Hi Matt,

Thanks for that report.

Cross comping on different platforms is a very useful way to find obscure C problem like uninitialized variables. Sounds like you've found one :-)

What SVN version are you using?

Pls email me a 700D encoded file (with teh bug) and I'll take a look.

Cheers,

David

On 15/06/18 06:05, Matt Roberts wrote:
I have been tinkering with the 700D version of the codec, and I found an interesting issue with respect to whether the machine producing the modulation.

This applies to the codec, *without* the audio hardware.  What I'm doing is encoding audio files into encoded DV audio files on different machines, then trying to decode them on another.  This can be reproduced using nothing more than the freedv_rx and freedv_tx utilities.

The sequence goes like this:

 1. Start with a clean WAV file, recorded from a microphone.
 2. Encoded the WAV file with freedv_tx ...
 3. Decode the output of #2 file with freedv_rx ...
 4. Play the result of #3 in Audacity, which also allows the waveform to
    be seen.

I can do this just fine with the 1600 codec, using any combination of Ubuntu Linux (U) and Raspbian.

With 700D, the U box can do the above sequence just fine. However, that's as far as it goes.  If I move the intermediate file between #2 and #3 from/to a RasPi device, the result is distorted audio at step #4.

The U box can't read RasPi encodings.  The RasPi can't read encodings from the U box.  The RasPi can't even decode it's own encodings.  But the U box can handle its own encodings.

I have been able to reproduce this on old RasPi 1 machines, and on newer 3B machines.  So it doesn't appear to be a hardware-revision-specific problem.

If anybody is interested in more detail, I'll try to produce some more data for you.

Still investigating...


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