Saturday, February 21, 2004

Smart Smoother HQ Samples

Here is an example of using Klaus Post's Smart Smoother High Quality filter. The source material is a VHS tape that I own that's a few years old, captured with a S-VHS VCR and a Hauppauge WinTV-dbx PCI card. Clicking on each image will show you the original 720x480 capture frame.

Raw capture:
- Note the tape noise, results in a JPEG image that is 40% larger then the "radius 13 threshold 25" image, which means that if I try to take this straight to MPEG2, the encoder is going to have to use 40% more bitrate (at a guess) to get good quality.


HiQ: radius 3 threshold 50 average
- Not really much better then the raw sample, 3 is too small of a radius to make much of an impact.


HiQ: radius 13 threshold 50 average
- Note the loss of detail, such as the bead of sweat on her cheek below the eye. A good bit of the loss of detail is due to the threshold of 50 though (see r13/t25 below).


HiQ: radius 13 threshold 100 average
- This shows what happens as you raise the threshold value.


HiQ: radius 13 threshold 200 average
- Worst-case sample of threshold blur.


HiQ: radius 9 threshold 25 average
- This is very close. Note the detail is still there when compared to the originial image, but almost all of the tape noise is gone without losing detail.


HiQ: radius 13 threshold 25 average
- Not much difference between radius 9 and radius 13. But radius 13 takes longer to process.


The HiQ filter does a very good job on cartoons like that shown. My personal preference due to time reasons is "radius 7 or 9 threshold 10 or 15 or 20" which gives me around 5-6fps on my Pentium 4 1.6GHz laptop (r9/t15). Threshold 25 seems a little fuzzy when compared to threshold 15 (sorry, no sample), but that may depend on the quality of your source.

I'm not sure how well these settings work when CG is mixed in with the traditional cel animation. I'll try to find a sample (I have a copy of the King and I, animated version, on tape which has some mixed CG/cel shots). Update: When playing with the filters "radius 7 threshold 20 amount 254 maintain 10 weighted with difference" seems to be a very good setting, but it's very very very slow (4-6fps on my AthlonXP 2600+ for a 720x480 30fps clip). So instead, I'm going to go with "radius 7 threshold 15 amount X maintain 5 average with difference" which is a good bit faster and seems to be a decent middle ground.

For the curious who wonder how I extracted these images. VirtualDub allows you to export individual frames to individual TGA or BMP files. Load up your AVI in VDub, select a sequence of half a dozen frames, then use the "File, ..." to write your TGA/BMP files. Change up your filter settings and repeat the "File, ..." command to export a new set. You'll also need to change your video compresion method to "None (RGB)" prior to export and each 720x480 TGA file will be around 900Kb (which eats up disk space pretty quick if you try exporting hundreds of frames).

posted by Wuphon's at 8:02 PM