2. The Test

HD Vs. SD

In order to test the quality of the recordings and different styles of compression, I recorded seven minutes of the Final round of the US Open in 1080i HD. I then compressed it into several of the available file formats offered by Beyond TV. High definition files inevitably lose some of their detail when they are re-encoded into formats using higher compression than MPEG 2. However, unless a direct comparison is made, the differences are usually not very noticeable and the significantly smaller file sizes are worth the slight sacrifice in quality.

I recommend you view the larger versions of the following screen captures (just click on each image), since the quality differences are much more clear in the larger image. In the images with mismatched resolutions, note that the lower resolution has been stretched to match the higher resolution for the purposes of this comparison. So in those images, the differences may be slightly exaggerated.

To start, Figure 1 shows a screen capture from the full-quality HD picture, which is in MPEG2 TS (Transport Stream) format.

Figure 1: Original full quality HD screen capture (click on image to enlarge)

To get warmed up and as a maximum file size difference comparison, Figure 2 shows a comparison between original HD recording and a standard definition (SD) compression of the same file using DivX Home Theater "high quality". The difference in image quality is obvious and probably not the best choice for HD enjoyment. The file size savings are appreciable, however, with the original file taking up nearly 700 Megabytes on my hard drive, which was knocked down to 40 Megabytes in 640x480 SD form.

Figure 2: HD vs. SD (click on image to enlarge)