Sony DCRHC96 Mechanical Shutter Progressive Mode
vs. Various Software Deinterlacing Algorithms

Analysis of "still image" quality

 

Since the camera can only shoot in one mode at a time, two different test clips had to be made, so it's not possible to compare identical frames. Clip 1 was made using Sony's "mechanical shutter" progressive mode. Clip 2 was made using its standard interlaced mode.

The person who made the clips * made them as similar as possible. Upon examination, I found that the subject matter and "pan speed" of clip 1, around frames 51 thru 56, is extremely similar to clip 2 around frames 57-62.

The only purpose of the pair of small time-slice thumbnails shown below is to demonstrate the above, so we know we're comparing similar things. In particular, note how the vertical lines on the building show a similar amount of horizontal displacement in each case. The frames are 1/25th sec apart in each case.

 

Clip 1 (progressive) , slices from frames 51-56 Clip 2 (interlaced) , slices from frames 57-62

 

In each of the six pairs of images below, the image in the left column is always clip1, frame 54 (identically repeated six times for easy comparison). The shot was made by simply advancing VDub to "54" and using the frame image "copy" function. That result into Corel PSP 11 and saving as a lossless .png to eliminate any additional artifacts.

The images in the right column all clip 2 frame 59 (i.e. 59a/59b, if you prefer). They only differ from one another in how were de-interlaced, as indicated by the each images corresponding caption below it. These too were made by simply advancing VDub to frame 59, copying/pasting [from its output window] to PSP & saving the result as the PNG image you see here.

The first is VDub's output with no filters applied, the next two were created with VDub's internal de-interlace in each of two different modes. For the final two, VDub's internal filters were turned back off but VDub was "fed" from AviSynth with the sophisticated* TDeint filter in place. The first of those two was made with TDeint's "mode 0" using default settings; the second was made using "mode 1" (with other settings at default). Since mode 1 doubles the frame rate. the captured frame you see is listed as frame 118 by VDub, rather than 59.


* "...a bi-directionally, motion adaptive (sharp) deinterlacer [which] can also adaptively choose between using per-field and per-pixel motion adaptively. It can use cubic interpolation, kernel interpolation (with temporal direction switching), or one of two forms of modified ELA..."

 


Progressive Mode
 
No De-interlacing
 

 


Progressive Mode
 
VDub "Blend"
 

 


Progressive Mode
 
VDub Duplicate Field 1
 

 


Progressive Mode
 
TDeint Kernel Interpolation (default)
 

 


Progressive Mode
 
TDeint Mode 1 (double frame rate)
Frame 118
 

 

The actual original files. These are the DV-type 2 AVI files straight from the camera.
Clip 1 (36.1MB)
Mechanical Shutter Progressive		 Clip 2 (36.1MB)
Standard Interlaced
* Acknowledgements: The original clips were all created on a Sony DCRHC96 MiniDV and generously made available by Doom9 Forum member Mtz, who originated the entire original discussion starting at this point in this thread.
- All stills and this webpage by Steve G (Doom9: "stegre"), 18 April 2007