Comparison of y4mscaler with yuvscaler
Frequency Response

yuvscaler is the video scaler which ships with MJPEGtools.

yuvscaler implements two scaling modes, "RESAMPLE" and "BICUBIC". The following table compares their performance in downsampling with y4mscaler's box and cubic kernels.

yuvscaler is invoked as follows for the test:

    yuvscaler -v 0 -M RESAMPLE -M RATIO_M_N_1_1 -O SIZE_120x120
    yuvscaler -v 0 -M BICUBIC -M RATIO_M_N_1_1 -O SIZE_120x120

 y4mscaleryuvscaler
M/N box cubic RESAMPLE BICUBIC
2/3
1/2
1/3
1/4

From this comparison, it is apparent that yuvscaler's RESAMPLE mode is equivalent to a box filter, and the BICUBIC mode is a cubic filter. The BICUBIC mode appears to have some subtle problems with some downscaling ratios.


return to y4mscaler

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Last modified: Sun Dec 11 14:55:29 EST 2005

©2003 Matthew Marjanovic.
This material may not be republished in any form without express written consent of the author.