IPB

Welcome Guest ( Log In | Register )

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
Post #1





Group: Members
Posts: 41
Joined: 28-March 08
From: UK
Member No.: 52368



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.
Go to the top of the page
+Quote Post
 
Start new topic
Replies
JJZolx
post Jul 23 2012, 21:24
Post #2





Group: Members
Posts: 395
Joined: 26-November 04
Member No.: 18345



Actually, it is being transcoded from FLAC. Why would that make any difference?

Where I've used this in practice before is in streaming my FLAC library from my home, transcoded to MP3, to my office. At the time, my home internet connection's upstream was only about 512 kbps and I found that because traffic fluctuated quite a bit I was only able to stream reliably at about 192 kbps. Using ABR worked just as reliably as CBR.
Go to the top of the page
+Quote Post
mjb2006
post Jul 24 2012, 22:44
Post #3





Group: Members
Posts: 756
Joined: 12-May 06
From: Colorado, USA
Member No.: 30694



QUOTE (JJZolx @ Jul 23 2012, 14:24) *
streaming my FLAC library from my home, transcoded to MP3, to my office.

What I meant was, depending on how this streaming is being accomplished, ABR might not make a difference.
The streaming software or gear that you're using is either
  1. taking the files "raw" and pumping them through the network—that is, if one file is 320 kbps CBR and the next is ~160 kbps VBR, that's exactly what's going out over the network, so on the receiving end you see the bitrate changing; or
  2. transcoding the files as it reads them—that is, no matter what format they are on disk, they get decoded and re-encoded with consistent parameters (that you configured in the streaming software) so what goes out over the network doesn't fluctuate.
If it's #2, then it doesn't matter whether you are making the files be ABR or CBR on disk before they're streamed.

This post has been edited by mjb2006: Jul 24 2012, 22:46
Go to the top of the page
+Quote Post
JJZolx
post Jul 24 2012, 23:56
Post #4





Group: Members
Posts: 395
Joined: 26-November 04
Member No.: 18345



QUOTE (mjb2006 @ Jul 24 2012, 15:44) *
What I meant was, depending on how this streaming is being accomplished, ABR might not make a difference.

The streaming software or gear that you're using is either

1. taking the files "raw" and pumping them through the network—that is, if one file is 320 kbps CBR and the next is ~160 kbps VBR, that's exactly what's going out over the network, so on the receiving end you see the bitrate changing


I didn't propose a scenario where we're streaming from files stored at random MP3 bitrates/encodings and trying to rate-limit it, but I suppose I also didn't specifically say we're not. Assume that the source is always lossless.

Take the case of a radio station that offers feeds in 96 kbps, 128 kbps and 256 kbps. To feed 'raw' files, as you say, they would rip and store their CDs as lossless files (perhaps FLAC) and then transcode to MP3 using the chosen encoding method, keeping files at each of the desired bitrates.

QUOTE
2. transcoding the files as it reads them—that is, no matter what format they are on disk, they get decoded and re-encoded with consistent parameters (that you configured in the streaming software) so what goes out over the network doesn't fluctuate.


Or do that, if there are sufficient computing resources. I see no difference at the client end. In either case you have complete control over the type of encoding, parameters, etc.

QUOTE
If it's #2, then it doesn't matter whether you are making the files be ABR or CBR on disk before they're streamed.


I'm still not quite following what you mean, unless you're thinking that the stream might be transcoded from MP3 files of some type.

This post has been edited by JJZolx: Jul 25 2012, 00:23
Go to the top of the page
+Quote Post

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


Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



RSS Lo-Fi Version Time is now: 28th July 2014 - 12:53