[speex-dev] @Christian Buchner: speex acm & netmeeting

[Christian Buchner]

Hi,

> I managed to get the codec into netmeeting. Unfortunately it doesn't 
> properly work. I tried to talk vie net, but only erranous packets are 
> decoded. Did I possibly register the codec wiht incorrecxt parameters or 
> is this a problem of the acm codec?

I can't tell why. Try to register mode 8kHz Mono mode Q3 or Q4 for
Netmeeting. Only these modes pack exactly 1 speex frame into one data
packet. That ensures lowest latency. Q0-Q2 in contrast pack 8 frames
into a packet which is inacceptable for realtime conversation. Q5
and upwards use 2 frames. All this is defined in codec.c in the
QualityInfo[] table.

The columns given below are
- Bits per Speex frame
- framesize (160 samples in NB mode)
- Speex Frames per Packet (see Wave nBlockAlign)
- effective bitrate in kbit/s

here's an excerpt for the 8kHz Mono modes

           43, 160,	8,	2150,	//	8000 1 0   !! extremely bad for NM
           79, 160,	8,	3950,	//	8000 1 1   !! (high latency)
          119, 160,	8,	5950,	//	8000 1 2
          160, 160,	1,	8000,	//	8000 1 3   !! Good mode for Netmeeting
          160, 160,	1,	8000,	//	8000 1 4   !! Good mode for Netmeeting
          220, 160,	2, 11000,	//	8000 1 5
          220, 160,	2, 11000,	//	8000 1 6   !! all these have
          300, 160,	2, 15000,	//	8000 1 7   !! so-so latency...
          300, 160,	2, 15000,	//	8000 1 8
          364, 160,	2, 18200,	//	8000 1 9
          492, 160,	2, 24600,	//	8000 1 10

<p>I would be interested in seeing the code for registering the Speex codec
with Netmeeting.

Christian

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