I finally decided to try one of these myself since it seems to have been a topic of some interest lately. I've uploaded the results here: http://www.vegasusers.com/testbench/files/generations/
Be sure to check out the readme.txt file for a description of what it all means.
I started out with the still image in the 0-start_image.png file. This image is lossless 4:4:4 created from various generated media and scanned 4:4:4 images. Note in particular the crisp edges and even color in the test bars in the upper left corner.
I rendered this image to a standard NTSC DV .avi file in Vegas 4.0d using the included SONY DV codec. The result is gen-00.png which is now 4:1:1 as per the DV spec. Note how the edges seem to spill into each other. Also the edges between the red sweater and black vest are very blocky.
diff-start-00.png shows the difference between the original image and the first DV version. The differences are slight, but noticeable.
This .avi file was then rendered to a new .avi file. Re-rendering, rather than simple copying, was forced by overlaying the new generation number on the frame. This result is shown in gen-01.png. There is very little difference between generation 00 and generation 01.
diff-00-01.png shows the difference between generation 00 and generation 01. There is almost no visible difference.
The process was continued, re-rendering each subsequent generation from the previous one, through 100 generations. The last generation is shown in gen-99.png. Even this far out, the image is still nearly identical to the first DV generation.
diff-00-99.png shows the difference between generation 00 and generation 99. The difference is so slight as to be almost unnoticeable.
It would appear that the major quality hit is the conversion from 4:4:4 colorspace to 4:1:1. Even this hit is minor and limited mostly to areas of extreme color contrast. The colorbars were affected the worst and the red/black of the sweater and vest somewhat affected. Skin tones, the leaves, the cookie, and other less than saturated colors were affected very little at all. Overall the color balance of the 100th generation was still very faithful to the original and the detail only slightly softer.
generations.avi is a short video showing the progression through each re-rendering generation. Place this video on Vegas' timeline and you can use the left & right arrows to step through them.
Be sure to check out the readme.txt file for a description of what it all means.
I started out with the still image in the 0-start_image.png file. This image is lossless 4:4:4 created from various generated media and scanned 4:4:4 images. Note in particular the crisp edges and even color in the test bars in the upper left corner.
I rendered this image to a standard NTSC DV .avi file in Vegas 4.0d using the included SONY DV codec. The result is gen-00.png which is now 4:1:1 as per the DV spec. Note how the edges seem to spill into each other. Also the edges between the red sweater and black vest are very blocky.
diff-start-00.png shows the difference between the original image and the first DV version. The differences are slight, but noticeable.
This .avi file was then rendered to a new .avi file. Re-rendering, rather than simple copying, was forced by overlaying the new generation number on the frame. This result is shown in gen-01.png. There is very little difference between generation 00 and generation 01.
diff-00-01.png shows the difference between generation 00 and generation 01. There is almost no visible difference.
The process was continued, re-rendering each subsequent generation from the previous one, through 100 generations. The last generation is shown in gen-99.png. Even this far out, the image is still nearly identical to the first DV generation.
diff-00-99.png shows the difference between generation 00 and generation 99. The difference is so slight as to be almost unnoticeable.
It would appear that the major quality hit is the conversion from 4:4:4 colorspace to 4:1:1. Even this hit is minor and limited mostly to areas of extreme color contrast. The colorbars were affected the worst and the red/black of the sweater and vest somewhat affected. Skin tones, the leaves, the cookie, and other less than saturated colors were affected very little at all. Overall the color balance of the 100th generation was still very faithful to the original and the detail only slightly softer.
generations.avi is a short video showing the progression through each re-rendering generation. Place this video on Vegas' timeline and you can use the left & right arrows to step through them.