Resolution 101 For Dummies

[FloridaGuy75]

Hello all,

 

Long time reader, but first time poster. I have found such a wealth of knowledge here.

 

Let me introduce myself, my name is Kevin, and I live in Sanford FL. I've always had an interest in Audio/Visual, and now I finally got hired. There is something I am a bit confused about, and its resolution. I hope that I don't get bashed for asking such a simple question, but I will admit - I am a bit embarrassed to ask my superiors at work.

 

At my previous job, we used a DCS-100, and a 9x12 screen - with that I knew it was always 1024x768, for the output of the switcher, and the laptop. But now we're dealing with wide screens, and that is where I am getting confused. The company I work for bought various sizes of 16x9 screens, along with Christie 10k lumens projectors, and fiber to hook it all up - but again, my question is resolution. We use display port to connect the laptops to the DCS 100 and sometimes our Barco 902's. On our laptops, what would I set the resolution on say a 9x16 screen? 1920x1080? And do I need to set the output of the switcher to whatever my laptop resolution is set at? Or would the laptop resolution not really matter, because the output of the switcher would scale it on its own?

 

I hope I am explaining this correctly. I apologize in advance for such a simple question. Is there an online calculator to figure out what resolution to output depending on the size of screen?

[empyfree]

Screen size is less important than screen aspect ratio. The important thing here is to make sure you're using 16:9 ratio resolutions throughout your system.

 

Work backwards.

 

1- make sure your Christie projectors are set to 16:9 screen shape. Some makes for models allow you to vary between 4:3, 16:9, and 16:10

 

2- set your switcher to output 1920 x 1080 (also known as "full HD" )

 

3- set your laptop resolutions to 1920 x 1080.

 

Voila, should all match up nicely.

[mac.calder]

Hi and welcome FloridaGuy75.

 

First off (as a bit of an FYI) - screens sizes are referenced Width x Height (so 12 x 9, 16 x 9 etc). Aspect ratios (that is the ratio of width to height) is written width : height - the common ones you will come up against are 16:9, 4:3 and 16:10.

 

How do you know which resolution to use? divide the width by the height. 16:9 screens and resolutions will give you 1.7777777778, 4:3 will give you 1.33333333, 16:10 will give you 1.6. If you do that to the screen size and then to the resolutions, if the resultant number matches, you are in a good place.

 

The scaler inside the 902/DCS will scale to match the switchers output resolution - yes - however scaling should be avoided wherever possible. It adds delay, it has some effect on quality and if your aspect ratio does not match then you either end up stretching the image or pillar boxing (or letterboxing) - that is, putting black borders either side of the image or on the top and bottom of the image - just like when you watch movies on your 16:9 display you will notice it is "letterboxed" down and does not fill the screen vertically - films are generally between 2.35:1 and 2.39:1.

 

Regarding what res, 1920x1080 is a safe bet for 16:9 - most devices support it. The other safe bet for 16:9 is 1280x720.

 

For 16:10, 1920x1200 is usually the go-to res.

 

For 4:3 (which is now generally considered obsolete) 1024x768 or 1600x1200 would be the usual suspects.

[indyld]

To check your res or screen size, take the horizontal resolution or width, divide it by 16 and multiply the result by 9 to give you the vertical res or height (for a 16:9 aspect ratio, obviously). Invert the calculations for finding out other stuff.

[David Lee]

Or would the laptop resolution not really matter, because the output of the switcher would scale it on its own?

 

If you set the EDID to the resolution you are projecting - in this case most likely 1920x1080 then the laptops will see this as the default resolution for the switch.

 

Now, next homework will be refresh rate and progressive or interlaced :)

[FloridaGuy75]

You guys are great! Thank you SO much for the responses. I TRULY appreciate it. Writing all this down for my own reference.

 

The last time I set my laptop to 1920 x 1080, and set the output of my 902 to the same onto a 9x16 screen however, it didn't fill up the screen. Had bars on the top and bottom. As a work around, I ended up going into custom aspect ratio in my 902 to fill the screen. Was that the right thing to do? If not, what's the trick to fill the screen?

 

Thank you again everyone!

[david.elsbury]

As Mac said- its 16x9 - not 9x16 :)

[David Lee]

It may be the projector is set to 19 x 10? Or if powerpoint the page setup was wrong.

[Joe Fernand]

Resolution, Aspect Ratios etc - it does get mighty confusing once you factor in all of the variables. At one end of the signal chain your have the Content and at the other end you have the screen you are projecting onto - ideally as the signal passes along the chain you have as few conversions as possible if you wish to retain the highest image quality and make full use of the imager device.

 

Your projection device has a 'native' resolution (based on the imager technology it uses) if you wish to use all of that resolution you ideally set the Source device to the same resolution and using test patterns you pixel map the Source to the Display device (ideally you disable all scaling and processing in the Projector) - if your content being played out by the Source is created with the same resolution you will then use all of the imager pixels, if not you will have black bars either Top/Bottom or Left/Right.

 

Where you are working with multiple Source devices and multiple content formats you will tend to use some form of Video Processor/Switcher to bring all of the Sources together for simplicity and also to avoid your Projection device reformatting itself every time it sees a different Source format (which looks crap onscreen in the middle of a presentation) - you aim to set the Video Processor Output to the Native pixel format of the Display to again avoid multiple processing (in the Video Processor and then again in the Display).

 

Ideally you use a Screen which is in the same ratio as the native format of the Projection device - if not you are again losing quality/resolution as you have to manipulate the image the Projector is Outputting.

 

I wouldn't be embarrassed - there are so many variables to contend with it will make your head hurt!

 

Joe

[Joe Fernand]

PS Pity about the dates but well worth considering getting yourself onto an ISF Course (if funds allow) - will provide a good grounding in Video basics.

 

https://www.imagingscience.com/courseschedule.php

 

Joe

[sameness]

As Mac said- its 16x9 - not 9x16 :)

 

 

Welcome the the American way of calling screen sizes...

[david.elsbury]

Really? Oh that's incredibly dumb :/

[Pete McCrea]

Never understood why they seem determined to give Height x Width for screen sizes but it seems to be standard :-(

 

Aim to get the switchers output to match the native resolution of the projector - so with most decent sized projectors its likely to be FullHD (1920x1080) or WUXGA (1920x1200). Older machines might be 4:3 so 1024x768. As you're in the USA you'll probably also want to set the refresh rate to 60Hz for most occasions - if you're in the UK then 50hz is generally preferred as content is normally filmed at 50Hz. Also with the PDS, it's good practice to set the EDID to match the output settings, which will then hopefully get the computers to give the right signal to the PDS, so minimising scaling needed to get it to the output.

 

You mentioned the content not filling the screen with the PDS. Sometimes they don't pick up the source laptop in the right way, so you have to go in and use the image sizing and ratio settings to get it to fit. Had that with both analog and digital inputs on them - sometimes taking a lot of manipulation to get the image right.