VirtualDub, TMPGEnc and Deinterlacing

[dirk67]

Hi,

I have been doing a lot of VCDs from analogue captures using VirtualDub and TMPGEnc 12j. I always did it by the book, I capture at full vertical PAL resolution, 352x576, than apply the VirtualDub filters smart deinterlace and bicubic resize to 352x288, then encode with TMPGEnc. It worked fine for me. Since my DVD player does not accept XVCDs, yesterday I did some tests with XSVCDs in VCD resolution. I captured a small AVI in 352x576 and converted it to MPEG2 using various different bitrates. For speed reasons I left out the filtering in VirtualDub for my tests. When I had found a working set of parameters in TMPGEnc, I converted a whole movie including the above mentioned filtering in VirtualDub. What amazes me is that the picture quality was worse with the VirtualDub filtering than without. I use the TMPGEnc template SVCD PAL with the following changes: vertical resolution 288, no interlace, 2 pass VBR max 2100 avg 1600 min 0. If I let VirtualDub do the deinterlacing and resizing, the picture gets quite unsteady, whereas if I feed the full resolution AVI to TMPGEnc, the picture is very quiet and the quality beats everything I ever did.
How can that be? I did NOT apply the deinterlace filter in TMPGEnc. I would have expected it to be the other way round. What does TMPGEnc do if it has to resize an interlaced source? If anyone is interested, I will do the same tests with the standard VCD template again.

[Luis]

Probably cuts alternates lines and interlacing is removed this way. This means that you are not getting more quality capturing at 352x576, and 352x288 would be ok (saving disk space). Try this and compare the final output. For sometime I am capturing at 480x288 from a Hi8 source, and then resize to 480x576 to produce svcd output; I find that quality is better this way than capturing at 480x576 and applying deinterlace filters.

[dirk67]

@Luis,

I was thinking the same, but just couldn't believe it, since every HowTo I read tells me to apply the smart deinterlace filter in VirtualDub. Leaving this out and capturing at half resolution would not only save me disk space but also encoding time! I will do the same test again with standard VCD and with a source captured at half resolution and post the results.

BTW, the quality leap of the 1500 avg kbps vbr compared to the 1150 kbps cbr is so outstanding, I'm already thinking about recapturing and encoding the more important movies and concerts...

[SatStorm]

The programs evolve and change but the guides remains as it is, 'cause new testings must be done and noone do them...
Anyway, try also this:
Capture an .avi at 352 X 576 or 704 X 576, which give you the full lines of an analogue source.
For VCD just load the .avi on TMPGenc 2.51, go to the advance menu, select de-interlace and set it to "odd field". No "adaption", "double", etc, simply De-interlace odd field. Now load the standard VCD template, unmark the "No motion search for still picture part by half picture" and hit encode. You have almost VHS.
Now, a usefull tip, sometimes works great: Use the "sharp" filter at 74 (both) without using the "soft block noise" feature. For same strange reason, tmpgenc on the new versions do better job that way... That creates VHS quality for sure on my eyes...
There gonna be blocks on same fast moving scenes (as usual for those bitrates), but overall the quality is very good. For a typical movie grabb, that settings are ok for me.
For TOP quality, you go for xSVCD. Load Sefy's xSVCD template for startpoint. I suggest to set 2pass VBR, with 1100average, 200min, 1600 max.
Hope I help you a bit....

[dirk67]

@SatStorm:

Capturing at full vertical resolution is what I've always been doing. The XSVCDs I'm doing are like Sefy's SxVCD combined with 2 pass vbr. Thus I can calculate the exact filesize and can utilize the whole disc(s) depending on the movie length.
Thanks for the tip, I will try TMPGEnc 2.51. I didn't try yet, because 12j was ok for me, and you know: Never change a running system...

[SatStorm]

Two things also, I forgot to mention:
1. Use smaller gops for better results.
2. For xSVCD, always set your output to "interlace", and the DC at 10. The remaining 288 lines shows better as interlace than progressive on any TV Screen!