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Old 21st December 2011, 13:41   #1  |  Link
survivor_evil
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Bitrate calculator for h264

Hi, Its been years since i seriously havent encoded a video. Then back i used ar calculator to calculate the best bitrate according to my settings using xvid or divx. I know gordian knot but i believe its outdated? Whats the best program for doing this with x264? thank you
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Old 21st December 2011, 14:30   #2  |  Link
sneaker_ger
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That kind of bitrate calculation is considered obsolete nowadays. Instead you pick a CRF value and x264 will try to keep the quality constant while calculating the necessary bitrate itself.

Last edited by sneaker_ger; 21st December 2011 at 14:42.
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Old 21st December 2011, 16:31   #3  |  Link
Vurbal
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Since some people need to encode for a particular file size, it's hardly obsolete.

Personally I like the bitrate calculator in MeGUI.
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Old 21st December 2011, 16:45   #4  |  Link
nm
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Quote:
Originally Posted by Vurbal View Post
Since some people need to encode for a particular file size, it's hardly obsolete.
Sure, but that's not the same as calculating "the best bitrate according to my settings", which has never made much sense.
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Old 21st December 2011, 17:35   #5  |  Link
Vurbal
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Quote:
Originally Posted by nm View Post
Sure, but that's not the same as calculating "the best bitrate according to my settings", which has never made much sense.
Ahh, I apparently read the original post differently, and perhaps incorrectly. I would certainly agree it's as simple as either whatever your selected CRF results in or your media demands.
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Old 31st December 2011, 06:12   #6  |  Link
StainlessS
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Sometimes you want to encode to a particular size, and no amount of saying CRF is
better is gonna change the requirements. I personally would like to see a bits per pixel
option allowing the user to select his/her own requirement. I dont care if I've gotta do
two pass, I want what I want, nuff said. Also, as good a CRF is (and I'm quite delighted
with it most of the time), you want to hit a file size EXACTLY, and WITHOUT guessing
what the output size might be +- 50%.
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Old 31st December 2011, 06:36   #7  |  Link
Dark Shikari
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Quote:
Originally Posted by StainlessS View Post
Sometimes you want to encode to a particular size, and no amount of saying CRF is
better is gonna change the requirements. I personally would like to see a bits per pixel
option allowing the user to select his/her own requirement. I dont care if I've gotta do
two pass, I want what I want, nuff said. Also, as good a CRF is (and I'm quite delighted
with it most of the time), you want to hit a file size EXACTLY, and WITHOUT guessing
what the output size might be +- 50%.
But if you already know what size you need, why do you need to know "bits per pixel"? Isn't this already served by simply setting the bitrate to whatever gives you the size you want, e.g. a DVD-R?
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Old 31st December 2011, 06:41   #8  |  Link
StainlessS
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Sorry, my own personal gripe, two seperate things really.
Bitrate calculator is good to ascertain if your requirements are met,
But I also like (require) that I am allowed my own opinion of what is required,
(right or wrong).

EDIT: the main reason is, it does without the frameSize/framerate calculation.
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Last edited by StainlessS; 31st December 2011 at 06:53.
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Old 3rd January 2012, 23:19   #9  |  Link
benwaggoner
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Also, bits-per-pixel isn't a good metric at all, since the same video at a higher resolution needs fewer bits per pixel. My rule of thumb has always been to use the power of 0.75 ratio.

Thus, if 960x540 looks good at 2 Mbps with a given source, the same source at 1920x1080 would look similarly good at around (2x2)^0.75=2.83 * 2 Mbps = 5.66 Mbps.

These days, I mainly use that to figure out the optimum frame size for different adaptive streaming bitrates. I generally like each bitrate to be about 50% higher than the next lower bitrate, so each step goes up 50% bitrate, 36% total pixels, and 16% in height and width.
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