Ideal Bits/(Pixel*Frame) Ratio

[manoflogan]

Hi,

I am starting to use Gordian Knot to rip DVD into avi files. I would like to know the ideal Bits/(Pixel*Frame) ratio to convert a d2v file to avs file to avi file for both 1 CD and 2 CD. I am confused about this as some files have an aspect ratio of 16:9 or 4:3.

Please help me here.

[CWR03]

There's no "ideal" number, plus the quality can vary depending on the amount of action in the video. It's mostly a matter of what level of loss you can deal with, which can only be based on your perception.

[manoflogan]

Hi CWR03,

What do you mean by amount of action in the video? How do i determines the level of loss acceptable? Is there is an indication for this? Please let me know.

[Sharktooth]

b/p*f is useless coz it doesnt include the source compressibility. so the results can wildly vary from a "static" movie to an "action" movie.

[CWR03]

How do i determines the level of loss acceptable?
By encoding and watching the video. The number is just a very rough guideline and was never meant to be used as a way to determine overall output quality. "Action in the video" refers to movement by characters, cameras, etc. If you took two films with the exact same resolution and length, let's say for example On Golden Pond (lots of still camera shots and characters just sitting still and talking) and Die Hard (Explosions, cuts, running, etc.), in order for the quality of each individual frame to be the same between the two films the bitrate for the latter would have to be much higher. The only indication of the level of acceptable loss is your own eyes.

[manoflogan]

So more the bit rate, more clear is the video, then...

[CWR03]

Not "clear," per se, but less blocky in areas of like color, less banding in areas of color transition. You can reduce the resolution of a video to lessen artifacts, and you will lose fine detail. If you're doing 2-pass encodes, the quality isn't based so much on bitrate as the bitrate is based on the file size you've specified. But yes, a larger specified size will yield an overall better quality file.