How do Live Switchers Work?

[Natan Pakman]

I am looking to use a live switcher for a shoot with 2 cameras and one computer monitor that will be outputting video footage (with audio) throughout the shoot.

I do not know quite how switchers work. Is it possible to output three sources (computer, and two hdv cameras) to a switcher and record onto one of the three sources, or is a separate recorder necessary? How can I maintain video and audio sync? Which cables and connectors do I need?

Would a datavideo se-500 or an edirol v-4 work or do I need something more powerful/expensive?

Any information would be appreciated.

[Shaun Roemich]

A live switcher will take a VIDEO feed from your cameras and allow you to output a VIDEO feed to an external recording device and/or video monitor. In order to use computer video, you will need to get VIDEO, not an RGB signal, out of either the computer video card OR go through a Scan Converter to lower XVGA or whatever resolution to video (640x480). This will potentially wreak havoc on fine line detail and/or text.

Some switchers allow audio to be fed through them and switched ("audio follows video" switching). Or take your audio sources, run them through an audio mixer and loop them into your recorder and/or display/PA.

To avoid down rezing your computer video, getting a more expensive switcher than can accept computer signals in and upres video is possible. Analog Way is one of the leading switcher manufacturers in this application, which then requires you to find a way to record the end product.

[Giroud Francois]

when i need the quick&dirty mix, i use a videonics MX1 and a VGAtovideo converter.
All cabling is simple coax. This case is when the video is the main feed and computer is just used for few titles or logos.
If the PC is feeding the main signal (lengthy powerpoint presentation or excel spreadsheet) and video is just for few sequence, i do the reverse.
I use a vga switch allowing to switch between the PC and the output of the videonics table.
you can find for very cheap, converter that convert the video to VGA signal.
it works very well and the nice thing is most vonverter are usually very cheap

[Natan Pakman]

Shaun, thanks for the info.

So, generally, a component or s-video (or composite video, I suppose) cable goes from each camera into the switcher, and then is output to the recorder? Can the video output on the switcher go to a computer and record directly into an editing application? (I assume I would need a something-to-firewire cable for that...

Regarding audio, if I run the audio from a mixing board to the same recorder I use to record the output from the switcher, I shouldn't have any sync issues, correct?


Which switchers allow you to use and output hdv sources, such as the Sony HDR-FX1?

[Shaun Roemich]

I missed this part during my initial response: if you are looking to live switch in HD, not SD, you'll be spending A LOT on a switcher (ie. $10k +) and a lot of the switchers in that price range want HD-SDI video, not analog component.

Input to a computer for recording could certainly be via capture card.

Sync issues should be non-existent or minimal if you keep the paths clean. The more devices either the audio or the video goes through before hitting the recorder, the greater the chance of sync issues. I do conventions in SD routinely and get a FOH (front of house) audio feed from the venue sound reinforcement system and pass it through my audio mixer before hitting the recorder, which is fed the analog output of my video switcher and I've never had sync issues. Of course, your mileage may vary... but if you're recording to NLE, slipping audio relative to video should be very simple IF you run into sync issues.

To the best of my knowledge, there still isn't a SUPER CHEAP video switcher on the market that can handle HD video. Everything I've researched starts around $10k and goes up quickly from there.

[Les Wilson]

This seems to be a common situation..wanting to switch between a couple video feeds and a computer. I recommend as Shaun did to uprez your camera's composite/s-video to that of the computer. Even tho your cameras are HD, you may not be able to afford a hi-res video switcher.

FSR makes a thes combo units that are both a switcher and a scaler (uprez) in one unit that will take various video feeds and let you hard cut between them and VGA from your computer all in a 1U rack unit. If you want to use hi-res video then you need a bigger budget. Eagle and Ross are two I've used with SDI.

[Natan Pakman]

This is great info, but I still don't quite understand this concept of scaling ("uprezing"). Does this refer to the fact of matching the resolution of the computer source video to the other two cameras through the switcher?


