[maemo-developers] [maemo-developers] WMA streaming

[From: Siarhei Siamashka]

On Monday 13 November 2006 22:08, Andrew Barr wrote:

> What are my options for Windows Media Audio streams on the 770? Most
> Internet radio streams (I mean simulcasts of real broadcasts in this sense)
> are offered in (at least) this format, which is supported by free software
> (ffmpeg) up to version 2, the latest version I've ever seen anywhere.
> However, no one seems to have had any luck with third-party codecs on this
> device, much less for streaming. Is this device powerful enough to handle
> decoding audio streams using C or ARM-assembly codecs (from ffmpeg)? It's
> likely that the bitstream would be 16 to 24 kbps. I understand free tools
> for the DSP aren't quite there yet, so that may not be an option.

FFmpeg library contains WMA decoder and MPlayer supports it at least on 
x86 desktop PC. There are some problems with its support on ARM though.

First and the most easy to fix is that WMA decoder seems to have some
alignment problems, so it crashes on any attempt to play WMA files. This is
quite easy to workaround by running 'echo 3 > /proc/cpu/alignment' as root,
see https://maemo.org/maemowiki/PortingFromX86ToARM and the links at it 
for more information.

A major problem with WMA decoder is that it uses floating point math. And
having no FPU in hardware, Nokia 770 does not seem to be able to decode 
128kbps WMA files to play them in realtime (sound is skippy). So it is not
very useful unless somebody finds (or implements) a fixed point WMA decoder.

However I also tested 20kbps WMA sample and it worked fine with CPU load 
at about 60%. So if anybody would like to have such low bitrate WMA
files/streams supported, I can have a look at these alignment problems, fix 
them and release updated version of MPlayer for everyone to use.