Thursday, March 25, 2004

New VirtualDub Filter Chain

Changed up my standard filter chain for clean OTA recordings on my SVHS VCR:

1. Capture at 704x480 YUY2 29.97fps 48kHz audio

2. Static Noise Reduction, Noise threshold 6, Interlaced. This gets rid of some of the noise in the signal.

3. Deinterlace (unfold), this is done prior to any filters that aren't interlace-friendly. What actually happens is that the image goes from being 704x480 interlaced to 1408x240 deinterlaced with the A/B frames side-by-side.

4. Dynamic Noise Reduction, Noise threshold 6, Not sure if this filter is interlace-friendly... if it is, I can get rid of the unfold/fold steps. Good for eliminating any shimmering noise between frames.

5. Deinterlace (fold), changes the stream back to interlaced.

6. Crop any tracking noise (usually 4 pixels), Resize using Lanczos3, interlaced to 352x476 (480 minus the number of lines cropped due to tracking noise), then expand/letterboxed back to 352x480 which centers the result vertically on the screen. The old fill method resulted in large black borders on the bottom of the frame if there was a lot of tracking noise to remove.

Speed: It took 24.4 minutes to convert a 7.2 minute clip, but CPU usage was only around 50% on my AthlonXP 2600+. Assuming I can identify the bottleneck, it could've been done in 12-13 minutes (around 1.4-1.5x) which is a good bit faster then 2D Cleaner or the Smarth Smoother filters.

posted by Wuphon's at 6:50 PM