Filesize / SVCD edit question, how many megs?...

the_ripper wrote on 6/21/2002, 10:00 AM

CAn any of you guys tell me what mpeg2 filesize is the max for a std 700mg CD? I know other files end up un the disk. I need to know so when a Render AVI to SVCD it is chunked up correctly, otherwise it will not burn on the CD. I see where Sonic Foundry gives the filesize and movie run-time, but that does not tell me the bottom line on the filesize, allowing for the other SVCD folders w/ driver files. the_ripper

Comments

kcarroll wrote on 6/21/2002, 10:23 AM

Ripper;

I usually plan my video for about 30 minutes of playback from a SVCD. This seems to leave me a bit of a safety margin.

kcarroll

the_ripper wrote on 6/21/2002, 12:13 PM

ahhh I see. Some SVDS I have watched were about 40 mins each but I have no idea what they used for tweaks and compressions. 30 mins seems fair, though I hoped to get 40 mins. Alot of old 1 hr shows break down to 40 mins after commercials are removed. about 825 megs (which is too much) .... the_ripper

kcarroll wrote on 6/21/2002, 1:16 PM

I know that you can stretch that 30 minutes out by modifying your setting. Quality will, of course suffer. I am not an expert on the subject of choosing bitrates and settings to maximize playtime, so hopefully someone else will jump in here! (Maybe Chienworks???)

kcarroll

Chienworks wrote on 6/21/2002, 2:13 PM

*looking around behind* ... who? me? ;)

Actually i've never made an SVCD, i've only tried VCDs. It seems to me that all the support files on the disc take up very little room indeed, leaving almost the entire disc for the media file. For a really quick and dirty estimate use the number 88,000 (for 650MB discs) or 95,000 (for 700MB discs), divide it by the length of your video in minutes, and this will give the combined video + audio average bitrate that should just fill the disc. You can also divide the number by the desired combined bitrate and end up with the maximum number of minutes that will fit.

88,000 / 50 minutes = 1760Kbps, subtract 128 for audio and that leaves 1632 for video.

95,000 / (224 audio + 2533 video) = 94,000 / 2757 = 34.5 minutes on a 700MB CD.

Of course, these are only for quick figuring. Allow a fudge factor if you want to be conservative. Your material will compress differently depending on many factors such as amount of motion, brightness, contrast, etc ... But hopefully it will be helpful anyway.

BillyBoy wrote on 6/21/2002, 2:38 PM

Hmm... I've made stacks and stacks of VCD's and SVCD's. How much will fit on any particular disc depends on more then using any formula. That at best is a rough ballpark figure. You'll have to forgive me, its been some time since I've used VideoFactory and accordingly I'm getting a little fuzzy on what VF can do compared to its big brother VV which I've moved up some time ago. Before I did I used TMPGEnc a lot and posted several articles on how best to use it under my old nick (WVG) so you may want to check those out if they're still on the server.

In general when you use variable bitrate (you should for SVCD) and/or some special template (I'm talking about TMPGEnc now, not VF or VV) you can get a LOT more than 30 minutes. Visit http://vcdhelp.com. Besides the always busy forums several guys have posted tweaked templates to massage TMPGEnc into getting the most bang for the buck. Quality wise I still think TMPGEnc and the MC encoder for MPEG-2 are neck and neck. So its a toss up if you're making SVCD or XVCD. However, I agree if you're making just regular VCD TMPGEnc generally gives better rendering.

Also in the vcdhelp forums there is frequntly talk about the newer 800MB CD's which can of course hold more data. Haven't tried any myself since I'm now going the DVD route, but I have seen them a CompuUSA stores. Like with other things they only work with some DVD players, something due to being able to read beyond normal boundries in effect reading an overburned area so something, I forget. Again ask over at VCDHelp.