[Speex-dev] VAD CPU usage

Nanang Izzuddin
Wed, 23 Apr 2008 04:56:03 -0000

Hi,

I experienced this problem as well when using speex in VoIP
application, I only tested the wideband mode:
- if silence is in the beginning, CPU is fine.
- if silence is in the middle (after voice), suddenly CPU increased
significantly.

I tried to reproduce the problem (in Mac/Linux):

* 1 second tone + 4 seconds silence
$ time ./speexenc -w --vad t400-sil-5s.pcm out-sil.spx
Encoding 16000 Hz audio using wideband (sub-band CELP) mode (mono)

real	0m0.650s
user	0m0.629s
sys	0m0.025s

* 5 seconds tone
$ time ./speexenc -w --vad t400-5s.pcm out.spx
Encoding 16000 Hz audio using wideband (sub-band CELP) mode (mono)

real	0m0.271s
user	0m0.246s
sys	0m0.028s

Attached is the PCM files used for this test.

Regards,
nanang


On 17/04/2008, Jean-Marc Valin <jean-marc.valin at usherbrooke.ca>
wrote:
> Sounds strange. Can you reproduce the problem with speexenc/speexdec? If
>  so, can you send a short file that triggers that along with the exact
>  command line?
>
>         Jean-Marc
>
>  Jozsef Vass a ?crit :
>
> > Hi Jean-Marc
>  >
>  > I am using speex in my voip app (wideband mode). I
>  > have noticed that when VAD kicks in, CPU considerably
>  > increases (bitrate decreases to 4 kbps). It takes
>  > about 7 ms to encode one frame versus 0.5 ms (for
>  > speech). This happens regardless preprocessor is used.
>  >
>  > Although the issue seems to be driver dependent, it
>  > occurs on XP, Vista and Mac OS X.
>  >
>  > Besides complexity and quality, this is the only
>  > parameter set for encoder.
>  >
>  > We use the latest released version, 1.2beta3.
>  >
>  > Are you aware of any possible problem in VAD?
>  >
>  > Thanks.
>  >
>  > Jozsef
>  >
>  >
>  >
>  >
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