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I hear a lot about CBR and VBR; what’s wrong with ABR?, Was “MP3 ABR WHY NOT.” (shouting won’t make anyone likelier to reply)
soylentgreen
post Oct 6 2011, 21:31
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I have read numerous forums and articles about mp3 cbr and vbr, some swear by cbr others vbr, the debate just goes on and on. I,ve tried cbr 256, vbr 256, cbr 320, cbr 192 cbr etc and I cant hear any difference. My question is why bother with cbr or vbr, why dont people just go with MP3 ABR, would this not be the ideal compromise, or I am missing something, as there does seem to be lack of mp3 abr on offer as downloads from the likes of Napster etc.
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shadowking
post Oct 7 2011, 01:31
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Also ABR / CBR is inferior to VBR in terms of pre-echo control. V5 can outdo ABR 170k in impulse handling. When using higher bitrate - 224 ~ 320k CBR / ABR converges so yes below that you could be getting the worst of everything. At high bitrate there might be an advantage: predictable size, max hardware compatibility, theoretical safety from aggressive VBR compression when psymodel is failing.

This post has been edited by shadowking: Oct 7 2011, 01:32


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Canar
post Oct 7 2011, 07:06
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QUOTE (shadowking @ Oct 6 2011, 17:31) *
Also ABR / CBR is inferior to VBR in terms of pre-echo control.
Sure, but don't sell ABR short here, it's designed to outperform CBR.

This post has been edited by Canar: Oct 7 2011, 07:06


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shadowking
post Oct 7 2011, 08:40
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QUOTE (Canar @ Oct 7 2011, 16:06) *
QUOTE (shadowking @ Oct 6 2011, 17:31) *
Also ABR / CBR is inferior to VBR in terms of pre-echo control.
Sure, but don't sell ABR short here, it's designed to outperform CBR.


Yes but CBR is underrated and doesn't fully 'starve' since lame uses a bit reservoir . Its just a little dumb that it encodes digital silence. Also ABR is really VBR without letting psymodel full control over bitrate so if some crazy player doesn't like VBR then its very possible that it doesn't like ABR. ABR might be the worse of everything in such case. I think it might have a niche at high bitrate 230 ~ 300 k or when going lower than 120 k.. likewise CBR 192 ~ 256 k is a good option for high quality / good size + 100% compatibility for every software and device ever made.


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mjb2006
post Oct 7 2011, 23:29
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QUOTE (shadowking @ Oct 7 2011, 01:40) *
Its just a little dumb that it encodes digital silence.

There's no getting around that in MP3, but unless you use the -F option, LAME will actually use low-bitrate frames for digital silence, even in CBR mode.
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Also ABR is really VBR without letting psymodel full control over bitrate

The documentation says that ABR is more like CBR in that actual quantization noise is not taken into account; rather, a prediction of the space needed for a frame is made by some other means. So I would look at ABR as more like "CBR with less restrictions on bitrate" rather than "VBR with more". Unless I'm not understanding something.
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Northpack
post Oct 8 2011, 11:40
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QUOTE (mjb2006 @ Oct 7 2011, 23:29) *
The documentation says that ABR is more like CBR in that actual quantization noise is not taken into account; rather, a prediction of the space needed for a frame is made by some other means. So I would look at ABR as more like "CBR with less restrictions on bitrate" rather than "VBR with more". Unless I'm not understanding something.

That's how I understood it too. LAME's ABR mode is very similar to Vorbis' ABR - it works more like an "extended bit reservoir" than a real VBR mode. This makes sense for internet streaming applications, where you usually have enough buffer size to afford this kind of ABR. Many radio streams are in fact (Vorbis) ABR.

I don't think there's any need for a two-pass VBR/ABR mode as proposed here. Why would you need that? To fit an album exactly into the remaining 50361KB on your portable? wink.gif

This post has been edited by Northpack: Oct 8 2011, 11:41
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Posts in this topic
- soylentgreen   I hear a lot about CBR and VBR; what’s wrong with ABR?   Oct 6 2011, 21:31
- - pdq   You might think of abr as being the worst of both ...   Oct 6 2011, 21:53
- - DVDdoug   QUOTE why dont people just go with MP3 ABR, would ...   Oct 6 2011, 22:50
- - kennedyb4   I don't think there has been a public test of ...   Oct 6 2011, 23:57
- - Canar   ABR is for the case where you want to optimize for...   Oct 7 2011, 00:24
- - shadowking   Also ABR / CBR is inferior to VBR in terms of pre-...   Oct 7 2011, 01:31
|- - Canar   QUOTE (shadowking @ Oct 6 2011, 17:31) Al...   Oct 7 2011, 07:06
|- - shadowking   QUOTE (Canar @ Oct 7 2011, 16:06) QUOTE (...   Oct 7 2011, 08:40
|- - Northpack   QUOTE (shadowking @ Oct 7 2011, 07:40) CB...   Oct 7 2011, 09:03
|- - mjb2006   QUOTE (shadowking @ Oct 7 2011, 01:40) It...   Oct 7 2011, 23:29
|- - pdq   QUOTE (mjb2006 @ Oct 7 2011, 18:29) There...   Oct 8 2011, 00:37
||- - mjb2006   QUOTE (pdq @ Oct 7 2011, 17:37) QUOTE (mj...   Oct 8 2011, 05:07
|- - Northpack   QUOTE (mjb2006 @ Oct 7 2011, 23:29) The d...   Oct 8 2011, 11:40
- - Northpack   QUOTE (soylentgreen @ Oct 6 2011, 20:31) ...   Oct 7 2011, 08:13
- - pdq   If abr were implemented as a smart, i.e. multipass...   Oct 7 2011, 13:51
- - halb27   In the roughly 120-240 kbps bitrate range, probabl...   Oct 7 2011, 14:19
- - benski   The main strength I've seen of ABR is the pred...   Oct 7 2011, 14:35
- - shadowking   --abr 140 is also good when you want to save space...   Oct 7 2011, 16:00
|- - Canar   QUOTE (shadowking @ Oct 7 2011, 08:00) --...   Oct 8 2011, 02:12
|- - shadowking   QUOTE (Canar @ Oct 8 2011, 11:12) QUOTE (...   Oct 8 2011, 02:22
- - JJZolx   Hope I don't get jumped on for reviving this t...   Jul 23 2012, 20:27
|- - mjb2006   That sounds reasonable, if you're streaming th...   Jul 23 2012, 21:15
|- - halb27   QUOTE (JJZolx @ Jul 23 2012, 21:27) ... H...   Jul 24 2012, 13:16
|- - JJZolx   QUOTE (halb27 @ Jul 24 2012, 06:16) An al...   Jul 24 2012, 15:53
|- - halb27   Probably you're right, and streaming works wel...   Jul 24 2012, 16:20
- - JJZolx   Actually, it is being transcoded from FLAC. Why wo...   Jul 23 2012, 21:24
|- - mjb2006   QUOTE (JJZolx @ Jul 23 2012, 14:24) strea...   Jul 24 2012, 22:44
|- - JJZolx   QUOTE (mjb2006 @ Jul 24 2012, 15:44) What...   Jul 24 2012, 23:56
- - Dynamic   Transcoding from FLAC or any other lossless is fin...   Jul 24 2012, 12:48
- - mjb2006   The popular streaming toolkits tend to be designed...   Jul 25 2012, 05:23


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