Hi again. We have the etsi cdecoder and speech decoder which works fine with sample code what we need is to link it with real time bitstream from osmo tetra decode. I understood this had already been achieved with Dieter's proof of concept code. Any chance of viewing this code even if incomplete ?. regards. graham
________________________________ From: "tetra-request@lists.osmocom.org" tetra-request@lists.osmocom.org To: tetra@lists.osmocom.org Sent: Saturday, 24 September 2011, 16:04 Subject: tetra Digest, Vol 9, Issue 3
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Today's Topics:
1. Re: tetra Digest, Vol 9, Issue 2 (Graham Palmer) 2. Re: play the voice signal ? (Dieter Spaar) 3. Re: play the voice signal ? (Pepijn van den Berkhof) 4. Re[2]: play the voice signal ? (Mccauley) 5. Re: play the voice signal ? (Holger Hans Peter Freyther) 6. Re: play the voice signal ? (Dieter Spaar) 7. tetra voice (fe8769)
Hi all I am still learning this level of coding. I am struggling to get the descrambled bitstream from the lower mac to the
channel decoder of the etsi codec. My setup has no problem decoding the data and reading it with Wireshark. Any help would be appreciated. Best regards. Graham
________________________________ From: "tetra-request@lists.osmocom.org" tetra-request@lists.osmocom.org To: tetra@lists.osmocom.org Sent: Saturday, 24 September 2011, 11:00 Subject: tetra Digest, Vol 9, Issue 2
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Today's Topics:
1. play the voice signal ? (Bigsat) 2. Re: play the voice signal ? (Dieter Spaar) 3. Re: play the voice signal ? (Pepijn van den Berkhof) hi,
I am using "fcdp-tetra_demod.py" with my funcube dongle and i can decode datas. The networks in my place are unencrypted. I saw on the "Dieter Spaar's blog" :
"I also implemented some proof of concept code which allows decoding speech traffic and converting it to raw audio using the TETRA reference codec. Please note that this cannot be used to listen to encrypted TETRA traffic, it only works if no encryption is used. "
Is it possible to release some part of the code necessary to decode Tetra voice or give some explaination of Gsmtap usage ?
thanks for answer
Hello Bigsat,
On Fri, 23 Sep 2011 13:49:43 +0200, "Bigsat" bigsat@gmail.com wrote:
Is it possible to release some part of the code necessary to decode Tetra voice or give some explaination of Gsmtap usage ?
Just in case, I have sent my "proof of concept" modification for voice decoding to the authors of Osmocom TETRA for proper integration a while ago. As far as I am aware the current source code should be able to decode voice or at least contain the instructions how to do it (the ETSI reference codec is most certainly not included for copyright reasons).
Best regards, Dieter
On Sat, Sep 24, 2011 at 8:56 PM, Graham Palmer graham.palmer69@yahoo.co.uk wrote:
Hi again. We have the etsi cdecoder and speech decoder which works fine with sample code what we need is to link it with real time bitstream from osmo tetra decode. I understood this had already been achieved with Dieter's proof of concept code. Any chance of viewing this code even if incomplete ?.
It doesn't apply anymore because of a lot of change in the code since then.
This should save the data in the bursts : 1) It's completely untested but that's where Dieters POC got the bits previously 2) It saves the data as '0' and '1' in a text file, you may need to change the etsi codec to read that 3) It will only give out garbage is there is multiple voice channel at once since it doesn't do any meta data interpretation to isolate channels and just save anything that's traffic (that was a limitation of dieter's POC as well) 4) I'm pretty sure it saves 'packet data' as well which obviously gives garbage.
diff --git a/src/lower_mac/tetra_lower_mac.c b/src/lower_mac/tetra_lower_mac.c index 7b62bb4..8a41ccb 100644 --- a/src/lower_mac/tetra_lower_mac.c +++ b/src/lower_mac/tetra_lower_mac.c @@ -184,6 +184,15 @@ void tp_sap_udata_ind(enum tp_sap_data_type type, const uint8_t *bits, unsigned DEBUGP("%s %s type4: %s\n", tbp->name, time_str, osmo_ubit_dump(type4, tbp->type345_bits));
+ if (tms->cur_burst.is_traffic) { + FILE *f = fopen("traffic.out", "ab"); + + for(i = 0; i < 216*2; i++) + fprintf(f, "%d", bits[i]); + + fclose(f); + } + if (tbp->interleave_a) { /* Run block deinterleaving: type-3 bits */ block_deinterleave(tbp->type345_bits, tbp->interleave_a, type4, type3);
-
Graham Palmer -
Sylvain Munaut