787MB fits on a 80min, 700MB VCD?!?!?!

briggs wrote on 3/8/2002, 7:48 AM

I just finished a project that was 77 minutes and 15 seconds long. I used VV3a to render and burn to VCD (on a 80 minute, 700 MB CD-R) in one step using the default MainConcept MPEG1 VCD-NTSC template.

I know that there is some "extra" data info that gets burned to a VCD so I wasn't sure that my 77:15:00 project would fit. It did fit (I viewed the beginning and end and it's all there) but what suprised me was that the mpg file that VV3 created turned out to be 787,685KB.

Was curious if anyone knows how a 787MB file (plus overhead files) fit on a 700MB CD-R????

Comments

p_l wrote on 3/8/2002, 8:29 AM

For VCD look at the time of the file.

If you're encoding to VCD (white book standard) then:

MPEG1 352x240, video=1150kbits/s & audio=224kbit/s

This works out to 1min=10MB. Notice that the bitrate is in kbit/s, that is per second. So the only thing that affects the size of your encoded MPEG is the bitrate and runtime of our source.

The size of the source doesn't matter! Neither the resolution of the source, nor the resolution of the encoded MPEG matter. Only the source runtime and bitrate.

VCD standard 1min=10MB. So a 60min video will encode to a 600MB MPEG.

Since x(S)VCDs are burnt as mode2 data (no error correction) you can store 740MB on a 74min CDR or 800MB on an 80min CDR. Notice that works out to 74min on a 74min CDR, and 80min on an 80min CDR (for white book VCD standard, if you change the bitrate you can fit more or less video per CDR).