[theora] ffmpeg2theora: Garbled AC3 Audio

[Jason Self]

I recorded a television show using my HDHomeRun. The resulting file
contains MPEG-2 video and AC3 audio. Specifically, ffmpeg2theora
shows:

Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 1280x720 [PAR 1:1 DAR
16:9], 38810 kb/s, 59.92 tbr, 90k tbn, 119.88 tbc
Stream #0.1[0x80]: Audio: ac3, 48000 Hz, 5.1, s16, 448 kb/s
Pixel Aspect Ratio: 1.00/1   Frame Aspect Ratio: nan/1

When I feed it to ffmpeg2theora using the -a switch for quality-based
encoding for the audio it sounds fine but as soon as I replace the -a
switch to specify a bitrate (specifically -A 128 -c 2 -H 44100) the
audio is garbled and sounds horrible.

This isn't new to 0.24 but with the alpha release of Theora 1.1
("Thusnelda:) I wanted to look into it Theora again.