[FFmpeg-devel] [PATCH] libavdevice: JACK demuxer

Michael Niedermayer michaelni
Sat Mar 7 22:03:13 CET 2009


On Sat, Mar 07, 2009 at 06:05:06PM +0100, Michael Niedermayer wrote:
> On Sat, Mar 07, 2009 at 04:32:53PM +0100, Reimar D?ffinger wrote:
> > On Sat, Mar 07, 2009 at 04:10:32PM +0100, Michael Niedermayer wrote:
> > > What you didnt consider though is that we will need a similar buffer for OSS
> > > and possibly others, the jack ringbuffer cant be used for these.
> > > 
> > > because we cant use jacks ringbuffer we need our own no matter what amount of
> > > extra bugfixing that involves, using jacks ringbuffer in one piece of code 
> > > and our own in another is no gain it just means more code& more bugs.
> > > 
> > > and after rethinking the code, iam pretty sure any such buffer will need
> > > memory barriers on some cpus
> > 
> > Note that MPlayer already has about 3 implementations of such a ring buffer
> > (admittedly it assumes atomic reads and writes to ints) e.g. in
> > libao2/ao_sdl.c and libao2/ao_jack.c, a implementation in libavutil
> > would be welcome thus.
> > I was once thinking about just using fifo.c, but since it uses bytes
> > as basic unit (instead of a e.g. 1kB block), it allocates exactly one
> > additional byte, causing alignment issues after the first loop through
> > the buffer.
> 
> id love to see libavutil/fifo extended to fix the 1 byte issue and 
> whatever else is needed.

the 1 byte issue should be fixed
can you confirm that this is enough for mplayer or is more needed?

[...]


-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No snowflake in an avalanche ever feels responsible. -- Voltaire
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