> From: "Paul Hartman" <[EMAIL PROTECTED]>
>
> Somebody pointed out to me that somewhere in the process of encoding a WAV
> to MP3, then decoding back to WAV some extra frames are added at the end
> (appears to be silence?). re-encoding and decoding this same thing
steadily
> makes it grow each time. It seems not necessarily to be any particular
> encoder or decoder, or any specific bitrate. Is there a explaination for
> this, and is there any way to prevent or correct this (so that a mp3
> decoded back to WAV can be as close as possible to the original)?
The explanation is twofold:
1) Encoding and decoding delays - of the order of 1000 samples; encoder- and
decoder-specific
2) Padding to frame bounaries - on average adds 1152/2 samples
The delays add silence to the beginning of the decoded signal; the padding
adds silence to the end.
If you know the combined (encoder + decoder) delay and the length of the
original signal, you can compensate for both effects with a little editing.
-- Mat.
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