Confused about minutes vs. megabytes

[vice86]

Can someone clear my confusion about burning minutes on a CD and not to worry about megabytes. Is it just as long as its 74 / 80 minutes I don't need to worry about the file size?...I read if a file size is like 750MB but still 74 minutes in length it will fit? What is this all about. Thanks!

[Al Bundy]

A (S)VCD has a different disc layout than a data CD. You can multiply 650MB(=74min) or 700MB(=80min) with 1.13 and the file will still fit on the CD.
A 650MB CDR can hold 650x1.13=734MB if burned as (S)VCD
A 700MB CDR can hold 700x1.13=791MB if burned as (S)VCD

1.13 is a bit on the save side. Probably you can use 1.14 or maybe even 1.15. Nero says 1.13

It is confusing, but watch the minute marker of the burn program. If it say 74 min, you'll know it will fit on a 650MB disc.

Hope this will help.

[vice86]

So let me just get this straight.....If I have an encoded mpeg file that turns out to be 1.4GB big....I can split the file up into an even 700MB and fit each 700MB file onto a 650MB CDRW? Thats pretty cool. I use VCD Cutter to cut the files down. I guess I can just move the marker over to 74 minutes of the movie and cut there and just make sure it falls under the approx. 734MB mark.

Thanks Al!

[Kdiddy]

However keep in miind, that above equation ONLY works at standard bitrates....higher bitrates cause less mins per disk & vice versa for lower bitrates..this is why it is VERY important to use a bitrate calculator

http://www.vcdhelp.com/calc

[Al Bundy]

Yep, you are right. That will fit easily. Kdiddy is right about the bitrates, though. If you use standard VCD template of TMPGEnc it will work.
SVCD is a bit different, because bitrate is not constant. I haven't burned SVCDs as much as VCDs but the multiplier should be about the same (1.13). On a normal 74min CDR a SVCD movie of about 45 minutes will fit. Watch the minute bar of your burn program. That will tell you if it will fit.

Calculate again for 90min (=800MB) CDRs!

Why cut VCDs after being encoded to MPG? You can use batch encode of TMPGEnc to encode half of the movie first and then the rest. Preferably with a small overlap of a few seconds. You can even let TMPGenc shut down you PC, if you have a ATX mainboard and ATX powersupply, when it finishes the encoding process.

Have fun

[hitechjunkie]

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR size=1 color=black></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2001-10-16 16:31:21, Al Bundy wrote:
Why cut VCDs after being encoded to MPG? You can use batch encode of TMPGEnc to encode half of the movie first and then the rest. </BLOCKQUOTE></FONT></TD></TR><TR><TD><HR size=1 color=black></TD></TR></TABLE>

just keep in mind that the file size for each segment, when using VBR, can and will vary in size, depending on the video data being encoded, even if there are equal number of frames being encoded to each half.

i recently encoded "the mummy returns" into two mpegs, splitting it just about down the middle. the first mpeg was just under 790mb in size, small enough to burn to 80min media, but the second mpeg, although roughly the same number of frames and movie minutes, was almost 860mb in size.

i have noticed that ending credits that scroll, tend to demand maximum video bitrates, while those that fade-in/out and are static, demand a lot less. something to keep in mind when batch encoding a movie and trying to decide where to make the split...

[thxkid]

not true, I encode SVCD's at CQ at 2520 and I can get 40min. on a 80min. CD-R and 49min. on a 99min. CD-R with great results.

[vice86]

Im NOT using the standard 1150 for vid bitrate....im using the calculator here on this site to figure it out...i drop the audio bitrate to about 160-192 and go from there with the video bitrate....while also keeping it to 2 cd maximum. Most of my bitrates are around 1400-1800. Is there some multiplyer for that?...I'm guessing that throws the whole 1.3 thing off.

[Kdiddy]

I dont see why you need the multiplier..you selected 2 CDs...so the video bitrate it gives you is the one you need for the movie to fit on 2 CDs period....why are trying to calculate the exact size??...but if you must know

file size in bytes = bitrate x total movie time in seconds / 8

for the above make sure you enter bitrate in bits not k or m, or if so, adjust your byte answer accordingly.