[FFmpeg-devel] [PATCH] Re: Reworking the codec lookup system

Michael Niedermayer michaelni
Tue Jun 12 01:23:32 CEST 2007


On Mon, Jun 11, 2007 at 06:00:21PM +0200, Nicolas George wrote:
> Le tridi 23 prairial, an CCXV, Michael Niedermayer a ?crit?:
> > our mpeg2 decoder can decode mpeg1 and 2, libmpeg2 can also
> > and iam sure there are mpeg2 decoders which would refuse mpeg1
> > and mpeg1 decoders which cant decode mpeg2
> Yes, but from the user point of view, there are two encoders and two
> decoders: mpeg1video_{en,de}coder and mpeg2video_{en,de}coder, the first
> being flagged with CODEC_ID_MPEG1VIDEO and the second with
> CODEC_ID_MPEG2VIDEO. The user does not know that they all rely on exactly
> the same functions.

users dont read avcodec.h or the doxygen docs about CodecID, its developers
who do and we should not attempt to hide such details from them otherwise
they for example might spend a lot of time writing code to distingush a
mpeg1 from a mpeg2 stream beliving they have to in order to decode it

> > also i think calling it "family" is not really clarifying anything
> Probably, but I can not find a better expression.

ive suggest a few options in a previous mail
for example
CodecID identifies the syntax and semantics of the bitstream

this is clear, codec family is not its just defining one ambiguous term
with another

> > Name of the codec implementation
> Ok.
> > > +    /**
> > > +     * Type of the codec: audio, video, subtitle, etc.
> > > +     */
> > >      enum CodecType type;
> > redundant
> Only if you remember that CodecType means audio/video/etc. But I do not
> insist on that one, I only added it because I documented the field above and
> the field below.

its seperate from codecid clarification so it belongs to a seperate patch
that said. if the user doesnt know what CodecType is she just clicks on
it in the doxygen docs, this is more effective than duplicating the docs
about every type every time a type is used


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

it is not once nor twice but times without number that the same ideas make
their appearance in the world. -- Aristotle
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