[FFmpeg-devel] Alternate HDCD format/rate support

[Burt P]

According to the Users' Manual, the PM Model Two would encode 
HDCD in any CD or DVD-Audio sampler rates, and at 16, 20, or 
24-bit output. While HDCD was (afaik) only published on CD, and
therefor 16-bit at 44100Hz, audio may exist in any other other formats
supported by the encoding equipment, so I've made an effort support them.

At the end of this set, auto-convert is disabled, as now the filter will
handle any format that might ligitimately have HDCD encoding. This was
requested by Nicolas George in an earlier conversation referenced in the
last patch's commit message.

Thanks for comments.
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Burt