[speex-dev] frame size
marc at wimba.com
Thu Oct 23 08:34:16 PDT 2003
Framesize always refers to the decoded data frame size in samples.
Framesize is dependent on the encoding mode
Narrowband (8kHz): framesize = 160 samples = 320 bytes of PCM
Wideband (16kHz): framesize = 320 samples = 640 bytes of PCM
Ultra Wideband (32kHz): framesize = 640 samples = 1280 bytes of PCM
The size of the encoded data depends on the quality setting, so if you
know for instance that you are using quality 3 on narrowband, that is
119 bits of encoded data per frame which is rounded to 15 bytes per
frame (without counting the ogg headers). If you are using VBR then the
number of bytes used to encode each frame (which says fixed in size)
If you have any other questions, don't hesitate to ask
Head of research
Ulrich B. Staudinger wrote:
> i have a simple question about speex frame size.
> i work with jspeex - but i think it's speex generic, the question i have.
> can i use any frame size i want? or does the size have be in a certain
> ratio to other numbers? and what does the frame size in the decoder
> mean? encoded or decoded packet frame size?
> how much data can i hand to the encoder to encode?
> if i hand i.e. 400 bytes to the encoder, what will i have in return?
> 180 bytes of encoded data?
> in gsm it was all so simple... i have 320 bytes and get 133 in return
> .... (i think those were the numbers).
> thanks for an answer,
--- >8 ----
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