Ogg for music, help needed

[SpikeSpiegel]

I have "some" questions about Ogg Vorbis compression (for music):

Let's say I want to convert some mp3s to ogg: which quality presets ("classic scale" -1.00 to 10.00 and "BeSweet scale" 0.001 to 1.00) correspond to Mp3 CBR @ 128kbit/s,160k and 192k?

Which is the best compromise between quality and file dimension? What about quality2? Is there much difference between q0,1,2,3? More in high or bass tunes?

Somebody say that q5 (or q4) is "lossless", some one else say q6 is better, who's right?

Which is the best CD-ripping/file-conversion program (it must support ogg, but not necessarily vob/lst/ac3 input)? What about Easy CD-DA Extractor6 and CDex(with or without oggenc)?

which is the best program/settings for CD->uncompressed wav conversion?

Which is the best song/kind-of-music to make tests(sometimes I can't tell the difference between mp3 128 and 192)?

[SpikeSpiegel]

Mp3 compression-quality is not linear (4example: the difference between CBR 112k and 128 is really higher than 160-192) so it's really easy to choose the "best compromise between quality and file dimension" in each case (128k for pc-speakers, 192k for advanced audio systems, etc).

With ogg it's a little more difficult to tell if the quality is near to CD and "how" much is the difference between QualityX and QualityX+1
I did some tests (mostly with jazz and classic music) and I can't tell the difference between Mp3 CBR @128k and Ogg Q0 (=64k), is it normal?

At the moment the trustworthiness of my tests is not really high (I can play ogg files only on my pc and even if the sound card is a SB Live, my Cambridge speakers are all but pro), so your help would be really appreciated

p.s. May the lowpass (at 20.000 Hz) improve noticeably the quality of low (0-2) quality ogg files?

[BoF]

Re: Ogg for music, help needed

Originally posted by SpikeSpiegel
Let's say I want to convert some mp3s to ogg

Transcoding a mp3 to ogg will cause a quality loss. we can notice that reenconding an ogg to another one (decreasing the quality level) will give a file as good as if it were encoded from the original source.

Originally posted by SpikeSpiegel
: which quality presets ("classic scale" -1.00 to 10.00 and "BeSweet scale" 0.001 to 1.00) correspond to Mp3 CBR @ 128kbit/s,160k and 192k?

According to the Xiph project, a q=2 (96kbps nominal bitrate) ogg should be better than a 128kbps cbr mp3.

Originally posted by SpikeSpiegel
Which is the best compromise between quality and file dimension? What about quality2? Is there much difference between q0,1,2,3? More in high or bass tunes?

It depends on the aim of the compression:
q=-1,0,1 : internet transfers, no high quality needed
q=2,3,4 : useful for encoding the audio part of movies. provide nice quality.
q=5,..,10 : archive, tends to be lossless.

Originally posted by SpikeSpiegel
Somebody say that q5 (or q4) is "lossless", some one else say q6 is better, who's right?

6 is better than 4/5 and 6 is lossly.

Originally posted by SpikeSpiegel
Which is the best CD-ripping/file-conversion program (it must support ogg, but not necessarily vob/lst/ac3 input)? What about Easy CD-DA Extractor6 and CDex(with or without oggenc)?
which is the best program/settings for CD->uncompressed wav conversion?

cd ripping:
Exact Audio Copy
ogg encoding:
OggdropXPd (GT3b1 for high quality)

[SpikeSpiegel]

I did some testing with Exact Audio Copy: quality looks great (no errors and high fidelity ripping CDs to wav) and it's faster than how I thought

Now I'm using OggDropXPdV1.7.4 CVS (I never use Quality>4 so GT3b1 should be useless), but when I convert mp3s it's a bit annoying the fact that I must convert them to wav first.
Do you think I can achieve the same quality using CDex (with oggenc.exe as external program or with the last .dll files) for direct mp3->ogg conversion?

Thanks for your help!

p.s. what about the lowpass (20000Hz)?

[BoF]

Originally posted by SpikeSpiegel
Do you think I can achieve the same quality using CDex (with oggenc.exe as external program or with the last .dll files) for direct mp3->ogg conversion?

We can't compare a cd-to-wav-to-ogg transcoding to a mp3-to-ogg one. oggenc and .dll files should be as good as oggdropXPd, and I pretty sure cdex decodes mp3 fine.

Originally posted by SpikeSpiegel
p.s. what about the lowpass (20000Hz)?

I don't know, I suppose oggenc enough nice to keep useful information.

[SpikeSpiegel]

Originally posted by BoF
We can't compare a cd-to-wav-to-ogg transcoding to a mp3-to-ogg one. oggenc and .dll files should be as good as oggdropXPd, and I pretty sure cdex decodes mp3 fine.

I was referring to mp3->ogg (with CDex) and mp3->wav->ogg (with EAC) conversion, is it the same or in any case (except ogg to ogg) "more passages"="less quality" or this is an exception?

I know that there could be a little quality loss, that's why I always try to avoid mp3 re-encoding, but sometimes (320Kbit/s) I must.

[BoF]

Originally posted by SpikeSpiegel
I was referring to mp3->ogg (with CDex) and mp3->wav->ogg (with EAC) conversion, is it the same or in any case (except ogg to ogg) "more passages"="less quality" or this is an exception?

codecs entries are usually uncompressed files, we can bet that CDex does mp3->wav->ogg too but wav is an internal state.

Originally posted by SpikeSpiegel
I know that there could be a little quality loss, that's why I always try to avoid mp3 re-encoding, but sometimes (320Kbit/s) I must.

of course, btw I'm wondering if 320Kbps for mp3 encoding is a lossless setting (?).

[Enchanter]

"of course, btw I'm wondering if 320Kbps for mp3 encoding is a lossless setting (?)."

No.

Simply because MP3 (and OGG) are LOSSY codecs. They discard information even with high bitrates.

If you are looking to go lossless, there are many TRUE lossless codecs. I personally use Monkey's Audio

[BoF]

Originally posted by Enchanter
I personally use Monkey's Audio

right and FLAC is another one.

I did some tests on a wav file (87.2 Mo), and here are the results of compression:

APE (Monkey's Audio), lossless, extra high --> 44.2% of original file size
FLAC (Free Lossless Audio Codec), lossless, level 8 --> 48.6%
OGG (Xiph project Ogg Vorbis, oggdropXPd GT3b1), lossly, q=10 --> 30.5%
MP3 (LAME Ain't an Mp3 Encoder), lossly, 320Kbps CBR --> 22.1%

We can see that higher quality for lossly codecs make files smaller than lossless codecs with higher compression level. Now we just have to taste sound differences...

[Enchanter]

May I add that with lossless codecs, one can rest assured that their compressed files will sound essentially and qualitatively the same as that of the original. With lossy codecs, you know that the sound has been altered somewhere along the line.

Regards.