PDA

View Full Version : Too much fast motion. Fast motion confusion


magicalpig
22nd January 2002, 19:46
I've been working on this one rip for about 9 days now, nonstop. I've tried 3 different resolutions (from 89:1 to 133:1 compression) and each time it's been favoring a fast motion encode for about 70% of the movie. I don't know what it is about this movie; it's not particularly fast motion.

I figured "it must like this FM encode because it's just the right size for reaching my 700MB constraint." So what I did was added a LM encode that would come out to be about the same size as this fast motion encode. It only wanted to use this same-sized LM encode like 0.2%!!

So apparently it likes the FM encode for reasons other than its size. Next I added a LM encode that would have approximately the same diff tracking rating. The size wasn't right though, so the FM was still favored 70%.

What I'm trying to do now is remove this FM encode (by overwriting with a copy of the most favored of the LM encodes). But I know a movie without any FM suffers, so I added 2 more FM encodes in the hopes that I could keep one that Fair Use only wanted for 20% or less. The new FM encodes were one half and one double the bitrate of the original FM encode which FairUse wanted to use for 70% of the time yet the total sizes of all 3 Fast Motion encodes are all pretty much the same!

This is what's really got me confused.
A FM-97 encode and a FM-170 encode are coming out at about the same size. So when I delete that one that was going to be used for 70%, one of the other FM's gets promoted to 70%.

Does anyone have any insight into the criteria by which FU chooses how to utilize each encode?

fu2k
22nd January 2002, 23:24
> A FM-97 encode and a FM-170 encode are coming out
> at about the same size.

FM encodings, by definition, use a minimum quantiser of 5. This means that they hit their "bitrate saturation" quite early, and allowing a higher bitrate will not produce any changes. This is why your FM encodings are all coming out roughly the same size. For the values you have specified, they are limited by the quantiser, not the bitrate.

> Does anyone have any insight into the criteria by which FU
> chooses how to utilize each encode?

It looks at each frame, and use a quality metric to measure it. Then it tries to find a constant quality level that gives the filesize that you want. The type of encoding is not considered by this algorithm, so it cannot show prejudiced.

> and each time it's been favoring a fast motion encode
> for about 70% of the movie

Make sure you look at the result before judging! It may be that this movie looks good with 70% FM.

If you really don't want this proportion of FM, then you can either use DT encodings, or remove all FM encodings and use a wide spread of LM encodings.

When replacing encodings, make sure you replace both the .AVI and .FUD files.

Sven Bent
27th January 2002, 03:01
Sorry to arqgue you bakc FU2k i really love you program
however most of the fills i encodet with high utilization of FM codesc.
got better when i re-ripped/Re-encodet it without the use of fast motion

so something must be screwed.

i never use the fm codec anymore in FU because it simply Degrades overall movie quality.
i testet with around 7 movies