Ben McMurry

Lastly, I would like to report on some findings I made with regard to Apple Devices and their supported video playback. I did some tests with h.264 video encoding. A lot of this won't mean much, but it's nice to write it down for future reference. Ipods do not support: b-frames cabac trellis 8x8dct Ipods Do support Resolutions greater than what is listed on Apple's website provided that the height does not exceed the listed height (i.e. 640x480 is listed as the max for the iPod touch, but it will play 855x480.) Of course, it won't show a high resolution, it will down-convert it to what it can show. 4 reference frames detecelining decoming I also have to note that handbrake's presets are pretty good for apple devices.

Two posts in one day? That's strange. In my effort to learn more about video, I explored some new features of current TVs. You might have seen that new TVs have crazy looking labels that say "120hz" or "240hz." What's that all about? Well, I don't want to get to technical here, but here is a little background information. Broadcast signals are typically 30 frames per second. That's 30 different images that you see on your screen per second. Well, actually it's 60 half images. Our brains can fill in information. TVs typically operate at 60hz. The hertz used to refer to energy passed through something in the tv, but now with LCD tvs they really refer to frames per second (fps). So, TVs work could for broadcast. Film, however, is usually 24 fps. In order to fill up the available 60hz, complicated math has to happen. 24 is not a multiple of 60, so a 3:2 pulldown happens. Some new frames are inserted . . . blah, blah, blah. So, you'll find t...

This week my students have been working on their video productions. They are required to make an instructional video. I thought that I would use this week to learn some more about video and decided to learn about up-conversion. I have read things here and there, but this week I did some experimentation of my own. The Basics Up-conversion is the process of "blowing up" video to take up more pixels. A DVD has about 855x480 (480p)(It's really 720x480 with non-square pixels, but that's the square pixel equivalent). Your high end HD videos, like bluray, are at 1920x1080 (1080p). HD signals look nice because there is more information. Up-conversion blows up the original image and then guesses what the missing pixels in between should be. This is pretty tricky. There are lots of different methods for guessing. Some are better than others. All Modern TVs up-convert. Most TVs are at 1920x1080. It converts any signal it gets to that resolution. Not all TVs up-convert equally. I...