Currently (in linux-2.6.24, but linux-dvb hg looks similar), the
dmx_output_t in the dmx_pes_filter_params decides two things: whether
output is sent to demux0 or dvr0 (in dmxdev.c:dvb_dmxdev_ts_callback),
*and* whether to depacketise TS (in dmxdev.c:dvb_dmxdev_filter_start).
As it stands, those two things can't be set independently: output
destined for demux0 is depacketised, output for dvr0 isn't.

This is what you want for capturing multiple audio streams from the same
multiplex simultaneously: open demux0 several times and send
depacketised output there. And capturing a single video stream is fine
not what you want: you want multi-open (so demux0, not dvr0), but you
want the TS nature preserved (because that's what you want on output, as
you're going to re-multiplex it with the audio).

At least one existing solution -- GStreamer -- sends all its streams
simultaneously via dvr0 and demuxes again in userland, but it seems a
b...