Sorry to drag up an ancient thread. I was wondering what specific modifications were needed for the general_work function of op25_decoder_ff.cc?

Does only returning synthesized frames work or does IMBE expect for some empty results to be inserted where there is no data to smooth things out? I am trying something similar using DSD and the WAV files I record with only synthesized data do not sound as good as audio played back with empty frames returned when no data is available.

Thanks for any tips you have!

Luke

--- In op25-dev@yahoogroups.com, "Balint" <balint256@...> wrote:

Dear all,

I've uploaded to the Files section of the board a new 'audio_p25_rx.py', which is the original file modified to output IMBE audio, and read/write WAV/float data files (since I don't have a USRP and use a discriminator tap).

Some notes:

# wx must be set to 'nongl' mode (widgets are the older non-OpenGL type)

# Make sure your ~/.gnuradio/config.conf has a '[wxgui]' section, which contains the line 'style=nongl'

#

# Voice output requires the environment variable 'IMBE' set to 'soft', AND modification to op25_decoder_ff.cc to prevent

# excessive zero values being output (which chops up the real output stream and produces too much silence) - this can

# be done by only producing 'general_work' output values when actual voice data is synthesised (i.e. return the number

# of synthesised samples produced and don't pad the output buffer with silence)

#

# If you want to capture using Wireshark, don't forget to run this as root!

# Use the '-w' wait option, then start Wireshark and begin capturing, then return to your terminal and hit any key.

In addition, I've found that software_imbe_decoder dies sporadically at 'decoder/src/lib/software_imbe_decoder.cc:1022'. I believe this is because the class member variable 'OldL' is left un-initialised, and used as such on line 1018. Adding 'OldL = 0;' to the class constructor (line 756) appears to fix the problem (and causes the 'OldL == 0' check on line 1005 to kick in).

Please let me know if you try the new Python code and have any problems.

Balint