Dot Pitch

With all the rumours of Apple announcing a large-format retina display, it got me thinking: If they did release a 27″ retina display, just how high of a resolution would it be?

To figure this we first need to know the dot pitch of Apple’s small retina display. The dot pitch is the distance between the subpixels of a display and is an indication of how sharp the image will appear.

You can calculate the dot pitch by first finding the screen’s resolution in pixels per inch. However, since screen resolution is typically measured as horizontal pixels by vertical pixels, and screen size is measured in diagonal inches we need to figure out what the screen’s resolution is in diagonal pixels. We can do this using the Pythagorean theorem:  Where a = horizontal resolution, b = vertical resolution, and c = diagonal resolution.

The iPhone retina display has a resolution of 960×640 so the diagonal resolution is:  = 1153.78. We now need to get the pixels per inch which we can do by taking the screen’s resolution and dividing it by the screen’s diagonal size which is 3.5″: 1153.78 / 3.5 = 329.65 pixels per inch.

Now that we have the resolution in pixels per inch we want to find out the dot pitch. Dot pitch is typically measured in millimeters per dot. So to convert dots per inch to millimeters per dot we divide the ppi value into the number of millimeters per inch: 25.4/329.65 = 0.077mm or 77μm which is pretty close to Apple’s claim of 326ppi and 78μm between pixels.

Now what we know what dot pitch qualifies as a “retina display” we want to find out given a certain dot pitch, aspect ratio, and screen size; what will the resolution of that display be?

Let’s say we want a 27″ 16:9 monitor with a retina display dot pitch of 0.077m. What we want to find is the scaling factor that we need to multiply the aspect ratio by to get the number of pixels.

If we take the equation for dot pitch, plug in what we know and put in variables for what we want to know (the scaling factor) we get this equation: . Now we have to solve for a.

First let’s simplify the bottom part.  can be simplified as  which equals . Once we add the square root we get . If we assume that a is positive then the square root of a² is a, and the square root of 337 is 18.36. That leaves us with . Which we can simplify by doing 18.36/27 = 0.68 then 25.4/0.68 = 37.35. So now we have  and can solve for a by dividing 37.35 by 0.077 to get a scaling factor of 485.06. Then we just multiply the scaling factor by our aspect ratio of 16:9 to get: (16*485.06):(9*485.06) which equals a resolution of roughly 7,760×4,365. Which would be a 33.8 megapixel display.

Incidentally, this is approximately equivalent to the defined resolution of UHDTV (Ultra High-Definition TV) which has a resolution of 7680×4320.

iTunes Match Helper

Since iTunes Match doesn’t give you a way to download the metadata on your matched songs like it lets you download a higher quality version I wrote a quick app to fetch the metadata from the iTunes Store for all of your matched songs. I had hoped to be able to have it automate the process of upgrading songs to 256kbps AAC but unfortunately iTunes doesn’t expose the iTunes Match Status to AppleScript so I don’t have any way of determining that a track has been matched until it’s already been downloaded. At some point I’d also like to add the ability to select which fields are updated and stop it from updating songs without any change. In case it isn’t obvious you can right click the song table to check or uncheck all of the songs at once.

You can download the app here: Download

I’m also releasing the source code in case anybody wants to see how it works. The code isn’t commented since I was just throwing it together for myself but the program is pretty simple. Basically it uses the scripting bridge and AppleScript to scan the iTunes database for files with a “Matched AAC audio file” type. It then extracts the iTunes Store ID from the file itself and uses the iTunes Search API to get the metadata for the song in a JSON format. Then it uses AppleScript again to write the new metadata back to the iTunes database. Feel free to use the code however you want.

You can download the source here: Download

Also a further note to everyone commenting. First, this will only find songs labeled as “matched” so it won’t update anything you haven’t redownloaded from iTunes Match. And second, Apple’s iTunes Match library appears to be larger than the library of songs available for purchase, so there will be some matched songs that it won’t be able to download information for because the ID doesn’t exist for sale in the store.

Coke Bottle from Slide Archive - Feb '72

Crater Lake - Crescent Lake, OR

This is from my trip to Oregon in July last year. Crater Lake was amazing and the pictures don’t really do justice to how huge it is. Unfortunately we were also being swarmed by mosquitos while we were there, but it was definitely worth it.

Shot on a Sony Z5U at 1080p24.

Shot with a Panasonic HPX-170 at 720p24.

This is my nature shoot project for our Corporate Video class, basically an exercise in color correction. Shot on a Panasonic HPX-170 at 720p24.

Corner of Hamburg and Hanover St. in Sharp-Leadenhall

Having inherited this project from another group I volunteered our group to work on this partly because I didn’t think our Lexington Market interview was very good and partly because despite the rather large amount of footage we had for this, the section of the interview where Colette and June talked about what had happened to their neighborhood where they were forced to move out, really caught my attention, because I had never heard of that before. So I based the audio documentary around that.

The hardest part of editing this was going through the 44 minutes of footage to find the few minutes of interview that I felt was really powerful and told a story. I also wished they had talked more about the history of Sharp-Leadenhall and what happened to them than about parking and the business of running the church which was what most of the interview was. But I still think what of the interview that did end up in the doc was really good, and I used narration to fill in the gaps.

As far as production, my favorite part of the whole documentary is the intro. Which actually came together by accident. I found the effect that I used to give their voices a more “tape recorder” kind of sound when I was trying to put EQ on and accidentally clicked something else and it sounded really cool. And I found the music while searching for blues jazz on freeplaymusic.com, and I wish I had more of that song but the entire piece of music was only 43 seconds long, so that intro is actually the entire song. That sort of mellow, simplistic, blue jazz is surprisingly hard to find.

Overall I’m quite pleased with the way the doc came out and I’d like to go back some time and get to do a more in depth interview about the neighborhood itself.

Listen here:

The Tale of John Dillinger – Spring ’09

Produced by: Kevin Vinck, Rachel Stump, Brian Debbie
Written by: Rachel Stump
Featuring the voices of:
Brian Debbie as Dillinger
Kevin Vinck as Pervis
Rachel Stump as Anna Sage
Additional voices: Earl Gray, Dominic DeLauney

Note: The background noise in this is from my air conditioner. It really is that loud so that’s not the H4n’s fault.