Pixels to Inches?

SusanS wrote on 3/1/2010, 3:34 PM
Hi everybody,
I've been away from computer for several weeks and now all keen to start making videos. Even got a new laptop with duo processor. (I know quad is better but this is a start.) Anyhow, here's the question:

On my computer screen, 10 pixels are approximately 1 inch. Is that approx the same for all computer screens?

If I render my video to 640 pixels wide by 320 pixels high, it's too large. If I render it to 320 by 240 (which is supposed to be the commonest for posting videos on a website), it's too small. A size about 5 inches wide by 3 1/2 inches high would be nice.

The default for Sony Vegas is 480 by 360 so that seems about right. If I first save it to my computer, will the physical size on my computer screen be the same as the physical size on my website? Just getting all hung up about how it will look.

Thanks in advance.

.....Susan

Comments

abelenky wrote on 3/1/2010, 5:46 PM
Your screen is almost assuredly NOT 10 pixels per inch.

Most modern screens are 96 pixels per inch.
Some older screens are about 72 pixels per inch.

If you have the stats for your monitor, you want to look for the term "dot-pitch" or "pixel-pitch" describing the pixel density and spacing of your screen.

But for general planning purposes, I would generally use 96 pixels per inch.

BTW: When you print things, most printers are 300 or 600 DPI (Dots Per Inch). Some high end laser printers get up to 2400 DPI.
SusanS wrote on 3/1/2010, 6:55 PM
OOPs! You're right of course! I meant approximately 100 pixels per inch!

......Susan
Former user wrote on 3/2/2010, 5:57 AM
But also remember, the size on the image/video will be affected by your screen resolution. If you have your screen set for 1600 x 1200, the image will be smaller than if you have it set at 800 x 600. The screen resolution is more a factor than your monitor pitch.

Dave T2
Chienworks wrote on 3/2/2010, 7:41 AM
Monitor size too. 1600x1200 will have larger pixels on a 24" monitor than 800x600 will on an 11" monitor. Ok, those are a bit extreme, but still the point is that there is no way to know how large any particular frame size will be on anyone else's monitor.

I would suggest though that if 640x480 is "too big for your screen", then your screen resolution is probably way to low to be useful for running a program like Vegas. You can probably safely assume that anyone viewing your videos has their screen set for higher resolution than you do.

I wouldn't consider running anything less than 1280x1024, and on that resolution 640x480 should only fill about 1/4 of the screen.

160x120 is about dialup webcam size.
320x240 is about web video size.
640x480 is about dvd / full quality size.
1280x720 is small HD size.
1920x1080 is full HD size.
david_f_knight wrote on 3/2/2010, 9:27 AM
The number of pixels per inch takes into consideration the monitor size (or rather renders it not relevant as far as determining the absolute size of your video image on the screen). The monitor size is relevant for determining the percentage of the screen area used by the video image, because larger monitors usually have more total pixels even though the number per inch is nearly constant among most modern displays (about 96 per inch as abelenky wrote).

Anyway, generally with CRT monitors it is perfectly fine to set the screen resolution to whatever you please (as long as it's supported), but for LCD, LED, or plasma monitors (i.e., nearly all monitors made within the last few years, and certainly all laptop screens), there is just one native screen resolution and using that screen resolution will clearly provide the best looking images. If you don't set your LCD monitor to its native resolution, you may end up trying to fix quality problems with your images that don't really exist.

Anyway, all this discussion about screens is getting a bit off track from your original question. The size your video appears on your website depends on how your website displays video, not necessarily how you render it within Vegas. For example, if you upload your video to YouTube and embed a link to it within your own website, then the embedded HTML code in your webpage determines the resolution/size of your video displayed on the screen. Generally, to obtain the highest quality and fastest uploads, you want the size you display your video on your webpage to equal the size that you rendered your video.

Another thing to take into account is the video aspect ratio. Generally speaking, to avoid distortion, you should have the aspect ratio of your source material (at least after cropping it) match the aspect ratio that you render your video which should match the aspect ratio of the HTML code that displays your video on your website.

Since you wrote that the 480x360 size appears about right on your computer (which has a 4x3 aspect ratio, by the way), I'd stick with those numbers with the HTML code you use to embed your video on your website. I think it's pretty safe to assume most people visiting your website will also have screens that are set to their native resolution and that will be about 96 pixels per inch, giving them about the same size view as you have.
Byron K wrote on 3/2/2010, 9:50 AM
I fully agree w/ all of the above.

Also, most websites now days have a standard width of 1024 pixels and some including our Sony Forum is 1200 pixels wide. So, depending on how your website is layed out you may want to keep this in mind.

A simple way to get pixel to inch comparison is to use Windows 7 MSPaint. It has a nice ruler that goes between pixels and inches.
- Click the Ruler check box
- Go to the Menu (in the upper left hand corner) and select Properties.
- Select the Pixels, Inches or Centimeter button
- Paste your image in MSPaint and now you can see exactly what dimensions it is in pixels and inches
SusanS wrote on 3/20/2010, 3:28 PM
Thank you everybody. The high quality of information in these Vegas Movie Studio forums is so awesome!!
Please don't think me impolite for not having gotten back sooner. My computer had some sort of rootkit virus. Everything's cleaned up again now. :-)
.....Susan