TmpGenc & Resolution Conversion

[alchemist]

I have a video file that is 576x432 and I need to convert it to DVD format with TmpGenc, but I'm having a bit of trouble with the settings.

Everytime I re-encode I either end up with video that is stretched or shrunk or video that is in a wrong resolution for use on a DVD. I want to go to 320x240 for this DVD. What do I need to change?

[wwjd]

I think 576x432 is PAL, if it is then you will need to convert to NTSC. I have not done that but I know there are guides and numerous threads on this site that should help you.

[alchemist]

No, it's not PAL. The Framerate is 23.976 (NTSC Frame Rate) and the aspect ratio is 4:3 (NTSC Full-Screen standard) so it's just a matter of converting the resolution...

What I'm trying now is setting the Source Format at VGA (1:1) and setting the output to 320x240 (Low-Res NTSC DVD) Still got about 15 minutes to go on the encoding.

[lordsmurf]

320x240 is not a DVD spec. You made a mistake. 352x240 was correct.

Anyway, you'll have a better quality end product if you use 704x480 or 352x480.

[alchemist]

Ok, so what settings to di Need to set in TmpGenc to get a 352x240 output with reasonable quality from 576x432?

On the video tab I have:

Stream Type MPEG-2 Video
Size: 352x240
Aspect Ratio: 4:3 Display
Frame Rate: 23.967 fps (internally 29.97fps)
Rate Control 2-pass VBR
Profile & Level: MP@ML
Video Format: NTSC
Encode Mode: 3:2 pulldown when playback
YUV format: 4:2:0
DC component precision: 10 bits
Motion search precision: Motion estimate search (fast)

On the advance tab I have:

Video Source type: Non-Interlace (progressive)
Field Order: Top Field First (field A)
Source Aspect Ratio: 1:1 (VGA)
Video Arrange Method: Full Screen (keep aspect ratio 2)

Is there anything I need to change?

[jimmalenko]

Your settings look fine for 352 x 240 MPEG-2, although I must ask why you're using 2-Pass VBR for 352 x 240 ? The only reason I could think of is because you're trying to cram this as small as possible ...

If you want the best quality, use 704 x 480 or 720 x 480 and use 2-Pass VBR with min 1000, max 9000 and avg calculated using a bitrate calculator.

[alchemist]

The only reason I could think of is because you're trying to cram this as small as possible ...

You hit the nail on the head. It's anime that I am backing up, and I want to get about 480 minutes on a DVD-9.

I used that bitrate calculator and came up with an average bitrate of 2085kbps, but would that be the same for 352x240 or do I need to use a different calculator for that?

[jimmalenko]

No, that same calculator will work fine irregardless of resolution. After all, Size = Bitrate x Time, so your resolution does not factor into the mathematical side of the equation. It does, however, enter the quality part. 2085kbps will be absolutely heaps for 352 x 240, and that's using 224kbps AC3 audio too. I'd do a CBR 2000kbps encode if I were you because there's no quality advantage IMO using 2-Pass VBR in this case, and a CBR encode will be twice as quick.

[alchemist]

So if I'm understanding you correctly I'm not going to see any difference in size between a 352x240 and a 704x480...

Am I reading that correctly?

[jimmalenko]

in filesize ? No, resolution plays no part whatsoever. Bitrate and running time are the only contributing factors to filesize. so two identical files, one 352 x 240 and the other 704 x 480, should theoretically come out at the same size if you use the same bitrate on each.

Resolution plays its part when you apply the bitrate to it (from a quality perspective) so you should choose either a suitable resolution for the bitrate you need to use (as calculated), or alternatively if you want to use a particular resolution, then you need to use a suitable bitrate, and may have to consider more than one disc.

[alchemist]

Ok. I understand now. I'm re-encoding at 704x480 at the same bitrate I was using before and I'm going to see how the quality is. If it's OK, I'll use the higher resolution.

Thanks for the help.