Odd MPEG1/2 technique: Good or Bad?

wdorr wrote on 5/13/2002, 2:37 PM

I've been using the following system:

900mhz Duron
416Meg Ram
5400rpm HD
Win Me
and VV3.

I've noticed that when trying to do MPEG2 with VV and the MC MPEG that it takes several hours to accomplish my goals. (Case in point. Trying to convert from 1 hour of MS Mpeg4v1 of animation (that, IIRC, I recorded at all the max settings initially) took me about 20-30hrs.)

The end result wasn't super great, noticing a lot of interlacing lines and so on during the video.

But I've tried something else. I first encoded the video files to MPEG1 (which I can do on a nearly a 1:1-1:2.5 ratio) at a higher CBR (something like 3Million, hopefully to cover any loss in quality). Near useless to me for SVCDs for what I'm trying to do, but I found that if I re-encoded the MPEG1 to MPEG2 with VBR (1.5M, 1.25, 192k -- the same as I was using before), it did the job at about a 1:4 ratio. After burning the MPEG2 to SVCD with VCDEasy and playing it back on a DVD player I found the results to be better than plain old VCD with only slight artifacting here and there at only major changes in video.

But even with all this, am I just fooling myself or is this actually a good way of going about it? I cut the total encoding time on this project from about 20hrs to about 6hrs; however, in all honesty,is the transition from higher BR MPEG1 to lower BR MPEG2 costing me quality that a better 'straight-to-lower BR-MPEG2' would give me with proper tweaking in the first place?

Comments

murk wrote on 5/13/2002, 5:37 PM

Honestly, VV3 sucks for encoding and transcoding. It is too slow and doesn't allow batch encoding. Use VV3 to edit your movies. Then render them to the best quality (DV or MPEG-2). Now you can transcode to a plethora of different formats. I use a really sweet piece of freeware called 'TMPGEnc'. This software allows you to batch transcode any number of files to any number of output formats. This only works with AVI(All Codecs), MPEG-1, and MPEG-2 files. You can just queue up your files as a batch process and let it run. TMPGEnc lets you specify many advance MPEG and AVI settings. I find that to transcode a 1 hour 704x480 MPEG-2 to a 320x240 MPEG-4 AVI, takes about 3 hours. I just load up the batch queue before bed, and wake up and the machine will be shut down(an option TMPGEnc provides) and I have new trancodings of my MPEG-2 video.

BillyBoy wrote on 5/13/2002, 6:19 PM

Maybe and maybe not. I've written about similar things I did to improve VCD's and SVCD's of which I've made many, first using Video Factory and now Vegas Video. While some have been skeptial and on the surface you would think it is a waste of time, seeing the final result is believing. I have taken rather poor quality MPEG-1 files, starting by rendering out to AVI, then back out to either new MPEG-1 or MPEG-2 for the purpose of making both VCD and SVCD files. I tried skipping the first step of converting to AVI and just tried to get the most out of the files I could with careful attention to filters like color curves and levels. The results were better going to AVI first.

While far from being technically expert on what's happening, I concluded that since the AVI file size is vastly larger, more information is available from which to make the second render better looking. While true any imperfections in the source file are still contained in the file, the careful massaging of the file eliminates or greatly reduces certain types of artifacting and interlacing lines. Why, I don't know, but it does. Not always, but often enough to make the effort worth trying. Now that I'm starting to make DVD's, the results are better still using the same inferior grade source files. Why it works, I don't know, I just know it does. :-)

pelvis wrote on 5/13/2002, 9:42 PM

Is there any way you can save out the animation in something other than MS MPEG4?

If you can render a .png or .tga still image sequence, or uncompressed .avi, and then encode that as MPEG-2, you should see much better results.

wdorr wrote on 5/14/2002, 2:05 AM

I was thinking that uncompressed AVI might compress to MPEG2 better, but HD space was/is an issue for my initial recording. (Only about 12gig free) If I get the chance, I'll try doing a couple minutes of uncomp. AVI capturing and rendering to time the difference.

When I said animation, I should have said "Invader Zim episodes I recorded off Nickelodeon..." Pretty much using Virtualdub to do the initial capture (and MS MPEG seemed to give me the best bang for my buck in quality:space ratio). I've been trying to totally bypass the need and use of a VCR.)

Whatever the case, I'm hoping to get a bigger (and faster) HD sometime. When that's done, I'll probably try my hand at more noncompressed footage, anyway.