[Asterisk-Users] agi RECORD FILE with offset

[John Hammen]

Hi All,

I've been playing about with the RECORD FILE agi function and am
finding two distinct problems with the resulting wav file when using a
non zero sample offset. Specifically, I call the function with a zero
offset and a given filename (the "original" recording), and then later
call it with the same filename and a non-zero offset (the "overdub").
When I do this, I experience the following:

* The file has a strange signal superimposed on top of the normal
recorded sound signal, from exactly the offset sample forward. In
Audacity it looks like a perfect sawtooth wave, however one made up of
distinct sharp samples. Needless to say, this produces an annoying
buzzing sound on top of the normal sound from the offset point
forward, that is to say that the "original" recording with offset 0
sounds great, and then the buzzing begins with the "overdub" recording
starting at the non-zero offset from the second RECORD FILE call.

* This strange signal, along with the intended recording, abruptly
ends at the point at which the "orignal" recording ended, although the
agi function does not return from the second RECORD FILE call until
the proper escape digit is pressed. Also, the file length appears to
be consistent with NOT cutting off the overdub. So it seems like the
second RECORD FILE command actually runs to completion propertly, but
does NOT actually add any samples to the file after the length of the
original recording. This might be Audicity, however, just refusing to
show data past the end of the sample size as read in the wav file
header if, e.g. the header is not updated at the end of the second
call.

So, the my real question is whether or not these are known bugs, or if
perhaps I've configured something wrong. Has anybody actually ever
gotten this agi function to work properly while using a non-zero
offset? I haven't seen any examples or discussion of this before...

Any help, comments, etc. would be greatly appreciated...

Kind regards,
John