|Diamond All-In-Wonder HD Premium AIW5000|
|Reviews - Featured Reviews: Video Cards|
|Written by Dan Ferguson|
|Sunday, 27 February 2011|
Page 7 of 13
TotalMedia has four fixed options for recording quality; 'High Quality', 'Standard Play', 'Long Play', and 'Extended Play'. Repeated tests indicate that the exact recording format for each option are automatically chosen by the software based on the broadcast resolution. For example, a high quality recording of both 1080i and 720p sources resulted in a 1920x1080 video, and a 480i broadcast resulted in 720x480 recording. The extended play option resulted in recordings with resolutions matching the broadcast resolution. There did not seem to be a way to capture really low quality video.Since even the lowest quality recording option results in adequate video the 'Extended Play' option was used for all tests. This mode represents the lowest resource demands for basic tuner functions. Extra features like higher recording quality, transcoding and multiple recording will demand even more system resources.
I was surprised to see such high resource utilization on my quad-core PC. My past experience testing on a dual core machine had lower CPU utilization. I can't help but wonder if there was a conflict or bug with my video driver that prevented the GPU from being utilized for any of the encoding.
The differences between resolutions is drastically obvious as more work is performed in encoding and saving the larger streams. The resources for 720p almost reaches that of 1080i since the double framerate of the progressive format saves twice as many frames per second. The 1080i is larger only due to the extra pixels.
At all three resolutions the ATI HD 650 had the lowest resource consumption, closely matched by the ASUS PHC3-150. The Diamond HD750 trailed behind using much more resources than the other cards.
The difference in resources required to record on top of just viewing TV wasvery small. In some cases the CPU utilization dropped. I can't think of a logical way to explain that phenomenon. Perhaps a video guru can add a comment. I know the difference is not due to the variation in recorded content. All runs were timed at 10 minutes and repeated multiple times. The CPU usage was very consistent between runs varying by less than one percent.
Since the CPU utilzation on the HD750 was higher than the other cards I would have expected it to have a better recording quality (more data captured takes more resources?). An analysis of the recorded videos shows this was not the case. The recorded content between the HD 650 and the PHC3-150 were quite comparable while the content from the HD 750 was notably less. I recorded multiple clips to verify, and the quality from the other cards kept coming out higher. It was not quite as consistent as the resource usage, but the relative differences were still evident. Based on my repeat testing the chart above exaggerates the differences between cards.
The bits per pixel reveal slightly more information about the recordings. The bits per pixel decrease with increasing recording resolution. This means that the higher resolution frames are of lower relative quality. But the advantage of having more pixels outweighs the slight degradation. The bits per pixel analysis highlights the PHC3-150 as having slightly better quality than the other cards. In this case the videos analyzed from the HD 650 and HD 750 had very similar qualities.
In this test system very few visual defects were noted in any of the recorded videos. There was some mild blockiness that is standard in transcoded mpeg videos, but it was not very noticeable. I attribute the difference to TotalMedia 3.5. Perhaps that is another explanation for the higher resource draw. Both ATI cards had a white line that periodically showed up at the very top edge of the video. This happened in both live and recorded TV. I think it is inherent to their choice of chips or board design. I did not notice any such defects from the PHC3-150. There were no dropped frames, no frame freezes or any other common defects from any of the recorded videos. Overall the videos from the ASUS PHC3-150 were of the highest quiality from both quantitative and qualitative perspectives.
The details from the recorded videos are shown below.
Recorded Video Details: