[Speex-dev] Re: aec

[Jean-Marc Valin]

First try your test #4 (same signal and offset) and swap the inputs.

	Jean-Marc

Le mercredi 09 novembre 2005 à 22:44 -0800, Jason Harper a écrit :
> I'm pretty much sure of it.  When I test inverting the
> inputs, my output is pretty much the same as my
> speaker signal.  Whereas the way that I normally test
> the output is my mic signal with very little
> attenuation.
> If you are interested I can send my test files; they
> are about 94KB each.
> 
> -Jason
> 
> --- Jean-Marc Valin <jean-marc.valin at usherbrooke.ca>
> wrote:
> 
> > Are you sure you're not just inverting the two
> > inputs?
> > 
> > 	Jean-Marc
> > 
> > On Wed, 2005-11-09 at 22:16 -0800, Jason Harper
> > wrote:
> > > I ran some further tests on mdf and here are the
> > > results:
> > > 1. reduced tail length to 100ms, aligned mic and
> > > speaker signals to within 10ms - almost no echo
> > > attenuation
> > > 2. aligned mic and speaker signals to within 5
> > samples
> > > - still almost no echo attenuation
> > > 3. ran testecho using the same file for mic and
> > > speaker - very good echo cancellation (of course
> > this
> > > is expected, but I needed to do a sanity check)
> > > 4. ran the same file for mic and speaker, but had
> > the
> > > mic signal delayed by 10ms - OK echo cancellation,
> > but
> > > noticeably degraded over previous test
> > > 5. same file for mic and speaker, but mic signal
> > > delayed by 40ms - noticeable echo attenuation, but
> > > still a large echo.
> > > 
> > > So far my testing is only showing good echo
> > > cancellation when the exact same file is being
> > used
> > > and is pretty closely aligned.
> > > 
> > > -Jason
> > > 
> > > --- Jean-Marc Valin
> > <Jean-Marc.Valin at USherbrooke.ca>
> > > wrote:
> > > 
> > > > This kind of behaviour is odd. One of the reason
> > > > could be the fact that
> > > > you're using a really long impulse response. Try
> > > > syncing your signals
> > > > and making the tail length more in the order of
> > 100
> > > > ms to 300 ms.
> > > > 
> > > > 	Jean-Marc
> > > > 
> > > > Le dimanche 06 novembre 2005 à 21:25 -0800,
> > Jason
> > > > Harper a écrit :
> > > > > Thanks for alerting me to the new changes.  I
> > just
> > > > > tried the latest code from SVN, but
> > unfortunately
> > > > I
> > > > > still have just about the same results.  The
> > > > estimated
> > > > > echo that gets subtracted from the actual echo
> > is
> > > > such
> > > > > a small signal that it doesn't really result
> > in
> > > > any
> > > > > noticeable echo attenuation.
> > > > > I currently have my filter size set to 2
> > seconds
> > > > even
> > > > > though the echo in my microphone file is only
> > > > about
> > > > > 180ms delayed from the signal in my speaker
> > file. 
> > > > I
> > > > > also double checked that the endianess of my
> > is
> > > > > correct, and that I am providing the files to
> > > > testecho
> > > > > in the correct order.
> > > > > Do you think that there could be some
> > > > characteristics
> > > > > to my echo that make it not work with the mdf
> > > > > algorithm?  How much echo attenuation should I
> > > > expect
> > > > > from the mdf algorithm before the preprocess? 
> > Are
> > > > > there any test speaker and mic files that I
> > could
> > > > run
> > > > > against testecho to see how it handles other
> > > > acoustic
> > > > > echos?
> > > > > 
> > > > > -Jason
> > > > > 
> > > > > --- Jean-Marc Valin
> > > > <Jean-Marc.Valin at USherbrooke.ca>
> > > > > wrote:
> > > > > 
> > > > > > I've recently made changes to the AEC.
> > Please
> > > > try
> > > > > > the code in SVN and
> > > > > > see if it works better.
> > > > > > 
> > > > > > 	Jean-Marc
> > > > > > 
> > > > > > Le jeudi 03 novembre 2005 à 22:36 -0800,
> > Jason
> > > > > > Harper a écrit :
> > > > > > > I've tried some further debugging to see
> > what
> > > > mdf
> > > > > > is
> > > > > > > actually doing.  Instead of sending:
> > > > > > > tmp_out = (float)ref[i] -
> > > > st->y[i+st->frame_size]
> > > > > > > to the output, I just sent
> > > > > > > st->y[i+st->frame_size]
> > > > > > > to see what was being subtracted from the
> > > > > > microphone
> > > > > > > input.  When I open this in Audacity, I
> > see a
> > > > very
> > > > > > > small signal at about -40dBm.  The actual
> > echo
> > > > in
> > > > > > my
> > > > > > > sample has a power closer to -20dBm.  So,
> > when
> > > > the
> > > > > > > -40dBm estimated echo is removed from the
> > > > -20dBm
> > > > > > > actual echo there is almost no perceived
> > > > > > difference in
> > > > > > > the echo power.
> > > > > > > I'm sure that there are others on the list
> > > > that
> > > > > > have
> > > > > > > had good success with the echo
> > cancellation
> > > > > > module. 
> > > > > > > Could anyone point me to reference test
> > files
> > > > that
> > > > > > are
> > > > > > > known to work well in testecho.
> > > > > > > I'd like to figure out if there is some
> > > > > > characteristic
> > > > > > > of my echo that makes it incompatible with
> > > > this
> > > > > > echo
> > > > > > > cancellation algorithm, or whether there
> > is
> > > > just
> > > > > > some
> > > > > > > configuration problem in my
> > implementation.
> > > > > > > Thanks for your time; advice is greatly
> > > > > > appreciated.
> > > > > > > 
> > > > > > > -Jason
> > > > > > > 
> > > > > > > ---
> > > > > > > > I have incorporated the speex echo
> > > > cancellation
> > > > > > into
> > > > > > > > my softphone project, but wasn't getting
> > > > great
> > > > > > > > results.  I decided to simplify the
> > problem,
> > > > by
> > > > > > > > recording speaker and mic files and
> > running
> > > > > > > > testecho. 
> > > > > > > > I've been pretty happy with the
> > preprocess
> > > > > > module
> > > > > > > > and
> > > > > > > > I wanted to focus on the mdf, so I
> > commented
> > > > out
> > > > > > the
> > > > > > > > call to preprocess in testecho.
> > > > > > > > When I run testecho my output file looks
> > > > almost
> > > > > > > > identicle to my mic file.  I don't see
> > any
> > > > > > reduction
> > > > > > > > in the power level of the echo.  I've
> > looked
> > > > > > through
> > > > > > > > some of the previous posts to this group
> > and
> > > > > > have
> > > > > > > > tried the obvious, such as increasing my
> > > > filter
> > > > > > > > length
> > > > > > > > and reversing the order of the files
> > passed
> > > > into
> > 
> === message truncated ===
> 
>