| Author |
Message |
Tom
Guest
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 Posted:
Thu Jan 06, 2005 7:22 pm Post subject:
AEC on two different devices |
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Hi,
I'm working on an acoustic echo canceller but I
can't get it to work when two different devices
are used for recording and playback.
I believe that this is because the near end signal
is recorded at a slightly different samplerate than
the samplerate by which the far end signal is played.
If someone has any idea on how to solve this problem,
please let me know.
Any help/pointers would be appreciated a lot.
Tom. |
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balchand
Guest
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| Posted:
Thu Jan 06, 2005 9:17 pm Post subject:
Re: AEC on two different devices |
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what technique u are using for that. an adaptive cancellation method
would easily tolerate slight differences in sample rates |
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Tom
Guest
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| Posted:
Thu Jan 06, 2005 9:43 pm Post subject:
Re: AEC on two different devices |
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I'm using a block frequency domain adaptive filter (which is
the LMS adaptive filter in the frequency domain).
But if I use a sample with samplerate 8000 for the far signal
and the same sample, resampled to 8001, then the filter does
NOT converge.... |
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Stephen Maudsley
Guest
|
| Posted:
Sat Jan 08, 2005 3:54 pm Post subject:
Re: AEC on two different devices |
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Tom wrote:
| Quote: | Hi,
I'm working on an acoustic echo canceller but I
can't get it to work when two different devices
are used for recording and playback.
I believe that this is because the near end signal
is recorded at a slightly different samplerate than
the samplerate by which the far end signal is played.
If someone has any idea on how to solve this problem,
please let me know.
Any help/pointers would be appreciated a lot.
|
The H.323 standard has to resolve some of these clock issues for
audio/video sync - can't remember haw it does it but might be worth
reading the specs. |
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Steve Underwood
Guest
|
| Posted:
Sun Jan 09, 2005 7:57 am Post subject:
Re: AEC on two different devices |
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Stephen Maudsley wrote:
| Quote: | Tom wrote:
Hi,
I'm working on an acoustic echo canceller but I
can't get it to work when two different devices
are used for recording and playback.
I believe that this is because the near end signal
is recorded at a slightly different samplerate than
the samplerate by which the far end signal is played.
If someone has any idea on how to solve this problem,
please let me know.
Any help/pointers would be appreciated a lot.
The H.323 standard has to resolve some of these clock issues for
audio/video sync - can't remember haw it does it but might be worth
reading the specs.
|
H.323 is just a telephony signalling protocol. It gets the audio and
video connected between the two (or more) parties, and gets out of the
way. The only video/audio signal negotiation it assists with is chooisng
which codecs are to be used.
Regards,
Steve |
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