[alsa-devel] Noisy audio - ALSA Configuration

Iovescu, Magdalena m-iovescu1 at ti.com
Wed Aug 15 23:03:54 CEST 2007

Does anyone have examples or documentation on how to configure periods,
frames and buffers for various sample rates?

I am writing a program to route a mp3 decoder output to ALSA on an ARM
processor, and I get noisy audio. For a CD quality stream (S16_LE, 44100
kHz, Stereo, 128 bps) I am using an output buffer of 44100 bytes, a
period of 44100/(channels*2). With a buffer this big, I do not get
underruns, but all the writes are short writes. I have not been able to
find the right configuration to avoid short writes, and more
importantly, to get good quality audio.

What do 'short writes' (I am using writei) really mean? Is this a
performance issue in the driver, or is mainly because of buffer setup?

I would really appreciate any help with this.


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