vcd compression

[Irvy]

this is the first for me here so if I am wrong then just say so, I wanted to know how would I be able to compress a vcd file. Imean, when I take a AVESQ file from a (vcd)disc and put it on my hard drive then I cant put that same file back onto a disc again. I knw that it has something to do with the compression but why doesn't it work

[redwudz]

VCD has a set bitrate of 1150kbps. You can't change that and stay within the VCD specification. See ' What is' VCD to the upper left for the specification. <<<<<< This means you can't really compress a VCD.

[Irvy]

thanks for reply, now how do I get it to go back onto a disc once I have put it onto a harddrive

[redwudz]

It's been a long time since I used the VCD format, but you probably have to reauthor the file. You should be able to use VCDImager and VCDImagerGUI or similar. You may have to rename the AVESQxx.DAT extension to .mpg for the program to accept it.

[Cornucopia]

2 things to keep track of here:

1. Windows CDXA headers
2. Difference between Mode1/Mode2Form1 Data discs and Mode2Form2 Data Discs

#1. When you rip the AVSEQ normally, you're getting the MPEG as a ".DAT" file, but you're also getting a bunch of padding created by Windows (or more likely, not ignored by Windows). Don't use Windows to copy the file. Use VCDEasy, VCDGear, or ISOBuster--all these have special recognition of the fact that these are Packetized MPEG streams in Mode2Form2 CDXA Tracks. What they'll give you will be a true, plain MPG. Much better to work with.

#2. My guess is that you are trying to burn NOT another VCD, but a Data CD. Data CD's would (usually) be Mode1, which have an available user data sector size of 2048bytes, which gives you the Max available CD disc of ~700MB. The MPG tracks on a VCD aren't burned as a standard DataCD, but as Mode2Form2 tracks. These have an available user data sector size of 2324bytes, which gives you the Max available CD disc of ~800MB.

So what happens when you pull a (equivalent)725MB MPG track off of a VCD, which balloons in Windows to 740. Now it's too big to be burned as a data disc.

What to do next depends on what format you want the final thing to be: another VCD? (whether dupe or compilation or edited), an MPEG file on a Data CD?, some other filetype?...

If A--you "re-author" a new VCD and it should take care of the Mode2Form2 stuff for you.

If B--you're going to either have to re-encode to smaller bitrate (and hence filesize), split the file to 2 discs, or put it on a larger disc (Overburned, 90/99min, DDCD?, HDburn?, or DVD).

If C--you're gonna have to give us more info. Who knows???

Scott