Just A Minute

 
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What mp3 quality do you want?

Messages in this topic: 15 View All
Clitheroe KidJul 22, 2009
 

 
The only way I have yet found of editing mp4 files without re-encoding them
is a Windows program called mp4Box.

It's a command-line only program, so is very cumbersome to use.

And in order to edit .aac files you must first "mux" them to mp4. This
doesn't involve any re-encoding, but just adds frame headers to the raw
data. FFMPEG will do this conversion.

I find that decompressing from MP4 to WAV (using my old copy of Cool Edit
Pro) and editing the resulting WAV file (and, optionally, normalizing it),
then re-encoding to MP4 at the file's original bitrate, is a more workable
solution, and doesn't seem to introduce any audible effects.

----- Original Message -----
From: "charles_454545" <charles@...>
To: <just-a-minute@...>
Sent: Wednesday, July 22, 2009 6:17 PM
Subject: [just-a-minute] Re: What mp3 quality do you want?


> --- In just-a-minute@..., "eriatarkae@..." <eriatarka1@...>
wrote:
>
> >> 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.
>
> > Definitely sounds like the right thing to do, but unfortunately I can't
work out how to. Any ideas what to edit to achieve this?
>
> get_iplayer is a perl script, so you can edit it in any plain old
> text editor. After googling around on hydrogen audio for about
> half an hour yesterday, I decided to upgrade to lame 3.98.2 (for
> its improved vbr) and use these arguments: "-q 0 -Y -v".
> So, I edited get_iplayer to replace this line:
>
> $binopts->{lame} = '-f';
>
> with this line:
>
> $binopts->{lame} = '-q 0 -Y -v';
>
> new versions of get_iplayer come out =constantly= so I wish
> there was a way to store these options somewhere :)
>
>
> >> 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.
>
> > There are a few caveats to this. Firstly, the raw .aac files
> > don't appear to play in iTunes (Quicktime only), and changing
> > the extension doesn't help either. This is a huge problem for
> > me, as iTunes is my central storage for all things JAM.
> > Secondly, I'm fairly sure that .aac is not a suitable format
> > for most people's usual use patterns - most mp3 players can't
> > play it, and car stereos don't usually play it either.
>
> Well, I'll keep uploading mp3s... it's going to be the
> lingua franca of the audio world for some time to come.
> (My Cowon D2+ doesn't support aac, and my personal
> preference would be ogg... ;)
>
>
> > As far as utilities go, they are not freeware. There's
> > Quicktime Pro or, for Macs, Fission. Quicktime Pro is
> > useful, because if you trim to the selection (which is not
> > immediately obvious, but there's a selection ruler across
> > the bottom) and save as an .mp4, then that will play in
> > iTunes. Fission - I have no idea, I'm on XP.
>
> Does trimming the ends and saving as mp4 cause a re-encode?
> Because if it doesn't re-encode, and if the results play
> nicely with iTunes/iPods/etc, that would be very nice indeed...
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>
>

 
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