Kostya Shishkov <[email protected]> writes: > Well, IIRC you can have some independent channel sets that are alternative to > each other (i.e. different sets of surround channels). So one has to determine > what channel sets you want to decode
But when parsing the stream, it's not what I want which determines the number of downmix coefficients present in the stream; that has to be determined from other in-stream data. Anyway, I found section 8.5.2.1 on reverse downmixing now, which makes it a little clearer (still not sure it gives a complete description of all cases, though). So I'll get back to that later. A related question is how all this fits into the libav framework. Can the application tell libav which channels it really wants (say, 2.0 stereo or 5.1), and have that information propagated to the decoder, e.g., dca? Hmm, that's the s->avctx->request_channel_layout? >> For the >> http://samples.libav.org/A-codecs/DTS/dts/Master%20Audio%205.0%2096khz.dts >> file, I get only a single channel set, with channels = 5, primar_ch_set >> = 1 and downmix_type 1. So N = 5+1 = 6, and since the primary flag is >> set, the final paragraph seems to apply, so M = 2 (downmix_type = 1 is a >> downmix to stereo). I'm not going to to anything with the coefficients >> now, but at least I think I know the number of bits (6*2*9) to skip. > > Seems right. Good to know. >> And one other thing: If anyone has access to a known-good decoder for >> dca xll, it would be great if I could get unpacked wav files >> corresponding to the dts/"Master Audio"* sample files. > > Yes. Can you or Mathias (madshi) do that? And put the files either next to the sample files, or somewhere else where I can download them. Regards, /Niels -- Niels Möller. PGP-encrypted email is preferred. Keyid C0B98E26. Internet email is subject to wholesale government surveillance. _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
