Bit Rate Numbers at DVinfo.net

Sean Malone · November 18th, 2009, 09:33 PM

This has probably been covered some ware but I can't find it. I remember reading a few years back that its best to set bit rates to a number that’s divisible by 32 (it was probably 8 or 16 in the early days). I don't know if its still applicable, but a guy in our building and I were discussing bit rates today and it came up. Is this another famous myth or is there any validity to it?

Perrone Ford · November 18th, 2009, 09:44 PM

Bit rates??? No. Frame sizes.. yes. But not by 32. Generally by 8 or by 4. Why on earth would bit rate need to be divisible by anything? With VBR it's essentially impossible anyway.

Sean Malone · November 18th, 2009, 10:15 PM

Sounds like myth. VBR is a great point. Glade I asked though, I didn't know about the "Frame Size" aspect of things.

Thanks,

Shaun Roemich · November 19th, 2009, 12:11 AM

MPEG-1 dimensions need to be divisible by 8, but not bitrate.

Robert M Wright · December 11th, 2009, 09:42 PM

Even if the codec doesn't require it, making frame dimensions divisible by 8 will help make encoding more efficient (even if just slightly).

November 18th, 2009, 09:33 PM	#1
Sean Malone Regular Crew Join Date: Dec 2007 Location: Denver, Colorado Posts: 40	Bit Rate Numbers This has probably been covered some ware but I can't find it. I remember reading a few years back that its best to set bit rates to a number that’s divisible by 32 (it was probably 8 or 16 in the early days). I don't know if its still applicable, but a guy in our building and I were discussing bit rates today and it came up. Is this another famous myth or is there any validity to it? __________________ Sean Malone

November 18th, 2009, 09:44 PM	#2
Perrone Ford Inner Circle Join Date: Nov 2006 Location: Tallahassee, FL Posts: 4,100	Bit rates??? No. Frame sizes.. yes. But not by 32. Generally by 8 or by 4. Why on earth would bit rate need to be divisible by anything? With VBR it's essentially impossible anyway. __________________ DVX100, PMW-EX1, Canon 550D, FigRig, Dell Octocore, Avid MC4/5, MB Looks, RedCineX, Matrox MX02 mini, GTech RAID, Edirol R-4, Senn. G2 Evo, Countryman, Moles and Lowels.

November 18th, 2009, 10:15 PM	#3
Sean Malone Regular Crew Join Date: Dec 2007 Location: Denver, Colorado Posts: 40	Sounds like myth. VBR is a great point. Glade I asked though, I didn't know about the "Frame Size" aspect of things. Thanks, __________________ Sean Malone

November 19th, 2009, 12:11 AM	#4
Shaun Roemich Inner Circle Join Date: Sep 2002 Location: Vancouver, British Columbia (formerly Winnipeg, Manitoba) Canada Posts: 4,088	MPEG-1 dimensions need to be divisible by 8, but not bitrate. __________________ Shaun C. Roemich Road Dog Media - Vancouver, BC - Videographer - Webcaster www.roaddogmedia.ca Blog: http://roaddogmedia.wordpress.com/

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December 11th, 2009, 09:42 PM	#5
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	Even if the codec doesn't require it, making frame dimensions divisible by 8 will help make encoding more efficient (even if just slightly).