Transcoding MP3, CBR at 320kbps

2009-05-05 13:29:47

Hi,
I fully understand why transcoding/reencoding is not a great idea but my ears are not too good (sat in front of too many crazy drummers for too many years), so the process is unlikely to be an issue.
I have inherited a bunch of MP3 files (about 1000), encoded using lame 3.97 at 320kbps and I want to transcode/reencode them to save some space.

Can someone please advise as to the best format for such a project and provide me with some settings? I apologise in advance to the audiophiles who may be squirming at the thought of transcoding/reencoding!

Cheers

Transcoding MP3, CBR at 320kbps

Reply #1 – 2009-05-05 13:39:06

The first thing is to do some listening tests to find out which -V setting is transparent enough to your ears after transcoding from the 320 cbr files.

Transcoding MP3, CBR at 320kbps

Reply #2 – 2009-05-05 14:23:04

In my experience, 320k lame is not bad for transcoding. Just convert to V4 / V5 or whatever you wish.

Transcoding MP3, CBR at 320kbps

Reply #3 – 2009-05-05 15:01:49

Over the weekend I transcoded some 320k CBR MP3s I had to -V5 and some using Nero AAC  -q 0.40, and they sound great to me..Playing them on the wifes Ipod and my Rockbox Sansa player...

Transcoding MP3, CBR at 320kbps

Reply #4 – 2009-05-05 15:17:24

Transcoding makes subtle problems in either codec far more audible.

In this case, both codecs are "mp3" so listen out for pre-echo / time domain smearing, and artefacts on "difficult to encode" sounds like "spikey" synths, harpsichords, trumpets etc. Content above 16kHz will also be trashed (probably with added ringing), but I'm guessing you won't be able to hear it (me neither!).

Adding --lowpass 16 will remove everything above 16kHz, which is probably preferable - unless the setting you choose already has a lower low pass by default.


Most things will still sound fine. Not always perfect, but good enough (IMO - YMMV!).

Cheers,
David.

Transcoding MP3, CBR at 320kbps

Reply #5 – 2009-05-05 19:37:04

Thanks chaps!!

I have just taken a couple of files and used Lame V4 and V5 and AAC  -q 0.45 and 0.40 and quite honestly I cannot tell the difference (admittedly, not in a blind test).

Subjectively, and I mean subjectively, Lame encodes don't seem as "bright" but I'm not sure I would pick them out on a blind test!

Does anyone know where to get new ears??

Cheers