[FFmpeg-devel] Meaningful return codes (was [PATCH 7/9] Replace AVERROR_NOTSUPP by AVERROR(ENOSYS))

[Víctor Paesa]

Hi,

>>> Furthermore, I'm not sure it's possible to do what you are
>>> suggesting. Let's say you want to express things like the allowed
>>> framesize. Some codecs accept only a fixed list of resolutions,
>>> others might only accept even resolutions, of maybe some resolutions
>>> within some range.
>>
>> max + multiple + fixed list would be enough ...
>
> Yes, for the contraints I mentioned that would be enough.
>
> Slightly OT: But sometimes you need even more complex contraints.   Some
> time ago I was looking into ways for describing some kind of   profile
> for specific devices. And it turned out to be quite hard imho   as some
> of the constraints weren't simple statements like
> "resolutions A,B,C are supported" but more like, "resolution A is
> supported with framerate < B and bitrate < C" etc.. I couldn't find a
> _simple_ way to describe such constraints.

You could describe such constraints using a FFMpeg evaluable expression
(http://ffmpeg.mplayerhq.hu/ffmpeg-doc.html#SEC16)

For example, full size DVD restrictions might be stated as:
(eq(W,720)+eq(W,704))*(eq(r,25.0)*eq(H,576)+eq(r,29.97)*eq(H,480))

Regards,
V?ctor