Hello everyone, i'm not sure if this is a proper section for my post. I just wanted to share my expression about Vorbis compared to OPUS format. Recently i moved my collection from MP3 to Vorbis AoTuV, and i'm pretty happy for that. I've read a lot of the new codec OPUS here in the forum, so i decided to compare it with Vorbis. Basically i'm encoding my songs at Q7, which is 224 target bitrate. In the Foobar's OPUS settings dialog my settings were 224/VBR, and encoded a FLAC file.
The Flac file was "Distant Mirror" from the Yello's album Motion Picture. Actually this song is very interesting! At first sight it's not something special, but when i encoded it to Vorbis Q7, I noticed that the dinamics of bitrate is huge (from about 180 to 415kbps) and the transitions are very fast.
The OPUS version of this file at 224/VBR is smaller than the Vorbis file with about a megabite, but the most interesting thing that i noticed was a very little lack of the high frequencies. Than i checked the spectum analizer, and it showed a clear cut of the high frequencies. I know its not accurate, and did an ABX test in Foobar. In some passages I can clearly define the difference between Vorbis and OPUS, yes it is very small, but its there.
Here is the screenshot of the Foobar's analizer :
(http://i.imgur.com/vYgmgDO.png?1)
Hi,
looks more like that scaling is different. Convert the FLAC to 48000 and redo your test.
Looks like FLAC and Vorbis go to 44100 and Opus to 48000 so it just looks like they have more information.
Can you make a screenshot comparisonwith Spek?
Well spotted by rudolf - the spectra do not line up. Opus indeed operates at 48 kHz, while your source and therefore the FLAC and Vorbis file are most likely 44.1 kHz.
Hi,
looks more like that scaling is different. Convert the FLAC to 48000 and redo your test.
Looks like FLAC and Vorbis go to 44100 and Opus to 48000 so it just looks like they have more information.
Can you make a screenshot comparisonwith Spek?
Hi again, its my fault, I thought that 48khz is only for internal purposes, because in the file properties the original sample rate is 44.1khz. I did a WAV file from the OPUS file using a resampler and now the graphics is ok.
Please let the administrator close my topic.
A last comment. I'm not saying you are doing this, but drawing conclusions about audible differences from spectrum plots is not a good idea.
It can give you an indication of what a difference might sound like, but audibility still needs to be judged by ear, not by eye.
A worse looking spectrum could actually sound better or you may not hear any difference at all.
I know its not accurate, and did an ABX test in Foobar.
I am curious and would like to see the ABX logs if you still have them.
xnor is right with comparing spectrums. But if you really have too, try out PQevalAudio.
https://hydrogenaud.io/index.php/topic,106208.0.html
It compares two files and gives you a rating.
Another thing to keep in mind is that Opus never encodes any audio above 20 kHz, since normal people don't hear that high. Some codecs (e.g. Vorbis) might go up to 21 or 22 kHz at high rate, which is why you might *see* a difference. I doubt you can hear it though.
Encoders rating (224 kbit/s):
1. Vorbis
2. Opus
http://soundexpert.org/encoders-224-kbps
I take it those results rely on artifact amplification.
Please understand that this forum doesn't recognize that method as a valid means of testing.
Hi guys. I love this forum, because there's so much to learn here, and the objectivity is the leading argument here. Like you all, I adore music and I listen it all the day. A year ago, my favourite music format was Lame's mp3. Now all my music is converted into q7 AoTuv Vorbis, and i'm satisfied. If you ask me, why? I can't give you a proper answer. File size, compared to what I feel when i listen the music, is what that makes me happy. I know, there's no place for feelings here, and that's why I admire this forum. Please take my apologies for my stupid posts! I decided to read the forum, without participating, since my competence is too low. Please let the administrator delete my thread, because I don't want to fulfill the forum with useless information! Greetings from Bulgaria, and keep going :)