m4a -> mp3 batch conversion - your opinion

[nickchen]

"Organized" myself some DVDs full with m4a music data, which is encoded with 128 kbit. Quite impressed, that sounds better than the odd 128 kbit MP3 format. As I plan to get a Zen Touch (only MP3 & wma) as portabel audio device, m4a is to be changed to MP3.

Found a tool that does overnight batch conversion to MP3. I tend towards 128 kbit m4a -> 160 kbit mp3, but I'm not sure at all how superior the m4a is in respect of sound quality. Maybe even 192 kbit are justified.

What is your opinion / experience about bitrate to chosen ?

Edit

my first poll

 

[Publius]

192kbps or -V2. Any bitrate you choose will be inferior though, even 320.

But really, the "correct" answer is just to rerip. Transcodes may look innocuous, but there are some ABX results on HA which are just scandalous.

 

[nickchen]

Right, kinda rerip with Soundforge would make perfect results, but that really can't be handled with thousands of files.

Never heared about V2 (only in respect of 1939-45, but this is not what you meant)

 

[KyPeN]

No matter what, it will sound worse than what you have.

Imagine, if you will, that your 128kbit m4a files sound like crap, but 192kbit mp3s sound sweet. How is the encoder supposed to take the crap and turn it into sweet?

Re-ripping is the only way to improve quality...

 

[Twombly]

Quote:

Originally Posted by nickchen Right, kinda rerip with Soundforge would make perfect results, but that really can't be handled with thousands of files. Never heared about V2 (only in respect of 1939-45, but this is not what you meant)

Ripping CDs for 24 hours straight is fun as hell.

No joke.

 

[nickchen]

Quote:

Originally Posted by Twombly Ripping CDs for 24 hours straight is fun as hell. No joke.

Last year, I ripped my complete classical CD collection (~200 CDs) into Mp3 256 kbit. Needed whole christmas holidays for that project. The poor CDrom's reading abilities decreased more and more, and when I was 3/4 ready, it died.

 

[Firestarter]

Quote:

Originally Posted by nickchen Last year, I ripped my complete classical CD collection (~200 CDs) into Mp3 256 kbit. Needed whole christmas holidays for that project. The poor CDrom's reading abilities decreased more and more, and when I was 3/4 ready, it died.

next time you might want to try and give the cdrom some time to cool down. EAC has a nice function that allows just that

[size=xx-small]only FLAC is worth of such a ripping session!

[/size]

 

[nickchen]

I know what you mean. It was just one of my old 1996 SCSI devices that was at the end of its lifetime anyway.

 

[GraDy]

Transcoding will always decrease the quality. To what extent greatly varies, but if you can, rerip.
When encoding to mp3, it is recommended to use the VBR presets. I'd say standard (-V2) is overkill, try medium (can't remember what -Vx-setting it's the same as)

 

[nickchen]

Being almost 40, I tortured my ears with diverse walkmen in the 80's and had an acute hearing loss in 2001. Maybe because of this I do not manage to hear differences between a transcoded 192 kbit MP3 and its 128 kbit M4A origin. Don't think it's my gear, it's not that bad.

Maybe I should cease that hobby and start rearing honey bees.

 

[blessingx]

I transcoded a bunch of 128 AACs to LAME MP3 "--alt-preset standard" and couldn't hear the difference. Transcoding is never ideal (though a bit overzealously frowned on here), but I think if you give it enough headroom the secondary artifacts will be minor (especially in comparison to the first in this case). For AAC/M4A (or even protected MP3) conversion to uncrippled MP3 at these bitrates I'd start testing transcoding at about a 1.5 the first compression.

And you may already know, but DBPowerAmp does conversions also. And although I'd recommend the LAME encoder in DBPowerAmp over iTunes branched FhG encoder, you could also download the iTunes and do the conversion there.

Finally transcoding can in some cases sound better, just not be more accurate to the original source.

And I didn't vote as I'd encourage using "--alt-preset standard" VBR, but it would be closest to 192 if those were the only choices.

 

[nickchen]

Thanx blessingx.

Did not know DBpowerAmp, looks quite nice & well structured. Guess I stay with my above mentioned (somewhat similar) GX Transcoder, mainly because it's freeware, whereas DBpowerAmps MP3 encoding abilities are restricted to 30 days for legal reasons.

A word about VBR: I'm not a fan, mainly because playing time displays nuts on almost any playing device. I rather choose higher CBR and resulting bigger file size.