale/qstride in the postproc api, which I
had no idea on how to get parameters for yesterday, so I left them 
unused. Upon looking at this now, the filter needs to be moved to
AvFormatDecoder::GetFrame() (needs access to AVFrame's qstride /
qscale_table members) to maximize the performance and quality of the
filters (But then we'll have a bounch of classes to handle this in
(every class that inherits DecoderBase)).

> I'll need to look at this and see how this works w/ the filter 
> API changes I'm working on.

Have you posted this to the list somewhere (could not locate it after a
fast search)? If not, could you mail me your progress?

> Btw, a good reference on formats is
>  http://www.thedirks.org/v4l2/v4l2fmt.htm.
> It's V4L2-oriented, but the information applies to pretty much anything
> that uses these formats. The format that you'll generally be getting from
> ffmpeg is YV12, which is listed there as YUV420P.

Excelent, I'll have a look at it right away.

Kenneth