Changing bitrate in TMPGenc for VCD to fit!

[thegeeman]

The VCD arena is something i have not yet tried and i am still finding my feet so please be gentle if i sound idiotic.

The aim is to create a VCD to fit on an 80min CD. Avi file details are:

Image: 592x320;
Audio: Duration, 1:23:31; Bitrate 121kbs; Lame MP3
Video: Framerate 25fps; Data rate 142kbps; Video sample size 12bit; video compression xvid.

To cut a long story short, i have trimmed the file to 80min and 34 secs. I want it on a 80min CD. I need to only marginally reduced the bitrate for it to fit. The problem is that the settings are all greyed out. I know to load in the unlock template to alter the bitrate. What i cannot get is the resulting end file size. I dont know if i've reduced it enough, too much or what. If i use project wizard i can see the projected file size but i cannot seem to 'load' in the 'unlock' template when the wizard is up to alter the bitrate.

Any suggestions please?

[Cornucopia]

4 ways to go here:

1. Stick with VCD standards, don't change bitrate, use OVERBURNING. Hopefully, that will get you that extra few seconds needed.

2. Stick with VCD standards, don't change bitrate, cut some more...

3. Stick with VCD standards, don't change bitrate, split onto 2 discs (see the GUIDES section <--)

4. Encode at XVCD (in this case slightly lowered) bitrate. No longer to standard, but probably still compatible with most players.

(Assuming you're going with #4)
You're on the right track. You don't, however, normally unlock from the wizard--you never mentioned it, but you are talking about TMPGEnc aren't you?

You can start with the wizard, and then stop before getting to the burn phase. Then you're no longer in the wizard. Then, you just [Load] the "Unlock" template, which is located in the EXTRAS subfolder within the TEMPLATES folder of the TMPGEnc application folder. Then you can adjust to your heart's content.

Whoops! Just noticed that you can, within the Wizard, unlock individual settings...
Just click the [Other Settings] button on the 3rd panel, or the [Expert] button on the 4th panel. Go to the tab/pane you need and unlock by clicking on the setting descriptor. Example: [Audio] pane, click the word "Bitrate:" and a popup will allow you to lock and unlock.

HTH,

Scott

[thegeeman]

Cornucopia

Apologies-i didnt mention it was TMPGenc; only on title. But hey, went with the lock/unlock when cursor over descriptor as you suggested. Bitrate only down by 50kbs to squeeze onto disc-hopefully. I hope such a relatively small decrease will not make such a noticeable difference-fingers crossed anyway.

Thanks alot. Appreciated.

[bloo]

Use 90/99 min Cdr

bloo

[abc-123]

You know... you can always use Biterate calculator to get the exact size you need. Don't forget that if you're going to author you'll need some extra bites there as well.

[jimmalenko]

You know... you can always use Biterate calculator to get the exact size you need. Don't forget that if you're going to author you'll need some extra bites there as well.

... or just use https://www.videohelp.com/calc.htm (same thing).

[aldaco12]

If the movie 'cleaned' is only 80' 34" --> overburn.
3.4 MB larger than 800 won't be a great problem (more: on a 80' CD you can fit 360,000 * 2352 = 846,720,000 bytes. Deducting 10.6 MB fo authoring you're left with 836 MB, which are about 83', not 80').

For a slightly larger movie (>> 80 but < 110') my suggestion is simply: don't make a VCD but make a SVCD split on two disks (more beautiful). You could aven try to make sort of a-non-standard VCD, Kwag's VCD or KVCD (it needs TMPGenc and some KVCD templates you can download from their site).
Read http://www.kvcd.net/portal/index.php (get there the templates) and read the nice guide written in http://www.desitorrents.com/forums/faq.php?faq=how_do_i (from: convert DVD to KVCD?) to find the tools (CQCalculator and CQMatic) which can help you in finding the maximum Q value to make a movie equal to 835 MB (KVCD need about 11.6 MB , for authoring, not 10.6).
The tools are not exceptional but slightly good, at leas you can find an 'approximate' CQ value to help you making a movie rather close to 835 MB. But to have a very good precision you'll need to modify couple of times the found CQ value manually (to speed the process the softwere extract a sample of the movie, and movie complexity is variable, so you can only find an approximate value).
I personally don't make KVCDs because I think that, even if I spend long time trying to find the optimal CQ value for that movie [at the decimal point precision (e.g. 74.3)] , I think that KVCDs quality is worse than VCDs, and you can notice it in the fast-moving scenes of a movie (images doesn't seem to scroll continuously, they seem to scroll by slight steps). I don't think that saving a 60 cents CD-R compensates for the losses.
More, SVCD final size is depends EXACTLY on the chosen bitrate, so you gan the encoding time lost finding exactly the right bitrate value to set.
SVCD's largest drawback is that multipass encoding (expecilly in TMPGenc) is much slower than 1-pass encoding, so wither you change encoder (like CCE instead of TMPGenc for SVCDs) or you put the AVI to encode before you go to sleep...
But many people like to use KVCDs to squeeze a 2h movie per CD-R, so test them, if you want to use them (use a CD-RW)...

[jimmalenko]

Ahhh yes, but 846,720,000 bytes = 807.5MB

[aldaco12]

Yes, sorry, often I like to make bytes/1000/1000 = MB for simplicity, instead of diung size/1024/1024. But my result doesn't change. A VCD is about 1000 bytes per minute, not 1024 bytes per minute.

[jimmalenko]

Yes, sorry, often I like to make bytes/1000/1000 = MB for simplicity, instead of diung size/1024/1024. But my result doesn't change. A VCD is about 1000 bytes per minute, not 1024 bytes per minute.

I'd say it's closer to 10305 bytes per minute, given that 1374 * 60 / 8 = 10305.

1374 being 1150 (video bitrate) + 224 (audio bitrate), 60 being the number of seconds in a minute and 8 being the number of bits in a byte ...

... but that's only using the max specs.

[aldaco12]

Nice estimate, and sorry for the bug (I wrote 1000 instead of 10,000).

A small notice: for KVCD , and I suppose you can do for VCD as well, you use 128 kbps MP2 audio instead of 224 kbps MP2 audio.

But, I insist, I think that playing with the 'overburn' feature (which you can use to gain up to 20 Mbytes, depending on the media type) can bring you more earnings...

[jimmalenko]

Nice estimate, and sorry for the bug (I wrote 1000 instead of 10,000).

Even still ...

A VCD is about 10000 bytes per minute, not 10240 bytes per minute.

Even with that adjustment, that statement is still inaccurate as per above !

A small notice: for KVCD , and I suppose you can do for VCD as well, you use 128 kbps MP2 audio instead of 224 kbps MP2 audio.

Yep, but that's making an XVCD.

IMHO, for the benefit of those players that are strict on the spec, probably wiser to keep the audio at 224kbps, and play with the video bitrate, as it can still be true VCD (and not XVCD) if using a video bitrate of say 1050kbps (whereas any change in audio bitrate makes it XVCD). The VCD 1.1 specs says that the video bitrate should not exceed roughly 1150kbps:

The Video CD specification requires the multiplexed mpeg-1 stream to have a cbr of less than 174300 bytes (1394400 bits) per second in order to accommodate single speed cd-rom drives.
...
The cbr mpeg-1, layer II audio stream is fixed at 224 kbps with 1 stereo or 2 mono channels.It is recommended to keep the video bit-rate under 1151929.1 bps

The point there being that the video bitrate doesn't have to be 1150kbps flat to remain to VCD spec (it can be less).

But again, that's probably just semantics. Depends a lot on your player's individual preferences / leniencies.