Newb question about A/B Switchers at DVinfo.net

Natan Pakman · May 3rd, 2010, 10:30 AM

I have been told that people can do live streaming and switching between two flip cams (on remote locations) by using a "simple A/B switcher." Can somebody explain to me what this is, and how it works in live switching?

Do A/B switchers use firewire? Is there a delay in switching between the two inputs?

I am a newb when it comes to these matters so any information would be appreciated.

David Stoneburner · May 4th, 2010, 06:51 AM

There are many types of switchers. Usually an A/B switcher refers to a device that takes in 2 video sources and then cuts between them or may do simple type transitions like a dissolve or basic wipes. In order to do a transition other than a cut, the sources need to be timed together or you will get a jump or glich when changing sources. This also happens on a crash switcher or a switcher that just cuts from one to another, but depending on sources may not be as noticeable. There are a lot of companies that make different switchers. Some are analog video in either in composite, s-video (Y/C) or component. There are some that take firewire in. There are even some software based switchers out there. Many of them will have some delay but depending on how much will not be noticeable, especially when somebody is watching a live stream, which would also be delayed. Usually the noticeable delay is when your doing Imag or live image magnification. Some switching systems even have built in graphics generators. Some companies to look for would be Edirol and Datavideo on lower end of the dollar scale. Higher end Tricaster, Sony and Panasonic. Really high end Sony, Grass Valley, Ross, etc. The list just keeps going. A cool product that I just saw is called Wirecast. It's a software based switching and streaming solution, that has graphic capability as well. Currently only does 1 camera input unless you try to trick it with another camera as an input from a computer, but there would be major delay doing it that way. Still interesting though.

Natan Pakman · May 4th, 2010, 10:03 AM

I might have thought that "A/B switcher" referred to a simpler device than a 2-way video switcher. Based on your answer, I guess a "simple A/B switcher" is synonymous with "cheap video switcher," is that correct?

David Stoneburner · May 4th, 2010, 10:32 AM

I guess you could look at it that way. In the home stereo world they could be called an A/B switcher or selection switcher. In video production/broadcast I've always known them as crash switchers and A/B usually will denote some type of syncing and transitions. The problem with crash switchers is that more times than not you won't get a clean switch between your sources.

May 3rd, 2010, 10:30 AM	#1
Natan Pakman Regular Crew Join Date: Feb 2009 Location: Los Angeles, CA Posts: 196	Newb question about A/B Switchers I have been told that people can do live streaming and switching between two flip cams (on remote locations) by using a "simple A/B switcher." Can somebody explain to me what this is, and how it works in live switching? Do A/B switchers use firewire? Is there a delay in switching between the two inputs? I am a newb when it comes to these matters so any information would be appreciated.

May 4th, 2010, 06:51 AM	#2
David Stoneburner Major Player Join Date: Jun 2003 Location: Orlando, FL Posts: 493	There are many types of switchers. Usually an A/B switcher refers to a device that takes in 2 video sources and then cuts between them or may do simple type transitions like a dissolve or basic wipes. In order to do a transition other than a cut, the sources need to be timed together or you will get a jump or glich when changing sources. This also happens on a crash switcher or a switcher that just cuts from one to another, but depending on sources may not be as noticeable. There are a lot of companies that make different switchers. Some are analog video in either in composite, s-video (Y/C) or component. There are some that take firewire in. There are even some software based switchers out there. Many of them will have some delay but depending on how much will not be noticeable, especially when somebody is watching a live stream, which would also be delayed. Usually the noticeable delay is when your doing Imag or live image magnification. Some switching systems even have built in graphics generators. Some companies to look for would be Edirol and Datavideo on lower end of the dollar scale. Higher end Tricaster, Sony and Panasonic. Really high end Sony, Grass Valley, Ross, etc. The list just keeps going. A cool product that I just saw is called Wirecast. It's a software based switching and streaming solution, that has graphic capability as well. Currently only does 1 camera input unless you try to trick it with another camera as an input from a computer, but there would be major delay doing it that way. Still interesting though.

May 4th, 2010, 10:03 AM	#3
Natan Pakman Regular Crew Join Date: Feb 2009 Location: Los Angeles, CA Posts: 196	I might have thought that "A/B switcher" referred to a simpler device than a 2-way video switcher. Based on your answer, I guess a "simple A/B switcher" is synonymous with "cheap video switcher," is that correct?

May 4th, 2010, 10:32 AM	#4
David Stoneburner Major Player Join Date: Jun 2003 Location: Orlando, FL Posts: 493	I guess you could look at it that way. In the home stereo world they could be called an A/B switcher or selection switcher. In video production/broadcast I've always known them as crash switchers and A/B usually will denote some type of syncing and transitions. The problem with crash switchers is that more times than not you won't get a clean switch between your sources.