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Re: What mp3 quality do you want?

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charles_454545Jul 21, 2009
 

 

>> get_iplayer --get --wav; then audacity to trim the ends.

> Hmm, interesting. I used get_iplayer --get --amode iphone;
> this produces a 128kbps mp3; then I used DirectWav mp3 splitter
> (which cuts the mp3 rather than decoding and reencoding) to trim
> the useless ends. On last week's BBC R7 update this gave me a
> file lacking the audible (if slight) high-end flutter that the
> low bitrate Real Audio stream has by default.
>
> I could upload my copy of that for reference if you'd like;
> it does seem like the best available.

I don't know if anyone but you and I are interested in this thread,
but it's certainly helpful to me: after digging into get_iplayer's
debugging logs, I discovered that it was giving me realaudio files
instead of aac because I didn't have flvstreamer and ffmpeg
installed. After installing them, get_player used flvstreamer
to pull get the flv file, and ffmpeg extracted the raw, unchanged
aac file from the BBC. :)

Your setup already does this, which is good, but unfortunately
get_iplayer's next step by default is to decode the aac and
re-encode it as an mp3 with lame's default settings. So both of
us are re-encoding to mp3, but you're doing it from better source
material (aac rather than realaudio). Overalll, your mp3 does
sound better. But it also introduces some thuddy distortion,
such as when Nicholas says "clever and erudite" at 0:50. Happily,
that distortion is not in the original .aac file, so it must be
a side-effect of get_iplayer's aac->mp3 pass. If you edit
get_iplayer in a text editor to add "-V 2" to the lameopts argument,
the output should be pretty close to ideal as far as mp3 files go.

The next question -- since most media players support .aac -- is
why not just keep the raw, original .aac files and avoiding the
aac->mp3 transcode step. If we can find a utility to trim the
extra six minutes off the ends, IMO that would be the Right Thing.

Charles

 
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