Uhm VCD 80 min but burn only 75 min (VCD specifications)

[dinkob]

Hi.

I am only burning VCDs, SVCD is cool but... I like VCD better actually.

Now, let's say I have a VCD 80 minutes in length (split in 12 tracks for example with TMPGENC).

I drag them to Nero but Nero says that it won't fit on the CD (700 Mb which is = 80 minutes cdda audio).

Now if I am not mistaken VCD specifications are the same as of Audio CD (meaning even though computer size is 740 Mb > burn to CDDA or VCD will fit on 650 Mb no problem).

So am I interpreting this wrong or Nero is wrong (I think this used to work on Nero before!!!).

Dinko

[kees1952]

To clarify things about CD storage:
We start with the audio CD. Sample rate: 44100 samples/sec, 16 bits, stereo giving 44100 x 2 x 2 = 164000 bytes /sec. A one speed CD reader reads 75 sectors each sec, so one sector contains 164000 / 75 = 2352 bytes.
The audio CD layout is the basic layout for all CD's, so all data CD's must fulfill this specification.
A 74 min CD contains 74 x 60 x 75 = 333000 sectors.

Due to sync blocks, headers, error detection and correction only 2048 bytes of the 2352 bytes can be used on a data CDROM so:

74 min CD: 333000 x 2048 / 1024 / 1024 = 650 MB data
80 min CD: 80 x 60 x 75 x 2048 / 1024 / 1024 = 700 Mb data
90 min CD: 90 x 60 x 75 x 2048 / 1024 / 1024 = 790 Mb data

and so on.

For video data the error correction is left out so we can use 2324 bytes of the 2352 bytes so:

74 min CD: 333000 x 2324 / 1024 / 1024 = 740 MB data
80 min CD: 80 x 60 x 75 x 2324 / 1024 / 1024 = 800 Mb data
90 min CD: 90 x 60 x 75 x 2324 / 1024 / 1024 = 900 Mb data

The first (2048 bytes per sector) is called data sector Mode 1 (CDROM) or Data-sector Mode 2 Form 1 (CDROM-XA).
The second (2324 bytes per sector) is called Data-sector Mode 2 Form 2 (CDROM-XA).

A VCD is a CDROM-XA Mode 2 CD containing both Form 1 and Form 2 sectors.

Hope this helps, Kees Janssen.

[Betamax]

I drag them to Nero but Nero says that it won't fit on the CD (700 Mb which is = 80 minutes cdda audio).

If your burner can burn disks of 700MB/80min and you're also using these kinds of disks, then it shouldn't be any problem.
Though if you create the wrong type of disk in Nero (say: an ISO9660/Joliet disk, which is a data-disk, with sectorsize of 2048bytes) you won't get a real VCD and you'll only can write 700MB.

Though if you choose the correct type of disk (=VCD, with sectorsize of 2352bytes, type Mode2-XA(/RAW)) you can fit about 800MB (and sometimes even a bit more) onto 1 disk.

Be sure you choose the correct format for your vcd's.

[vitualis]

https://www.videohelp.com/forum/userguides/135642.php

Regards.