Couple AGK Questions

[directhex]

1. When encoding DVD source to xvid, my heights are going from 480 to 416. How do I keep the original source height?

2. What settings get me the absolute best quality the codec can capture? Size constraint is not a major issue for me. I tried 100% quality 1 pass encode and get a 2gb file for a particular source. I tried the same source with 2 pass and set the target size for 4gb, and the result is a 2.8gb file. What is technically different between these two files?

Thanks in advance.

[directhex]

Ok, my understanding (from reading some other threads) is that AGK is trying to convert the DVD source to the playback AR (which in my case should be 16:9) at what ever resolution the target width is set to. But, if I choose 768 fixed width, I would think I should get a height of 432 (since 432 * 16 / 9 = 768), but instead I get 448 for height.

Using "Override input AR" to 16:9, here are the results i get with some fixed width's:

848 x 496 : AR = 1.71
832 x 480 : AR = 1.73
816 x 480 : AR = 1.70
768 x 448 : AR = 1.71
752 x 432 : AR = 1.74

Am I missing something here? It seems there are better matches that get closer to 1.778.

[manono]

Hi-
But, if I choose 768 fixed width, I would think I should get a height of 432 (since 432 * 16 / 9 = 768), but instead I get 448 for height.
And there aren't any black bars in the vobs being cropped away? You might try going into the Hidden Options and checking the "Force ITU Resize Method" box and see if you like the results any better.

[directhex]

Actually no, the video source does not contain black bars. But, DGIndex reports it as 16:9 and it look good at 16:9(forcing a vob clip to 16:9 in xbmc).

Is it possible to force 720x480 encode in AGK and apply an AR afterwards manually with an external tool?

I will try the force option you suggested when I get home and see if it helps.

[manono]

Is it possible to force 720x480 encode in AGK and apply an AR afterwards manually with an external tool?
Yes. In the Hidden Options, under Autocrop, check "Tune AutoCrop Parameters" and set the Threshold to zero. Under Aspect, tick "Original". Back in the Advanced settings set the width to 720. That'll give you an uncropped 720x480 encode. I think. Someone correct me if I'm wrong about that. And set the DAR afterwards using MPEG4Modifier.

[directhex]

Great, thank you for the help. Getting 720x480 output now.

Would you happen to be able to explain about what is technically happening between 100% quality single pass encoding and using 2 pass but setting the target size greater than the codec can generate (5 gb for example)?

[manono]

No, I forget. There are some differences between the two, but I forget exactly what they are. Matrix, maybe? 2-pass using quant 1 when it can't produce the desired size, maybe? Maybe someone else will come along that knows why you got 2 very different sizes for what seemingly should produce pretty similar sizes.