whoa?! why are svcds 800mb?

[speedy726]

why is it that when i put a svcd in my cd rom drive and i check the properties it's well over 700mb [which is the capacity of the disk]? Is it really 800mb or is it a trick the vcd is playing on my computer. If this is actually true, am I able to make my mpeg2 files up to 800mb in size and be able to burn it on a 700mb 80min cdr?
[confused at the mo]

[Digifreak]

Suprise! Yep, you can fit over 800 Mb on a disk in (S)VCD. The format is written differently than regular files. As long as your SVCD mpeg does not exceed about 805-810. I use the java bitrate calc. under tools and my files all end up 805 and image and burn without a hitch.

[revjake]

It works that way because VCDs and SVCDs (and audio CD, btw) don't have the extra error correction bits added to them that CDs formatted for computer data do.

Why? Simple. If you get a tiny read error in your video or audio when it's in your DVD player, you'll likely not notice it (except for a slight flickering in one frame). If there's an error in, say, the win.exe file you're trying to install from a CD-ROM, the whole program won't work. Hence, more error correction bits for the computers, less for the VCDs.

[speedy726]

Cool!! I didn't know you could do that. However, will it affect the way my cd burner burns things? I know Nero says that warning "overburn at your own risk" so i just want to know if its safe. Thank goodness I found about this now and not later on. I could use that extra 100mb!!! Does this work with normal VCDs or is it only applicable to SVCDs?

[sokhapkin]

In short, each sector on CD is 2352 bytes long. Data CD uses 2048 byte per sector only, the rest used to store error correction bits. Video and Audio CD formats uses full sector lenght. Because of it you can fit 2352/2048=1.148 times more data to video CD. But Video CDs have no ability to restore the data on read error.

[Allan55]

I know Nero says that warning "overburn at your own risk

Leave "overburn OK" turned-off. If Nero doesn't complain about your (S)VCD being too long you're not overburning; regardless of the size of the MPEG on your HD.

Over time, "74-80 minutes" and "650-700" MB have become gospel but they only apply to their specific formats (purposes). Other formats have different rules.

[vitualis]

You can fit up to one 796 MB (approx) MPEG file onto an 80 min CD without overburning if you are making a VCD or SVCD.

You can do the maths yourselves:
1. 2324 bytes/sector of user data for S/VCD
2. 75 sectors a second
3. approx. 79min 46sec available on an 80min CD (when you take into account some overhead).

Of course, if you overburn, you can fit more.

Regards.

[Bounty Hunter]

where is the overburn feature in VCDeasy? or is that automatically applied to every disc burned using VCDeasy?

[Bounty Hunter]

alright, i have found the overburn feature in VCDeasy, it is located in the -Settings - CDRDAO, and then under CD writer, the first box that can be ticked is for Allowing overburn.

am i correct in asuming that i should check that box before burning to fit approximately 795 MB's on one disc?

[vitualis]

You can burn up to 795 MB or so on an 80min CD without overburning (thus it shouldn't matter whether the box is ticked or not).

However, just leave the box ticked unless you have a problem with it.

Regards.