[FFmpeg-user] Efficient Audio encoding from a PI

Kai Hendry hendry at iki.fi
Fri Aug 2 09:51:50 CEST 2013

Hi there,

I'm trying to stream audio from a Raspberry PI with a USB attached
GOMIC. The problem is when I try HTTP Live Streaming [1] with h/w
encoded video & aac audio I get ALSA xruns:

Not quite sure what a "xrun" actually is. I'm going to guess an under
run, since the PI 's CPU seems maxed out.

If I just run the audio process, without video:
ffmpeg -f alsa -ac 1 -i hw:1,0 -acodec aac -strict experimental -y

I can see it's taking 70% of my PI's CPU! Is there some good
strategies to make the voice perhaps lower quality and hence less
likely max CPU and pause / stutter on playback?
I don't know what settings to play with.

I believe I have to use the "aac" codec, since we want it to work from IOS.

Many thanks!

[1] https://github.com/AndyA/psips

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