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Opus 1.1 alpha version (not BABYEATER), [split from the good old megathread]
jmvalin
post Mar 16 2013, 00:37
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QUOTE (IgorC @ Mar 14 2013, 22:37) *
The noise is constant during the whole tonal part (1.5-15 sec)
Those are not an attacks but the constant noise at notes. The tones sound more "hairy".
That's the only appropriate description that comes to mind right now.
The quantitative part is hard. Not sure but I _think_ there is some noise in 4-8 kHz and 12-14 kHz ranges.
Both are enough audible.


Well, I listened to the encoded file at 64 kb/s (70 kb/s actual output) and I could barely ABX (wasn't with headphones, but still). I can revisit this later, but at this point I doubt there will be much I can do for the artefacts you've been hearing at 96 kb/s. Note that I'm not saying it's perfect, just that there was nothing that struck me as obviously wrong (i.e. a bug) with that file.
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IgorC
post Mar 16 2013, 02:28
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OK. And yes, You're right. This isn't a day and night difference but still.

Also the sample of harpsichord hasn't constant quality but rather it starts with the same constant noise and then go to high quality. Generally Opus 1.1a is smart to increase a rate on difficult parts (on tonal samples in this case) but the encoder doesn't react instantly and only slowly increases the rate from begining of this sample.

This post has been edited by IgorC: Mar 16 2013, 02:29
Attached File(s)
Attached File  harpsichord.zip ( 1.22MB ) Number of downloads: 74
 
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jmvalin
post Mar 16 2013, 02:50
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QUOTE (IgorC @ Mar 15 2013, 21:28) *
Also the sample of harpsichord hasn't constant quality but rather it starts with the same constant noise and then go to high quality. Generally Opus 1.1a is smart to increase a rate on difficult parts (on tonal samples in this case) but the encoder doesn't react instantly and only slowly increases the rate from begining of this sample.


Haven't listened to the file, but one thing I'm currently working on is adding (optional) look-ahead to help reacting faster to changes. So in theory that could help here. Just curious, what happens if you create a file that repeats the segment twice and encode it? Is the beginning of each segment worse, or just the beginning of the first one?
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IgorC
post Mar 16 2013, 03:05
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It behaves exactly the same. Both beginnings have the same artifacts on 2x concatenated source.

P.S. Forgot to mention, there is a silence during the first second. Might be useful.

This post has been edited by IgorC: Mar 16 2013, 03:08
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jmvalin
post Mar 16 2013, 03:35
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QUOTE (IgorC @ Mar 15 2013, 22:05) *
It behaves exactly the same. Both beginnings have the same artifacts on 2x concatenated source.


Had a closer look and I now understand the issue. The pitch of the first three notes is too low for the tone detector (too low resolution). It's only at the fourth note that it realizes there's something tonal here. There isn't much I can do about that one at least for now.
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IgorC
post Mar 16 2013, 03:56
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No hurry at all. If it will be improved at some point it will be great smile.gif . Anyway as for now I can't find any audio format that will be any better overall than Opus at 64-96 kbps and higher. (those are not just beautiful words and pink pony stuff or so, actually have made tests)
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darkbyte
post Apr 1 2013, 18:10
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I wonder if there's any new builds we can try. smile.gif
I'm already very pleased with Opus @80kbps but there's always room for improvements.


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lithoc
post Apr 2 2013, 06:33
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QUOTE (darkbyte @ Apr 2 2013, 01:10) *
I wonder if there's any new builds we can try. smile.gif
I'm already very pleased with Opus @80kbps but there's always room for improvements.


I'm trying 48-64kbps. So far 48kbps impressed me how they preserve the details at such low bitrate.

But I think we are at different ball game comparing with MP3 or AAC as we already know how to spot their weakness.

This is new codec and really know how to trick our ears

May be aging takes into consideration as well due to hearing loss.

Kudos to the developer who bring this codec free to the world!!!

This post has been edited by lithoc: Apr 2 2013, 06:37
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eahm
post Apr 2 2013, 06:42
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Every codec knows how to trick our earing, don't get into the hype because placebo gets stronger (against others) when hype is high.

Opus is good but still new like you said, they released three versions in few months and 1.1 is coming. I still like AAC the most, it's amazing how low you can go with AAC as well...and it's compatible with almost everything.

It's time for MP3 to disappear for sure, Amazon and Google should have picked AAC.

