Hi David I have realized the code. The tests with files runs ok. But on the outputstream on the rx-side, I have to upsample again to 48kHz (from 8kHz after codec2-decoding). But here I get again 640 Samples, which, wenn upsampled will only give 3840 S. But on the input, I have to use 4096 Samples to get the 640 from freedv. So, there is again a mismatch. Currently, I fill in 0-samples, when the supply from the freedv does not fulfil the requests. This is not a critical problem, since it is on the audio output side, but I want to be exact.
But probably, I miss again a point. Alfred On 20.08.2015 22:05, David Rowe wrote: > Hi Wully, > > The input sample rate for the speech samples is 8000Hz, output sample > rate for modem (in 700(B) mode) is 7500Hz. > > So with the 80ms frames that 700 uses: > > input speech: 8000 samples/s * 0.08s = 640 samples > modem output: 7500 samples/s * 0.08s = 600 samples > > - David > > On 20/08/15 22:57, wully wrote: >> Hi >> >> I am implementing the 700 mode now. First, I want to transmit. >> But I have a problem: >> >> When i ask for the speech- and modemsamples by >> >> speechsamplecount = freedv_get_n_speech_samples(freedv); >> modemsamplecount = freedv_get_n_nom_modem_samples(freedv); >> >> >> I get 640 for the speech, which is ok for processing the data at 7500 Hz >> samplerate. >> (Starting from 48kS/s downsampling). >> >> But the modemsamplecount reads 600. >> >> So, this would mean, that in my flow of speech at 7500Hz I would not get >> the necessary amount of >> samples (the same). I don't understand this. When I get only 600 >> modemsamples, my flow >> comes into starvation. >> >> What do I miss here? >> 73, hb9epu, Alfred >> >> >> >> >> ------------------------------------------------------------------------------ >> _______________________________________________ >> Freetel-codec2 mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 >> > ------------------------------------------------------------------------------ > _______________________________________________ > Freetel-codec2 mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 ------------------------------------------------------------------------------ _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
