The Problem
One would think that of all things, getting your video to show in the correct aspect ratio would be something that just happens. In reality, we find however that this is not the case. The most common problem people seem to have is what I call a “squished” video. A squished video is one where it seems the video is too tall or that it got squished from the sides (pressed in). Another common problem is that that the video frame is really in 4:3 aspect ratio while the picture (the video) within is in 16:9 but a lot of space is wasted due to letterboxing. In other words, it’s not as wide as it should be or the actual video is not the dimensions you expect.
The image below shows a frame of an HD Video that is in the correct aspect ratio of 16:9.
This next image shows a frame of the same HD Video but "Squished". Notice that the video is really in a 4:3 aspect ratio and not 16:9 aspect ratio as it should be. Things look taller and thiner (squished).
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This image shows another common problem. The video picture appears in the correct aspect ratio of 16:9, however the video itself is in a 4:3 aspect ratio. The encoder has compensated for the difference by letterboxing the video, effectively making the video a lot smaller than it should be in order to fit.
Why does something so simple end up being so difficult
I think these issues stem from a few things that are seemingly disconnected.
- The way your camera records and outputs video
- The editing software you use and the abundant choices it offers for encoding, none of which really seem to apply to what you're trying to do.
HD, HDV, Full Raster
The video output by HD Video cameras comes in at least 3 flavors. This is directly related to the type of HD video your camera captures or outputs. Standard HD (or full HD) is 1920x1080 (16:9 aspect ratio) or also called full raster. Here are some of the HD formats and their raster dimensions.
| HDV, XDCAM |
1440x1080 |
| AVCHD, XDCAM EX |
1920x1080 |
| DVCPro HD |
1280x1080 |
Pixel Aspect Ratio
Before going on, I’d like you to understand another concept. Pixel aspect ratio or PAR. Yes, I do mean pixel aspect ratio and not video aspect ratio. TV screens have rectangular pixels. That is each pixel is wider than it is taller. Wider by a factor of 1.3333333333333333333. So the pixel aspect ratio of TV monitors is 1.3333333333333333333:1. Computer monitors have square pixels (and so a pixel aspect ratio of 1:1). Are you beginning to see where we’re going with this? No? Ok, no problem. If you multiplied 1440 x 1.333333333333333333 you’ll get 1920. What this means is that a squished video would actually look normal when viewed on a TV monitor, because the TV stretches your video out.
This might actually confuse you more instead of clearing things up, but bear with me a moment. It’s important to know that there is a difference between encoding for DVD or Blu-ray and for online viewing. The trick is to keep in mind, that when encoding video for online purposes, be sure to choose the Square Pixel option. That’s not the only thing but just one of the things to keep in mind.
Video Editing Software
Video editing software have their own terminology for the various attributes one can choose when attempting to encode video. To further aggravate matters, your editing software most likely compensates for the difference in pixel aspect ratios, while editing and so you don’t see the issue at the time of editing but only notice that your video is squished after encoding.
The Solution
Finally, here are the settings you should use to ensure your video is rendered with the correct aspect ratio.
- Choose Square pixels - Do not choose Widescreen 16:9, HD Anamorphic 1080 or any other option
- Make sure you choose or set the correct dimensions (1920x1080 or 1280x720). For most online video hosting services that support HD video you’d probably choose to encode at 1280x720.
The image below shows and annotated version of Adobe Premiere Pro CS3's Media Encoder screen with the wrong settings.
The image below shows and annotated version of Adobe Premiere Pro CS3's Media Encoder screen with the Correct settings.
I hope this article has helped you better understand the cause of your issues and the solution.
I've encoded the same source video using the above two settings so you can see the difference for yourselves. The first one is the correct aspect ratio, while the second is the squished aspect ratio version.
