[maemo-developers] DSP vs CPU for multimedia,Re: [maemo-developers] Audio enabled dev-platform?

[From: Devesh Kothari]

ext Frantisek Dufka wrote:

>BTW, did you think about using main CPU for decoding multimedia too? I 
>was a bit shocked when playing the Ice Age trailer and saw in load 
>plugin that main CPU is completely idle and both video and audio is 
>decoded by DSP. I have no benchmarks or practical experience so far but 
>from the documentation about C55x and ARM926TEJ it looks like the main 
>cpu with edsp instructions could do similar work in similar speed as DSP 
>does. If multimedia jobs could be distributed across both cpus (like dsp 
>doing audio and color conversion into framebuffer, mpu decoding video) 
>we could see higher resolution or frame rates.
>
>  
>
I am not an expert in this area, but if I understand correctly the
way it is architected is that n770 has gstreamer dsp sinks for different
formats like mp3 etc which work using DSP gateway with their
counterpart on the DSP. DSP controls all the audio rendering hardware.
But I think it should still be possible to construct a gstreamer pipeline
which would for example do ogg decoding on arm side and feed to the
DSP PCM sink or something. But  I am just reasonably guessing :)

>Is the gstreamer framework able to support more implementations for same 
>codec (DSP vs CPU) and chose one based on priority? Will the stuff you 
>are talking about releasing in future be enough for hacking in this area?
>
>  
>
You can hack I guess even today, but you would have to try it on the
real product. You cant try it on the developer rootfs, which gives you
a lot many other tools too, which ease development and hacking.

check
http://repository.maemo.org/pool/maemo1.1rc7/free/source/g/gstreamer0.8-osso/

Devesh

>Frantisek
>
>Devesh Kothari wrote:
>
>  
>
>>improving multimedia support is one of priority area. I hope we are able
>>to push that out. Just to let you know we are working on it :) AFAIK it
>>is mostly issues related to redistribution of the DSP side stuff (even
>>in binary) which would enable the layer below DSPGateway.
>>
>>Devesh
>>
>>    
>>
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