> Hi all,
>
> just gave it a try:
>
> lame -b 128 -X5 -v -V 4 -h -k -d --resample 48 in.wav out48.mp3
>
> The .wav file was grabbed from an audio-CD (44.1 kHz). mp3 sounds
> horrible, way too fast. Is this a feature or should the resampled file
> sound like the original? The FhG resamples to 48 kHz without any
> noticeable speed-up. FhG does the resampling even by default, if you
> choose 320 kBit.
>
> Ok, it's lame 3.35, haven't tried out the 3.36 but since this is not
> mentioned in the history-file, I suppose 3.36 behaves the same.
>
> Kind regards Frederick
>
The bug is that the error message "Error: resample code not yet written!"
was not being printed :-)
I think the upsample to 48kHz at 320kbs because (IIRC) a
44.1kHz and lower 320kbs frame violates some ISO restrictions
on max buffer sizes. Fortunatly most decoders allow for
larger buffer sizes. Other than that, is there any reason
to upsample?
I have been thinking about the downsampling: I think
we should just add a simple linear downsampler, with
the tapered lowpass sox type filter applied directly to our
MDCT coefficients. This would require very little extra
work, and my guess is the aliasing from linear downsampling
is insignificant compared to what MPEG2 compression does to
the high frequencies.
Has anyone who uses sox/MPEG2 noticed a difference between
the sox 'resample' option and 'polyphase'?
Mark
--
MP3 ENCODER mailing list ( http://geek.rcc.se/mp3encoder/ )
