[RFC] Summer of Code -- OSSv4 audio compatibility

Yuriy Tsibizov Yuriy.Tsibizov at gfk.ru
Wed Aug 23 07:51:58 UTC 2006

> Hello, current@ & multimedia@!
> ====== Summary ======
> I participated in Google's Summer of Code this year, working on adding
> support for 4Front's OSSv4 API.
> Unfortunately, more of the API specifications were still under
> construction than I expected, so I focused entirely on the audio
> collection of ioctls and maybe just one or two mixer ioctls.  While
> official documentation isn't yet available, the mixer 
> extensions, which
> are one of the coolest parts of the new API, are my top priority.  (I
> think I now have enough reference material to begin work in 
> that area.)
> For information on the ioctls, please take a look at
> http://wiki.freebsd.org/RyanBeasley/ioctlref .
> ====== Patch Info ======
> A patch against recent -CURRENT is available at
> http://www.leidinger.net/FreeBSD/sound/rbeasley_sound.diff .
> Comments, suggestions, etc., would be hugely appreciated!
Ryan, will there be any changes for hardware drivers?

And, as I know you have emu10kx-compatible sound card, can you 
test your sound buffering changes with EMU_PLAY_BUFSZ set to 
EMUPAGESIZE*2 or larger (dev/sound/pci/emu10kx.h, line49).

With 4K (=EMUPAGESIZE) playback buffer sound does not has lag or lost
samples, but there was problems
with large one

On opposite side, with small buffer I have a lot of noise when my system
has a lot of disk activity or kernel printf's.

You can use http://www.linksplace.com/wavsounds/pong.wav as a good
sample of "bad file" for large buffer.


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