[Speex-dev] frame_size parameter

danflu at uninet.com.br danflu at uninet.com.br
Tue Mar 10 15:12:43 PDT 2009


I'm using the echo cancellation api and I would like to
clarify the 'frame_size' parameter used in

In the 'docs' it says:

"...where frame_size is the amount of data (in samples)you
want to process at once..."

So... here are my questions:

if I use stereo input/output do I have to put the samples
doubled ?
For example... if I'm using 100 ms on mono 8khz I just pass
800 as 'frame_size', but if I switch on using stereo will I
have to put 1600 samples to represent the same 100 ms? I'm
looking at the code of 'speex_echo_playback' and I see the
following snippet:

for (i=0;i<st->frame_size;i++)
    st->play_buf[st->play_buf_pos+i] = play[i];

So... if my buffer is stereo and I put 800 samples as
'frame_size' the previous loop will just copy half of the
'play' buffer data (50 ms) or am I missing something ?

Thanks in advance,

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