You may rip off my epaulets
Norm Strong
at 128kb/s. I expected a significant, if not dramatic degradation in
quality. I could not hear a difference--not the slightest. I ripped
this disc using CDex; it got through the track at 22x. This is
blazingly fast. Most of my ripping programs run at 8x; sometimes
even slower.
After that shock, I decided to press my luck. I ripped it at 64kb/s,
and then 32kb/s. I managed to persuade myself I could hear some
degradation at 64kb/s. But I wouldn't bet on it. 32kb/s is
definitely inferior whenever anything like castanets or triangles,
xylophones etc. is being played. But with a soprano voice and piano
accompaniment, the slowest speed is still pretty good.
I guess I should be drummed out of the hi-fi corps.
Norm Strong (nh...@aol.com)
Seattle WA
Sverre Brubaek
I did a similar experiment. First i checked without knowing what
artifacts MP3 encoding would introduce. The result was similar to
yours: I failed to reliably detect a 64kbps MP3.
Afterwards I read up on the typical artifacts and repeated the test.
This time I could detect up to 160kbps.
Lesson learned: Listner training is crucial.
Test was done with software ABX comparator (www.pcabx.com) on boston
acoustics computer speakers. 20 repetitions for each test.
--
They both savoured the strange warm glow of being much more ignorant
than ordinary people, who were only ignorant of ordinary things.
-- Discworld scientists at work (Terry Pratchett, Equal Rites)
Espen Braathen
meldingsnyheter:9uduu...@enews2.newsguy.com...
> I just ripped one of my very best demo quality CDs to a LAME MP3 file
> at 128kb/s. I expected a significant, if not dramatic degradation in
> quality. I could not hear a difference--not the slightest. I ripped
> this disc using CDex; it got through the track at 22x. This is
> blazingly fast. Most of my ripping programs run at 8x; sometimes
> even slower.
Unless you takes the actuall layer III encoding into the equation;
the "ripping" speed is usually limited by the CD-ROM drive. Plextor
drives has the best reputation; the latest top performer manages DAE
at almost 40x speed.
--
Espen Braathen
WEB: http://espen-b.home.online.no
Chris Mauritz
I also use CDex + lame. Though I tend to rip using VBR with a
maximum of 320kbits/sec and minimum of 96kbits/sec and I can't tell
any difference either. However, I can definitely hear artifacts at
160kb and lower bitrates.
I won't be chucking my CD collection anytime soon, but this makes it
extremely painless to have an easy to manage "jukebox" of thousands
of CDs for the cost of a low end PC, a couple of cheap 120gig IDE
drives and a decent sound card.
Cheers,
C
--
Chris Mauritz
ri...@mordor.net
Alan Hoyle
In a tangential direction, have there been any studies or comparisons
done comparing the quality of Ogg Vorbis files with .mp3 files at
equivalent bitrates? For those of you who haven't heard of it, Ogg
Vorbis has the advantage of not being a patented technology which
allows royalty-free creation of encoders.
cf:
http://www.xiph.org/ogg/vorbis/
-alan
--
Alan Hoyle - al...@unc.edu - http://www.alanhoyle.com/
"I don't want the world, I just want your half." -TMBG
Get Horizontal, Play Ultimate: Ring of Fire - Spear
jj, DBT thug and skeptical philalethist
>I just ripped one of my very best demo quality CDs to a LAME MP3 file
>at 128kb/s. I expected a significant, if not dramatic degradation in
>quality. I could not hear a difference--not the slightest. I ripped
>this disc using CDex; it got through the track at 22x. This is
>blazingly fast. Most of my ripping programs run at 8x; sometimes
>even slower.
Norm, it takes a while to learn how to hear the artifacts in an
audio coder. Just released at this AES was a CDrom that helps
to train people to hear coder artifacts.
Your experience is typical of people who haven't heard much coded
music. After a while, you'll start to hear more artifacts.
This is, of course, why training is essential.
--
Copyright j...@research.att.com 2001, all rights reserved, except transmission
by USENET and like facilities granted. This notice must be included. Any
use by a provider charging in any way for the IP represented in and by this
article and any inclusion in print or other media are specifically prohibited.
Arny Krueger
news:9uh1m...@enews2.newsguy.com...
> On 3 Dec 2001 19:02:45 GMT, Espen Braathen wrote:
> > Norm Strong <nh...@aol.com> skrev i
> > meldingsnyheter:9uduu...@enews2.newsguy.com...
> >> I just ripped one of my very best demo quality CDs to a LAME MP3 file
> >> at 128kb/s. I expected a significant, if not dramatic degradation in
> >> quality. I could not hear a difference--not the slightest. I ripped
> >> this disc using CDex; it got through the track at 22x. This is
> >> blazingly fast. Most of my ripping programs run at 8x; sometimes
> >> even slower.
Ripping speed is very dependent on the condition of the disc. It is
also IMO important to ensure that discs are being ripped accurately.
This can be determined by ripping the same track twice and comparing
the results. The goal is for the two files to be bit-for-bit
identical. This goal is achievable but not always achieved.
> > Unless you takes the actual layer III encoding into the equation;
> > the "ripping" speed is usually limited by the CD-ROM drive. Plextor
> > drives has the best reputation; the latest top performer manages DAE
> > at almost 40x speed.
This is pretty impressive if these speeds are obtained with zero
errors. Your average $50 CD ROM drive runs at more like the 8x
previously mentioned, if it can even read with zero errors.
> In a tangential direction, have there been any studies or comparisons
> done comparing the quality of Ogg Vorbis files with .mp3 files at
> equivalent bitrates? For those of you who haven't heard of it, Ogg
> Vorbis has the advantage of not being a patented technology which
> allows royalty-free creation of encoders.
You can compare a number of MP3 coders by downloading files from
http://www.pcabx.com/product/coder_decoder/index.htm , including Ogg
Vorbis. I think that the latest-greatest version is not represented
there. I know that some earlier versions of Ogg were pretty bad. By
pretty bad I mean that it was relatively easy to distinguish the
changes that the Ogg Vobis coder made to music when it was coded and
decoded.
I think it is important for listening tests to be bias-controlled
because our expectations can affect our ability to hear subtle
differences. Therefore I give away bias-controlled listening software
at www.pcabx.com .
Darryl Miyaguchi
A different approach from the single-listener/ABX approach is to use a
group of people performing a blind test to evaluate codec quality.
You can participate in an ongoing listening test of various codecs,
including Ogg Vorbis and Lame mp3 at:
http://ff123.net/128test/instruct.html
Individual listeners are encouraged to use ABX if they think they hear
subtle differences. Interim results are here:
http://ff123.net/128test/interim.html
A previous test using an earlier incarnation of Ogg Vorbis (Release
Candidate 2) was performed at 128 kbit/s, and the results are here:
http://ff123.net/128tests.html
Current Ogg Vorbis at 128 kbit/s (pre-RC3) is considerably improved
even over RC2, which in turn was improved over Beta 4. I believe the
samples at Arny's site were from a Beta version of the Ogg Vorbis
encoder. In my opinion, Ogg Vorbis in its pre RC3 state is now better
than the best mp3 encoders at 128 kbit/s, and is possibly the best
codec at this bitrate, period.
ff123