This post has been edited by eahm: Apr 2 2013, 06:44


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wswartzendruber
post Apr 6 2013, 03:46
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I'm sitting here telling myself that Google Music will soon be switching to Opus for streaming.
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Mach-X
post Apr 6 2013, 04:20
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Coffee. Oh and as long as Starbucks coffee exists, so will mp3. As long as the mobile market is split between Android/iPhone/windows phone it will always be around.

This post has been edited by Mach-X: Apr 6 2013, 04:23
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softrunner
post Apr 7 2013, 23:11
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As I wrote before, Opus 1.1 alpha has some bugs, though version 1.0.2 is not perfect also. Check these samples. Some examples:

For 1.1 alpha at some frequencies the signal just disappears, while for both versions a lot of loud artefacts are present. Of course, all this is audible, I posted 408 Opus samples at the link above (someone needs ABX logs?).
Another problem: Opus increases bitrate even if there is no progress in quality, while Vorbis on q10 has 20 kbps, and it is perfectly OK on 15 kbps.
What I want to know is whether these artefacts can be removed in future versions, or they are the part of Opus algorithm? For example, Musepack also failed on this samples, though it is developed for many years...
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saratoga
post Apr 7 2013, 23:15
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QUOTE (softrunner @ Apr 7 2013, 17:11) *
What I want to know is whether these artefacts can be removed in future versions, or they are the part of Opus algorithm? For example, Musepack also failed on this samples, though it is developed for many years...


Sure, representing stuff like this is doable in an MDCT codec like vorbis or opus. But samples like this aren't music, so its probably not something encoders are made to deal with.
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softrunner
post Apr 7 2013, 23:19
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QUOTE (saratoga @ Apr 8 2013, 02:15) *
Sure, representing stuff like this is doable in an MDCT codec like vorbis or opus. But samples like this aren't music, so its probably not something encoders are made to deal with.

Have to double my post:
QUOTE
Well, electronic music may contain whatever signals possible, there are thousands of various plugins/generators etc...

It should be respected also.
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saratoga
post Apr 8 2013, 00:35
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QUOTE (softrunner @ Apr 7 2013, 17:19) *
QUOTE (saratoga @ Apr 8 2013, 02:15) *
Sure, representing stuff like this is doable in an MDCT codec like vorbis or opus. But samples like this aren't music, so its probably not something encoders are made to deal with.

Have to double my post:
QUOTE
Well, electronic music may contain whatever signals possible, there are thousands of various plugins/generators etc...

It should be respected also.


If you find an example of electronic music that breaks one of those encoders, you should report it. Until then, its a bit premature.
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jmvalin
post Apr 8 2013, 03:01
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QUOTE (softrunner @ Apr 7 2013, 18:11) *
For 1.1 alpha at some frequencies the signal just disappears, while for both versions a lot of loud artefacts are present. Of course, all this is audible, I posted 408 Opus samples at the link above (someone needs ABX logs?).
Another problem: Opus increases bitrate even if there is no progress in quality, while Vorbis on q10 has 20 kbps, and it is perfectly OK on 15 kbps.
What I want to know is whether these artefacts can be removed in future versions, or they are the part of Opus algorithm? For example, Musepack also failed on this samples, though it is developed for many years...


Yes, that problem was reported before and is not fixed in git. See this post (and related) for more details. I don't care about wasting bits on artificial signals like that, but the tone disappearing was not acceptable. If you try the latest git, it should all work.
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Gainless
post Apr 8 2013, 20:36
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Ok, so here's another ABXable issue with tonality:

Attached File  Albibeno__Sample_1_.flac ( 498.12K ) Number of downloads: 57

Attached File  Albibeno__Sample_2_.flac ( 734.02K ) Number of downloads: 68

Interesting about it is, that the first one is totally fine, but the second has a tonal distortion (around second 2,3 on the right channel), although the tonal input is the same in both, just set into a different sound stage. Tested it with the official 1.1 alpha and 1.0.5. build (which performed worse btw) at 192 kb/s.

This post has been edited by Gainless: Apr 8 2013, 20:41
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Gainless
post May 6 2013, 17:13
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I've played a bit around with different framesizes for the two Albibeno samples and found that the issue of the 2nd one (a distortion on the right channel around second 2,2) is improved with a forced size of 10 ms, used CBR for the comparison of course. Maybe worth a fix?

This post has been edited by Gainless: May 6 2013, 17:15
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