Re: [Bluez-devel] sbc and fixed-point progress

Brad Midgley
2005-08-22T07:22:07Z

Victor

>> I do not have HW to test arm specific version real time, hope no
>> suprises there, but I could have missed something when integrating it
>> into sbc code (it decodes well, but how fast, I will try only monday
>> evening).
>
>
> Ok, I'll load it on gumstix now and give it a try.

This is almost perfect. On a 400mhz gumstix (pxa255), I'm able to send a
5-minute audio stream with only about three breaks in the audio (about 5
seconds each).

I think it will work flawlessly in 4 subbands or if we can shorten a few
of the ops from 64 to 32 bit.

I committed what's there and used __arm__ for the conditional asm code.

>> Using a2play needs to tweak 87 magic number, otherwise it drops samples?
>
>
> yes, this is disappointing. We may need to find another way to get
> reliable timing than setitimer.
>
> I did change the first usleep(10) to usleep(1000) and that *may* help
> with this problem by ensuring that we always interrupt the usleep
> syscall consistently. I don't have my hp headphones (the set that's very
> sensitive to timing) handy to test.

fwiw, I had to use the -n flag to a2play so it wouldn't use itimer at
all. This flag tells a2play to just send the audio as fast as it can
encode it.