Could you provide an example of a (sd) mixer that would provide scaling? I looked up FSR switchers and they were in the 20-30K range, a little high for my purposes.

[John Miller]

For DV camcorders (or HDV in DV mode) and a Windows system, I have developed a *software* switcher that keeps everything in the DV format. At the moment, it is free (it has a clunky interface at the moment but works). It fully syncs the inputs so that there aren't any glitches when switching.

http://www.enosoft.net/dl.php?filena...erFilter32.msi

Only potential issue right now is taking the audio from the mixing board. However, if you feed it into your computer's line input, you can set things up to replace the audio of the switched video with your desired one.

(The plan is to add many more features and a versatile/easy interface).

[Shaun Roemich]

Originally Posted by Natan Pakman

Could you provide an example of a (sd) mixer that would provide scaling?

First problem with this statement is that you are creating another down-the-line issue for yourself, namely how do you record this signal if you are going to start dealing with greater than SD resolutions (ie. UXGA etc.)?

There aren't any recording solutions that come to mind that will accept RGB signal and if you are getting into switching HD, the price goes up AND the availability of capable record decks goes down (you won't be able to find a switcher that has an HDV out on Firewire - at best, you'd get HD-SDI. Now what deck/format do you record to?)

[Natan Pakman]

Originally Posted by Shaun Roemich

First problem with this statement is that you are creating another down-the-line issue for yourself, namely how do you record this signal if you are going to start dealing with greater than SD resolutions (ie. UXGA etc.)?

There aren't any recording solutions that come to mind that will accept RGB signal and if you are getting into switching HD, the price goes up AND the availability of capable record decks goes down (you won't be able to find a switcher that has an HDV out on Firewire - at best, you'd get HD-SDI. Now what deck/format do you record to?)

Shaun,

I think that this is the second problem with my statement, while my first is that I don't understand exactly what scaling is: I assumed it referred to matching the computer's resolution to the other video sources in the switcher, not making it greater-than-sd. Please explain this, as I'm highly confused.

I don't yet have a deck that I record to, I use a Sony HDR-FX1. I'm in the pre-planning stage of shooting a radio show from a studio, and I am looking to understand exactly how switchers work and which products I should be looking at. Given that everything indicates that HD switching will be way too expensive, I'm looking for a switcher that will take at least 2 video sources and 1 computer, and output it to a recorder (I could get a 250GB hard disk recorder for that).

[Les Wilson]

Scaling is changing the resolution. SD in NTSC-land is 640x480 or 720x480. Computers have many resolutions but are mostly (these days) 1024x768 and up.

Uprezing Video is changing it to a higher resolution. If you are switching in Computer resolution and mixing it with SD video and recording SD, you need to downrez your computer or crop it to something that fits in the 720x480 SD resolution. You will need a quality scaler to downrez your computer to video. This is sometimes called a scan converter. Quality matters A LOT when it comes to text. A decent scan converter will cost hundreds of dollars. I've used an Extron in the past and found it quite good. Consumer scan converters for analog TVs (pre-digital) were not so good.

[Guy Cochran]

There are a few HD Mixer / Switchers that are fairly common from Edirol, Panasonic and Grass Valley.

I'm currently using, and know a few people with the Edirol V-440HD. It an analog HD mixer so the inputs are Component and RGB (VGA).
It works amazing!

On the used market, you're still talking in the $7-10k range for a V-440HD

A few customers have switched to newer cameras with HD-SDI and are in love with the new Panasonic AV-HS400 Learn about Panasonic's AV-HS400A

The big reason is all digital - HDSDI in's and out with DVI too! Resulting in a beautifully clean signal, especially over long runs. The other cool feature is that you can use one huge monitor, say a 42" Plasma and gang all your Cameras on 1 screen. That makes it easier than lugging around or buying a bunch of monitors.

