68 lines
2.4 KiB
Plaintext
68 lines
2.4 KiB
Plaintext
this is a small utility program illustrating the use of the new (2020)
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TRAU related blocks like I.460 mux, TRAU frame synchronizer, TRAU frame
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decoder and trau2rtp conversion.
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The only argument to the progrmam is the input file, which can either be
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* a DAHDI device like /dev/dahdi/chan/004/002 to use TS2 on span/line 4
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* a pre-recorded capture file containing raw binary 64k timeslot data
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The tool will automatically determine if a regular file or a DAHDI device
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was passed, and behave accordingly.
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== reading capture files
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There are FR and EFR exampel captures included.
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The input data (*.log.bz2) was generated using strace on an osmo-nitb process
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while a MO-to-MT call was running on two sub-slots of TS2.
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The strace log is converted to a binary stream of the raw 64bit E1 slot
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using strace-write-parse.py
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You can use the too like this:
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* start osmo-gapk as a RTP to ALSA sink like
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osmo-gapk -I 127.0.0.1/9999 -f gsm -g rawpcm-s16le -A default # for FR
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osmo-gapk -I 127.0.0.1/9999 -f rtp-efr -g rawpcm-s16le -A default # for EFR
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* run trau2rtp to read the bin file and generate RTP:
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./trau2rtp e1_ts2_fr.bin # for FR
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./trau2rtp e1_ts2_efr.bin # for EFR
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== Interfacing a DAHDI device
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It can be operated in two modes:
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a) local loop between sub-slots 1+2 (bit-offset 2 + 4), i.e. connecting the first
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two calls on a 'typical' TRX0 where the first sub-slot (bit-offset 0) is not
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used,
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OR
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b) interface between 64k TRAU slot and RTP. IP addresses + port numbers are
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compiled-in, you need to modify them accordingly.
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In mode "a", you can use it to have voice calls for low-level debugging without a media
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gateway.
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In mode "b", you can e.g. play back audio from an exterenal RTP source and listen to it
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over the GSM attached mobile phone.
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Command line for playing back EFR via RTP:
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./osmo-gapk -f amr-efr -i ../tests/ref-files/hhgttg_part1_5.s16.amr-efr -g rtp-efr -O 192.168.11.179/8002 -t -l
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Command line for playing back FR via RTP:
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./osmo-gapk -f gsm -i ../tests/ref-files/hhgttg_part1_5.s16.gsm -g gsm -O 192.168.11.179/8002 -t -l
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The '-l' option is experimental and requires gapk patch I2d552695dfb4cc96039838e79e0f5ae25a6737c8. If you want
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to use it with EFR, you need to change pq_file.c to skip the AMR file header when rewinding:
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- fseek(state->fh, 0, SEEK_SET);
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+ fseek(state->fh, 6, SEEK_SET);
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The code has been tested against BS-11 and RBS6000/DUG20 in both modes (loop vs. RTP) and for FR and EFR.
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