Compressibility

[craigcharlie]

Hi there,

First post in this forum, so please go easy on me :)

I've looked through the stickies and the guides (on doom9 etc) and I'm not really understanding what the "compressibility percentage" in the autogk log tells you. Is it how much the file can be compressed, or how much it will be compressed?

In a similar vein, can anyone tell me how to run a compressibilty test from gordian knot? I've seen a couple of posts on this forum that state that you can use GK to run a compressibility test in order to help predict what the final output size will be for a given quality for a given file. I'm interested in this because the 2 pass encodes take so long on my machine....

thanks for any help,
Charlie

[Axed]

Hi there,

First post in this forum, so please go easy on me :)


Welcome to the forums craigcharlie.


I've looked through the stickies and the guides (on doom9 etc) and I'm not really understanding what the "compressibility percentage" in the autogk log tells you. Is it how much the file can be compressed, or how much it will be compressed?


Well, it is just an estimate of how much the file can be compressed. But, its usually extremely accurate, and if you adjust the resolution/bitrate to around 80% compressibility it leaves enough room for any error.


In a similar vein, can anyone tell me how to run a compressibilty test from gordian knot? I've seen a couple of posts on this forum that state that you can use GK to run a compressibility test in order to help predict what the final output size will be for a given quality for a given file. I'm interested in this because the 2 pass encodes take so long on my machine....

thanks for any help,
Charlie

Its extremely simple to run the test in GK. Have another look at the guides, especially this part. (http://www.doom9.org/gknot-xvid.htm) Have another read thru it, and if you have any more questions post them in here.

[jggimi]

Not quite on how much it can be compressed, rather 100% is equivalent to the maximum bitrate possible for the filtered/resized/cropped content. Best practice currently is to use a figure in the 60-80% range.