similar to: Acoustic echo cancellation

> Hi, > > I have a scenario in a mobile VoIP app that requires echo cancellation but > is somewhat different from what's described in the docs. > > Audio is received from and sent to the network at 8000Hz. Each packet > contains 160 samples worth a playback of 20ms. > > But the hardware requires aggregation for both playback and capture. So for >

2011/4/20 Li Maoquan <limaoquan2000 at 126.com> > Simply to say, in a quiet room, you can play a impulse signal and then find > it's impulse response signal from the > microphone. For example, if the delay between the impulse signal and its > response signal range from 500 to > 3000 cycles, you can buffer the far-end signal to 0-300 cycles and set the > filter length

>>>> Hi, >>> >>> I have a scenario in a mobile VoIP app that requires echo cancellation but >>> is somewhat different from what's described in the docs. >>> >>> Audio is received from and sent to the network at 8000Hz. Each packet >>> contains 160 samples worth a playback of 20ms. >>> >>> But the hardware

Hi, I have a scenario in a mobile VoIP app that requires echo cancellation but is somewhat different from what's described in the docs. Audio is received from and sent to the network at 8000Hz. Each packet contains 160 samples worth a playback of 20ms. But the hardware requires aggregation for both playback and capture. So for playback, I coalesce 4 packets in a buffer and queue them as a

Simply to say, in a quiet room, you can play a impulse signal and then find it's impulse response signal from the microphone. For example, if the delay between the impulse signal and its response signal range from 500 to 3000 cycles, you can buffer the far-end signal to 0-300 cycles and set the filter length to 4000. It is also called to align far-end signal and near-end signal. BTW: Speex

>> Simply to say, in a quiet room, you can play a impulse signal and then find >> it's impulse response signal from the >> microphone. For example, if the delay between the impulse signal and its >> response signal range from 500 to >> 3000 cycles, you can buffer the far-end signal to 0-300 cycles and set the >> filter length to 4000. It is also called

_____ From: Mohammed Sulaiman [mailto:mhh.sulaiman@talk21.com] Sent: Monday, February 11, 2008 12:53 AM To: Dennis Liu Subject: RE: [Speex-dev] Echo Canceller on Windows Mobile Hi, thanks. One question did you use these 2 functions speex_echo_playback speex_echo_capture No, I didn't use them. I use my own code to buffer microphone and speaker data. or do you have your audio in

Hi So in your case if you don't want to use speex_echo_cancellation than you should do next way: Save the playback frames (clean echo) within separate playback thread with speex_echo_playback func. Then use speex_echo_capture - it will remove the clean echo frame (saved with speex_echo_playback func) from const spx_int16_t *rec buffer (saved with speex_echo_capture) and you will get

2006/11/2, Jean-Marc Valin <jean-marc.valin@usherbrooke.ca>: > > Today I tried speex echo cancellation on my VoIP application running > > on a windows mobile based PDA (OMAP1510 168MHz). The result is > > disappointing: it takes 150-250 ms to do echo cancellation (by calling > > speex_echo_capture() ) for a 20 ms frame! > > Are you by any chance using an insane

Well, I'm not a professional in AEC theory, but what I've mentioned is: speex_echo_state_init(20, 320*10) - frame size should correspond to 20ms. At your sampling rate (16000hz) is should be 16K*0.02 = 320. The same I can notice about echo tail. 100ms: 16000*0.3 = 4800, not 3200 as you has. But that's not crucial I think. Just wanna you get the point. "Internally,

Hello, i'm adding echo cancellation to my voip application, but when i call speex_echo_capture() or speex_echo_playback() causes an assertion failed, it seens that there is a delete in any where. i've encapsulated echo canceller in a class that storage the state and simply call the functions: void EchoCanceller::Playback(short *echo_frame) { speex_echo_playback(echo_state,

Hi Jean Marc, We are running the speex echo canceller code on a Windows Mobile smartphone using a TI OMAP 201MHz 850. We are making voip calls and audio is working without echo canceller code. Simply adding the following 2 functions whether the echo cancellation is wired in (ie we use the output frame ) or not performance becomes terrible. Note 2 separate threads are used to handle audio.

Hi Jean-Marc and all others! I am having some troubles with the echo cancellation feature of speex in a voip project. I have two threads, one for sound input and one for sound output. In the output thread, I call speex_echo_playback(). or every frame sent to the sound card. In the input thread, I call speex_echo_capture() for every frame captured from the sound card. Also, I do

As for me - speex_echo_cancellation is a better choise. Try using it in capture thread instead of those speex_echo_capture and speex_echo_playback functions. And please, describe your problem in details. Cause the fact that you "didn get echo cancellation" doesn't mean you are doing smth wrong. Regards, Anton A. Shpakovsky -----Original Message----- From: speex-dev-bounces at

On 01/19/2011 06:44 PM, LiMaoquan2000 wrote: > > Hi all, > > We have discussed so many about sampling rate asynchronous (or offset) > between rendering (D/A converter) and capturing (A/D converter) of > most PC soundcards. It seems all acoustic echo cancellers, include AEC > in speex, can not deal with this trouble, because it causes a drift of > echo path and also

On 01/20/2011 04:26 AM, Steve Underwood wrote: > On 01/19/2011 06:44 PM, LiMaoquan2000 wrote: >> Hi all, >> >> We have discussed so many about sampling rate asynchronous (or offset) >> between rendering (D/A converter) and capturing (A/D converter) of >> most PC soundcards. It seems all acoustic echo cancellers, include AEC >> in speex, can not deal with this

Anton A. Shpakovsky <saa <at> tomsksoft.com> writes: > > As for me - speex_echo_cancellation is a better choise. Try using it in > capture thread instead > of those speex_echo_capture and speex_echo_playback functions. > > And please, describe your problem in details. Cause the fact that you > "didn get echo cancellation" > doesn't mean you are

Hi Anton Thanks for the info... What if I use this function do I still need to sync the playback and capture? Assuming that the captured voice (*rec) already contains the echo which I need to cancel out... -------------------------------- void speex_echo_capture (SpeexEchoState *st, const spx_int16_t *rec, spx_int16_t *out) Parameters: st Echo canceller state rec signal

Hi All I am using speex in one of my WinCE project. I have been trying to use speex to perform denoise on the captured audio packet and echo cancellation. Following behavior I have observed while using various options. I would really appreciate if you could help me with the issues I am facing. 1. Denoise: I have written the following to code to perform denoise. //To initialize speex

I did the test on another PDA which runs XScale 416Mhz CPU, the EAC arithmetic could be done in 1ms, but for the previous PDA (TI OMAP 168Mhz), it take more than 100ms! Though EAC could run in time on the new PDA, it did no help to cancel the echo, here is my test scenario: Init echo_state: echo_state=speex_echo_state_init(160,1120); int tmp=8000;