[MPlayer-users] mplayer 1.0rc3 - CPU load issues

[John Stirling]

We've compiled for arm and have an audio device fixed at 48829hz. We are 
having some issues with audio quality when we set this option
-af-adv force=2

If we remove the option then audio quality is fine, but CPU load goes up 
from eg 23% to 46% when playing M4A (44.1khz, 243kbps)

If we set these options
-af-adv force=2 -af resample=48829
the CPU load goes up eg from 23% to 40.1% when playing M4A (44.1khz, 
243kbps)

It seems like quite a big jump in CPU load just to deal with the 
resampling. A comparable test using eg helix goes from 34% -> 36%.

If we keep the option in but provide the audio clocks externally so 
there is no need for resampling audio quality seems fine.

Some questions

. Does the increase in CPU load when switching from force=2 to force=1 
sound about as expected
. Does the increase in CPU load when switching from [-af-adv force=2] to 
[-af-adv force=2 -af resample=48829] sound about as expected
. When the audio device natively supports the sample rate of the source 
content will -af-adv force=2 have a (or much) negative effect on audio 
quality. It seems fairly good to me..

We'd ideally like to keep CPU load close to what we're seeing with 
[-af-adv force=2] but without the audio quality issues. I suspect we 
need to make the audio device natively support all frequencies but would 
prefer a software solution. I notice ->mul is a double which might be 
having some effect when resampling is required...

Thanks
John











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