Here is a video where I use the V-440
YouTube - Our new HD Studio - how we do it.
And an older video with a standard def mixer
Edirol LVS-400 and V-4 Video Mixers

One more option if you do not need to do totally live, and only have two cameras is to add two Blackmagic Intensity Pro cards to a computer and use On-air. That's just $199 per card and it's a recorder. You can feed component or HDMI into those.

[Natan Pakman]

Originally Posted by Guy Cochran

There are a few HD Mixer / Switchers that are fairly common from Edirol, Panasonic and Grass Valley.

I'm currently using, and know a few people with the Edirol V-440HD. It an analog HD mixer so the inputs are Component and RGB (VGA).
It works amazing!

On the used market, you're still talking in the $7-10k range for a V-440HD

A few customers have switched to newer cameras with HD-SDI and are in love with the new Panasonic AV-HS400 Learn about Panasonic's AV-HS400A

The big reason is all digital - HDSDI in's and out with DVI too! Resulting in a beautifully clean signal, especially over long runs. The other cool feature is that you can use one huge monitor, say a 42" Plasma and gang all your Cameras on 1 screen. That makes it easier than lugging around or buying a bunch of monitors.

Here is a video where I use the V-440
YouTube - Our new HD Studio - how we do it.
And an older video with a standard def mixer
Edirol LVS-400 and V-4 Video Mixers

One more option if you do not need to do totally live, and only have two cameras is to add two Blackmagic Intensity Pro cards to a computer and use On-air. That's just $199 per card and it's a recorder. You can feed component or HDMI into those.

Guy,

If I used the Edirol LVS-400 and connected two hdv cameras to it, would I get the same 16:9 aspect ratio but 720/480 resolution? If I also connected a computer to the switcher as a third input, would I need a separate scan converter to downrez its resolution as Les Wilson suggested on this thread?

If I used the Blackmagic cards and On-air, could I switch between the two cameras and a computer source (such as video clips in windows media or quicktime that are opened on the same computer that is running On-air)? Would having two firewire ports work, or are the cards with HDMI/component necessary?

I'm a bit confused with all this but I believe I'm almost there.

[Guy Cochran]

Originally Posted by Natan Pakman

Guy,

If I used the Edirol LVS-400 and connected two hdv cameras to it, would I get the same 16:9 aspect ratio but 720/480 resolution? If I also connected a computer to the switcher as a third input, would I need a separate scan converter to downrez its resolution as Les Wilson suggested on this thread?

If I used the Blackmagic cards and On-air, could I switch between the two cameras and a computer source (such as video clips in windows media or quicktime that are opened on the same computer that is running On-air)? Would having two firewire ports work, or are the cards with HDMI/component necessary?

I'm a bit confused with all this but I believe I'm almost there.

The LVS-400 is Standard definition and offers S-Video as well as BNC inputs in a 4:3 aspect ratio. There is a newer mixer by Edirol with a built in scan converter Edirol V-8 Video Mixer - it is also 4:3.
On-air only works with two Intensity Pro cards via HDMI or component. If you want Firewire, hmm.... if this is just for web use, have you seen Telestream Wirecast - Overview and the http://www.newtek.com/tricaster/

[Natan Pakman]

Originally Posted by Guy Cochran

The LVS-400 is Standard definition and offers S-Video as well as BNC inputs in a 4:3 aspect ratio. There is a newer mixer by Edirol with a built in scan converter Edirol V-8 Video Mixer - it is also 4:3.
On-air only works with two Intensity Pro cards via HDMI or component. If you want Firewire, hmm.... if this is just for web use, have you seen Telestream Wirecast - Overview and the NewTek TriCaster

1. Are there any SD switchers that output in 16:9 in the same general price range of 1-3K?

2. If I use On-air with the Intensity Pro cards, would I be able to integrate, as a video source, a computer (screen) itself? So, in On-air, would I be able to have 2 video camera inputs and one additional computer as a third "camera"?