[mythtv] Prefer lower-numbered audio stream

[Daniel Thor Kristjansson]

On Wed, 29 Dec 2004, Doug Larrick wrote:
]Daniel Thor Kristjansson wrote:
]> Most of audio information with ATSC is not in the stream that ffmpeg sees.
]> Even the limited audio descriptor sometimes present in the PMT is jettisoned
]> with the PMT rewriting. I don't think ffmpeg even tries to look at this
]> information, but we don't save it in the recording to begin with.
]
]Yes, that's true, though if needed we could preserve the audio information from
]PMT while rewriting.  The good news is that it *is* still present in the AC3
]stream itself.  The only use for preserving this data in PMT would be for
]non-AC3 streams (from DVB maybe?)

DVB, I believe, always includes this info in the PMT. In ATSC it is 
optional.

-- Daniel