[vorbis-dev] Serious, inacceptable artefacts with Ogg Vorbis
michael.noisternig at sbg.ac.at
Tue Sep 17 15:21:12 PDT 2002
I recently participated in a public listening test that was held by
German magazine c't. They had two categories, 64 kbps and 128 kbps.
I only participated in the 64 kbps test where there were 7 .wav files,
with 1 of them the original one and the other 6 being encoded with
different encoders. Without knowing which file was encoded with which
encoder you had to give each one a place in your ranking.
The samples were 20 secs long with a pop, a (sort of) jazz and a
I was really surprised when I got the results seeing that Ogg Vorbis got
last place in my ranking. Not only that, but it even was ranked 2nd
place by the other people in average. (Though that doesn't mean too much
seeing that many people couldn't even pick out the uncompressed wav.)
So what made me rank it that bad? I noticed strange artefacts in the
entire Ogg Vorbis encoded sample already when I got through the list the
first time. But when I listened to it with headphones the artefacts got
really *inacceptable*. I don't know how to describe them, maybe echoing
or bubbling. They made me rank MP3 and Real even better than Ogg Vorbis
although they had cut away all the high frequencies!
Still surprised (and disappointed) by Ogg Vorbis' bad quality I compared
the actual 1.0 with an old RC2. And surprisingly again the artefacts
in the old RC2 were much less then in the actual one, though there was a
lot more noise.
Hoping and to make sure my complaints are taken serious I have encluded
my personal ranking for the listening test:
Platz 1: unkomprimiert (WAV)
Platz 2: Windows Media Audio
Platz 3: MP3Pro
Platz 4: AAC
Platz 5: RealAudio
Platz 6: MP3
Platz 7: Ogg Vorbis
I still have the samples so I can send them to you if you want.
But anyway, I can reproduce the artefacts with any audio data and Ogg
I don't know, am I the only one who hears those artefacts (it seems a
bit like this)? Anyway, I'm hoping to get some comments.
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