Psychovisual & Size ??

[griffy]

Hi all.

Just encoded my first 3 movies with Pyscho turned on as per Dooms latest CODEC comaprison.

I aim for a 800 Mb file size using Ogg for audio. This has been workin well for a long time, file sizes are always within a Mb or so.

UNTIL NOW

My last 3 movies came out at:

91min 562 Mb @ 640 x 272
81min 580 Mb @ 640 x 352
111min 481 Mb @ 640 x 272

Now obviously Pyscho affects file size HUGELY. The movies all look fairly decent, but out of sheer stuborness and principal, I am not going to burn 481 Mb to a 800 Mb CD......it's just not on :)

Is there a (semi) accurate way to get better file size prediction when using pyscho ?

I will try increasing the res to 720 x XXX, but I will still have size prediction problems.
If not I guess its back to not using it

Any ideas from you DIVX 5 encoding Gurus out there ??

Regards

Griff

[DJ Bobo]

Psycho has no impact on file size (and I don't use it since it makes quality only worse on the things I tested)
Your movies are simply saturated (= reached max quality = can't get any bigger at the resolution you choosed), that's all, look at the sticky in this forum.

[Acaila]

Ofcourse the first thing we all would like to know (:)) is whether or not those three movies are all saturated.
If you still have your logfile could you check if every frame is encoded with a quant of 2? Otherwise please repeat one of those movies with a 1-pass mode constant quantizer of 2 to see if you get the same filesize.

Psycovisuals are supposed to increase compression a bit, but the codec should normally compensate for this and just increase the bitrate so the output filesize is what the user wants and not smaller. So you shouldn't see any effect on filesize unless the codec is already using lowest possible quantizer and can't compensate any further.

EDIT: I guess DJ Bobo beat me to it :)

[griffy]

Thanks guys, I just figured that doing 3 movies at once with the only thing different being psycho I just assumed it was the cause.

I can't believe I got THREE movies that were all saturated. I haven't had a movie come out undersize for so long I didn't even consider it


DUH !!

Thanks for the replies

[theReal]

Are you sure this one is saturated?

111min 481 Mb @ 640 x 272

Must be very compressible!!!
But I agree psy settings don't affect the filesize, only the looks of the video (I checked this on different movies with a compress test).

[griffy]

Yeah, that particular movie is 'From Hell' Johnny Depp & Heather Graham

Quite a dark movie, I redid it again with the same setting and no Psych and it did turn out bigger, 523Mb Vs 481. So it seems Psych does make some difference in size.

I also coded it at 720 x 304 with psych and it still turned out to be undersized at 564 Mb....its bloody annoying, I'll have to do the audio again to fill the disc :)

Thanks again to all

Griff

[Emp3r0r]

i agree it is annoying. it seems some saturated movies could have some better quality. i use XviD when any of my movies are saturated. i think the fact that it happens reflects poorly on a codecs ability to produce optimum quality.

[Dagon]

From Hell, is nearly all night scenes...I had the same thing, a pretty huge undersize. The Other's is the same way, both fit on a single cd with room to spare.