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Prepare MP3/WMA Audio
If you choose to use MP3 or WMA audio, you can set the bitrate you want. If you need audio that is smaller than the original AC3, MP3 or WMA
is the way to go.
WMA (Windows Media Audio V2) has maximum bitrate is 64kbps which isn't very
HQ, though is much better than MP3 at comparable bitrate. Consider it when you
need extreme efficiency. I find it suites well with capture sources where source
audio isn't DVD quality to begin with so using WMA can free up more bitrate to
increase video quality.
Encoding
For MP3, use LAME. Encode the source WAV file with Lame (very simple to do
with RazerLame), then add the RIFF header with WaveMP3 which can then be loaded to VirtualDub for direct stream copy.
You may wish to increase the low pass filter setting from the default (15khz
in 128kbps, 18khz in 160kbps) to something like 18-21 (I prefer 19.5). In
RazerLame it can be found under the Audio Processing tab. Check "Lowpass
Filtering Frequency" box and enter the number. I feel that frequency response is more important in movies than keeping more details in the mid-range. Opposite argument can also be made, but that's just IMO.
For WMA, just load the source wav file in VirtualDub/Nandub and set the compression codec at the next step. You
will need to configure 48->44khz conversion if that wasn't done when saving
the DVD2AVI project as WMA codec needs the input audio frequency to match that
of output.
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