ConvertXtoDVD question

[tmac2085]

I have two movie avi files one is 701MB and another that is 1.35GB. And when i add them into the program it says its 4.9GB. How can this be? I can't even burn this to a DVD. Any ideas?

[redwudz]

The size of a AVI file has no real relation to the size of the same file encoded to MPG-2. Actually I'm surprised it didn't come out much bigger.

If they are parts of the same movie, burn them as a oversize DVD to your hard drive, then run the DVD file from the hard drive through DVDShrink to reduce it to DVD-5 size and burn that to DVD. If they are separate files, just process them separately and burn two DVDs.

If you just mean that ConvertXToDVD shows the input files to be bigger, then something is misreading the size. Either way, I doubt two will fit on a DVD without some further processing.

[tmac2085]

i'm dling 2 videos now at around 700MB each. Will ConvertXtoDVD put them on a DVDR without going over? Also is it normal for that program to convert for around 2+ hrs? Thanks!

[guns1inger]

You really need to read more to understand how this works.

What you download is not DVD compliant. If you want it to be compliant, it has to be re-encoded correctly, and authored into a DVD. You are probably downloading .avi files compressed with a mpeg4 variant - Xvid/Divx etc. DVD requires mpeg2 video (mpeg1 if working at VCD resolution). There is no absolute ratio between mepg4 and mepg2 when converting, but a good general rule is that to maintain the quality of the original you need to use a bitrate 3 - 4 times that of the original. As bitrate determines size, expect your videos to expand to at least 3 - 4 time the size of your originals. Encoding is a CPU intensive process. ConvertXtoDVD is one of the fsater encoders. Other could easily take 3 to 4 times as long.

The second thing you need to consider is how much you squeeze onto a disc. Discs are cheap, quality is not as easily replaced. Running time x bitrate = space. Space is a constant - 4.38GB for a single layer disc. Therefore, the longer the running time, the lower the bitrate. The lower the bitrate, the lower the quality, generally speaking. If those files run, say, 100 minutes each, you will get reasonably quality putting just one on a disc. If you put two of them on the one disc, the bitrate becomes very low, and the quality drops off accordingly. If you want to preserve the quality at all, you are better off putting 3.6gb on one disc and having some unused space, than shoe-horning 2 movies onto a disc and having very low quality.

To give you an idea of space consumption, a single layer disc will hold approx 1 hour of video encoded at the maximum video bitrate (9800kbps) with 192kbps AC3 audio.

Your 100 minute movie, with the same quality audio, will get a bitrate of around 5890kbps. Acceptable.

Two 100 minute movies on the one disc will get a bitrate of approc 2850kbps. For full D1 resolution, this is very low, and will show up as artifacts and blocking.