When it comes to testing something like this, the results are entirely speculative. When I viewed movies I looked for any stuttering in either video or audio from all supported sources, and also compared the visual quality to another LCD display on the PC to see if the quality showed any signs of degradation. I also took a look at the quality from the upconverting of media content to see if there was a difference.
That said, I will say right up front that I was very impressed with the output quality. Upconversion did improve video quality giving it a crisper appearance that enhanced the viewing pleasure of the content. While I am going to include some photographs of the output, I will remind viewers that the camera will always pick up small details that the human eye will not notice. At no time during the viewing of content did I see any blocks or large pixels during playback, but the photo will often pick up these features due to the extended time that the shutter remains open. This is a fact of life, so I thought it best to bring this out at the beginning.
The movie these photos were taken from was the new release of The Andromeda Strain, a two-part miniseries that was released by A&E not too long ago. The video file is a standard definition version and the 780HD was set to display this at a resolution of 1080i with upconversion taking place due to the use of the HDMI connectivity. The movie was being played from the internal hard drive, but I did not see any differences when streaming it from both wired and wireless network setups.