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What mp3 quality do you want?

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Clitheroe KidJul 22, 2009
 

 
Charles,

Someone else is *very* interested in this thread - me!

I think you will find that flvstreamer is capable on its own of capturing
the flv stream (which is actually an aac file inside an flv wrapper),
without any involvement of get_iplayer.

It's get_iplayer that's converting your aac file to mp3. If you cut
get_iplayer out of the picture you will simply get the flv stream, with an
aac file wrapped up inside it.

And there are lots of programs which can extract an aac file from the flv
wrapper, e.g. ffmpeg.

Please tell me: what Operating System are you using? This makes a *big*
difference to how get_iplayer and flvstreamer work!

Stephen

----- Original Message -----
From: "charles_454545" <charles@...>
To: <just-a-minute@...>
Sent: Tuesday, July 21, 2009 3:54 PM
Subject: [just-a-minute] Re: What mp3 quality do you want?


> >> 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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