DivX5 Pro options

[alc101ma]

Have you guys tried the DivX5 Pro options: bi-directional encoding, gmc, quarter pixels, and psychovisual enhancement?

I have read that bi-direction encoding will make the file smaller and should be used. This is just making the encoding longer but better, right? The gmc option I don't know about. Doom9.net says quarter pixels is a bad option. Last, what about psychovisual enhancement? How much will this decrease the file size and how much, if at all, does it hurt image quality?

Also, do these options work better/worse for different types of movies? ie action films, slow films, cartoons

Thanks!

[khp]

Re: DivX5 Pro options

Originally posted by alc101ma
Have you guys tried the DivX5 Pro options: bi-directional encoding, gmc, quarter pixels, and psychovisual enhancement?

Yes.

Originally posted by alc101ma

I have read that bi-direction encoding will make the file smaller and should be used. This is just making the encoding longer but better, right?

No, playback will also be a bit more cpu intensive. And the b-frames will be encoded at a slightly lower quality.

Originally posted by alc101ma

The gmc option I don't know about.

GMC also makes encoding slower, and playback slightly more cpu intensive. In quality based encodeing it will result in slightly smaller files, which means that you will get slightly better quality with bitrate controlled encoding.

Originally posted by alc101ma

Doom9.net says quarter pixels is a bad option.

The problem is that Q-pel can very easily cause artifacts when encoding at low bitrates.

Originally posted by alc101ma

Last, what about psychovisual enhancement? How much will this decrease the file size and how much, if at all, does it hurt image quality?

I'am sorry I haven't tested this much, but hopefully it won't change the filesize much, the point of using bitrate controlled encoding is to have precise filesize prediction. What the psychovisual enhancement tries to do, is to improve the quality where it's noticeable, and decrease the quality where it's not noticeable. This works on both inter- and intraframe level.

Originally posted by alc101ma

Also, do these options work better/worse for different types of movies? ie action films, slow films, cartoons

I don't know. I suppose B-frames will be most effective in action movies.