DivX to SVCD

[spidey]

Hey All,

Hope everyone's good.

Recently in all my DivX conversions I have tried a new method and I wanted to bounce it off you guys.

I first strip out the wav for the audio source, then in the TMPG wizard load the DivX clip for the video source.

I split the file into 2 portions to split it to 2 discs using the Source Range. Now at the end of the process it gives you a good bit rate for a CBR SVCD encode (per project) - I have been going into the settings and changing it from CBR to Manual VBR - and using the CBR value given by the wizard + 50 and then making the low range about 100 kbps or so less.

I am assuming this is giving it a decent range to fluctuate for the VBR encoding and would be better obviously than the CBR.

I know a multi-pass encode would be best, but is this a good alternative due to time spent on the encodes ?

Also, how would Constant Quality VBR stack up ? My only concern there is the lack of being able to predict the file sizes due to the % adjustment of quality. What is a good % to use in there if I was to continue using the TMPG wizard to figure the max bit rates ?

Any ideas and input is very appreciated. Thanks Guys

[incognito]

I almost always use cq_vbr for my svcd transfers.

I think the quality is much better than cbr, but the encoging time
is less than full vbr -- a good compromise.

The filesize problem is one I haven't licked yet. I get about an hour
of video on an 800M CD at around 1600, but for a 42 minute tv
episide I find I can go up to around 2100, and 1950 is perfect for most
sopranos episodes (in case anyone was wondering).

I use 77 as a quality setting.

[spidey]

Thank you Incognito

I am still wishing there was a good way to figure that last variable to (for the quality %)

In using the Manual VBR is that at 100 % quality ? If so, I'd recommend trying what I described above as it lets you fully max out the discs each time custom to the size or range of your source.

It has worked very very well. I am just curious what the differences, if there are any, between the VBR types (other than the SVCD CBR and Multi-Pass VBR).

Thank you again

[banjazzer]

Well, I will suggest something here - and I would urge you to try it before commenting. You start, as you have, with your DivX and your extracted wav. Use a recent copy of TMPGenc which has the project wizard. Allow about 50-60 mins per CD, so from the start you should know your target number of CDs. Start the project wizard. When you get to the bitrate settings, choose *Expert*, and then choose 2-pass VBR. Alter min-bitrate to 755. Alter max-bitrate to 2496. leave the av-bitrate as isfor now. Select *Enable padding*. Next, alter the CD setting to 80 min, and adjust the average bitrate until you get close to 200% or 300% of disc capacity, depending on the number of discs you have chosen. Then, let the encode commence. It is 2-pass, so it takes twice as long, and you won't see anything until the 50% mark. But you will get a pretty exact filesize for the number of discs you have chosen. You will get better quality (allegedly) using the CQ setting, but you won't have anything like the accuracy in producing the final file-size.

[spidey]

banjazzer,

I will give that a try. I do know that the 2 pass could by far yield higher quality, and grade. As well as the other VBR formats only do a single pass.

Does it offer superrior quality compared to using the CBR calculations and then creating a range though in Manual VBR ?

For instance, using the wizard, I may get a value of 2300 cbr for a range. Then I go into the "EXPERT" settings area and change it to Manula VBR and set the max to 2350 and the minimum to 2150 (with padding I believe). This I am guessing is giving me virtually a CBR type file BUT it is giving it some range to work and encode into.

I was thinking this was almost giving you a best of both worlds type quality (granted not a good multipass encode, but) - a variant range to encode to, while keeping the quality and botrates way up.

I'll give the multi-pass a try. I just wanted to avoid the 2 pass only due to time constraints. Thank you again very much Any other ideas or feedback would be great

[spidey]

The only other thing I'll say as to the Manul VBR switch in place of the CBR as I have described above, is it does give an almost perfect size match as to your disc's and how you figure it in the Wizard.

So it actually is letting you use the Wizard to figure out your bitrates, while then subbing in what I am guessing should be a better encode method then the CBR it used to figure them from your Sources.

I guess my big question might be,

How does Manual VBR stack up against any of the other VBR methods quality wise ? Planning and preparing (filesize) - wise it has been very predicatble. I was just concerned as to the quality or performance comparisions as well.

Again, thank you all very much.

[banjazzer]

CQ and Multi-pass VBR are always going to give the best results. Just think - with CBR even the credits are going to get the max bitrate. The beauty of CQ/VBR is that the more of the movie that doesn't need a high bitrate, the more bits are left for the rest. 8) And that's the way it works!

I wrote this before seeing your manual VBR stuff. I'm still not sure how manual VBR works.

[banjazzer]

Only problem is - if we try everything suggested here, there's no time left to watch these damn movies. 8) 8)

[spidey]

You're absolutely right on that Bud !!!!!

How does Manul VBR differ then ? I was under the assumption the only thing Manual in it was just setting the ranges ????

How does it's VBR differ from the CQ VBR ? Wouldn't Manul VBR be set at that same % all the time (assuming 100 %) as their no adjust ment for it ????

Thanks again for any info

[banjazzer]

The answer is here. http://tangentsoft.net/video/mpeg/enc-modes.html When you understand it - please explain it to me! 8)

[spidey]

Ok, I think I recovered....

I think what the CQ % level does is "compensate" for any drops....that's my take anyhow. THis quote I think sort of says that...but my head was spinning !!!!!
In regular VBR modes, the quality level is varied continuously to keep to a desired bit rate. CQ modes let you pick a desired quality/Q level, and let the bit rate vary to compensate. This means that you cannot predict the bitrate output from a plain CQ mode: the complexity of the video, the encoder's settings, the encoder's particular algorithm, and the pre-filtering you've done on the video all affect the output bit rate. You can't possibly take all this into account and make an accurate guess at the output bit rate when using a CQ mode

-----

It says as far as single pass VBR, that you specify a bitrate and the encoder almost guesses as it goes through, whereas the multi-pass obviously gives it an "informed idea" as to what is coming when during it's subsequent passes.

I guess it gave us the answers But I still can't tell if there's any bad idea as to going with a single pass VBR if the quality is good.......

I think we need to just worry about watching the movies !!!!!! I guess if it's not broken we shouldn't fix it !!!!!!

Thank you again very much banjazzer !!!!!!

Hope you're having a great night !!!!!!

[banjazzer]

hehe. I'm just about to go watch England struggle against South Korea. I think you will like the accuracy of 2-pass VBR. However, when the TMPGenc calc suggests the average is very close to the max bitrate, I just go ahead with a CBR at the average bitrate. That way I at least get to watch the movie before I have to go to bed.