Bitrate and different compressions

[Eric#]

Hi guys,

i encountered strange results while testing different compression-methods.
I always thought BITRATE = FILESIZE (B) / MOVIE-LENGTH (s) * 8.

So if the length and the bitrate of the movie is constant, i just choose different compression-algorithms, the SIZE should stay constant as well.

I took as source a MPEG-1 1150 Kbps movie (audio MPEG-Layer II 224 kpbs) and converted it (for testing only one minute to make it faster )

MPEG-1: 10257 KB
XVID: 10148 KB
DivX 5.01: 7188 KB
DivX 4.12: 7142 KB
DivX4 LOW Motion: 6912 KB
DivX4 FAST Motion: 3276 KB (?! wtf - but it looks great, no different to the original)

Can someone explain me this BIG difference in the size?
I used VDub with full-processing mode and MPEG Layer 3, 224 Kbps Audio for the DivX-Conversion (Video-Rate remained at 1150 of course).

Especially i don't understand the really small size of the FAST Motion variant...

regards, Eric

[KingJohn]

Your just using codec's that are better at some things than others, do the same thing with an animated film, you might see different results again. Did you also set the number of Keyframe ?

BTW "Eric" have you seen Salvation ?

[Eric#]

Your just using codec's that are better at some things than others, do the same thing with an animated film, you might see different results again. Did you also set the number of Keyframe ?

I used the default, which is one keyframe every 10 seconds.

However - i am aware that i will get different results with different movies.
But what wonders me the most is why do i get different sizes with the SAME bitrate?
You always read: "if you want to put the movie on a 700 MB CD-R, use this formula: 700MB / LENGTH * 8 = VIDEORATE+AUDIORATE"
That's what i did in a way. Just with different codecs. And got variations of more than 300%
That's the same if i would want a 700 MB movie but get a 250 MB movie as result.. wouldn't fill up the CD at all. ;P

BTW "Eric" have you seen Salvation ?

Unfortunately NO - is it recommendable?
Saw (of course ) THE CROW - which is one of my favorites. Also CROW II, which i didn't like at all..

[KingJohn]

Hi, what I was saying was basically some codec's are better at compressing than others, and some do a better job on a particular type of movie. Despite your bit rates, they are still capable of compressing down more with each codec you use.

Winzip V WinRAR V WinAce

It was interesting to see the results, I also did the same thing many moons ago

DivX 5.01: 7188 KB
DivX 4.12: 7142 KB

Only goes to show that the open source DivX codec is as good as the final release of the commercial product.

No DivX 3.11 Alpha in that list then, The codec you can see with the best results is obviously one of the most used "DivX FAST Motion" one of my favorites also.

Maybe you should do the same thing all over again "Without the audio" to be fair

The Crow 3, Salvation is very good. Its not available in the UK but I did get a DVD from France, with English and French Subs or French and English Sub's .

I thought it was pretty gruesome at times. I did share it on Kazaa for a while, so a few people have it now. You wont beat Brandon, but Vincent Perez does a good job in Salvation.

[Eric#]

Ok, the results WITHOUT audio are:

DivX4 FAST: 1590 KB
DivX4 LOW: 5224 KB
DivX 4.12: 5456 KB
DivX 5.01: 5500 KB
XVid: 8462 KB

Heheh.. wow.. now FAST MOTION is even BETTER compared to the others

However.. why i was testing this is because i have some MPEGs left on my harddisk which are too big to fit on a CD - and now i want to convert them to DivX to make 'em smaller..
Hmm.. will open another thread about this 'cause a new question just arose..

Couldn't test the DivX 3 - codec, it seems that the Nimo Codec Pack removes it?!

The Crow 3 - why you don't share it anymore?
I could give you Crow 2 instead! HE-HE

[KingJohn]

I was kidding about 3.11 Alpha
Coder & decoder DivX V3.11a (3.11Alpha Low Motion)(Div3)
Coder & decoder DivX v3.11a (3.11Alpha Fast Motion)(Div4)

Nimo, as you know does install them, and it is one of the best. You have to be careful sometimes. Installing hacked codec's is just fine but install the regular ones can overwrite what you got, like the M$ MPEG-4 V3 (ASF Only) and locked, but not so with the hacked version.

Thanks for the offer of Crow 2, However I already have that and the Crow on DVD

Well um, you see sometimes you select a folder and tell it to delete, but then a split second later you think... No not that folder...

So I deleted it by mistake I need to make another copy of the DVD

[Eric#]

Forgot to mention - DivX4 FAST (and LOW) MOTION are not only the BEST, they were also the FASTEST codecs during my tests.
It took about 55 secs, whereas DivX5.01 and 4.12 took little bit more than a minute.. interesting

Guess i will test it again over night with a FULL MOVIE, hehe...