call me daft ....but

[Anrasp]

.....I cannot understand the following.

After encoding a .avi with Virtual Dub and Tmpgenc I was left with a file whose size was 780 Mb.

I however managed to burn this file on a 80min - 700 Mb CDR with VCDeasy.

Can someone enlighten me how this thing works ? do 80 min CDR's hold more data than 700 Mb ?

[steveryan]

How come that I can fit 740 MB on a 74 min CD or 800 MB on a 80 min CD?
A VCD,XVCD,XSVCD or SVCD are burned in mode 2 form 2 instead of ordinary data mode where you fit 650 MB on a 74 min CD. The mode2 form2 has less error correction than data mode.

80 min CD
VCD/SVCD/XVCD mode
Mode2 Form2 = 2324 bytes/sector = 360 000 * 2324 = about 800 MB on a 80 min CD.
Data mode
Mode1 Form1 = 2048 bytes/sector = 360 000 * 2048 = about 700 MB on a 80 min CD.

(a 80min CD has 75 sectors/s = 80min CD * 60 * 75 = 360000)


74 min CD
VCD/SVCD/XVCD mode
Mode2 Form2 = 2324 bytes/sector = 333 000 * 2324 = about 740 MB on a 74 min CD.
Data mode
Mode1 Form1 = 2048 bytes/sector = 333 000 * 2048 = about 650 MB on a 74 min CD.

(a 74min CD has 75 sectors/s = 74min CD * 60 * 75 = 333000)


There you go, makes perfect sense

[Anrasp]

@steveryan ...now it does ! thanks for the clarifcation !