Hydrogenaudio Forums > speex_encoder_ctl always returning 0 (DTX)

Full Version: speex_encoder_ctl always returning 0 (DTX)

Hydrogenaudio Forums > Lossy Audio Compression > Speech Codecs

JimmyJames

Jun 23 2005, 08:00

I'm currently playing with the Asterisk source code getting it to support Speex DTX mode. There are a few bugs left to sort out but one of the problems I've got is determining if a given frame in DTX is silent and need not be transmitted.

The libspeex API reference guide says that a call (any call?) to speex_encoder_ctl should return 0 in the case of silence (and 1 otherwise) but every time I call it I get a return value of 0, regardless of whether there's silence or not.

I'm currently trying to doing a:

CODE

int dtx_transmit = speex_encoder_ctl(tmp->speex, SPEEX_GET_FRAME_SIZE, &tmp->framesize);

After every call to:

CODE

speex_encode(tmp->speex, fbuf, &tmp->bits);

Has anyone been able to determine silence status using speex_encoder_ctl? Please let me know if I'm using it incorrectly.

Thanks,

James

JimmyJames

Jun 23 2005, 08:28

Hold the phone...

It seems that speex_encode returns the dtx-silence flag, as would make sense, rather than speex_encoder_ctl as claimed in the documentation.

The lesson here? Never trust an API

jmvalin

Jun 24 2005, 05:51

QUOTE (JimmyJames @ Jun 23 2005, 04:28 PM)

Sorry about that. I fixed it in SVN. Any other stpuid thing in the API doc?

JimmyJames

Jun 24 2005, 06:01

QUOTE (jmvalin @ Jun 24 2005, 03:51 PM)

Sorry about that. I fixed it in SVN. Any other stpuid thing in the API doc?

No worries Jean-Marc.

The only other problem I noticed in the codec manual is in section 4.5

QUOTE

That terminator consists of the code 15 (decimal), encoded with 5 bits, as shown in figure 4.

with no figure 4 shown. Not that we need a figure anyway.

Thanks for all your work putting Speex together - great piece of software!

jmvalin

Jun 27 2005, 05:17

QUOTE (JimmyJames @ Jun 24 2005, 02:01 PM)

The only other problem I noticed in the codec manual is in section 4.5

QUOTE

That terminator consists of the code 15 (decimal), encoded with 5 bits, as shown in figure 4.

with no figure 4 shown. Not that we need a figure anyway.

Thanks for all your work putting Speex together - great piece of software!

Oops... I meant *Table* 4.

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