[speex-dev] Chopping off the wideband?

Jean-Marc Valin jean-marc.valin at hermes.usherb.ca
Tue Feb 18 22:40:29 PST 2003


> Hmmm, define working and stable :)

By that I mean that you're fine with releasing it with your name on it
and not be afraid to get flamed.

> <braindump topic="speexcat">
> It began as a merge between speexdec and speexenc from 1.0beta3,
> with the encoding/decoding removed, and simply piped in and out from
> ogg streams. I never expected it would work joining different
> bitrate/encoding streams, but just then I tested joining an 8000Hz
> narrowband stream with a 16000 Hz wideband, and the output sounds
> pretty sane. The interface is:

Well, I'm guessing that if you join a narrowband and a wideband stream
with speexcat, you lose the high-band in the second part, right? To make
speexdec handle chained streams, it would have to handle new headers
with different sampling-rate, channels, ...

> Ideally, you should be able to specify the time as
> hours:mins:seconds.splitseconds rather than frame numbers (by bash
> you can just do $(((min*60+sec)*50)) but it's tacky).
> 
> I discovered the magic number 50 somewhere as being the number of
> speex frames per second... is this a universal constant that can be
> guaranteed?

Only if you use 8/16/32 kHz, otherwise the real value is
sampling-rate/samples-per-frame.

        Jean-Marc


-- 
Jean-Marc Valin, M.Sc.A.
LABORIUS (http://www.gel.usherb.ca/laborius)
Université de Sherbrooke, Québec, Canada

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