Hi, We have an application in our institute that will require recording of a digital signal via an optical cable. We have to be able to guarantee perfect bitwise reproduction of the signal (the odd bit error is not a problem). We're thinking of using SPDIF and ALSA to capture the signal (obviously we'll have to make sure the signal is properly encoded to begin with). However, after some initial attempts, it's becoming clear that ALSA can't necessarily guarantee bitwise perfect capture. ALSA might change the format, or resample the signal after capture (although I've heard that can be turned off with "snd_pcm_hw_params_set_rate_resample (capture_handle, hw_params, 0)"). Also, the card that we've been playing with so far (SB Audigy2 ZS) apparently performs some low-pass digital filtering on the input stream anyway, and is therefore no use to us. So my question is: can this be done? Is there a way of setting up ALSA to produce an unaltered version of the SPDIF input stream? This will undoubtedly require a particular combination of hardware and driver. If so, which card/driver would be recommended? Ideally, we would like to capture the raw SPDIF subframes. Is that possible, and if so, how? Any help would be greatly appreciated! Thanks, Donald. -- Jacques-Donald Tournier (PhD) Brain Research Institute, Melbourne, Australia Tel: +61 (0)3 9496 4078 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
