On Sun, 21 Mar 2004, Boris Shingarov wrote:

> Can mplex include an uncompressed PCM stream?

        Yes, it can.

> I tried
> mplex -f 8 -o birthday1.mpg birthday1.mpv birthday1.pcm
> but mplex says 'Unrecognised format'.

        It is necessary to use the "-L" (or --lpcm-params) option and 
        specify the characteristics of the audio file.

        from the mplex manpage:

       -L|--lpcm-params
              samples_per_sec:channels:bits_per_sample
              [, samples_per_sec:channels:bits_per_sample
              A  comma-seperated  list  of  paramter sets for the
              lpcm audio streams (given in  the  order  the  lpcm
              streams  appear on the command line).  Each parame-
              ter set comprises the sampling rate in Hz, the num-
              ber  of channels, and the number of bits per sample
              seperated by  colons.   For  example,  the  default
              48kHz  two-channel  16-bit audio would be specified
              as 48000:2:16.

              Note: these parameters are necessary because  mplex
              expects  raw  LPCM  audio data without any headers.
              That is: for each sample point a group of 16,20, or
              24  bit  amplitude  values,  one  for each channel.
              Amplitude values are signed  with  the  constituent
              bytes  in big-endian (most significant bytes first)
              order.

> I tried wrapping it into wav so mplex could look at the riff header, but the
> result is the same.  In the man page I read that "mplex can take ac3 and
> mp2".  Is this right, and it doesn't know anything about pcm?

        What version of mplex are you using?   If the manpage does not have
        the paragraphs above then the version of mplex is too old - upgrading
        to a newer version of mjpegtools will solve the problem you are
        having.

        It would be nice if mplex did understand .wav files and obtained the
        necessary information automatically but at the present time that is
        not how mplex works.

        The PCM data has to be in big-endian format and for DVDs must be at
        the 48k sampling rate.

        Cheers,
        Steven Schultz



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