Why does the size become smaller?

[needshelp]

Whenever i convert a divx file to mpeg using TMPGEnc it shrinks to almost half the size when it is finished. Also when I play it on my computer before i burn it I find that many of the things in the background have become blocky and less crisp than in the original divx file. Why does this happen?

[devinemi83]

Because you applied "lossy" compression. The mpeg video standard really squeezes video down. The more you squeeze the more quality you lose. If you increase you bitrate you will be able to raise you quality.

[needshelp]

What bitrate would you suggest then? I would however like to keep the file size down enough to be able to fit a normal movie on two disks.

[KingJohn]

Whenever i convert a divx file to mpeg using TMPGEnc it shrinks to almost half the size

Something is wrong here, converting from a DivX to a Mpeg 1 in TMPGEnc will usually double the size. Mpeg 4 are usually much smaller than Mpeg 1.

I say usually, but if you had downloaded a full movie in DivX and the quality was reasonable, then chances are if will be much larger when converted.

In TMPGEnc you should load a VCD template, that is if you want to put it on a VCD, this ensures that the output will be correct including the bitrate.

Highly compressed Mpeg 4, may increase in size, but the quality would be so bad, there would be no point in converting it to anything else.

For example a 700MB DVD rip to DivX 3.11 Alpha, would produce a 2 disk mpeg 1 conversion, with 1GB +

[needshelp]

Sorry, I just realized that i said size in my original post. The reference to size was not to file size which does indeed grow to a gig or more. What I meant was that the screen size was smaller. So i guess that would be the resolution.

But only lately has the resolution size started to shrink and become blocky. I always use divx files that are atleast 600mb, and are usually in the 700's, and they are always of good quality even at full screen.
Plus i do use the VCD NTSC template whenever i am converting.

Also, the file is only blocky when I increase the size to full screen on my computer. Until then the quality apears to be just as good as the original divx file, but it is so small on the screen.

So my question is still why are my VCD's small and blocky when I am using the VCD template.

Also, could the motion search precision have any effect because one guide I read said to set it to highest quality (very slow). So this is what I always set it to.

Thanks in advance for any help anyone can provide, and thank you to those who have already responded.

[KingJohn]

Ok, if you take a picture "any picture" and magnify it several times, eventually you will see many blocks, and the quality will get worse the more you magnify. If your source is say 80X80 and you magnified it to 800x800 then its going to look very bad.

Your source needs to be somewhere near the final output size, you should select "Full screen > keep aspect ratio" this will make sure that no stretching happens, but if your input is very small, and changing it to the VCD size means expanding it, then the output is going to be very bad.

You can take a look at what is going on with "Setting > Advance > Clip frame" from there you can also experiment with different aspect ratio's and clipping boarders.

Video-CD NTSC (MPEG-1 352x240 29.97fps CBR 1150kbps, Layer-2 44100Hz 224kbps)

That's 352x240 the source needs to be very close to that, usually they are much larger, and shrinking them down will improve the quality. Viewing them on full screen on a PC wont give the same results as what it may look like on a VCD

[needshelp]

Ok, that is what i wanted to know. I am not near a DVD player other than the one on my laptop, so i worried that it wouldn't look good when i finally played it on a DVD player. Thank you everyone for you help.