On Mar 11, 2011, at 13:31, Terry Hancock wrote: > Right now, I'm thinking, the "best practice" is going to be to > multiplex _channels_ within the audio codec (i.e. FLAC or Vorbis), > while each _track_ is a separate audio stream in the Ogg file. > > Does that make sense?
Yes, I think that's the only sane way to do it. Besides, FLAC has a limit of 8 channels, so if you have one 7.1 surround track then you would not be able to add any more channels anyway. Best to keep the tracks separate, but carried in the same stream. > Do players actually support this? I seriously doubt it. You're talking about the cutting edge. Very few players even support surround playback of a single track, much less dealing with multiple tracks with multiple channels each. At this time, there is only one standard. As you mention, DVD has the features that you want, and thus you're not really going to find any players that support something other than DVD. DVD follows the MPEG specification for multiplexing multiples independent media streams into one single stream. This is how you get multiple video angles and multiple soundtracks. As far as I know, there is no competing standard, thus, if you want to multiplex more than one audio (sound)track into a single file/stream, then you're probably going to have to use the MPEG stream standard (I forget the precise term). Granted, formats like Ogg support similar features, at least theoretically, but I don't think anything out there is compatible. > And > > What tools exist to merge separate single-channel FLAC files into a > multichannel FLAC? As far as I know, there are absolutely zero tools for directly manipulating FLAC files (other than meta data). The standard procedure with FLAC is to decode the files into some standard uncompressed format like AIFF or WAV, and then perform your merging on the standard uncompressed data. Then, once you have the multichannel uncompressed master, you would encode the new file into FLAC format. I have been working on a tool to directly split FLAC files that have very long sections of pure silence in them (on the order of several minutes, not seconds), and I have noticed that the libFLAC API does not make this easy. I have the impression that the intention is not to even support direct manipulation of FLAC without an intermediate decode and encode. This actually makes some sense, because the MD5 error checking stamping must be recalculated for each FLAC file, and you need the decoded data to do that anyway. Brian Willoughby Sound Consulting _______________________________________________ Flac mailing list [email protected] http://lists.xiph.org/mailman/listinfo/flac
