Subtitles of the Movie

Standards bodies in various parts of the world have defined standards for broadcast television and when you're encoding video for Flash very likely you'll be starting with video that conforms to these standards and it's going to affect how you encode your video, and so these terms show up in the Media Encoder. The two that you're most likely to encounter are PAL, Phase Alternating Line, and NTSC, National Television System Committee. PAL is a standard that is used in Europe and also parts of Asia and South Africa, and NTSC is used in North America, Central America, the Philippines, South Korea, and Taiwan. Among the most important parameters that these standards define are Frame Size, Frame Rate, Display Aspect Ratio, Pixel Aspect Ratio, and Field Order. So, for example, NTSC has a Frame Size in the file of 720 by 480, a Frame Rate of 29.97, a Display Aspect Ratio of 4 by 3, so this means that on the television screen the image is 4 by 3. A Pixel Aspect Ratio of point 9091 Ð we'll look at that a little bit more in a minute Ð an Interlaced video, that is, video in which each frame consists of two fields that have to be combined to make a full frame. PAL has a Frame Size of 720 by 576, a Frame Rate of 25, a Display Aspect Ratio of 4 by 3, a Pixel Aspect Ratio of 1 point 0926, and also Interlaced video. Computers can show a variety of frame sizes, a variety of frame rates, a variety of display aspect ratios. They have square pixels and progressive video, that is, video in which each frame is complete unto itself Ð there are no fields that have to be combined. Let's just briefly look at this Pixel Aspect Ratio. This has to do with the shape of each pixel. A pixel can be square, computer pixels are square for example, and pixels can be rectangular, and television pixels are rectangular. So let's just go into the Media Encoder, take a look at some of the Presets. So, here we have NTSC Source. Let's take a look at that. So, with NTSC Source we want to encode to 640 by 480. Notice it's not the same as the source. The NTSC Source Ð let's go back to that again Ð the NTSC Source is 720 by 480, but because the pixels are a different shape in that source for the computer to compensate for the square pixels we want 640 by 480. The Frame Rate here is the same and because we're going to be displaying this on a computer, we're going to be using Progressive video in the encoded FLV. We can choose Presets here, too. Let's choose another one, let's go ahead and choose a PAL Source. Here you see 25 frames per second, 786 by 576, and Progressive video. So, once again, let's compare this: 786 by 576. It's not the same. Again, it's compensating for the different Pixel Aspect Ratio. And in the next tutorial, we'll go into this pixel aspect ratio a little more deeply.