[FFmpeg-devel] [PATCH] Test pattern generator

Michael Niedermayer michaelni
Wed Oct 17 21:33:27 CEST 2007


On Wed, Oct 17, 2007 at 12:52:19PM +0200, Nicolas George wrote:
> Hi.
> Le quintidi 25 vend?miaire, an CCXVI, Michael Niedermayer a ?crit?:
> > yes and i was just about to reject this one as well :)
> > 
> > theres no sense in bloating libavformat up with such "demuxers"
> > if anyone wants that it can be done by a small program using libavformat
> > like output_example.c or apiexample.c
> As a matter of principle, you are right.
> But I decided to make it an internal module for the following practical
> considerations:
> - The purpose is to make troubleshooting easier by reducing the possible
>   causes of problems. Having the stream in a separate tool means a few more
>   possible cause of problems: the test pattern needs to be muxed, piped and
>   then demuxed, causing possible A-V desync and pipe problems.
>   By the way, I have no idea what would be the best muxer to pipe raw RGB
>   video and PCM audio.

and if you are affraid of the libavformat avi muxer not working properly
it should be quite easy to just hardcode the few bytes of the avi header
which are needed like in 
const uint8_t header[]={...}; 
fwrite(header, header_len)
and then have a simple loop which writes the raw frames with their length and
stream number, thats all, you dont need anything else to make a working avi

> - People will never have the test pattern generator near at hand when they
>   need it, especially when people on the -users mailing-list tell them to
>   try it. This would cause some more mail exchanges.
> Now, I would be perfectly happy to turn this test pattern generator into a
> separate program (provided I get advice on the muxer to use), but I am
> afraid this would impair its usefulness.
> By the way, I totally agree with the fact that a test pattern generator has
> nothing to do in a library of audio and video formats. But video4linux and
> x11grab are not audio-video formats either, are they?

no, and they shouldnt be in libavformat, we just lack of vounteer to
add a new libavsomething and move them there

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Those who are too smart to engage in politics are punished by being
governed by those who are dumber. -- Plato 
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