View Full Version : OGG Vorbis on DSP
04-03-2008, 08:44 PM
I was wondering if there is anyone working on a DSP-based ogg-vorbis codec? Is the mogg codec ( https://garage.maemo.org/projects/mogg ) using the dsp? I couldn't find any information about that and the discussions on this board kinda ended inconclusively about DSP support for OGG Vorbis?
04-04-2008, 02:10 AM
I believe there is no DSP-based OGG support, only SW-based. It's been asked from Nokia quite a lot, but they still haven't come through.
04-04-2008, 03:08 AM
I was wondering if there is anyone working on a DSP-based ogg-vorbis codec?
Yes, search maemo-developers list or check this http://maemo.org/community/wiki/dspprogramming/ for further pointers.
04-04-2008, 04:37 AM
This is a DSP based OGG Vorbis decoder: https://garage.maemo.org/projects/dsp-tremor/
I hasten to add that although it runs, it doesn't yet recognise a vorbis stream as being valid. I'm working through the code to see where it produces a different function call list/outputs to the standard lowmem-no-byte code running on x86 (for convenience).
The reason for the differences in the first place is that the DSP uses a 16bit char; this means that quite a lot of code has to be altered (i.e. things like bitreading code and CRC calculation so far amongst other smaller and less centralised bits). There is still more to be altered, especially the iDCT code.
There's been no changes to the project since earlier in the year as I've been away on holiday (3 weeks) then very busy since I got back. I am planning to get cracking again though. Take a look at the news item and the mailing list for that project to give my current status.
Help gladly accepted! Either send an email to the dsp-tremor-devel list, or give me a shout on irc (#maemo) if you're interested. I'm happy to help people setup their toolchains, etc., and even if you don't want to do that, thoughts/patches on how to change various functions to handle the 16bit char will take some of the work off my back.
04-04-2008, 04:50 PM
Cool, I'll definitly have to take a look at the code when I get more time. (finishing thesis right now)
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