James Le Cuirot wrote: > > "Since compressed data is transmitted in place of PCM data, the bitrate > of the compressed stream must exactly match uncompressed stereo 16-bit > PCM bitrate. As a rule, compressed stream (even a multi-channel one) > having a lower bitrate, compressed stream must be padded with zeros to > match PCM bitrate." It might be helpful to ignore compressed (AC-3 or DTS) bitstreams and focus simply on a linear PCM bitstream. S/PDIF has no predefined bitrate and will transmit a 16/48 PCM bitstream at a different bitrate than a 24/96 PCM bitstream. As far as bringing AC-3 and DTS bitsteams back into the equation, exactly how that data is transmitted might be up to some padding rules. I don't know. I just assume that if I record the entire bitstream to storage I can then run a basic stream decoder over the stored data and recover my audio without issue. (That's my assumption, anyway ... learning now how to determine if those assumptions are valid or not.) First thing I need to do is figure out which of the access/format/channels/rate/period/buffer settings I need to mess with once I open an S/PDIF device. Then, figure out how to read the raw S/PDIF data accurately and record it to storage. Once in storage I can deconstruct the S/PDIF stream using tools you've mentioned before in this thread. Tons of fun learning, but it sure is a steep curve. Paul Braman ------------------------------------------------------------------------------ Nokia and AT&T present the 2010 Calling All Innovators-North America contest Create new apps & games for the Nokia N8 for consumers in U.S. and Canada $10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store http://p.sf.net/sfu/nokia-dev2dev _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
