VBR Vs. CBR Mp3

[ZooMati]

Im not an experienced xvid encoder but I got a clue of how its done. Ive just ripped my 5th DVD and encoded it to xvid. The IVTC, AR ect. is perfect but Ive stumbled across an problem doing the sound encoding. I used BeSweet v1.5b29 to encode the AC3 file to a 160kbs VBR Lame. When I was muxing the mp3 and the encoded xvid Dub varned me about my VBR format and wanted to re-encode the sound to CBR. After Dub re-encoded the sound to CBR it was out of sync. Anyway, to make a story short.. I re-encoded the AC3 to CBR and muxed it again. Now im missing about 6Mb to fill a cd. My question is, whats the big diff between VBR and CBR ? Will anyone notice ? Or should I go with the CBR ?

- Zo

[mob]

VBR is what the "quality freaks" prefer.

It will enable you have the audio take up less space and still sound great... leaving the extra space for the video.

I prefer VBR. Most people do too.

[mob]

It may not have sounded so clear in my post above.

Let me clarify...

CBR - Quality stays the same (for example 128kbps) throught the whole audio.

VBR - Quality changes from high to low throughout the whole audio. So like if there is a moment of silence then you dont need to be using 128kbps and so it will encode at say 96kbps.... then on a part where alot of sound and action is happening it will need more so it will encode that part at say 192kbps...

VBR jumps around all the time... giving you the quality only where you need it. In the end it should give you a smaller audio file than when encoding in CBR.

[ZooMati]

Mob, Thx man.. I`ll stick to the VBR then.

- Zo

[OmegaSupreme]

When encoding to xvid, you should go with CBR because some players have compatibility problems with VBR mp3s.

[ZooMati]

When encoding to xvid, you should go with CBR because some players have compatibility problems with VBR mp3s.

Well, You got a point but Im kinda agree with mob here. Ive been looking through some nfo files and I notice that most groops use VBR. Most people who has problems with playing xvid ect. ask around and they all get the same answear: "get proper codec/player".

- Zo

[ZooMati]

It may not have sounded so clear in my post above.

Let me clarify...

CBR - Quality stays the same (for example 128kbps) throught the whole audio.

VBR - Quality changes from high to low throughout the whole audio. So like if there is a moment of silence then you dont need to be using 128kbps and so it will encode at say 96kbps.... then on a part where alot of sound and action is happening it will need more so it will encode that part at say 192kbps...

VBR jumps around all the time... giving you the quality only where you need it. In the end it should give you a smaller audio file than when encoding in CBR.

Now I came across an other intresting problem, reg. dub wont let me keep the audio as it is. I need to cut out 2Mb of the cast but dub still re-encoding my sound to cbr. That makes my xvid out of sync. Is there an way to cut some some frames of the end of the movie whithout dub re-encoding my audio to cbr ?

- Zo

[mob]

It may not have sounded so clear in my post above.

Let me clarify...

CBR - Quality stays the same (for example 128kbps) throught the whole audio.

VBR - Quality changes from high to low throughout the whole audio. So like if there is a moment of silence then you dont need to be using 128kbps and so it will encode at say 96kbps.... then on a part where alot of sound and action is happening it will need more so it will encode that part at say 192kbps...

VBR jumps around all the time... giving you the quality only where you need it. In the end it should give you a smaller audio file than when encoding in CBR.

Now I came across an other intresting problem, reg. dub wont let me keep the audio as it is. I need to cut out 2Mb of the cast but dub still re-encoding my sound to cbr. That makes my xvid out of sync. Is there an way to cut some some frames of the end of the movie whithout dub re-encoding my audio to cbr ?

- Zo

I'm not familiar with the program but cant you use vitualdub to cut out the frames at the end? I Know you can select direct stream copy for both audio and video or just one or the other. You can select direct stream copy on the audio and then be able to keep your audio untouched as you cut parts out. No need to re-encode the whole thing all over. The more you re-encode, the more quality you will lose.

[VidGuy]

mob - you need to be careful about your wording.....

CBR - BITRATE stays the same (for example 128kbps) throught the whole audio (not quality - the quality jumps up and down depending on whether 128kbps is "good enough" for the complexity of the sound at that point in time).

VBR - BITRATE jumps up and down, in an attempt to keep the quality consistent.


Zoomati - use AviMuxgui (see Tools section) - it's a free tool that does a terrific job muxing VBR mp3 with xvid/divx to create a perfectly sync'ed AVI. "Nandub" (a variant of VirtualDub) also creates a sync'ed AVI with VBR.

[mob]

That's correct vidguy. CBR and VBR deal with the changes in the bitrate which ultimately lead to quality.

You brought up another point which I didn't address. That is, with CBR not only are you using too much bitrate at some points of the audio, but there are also times when you don't use enough bitrate aswell. Both problems are solved with VBR.

What it all comes down to is this, if you are looking for the smallest possible audio file size with the best possible sound than VBR is your choice.

A reason for using VBR... like I mentioned above, is so that you can have a smaller sized audio file which will leave more room for a higher quality video. For that reason alone it is the method of choice for most people.

If filesize is not an issue for you, then you can always encode at 320kbps CBR and you're good to go.

[ZooMati]

mob - you need to be careful about your wording.....

CBR - BITRATE stays the same (for example 128kbps) throught the whole audio (not quality - the quality jumps up and down depending on whether 128kbps is "good enough" for the complexity of the sound at that point in time).

VBR - BITRATE jumps up and down, in an attempt to keep the quality consistent.


Zoomati - use AviMuxgui (see Tools section) - it's a free tool that does a terrific job muxing VBR mp3 with xvid/divx to create a perfectly sync'ed AVI. "Nandub" (a variant of VirtualDub) also creates a sync'ed AVI with VBR.

Thx man, I`ll try this one

- Zo

[Bjs]

The answers to the question why its out of sync or smaller than before should be obvious now , dont use vbr , use cbr only and you'll have no problems .

I personally use mp3 audio at 96k cbr for all my mpeg4 conversions (dvd to 1 cd) , and they play on my msx-888 home dvd player , with no audio sync issues .

And at 96k , the audio is nice and small , giving the video encoding the best chance of high quality no matter the codec used (3ivx , ms3 , divx , xvid or realmagic) .

[MessiaH289]

I've been using XviD video and VBR MP3 192kbps audio for all my MPEG4 encodes and it's been great and plays great on my Philips DVP642.

[jimmalenko]

In the end it should give you a smaller audio file than when encoding in CBR.

Not exactly. A VBR with min anything, ave 128 max anything will have the same filesize (in theory, with negligable difference in practice) as a CBR 128.

Now im missing about 6Mb to fill a cd. My question is, whats the big diff between VBR and CBR ? Will anyone notice ?

I wouldn't be real concerned with 6MB free

What do you mean by "Will anyone notice" ? Who else is going to see it ?

[MessiaH289]

Differences between VBR and CBR MP3 sound is mostly noticable by the human ears if that's what you mean.

[Ivo Ivanov]

I have a few too "funny" CDs with VBR. The video VBR is recomended (not for standard VCD), but with audio VBR - this is too much!