[Speex-dev] 8.4kbps data rate in 8kbps nb mode

Andy White
2005-11-17T06:34:11Z

I know that most of the narrow band submodes don't have an exact multiple of
eight bits in each frame

79 bits for 3.95kbps
119 bits for 5.95kbps ...etc

This means that you have a few unused bits when transporting Speex in the Ogg
format (you can achieve a lower number of unused bits if you change the number
of frames per Ogg packet to suit the mode).

However, in 8kbps mode, the number of bits per frame is 160. I would have
expected this to fit into an Ogg segment 20 bytes long. However, when I use
(speexenc -n --quality 3) to encode at 8kbps the Ogg segments are each 21 bytes
long.

Is this an error, or is there extra information put in the 21st byte?

I'll have a hunt through the code, but thought someone might have come
across
this before.

Regards,

Andy