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Comparing YUV conversion approaches.

This is comparing different ways to do the YUV conversion. We are doing it in both 420p and 444p since 444p is a fairer binary image comparison. The takeaway should be to use the libswscale filter. The code to generate these files is here.

yuv422p10le encodes YUV444p encodes (Chrome Only) </div>

Reference PNG Source PNG file yuv422p10le encodes Default Encode (terrible) Basic ffmpeg conversion, no colorspace specified, ffmpeg assumes bt601 colorspace. This is a terrible filter, significant color changes from PNG file. ffmpeg flags to add: Full creation commandline: ffmpeg -y -r 1 -i ../sourceimages/chip-chart-1080-noicc.png -c:v libx264 -preset placebo -qp 1 -x264-params "keyint=15:no-deblock=1" -pix_fmt yuv422p10le -qscale:v 1 -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 13 ./chip-chart-yuvconvert/basic.mp4 OIIO idiff output idiff -o ./chip-chart-yuvconvert/chip-chart-1080-noiccdiff.png ../sourceimages/chip-chart-1080-noicc.png ./chip-chart-yuvconvert/chip-chart-1080-noicc-basic.png b'Comparing "../sourceimages/chip-chart-1080-noicc.png" and "./chip-chart-yuvconvert/chip-chart-1080-noicc-basic.png" Mean error = 0.265387 RMS error = 0.501056 Peak SNR = 6.00228 Max error = 1 @ (0, 0, A) values are 0, 0, 0 vs 0, 0, 0, 1 2073600 pixels (100%) over 1e-06 2073600 pixels (100%) over 1e-06 FAILURE 'ERROR! Colormatrix filter (close) Using colormatrix filter. colormatrix only supports 8-bit per component images. Visually its getting pretty close. ffmpeg flags to add: -sws_flags spline+accurate_rnd+full_chroma_int -vf "colormatrix=bt470bg:bt709" Full creation commandline: ffmpeg -y -r 1 -i ../sourceimages/chip-chart-1080-noicc.png -sws_flags spline+accurate_rnd+full_chroma_int -vf "colormatrix=bt470bg:bt709" -c:v libx264 -preset placebo -qp 1 -x264-params "keyint=15:no-deblock=1" -pix_fmt yuv422p10le -qscale:v 1 -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 13 ./chip-chart-yuvconvert/colormatrix.mp4 OIIO idiff output idiff -o ./chip-chart-yuvconvert/chip-chart-1080-noiccdiff.png ../sourceimages/chip-chart-1080-noicc.png ./chip-chart-yuvconvert/chip-chart-1080-noicc-colormatrix.png b'Comparing "../sourceimages/chip-chart-1080-noicc.png" and "./chip-chart-yuvconvert/chip-chart-1080-noicc-colormatrix.png" Mean error = 0.251864 RMS error = 0.500034 Peak SNR = 6.02 Max error = 1 @ (0, 0, A) values are 0, 0, 0 vs 0, 0, 0, 1 2073600 pixels (100%) over 1e-06 2073600 pixels (100%) over 1e-06 FAILURE 'ERROR! Colorspace filter Using colorspace filter, better quality filter, SIMD so faster too, can support 10-bit too. Visually pretty close to colormatrix, but slight improvement based on colormatrix values. ffmpeg flags to add: -sws_flags spline+accurate_rnd+full_chroma_int -vf "colorspace=bt709:iall=bt601-6-625:fast=1" Full creation commandline: ffmpeg -y -r 1 -i ../sourceimages/chip-chart-1080-noicc.png -sws_flags spline+accurate_rnd+full_chroma_int -vf "colorspace=bt709:iall=bt601-6-625:fast=1" -c:v libx264 -preset placebo -qp 1 -x264-params "keyint=15:no-deblock=1" -pix_fmt yuv422p10le -qscale:v 1 -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 13 ./chip-chart-yuvconvert/colorspace.mp4 OIIO idiff output idiff -o ./chip-chart-yuvconvert/chip-chart-1080-noiccdiff.png ../sourceimages/chip-chart-1080-noicc.png ./chip-chart-yuvconvert/chip-chart-1080-noicc-colorspace.png b'Comparing "../sourceimages/chip-chart-1080-noicc.png" and "./chip-chart-yuvconvert/chip-chart-1080-noicc-colorspace.png" Mean error = 0.251258 RMS error = 0.500027 Peak SNR = 6.02013 Max error = 1 @ (0, 0, A) values are 0, 0, 0 vs 0, 0, 0, 1 2073600 pixels (100%) over 1e-06 2073600 pixels (100%) over 1e-06 FAILURE 'ERROR! libswscale filter + flags (best) Using the libswscale library. Seems similar to colorspace, but with image resizing, and levels built in. This also has a number of libswscale parameters. Visually this is close to the above two, but slight improvement based on colormatrix results. ffmpeg flags to add: -sws_flags spline+accurate_rnd+full_chroma_int+full_chroma_inp -vf "scale=in_color_matrix=bt709:out_color_matrix=bt709" Full creation commandline: ffmpeg -y -r 1 -i ../sourceimages/chip-chart-1080-noicc.png -sws_flags spline+accurate_rnd+full_chroma_int+full_chroma_inp -vf "scale=in_color_matrix=bt709:out_color_matrix=bt709" -c:v libx264 -preset placebo -qp 1 -x264-params "keyint=15:no-deblock=1" -pix_fmt yuv422p10le -qscale:v 1 -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 13 ./chip-chart-yuvconvert/splinecolormatrix.mp4 OIIO idiff output idiff -o ./chip-chart-yuvconvert/chip-chart-1080-noiccdiff.png ../sourceimages/chip-chart-1080-noicc.png ./chip-chart-yuvconvert/chip-chart-1080-noicc-splinecolormatrix.png b'Comparing "../sourceimages/chip-chart-1080-noicc.png" and "./chip-chart-yuvconvert/chip-chart-1080-noicc-splinecolormatrix.png" Mean error = 0.251215 RMS error = 0.500029 Peak SNR = 6.02009 Max error = 1 @ (0, 0, A) values are 0, 0, 0 vs 0, 0, 0, 1 2073600 pixels (100%) over 1e-06 2073600 pixels (100%) over 1e-06 FAILURE 'ERROR! YUV444p encodes (Chrome Only) Default Encode (terrible) Basic ffmpeg conversion, ffmpeg assumes bt601 colorspace, now at 444. Results look terrible. ffmpeg flags to add: Full creation commandline: ffmpeg -y -r 1 -i ../sourceimages/chip-chart-1080-noicc.png -c:v libx264 -preset placebo -qp 0 -x264-params "keyint=15:no-deblock=1" -pix_fmt yuv444p10le -qscale:v 1 -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 13 ./chip-chart-yuvconvert/basic444.mp4 OIIO idiff output idiff -o ./chip-chart-yuvconvert/chip-chart-1080-noiccdiff.png ../sourceimages/chip-chart-1080-noicc.png ./chip-chart-yuvconvert/chip-chart-1080-noicc-basic444.png b'Comparing "../sourceimages/chip-chart-1080-noicc.png" and "./chip-chart-yuvconvert/chip-chart-1080-noicc-basic444.png" Mean error = 0.265202 RMS error = 0.501036 Peak SNR = 6.00262 Max error = 1 @ (0, 0, A) values are 0, 0, 0 vs 0, 0, 0, 1 2073600 pixels (100%) over 1e-06 2073600 pixels (100%) over 1e-06 FAILURE 'ERROR! Colormatrix filter (close) Using colormatrix filter. colormatrix only supports 8-bit per component images. Visually pretty close, but still off. ffmpeg flags to add: -sws_flags spline+accurate_rnd+full_chroma_int -vf "colormatrix=bt470bg:bt709" Full creation commandline: ffmpeg -y -r 1 -i ../sourceimages/chip-chart-1080-noicc.png -sws_flags spline+accurate_rnd+full_chroma_int -vf "colormatrix=bt470bg:bt709" -c:v libx264 -preset placebo -qp 0 -x264-params "keyint=15:no-deblock=1" -pix_fmt yuv444p10le -qscale:v 1 -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 13 ./chip-chart-yuvconvert/spline444colormatrix2.mp4 OIIO idiff output idiff -o ./chip-chart-yuvconvert/chip-chart-1080-noiccdiff.png ../sourceimages/chip-chart-1080-noicc.png ./chip-chart-yuvconvert/chip-chart-1080-noicc-spline444colormatrix2.png b'Comparing "../sourceimages/chip-chart-1080-noicc.png" and "./chip-chart-yuvconvert/chip-chart-1080-noicc-spline444colormatrix2.png" Mean error = 0.251596 RMS error = 0.500007 Peak SNR = 6.02048 Max error = 1 @ (0, 0, A) values are 0, 0, 0 vs 0, 0, 0, 1 2073600 pixels (100%) over 1e-06 2073600 pixels (100%) over 1e-06 FAILURE 'ERROR! Colorspace filter Using colorspace filter, better quality filter, SIMD so faster too, can support 10-bit too. Visually slight differences, but getting closer. ffmpeg flags to add: -sws_flags spline+accurate_rnd+full_chroma_int -vf "colorspace=bt709:iall=bt601-6-625:fast=1" Full creation commandline: ffmpeg -y -r 1 -i ../sourceimages/chip-chart-1080-noicc.png -sws_flags spline+accurate_rnd+full_chroma_int -vf "colorspace=bt709:iall=bt601-6-625:fast=1" -c:v libx264 -preset placebo -qp 0 -x264-params "keyint=15:no-deblock=1" -pix_fmt yuv444p10le -qscale:v 1 -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 13 ./chip-chart-yuvconvert/spline444colorspace.mp4 OIIO idiff output idiff -o ./chip-chart-yuvconvert/chip-chart-1080-noiccdiff.png ../sourceimages/chip-chart-1080-noicc.png ./chip-chart-yuvconvert/chip-chart-1080-noicc-spline444colorspace.png b'Comparing "../sourceimages/chip-chart-1080-noicc.png" and "./chip-chart-yuvconvert/chip-chart-1080-noicc-spline444colorspace.png" Mean error = 0.250951 RMS error = 0.500002 Peak SNR = 6.02056 Max error = 1 @ (0, 0, A) values are 0, 0, 0 vs 0, 0, 0, 1 2073600 pixels (100%) over 1e-06 2073600 pixels (100%) over 1e-06 FAILURE 'ERROR! libswscale filter + flags (Match) Using the libswscale library. Seems similar to colorspace, but with image resizing, and levels built in. This also has a number of libswscale parameters. Looking at the oiio difference, this is the first one that has an identical result to the input image. ffmpeg flags to add: -sws_flags spline+accurate_rnd+full_chroma_int+full_chroma_inp -vf "scale=in_color_matrix=bt709:out_color_matrix=bt709" Full creation commandline: ffmpeg -y -r 1 -i ../sourceimages/chip-chart-1080-noicc.png -sws_flags spline+accurate_rnd+full_chroma_int+full_chroma_inp -vf "scale=in_color_matrix=bt709:out_color_matrix=bt709" -c:v libx264 -preset placebo -qp 0 -x264-params "keyint=15:no-deblock=1" -pix_fmt yuv444p10le -qscale:v 1 -color_range 1 -colorspace 1 -color_primaries 1 -color_trc 13 ./chip-chart-yuvconvert/spline444out_color_matrix.mp4 OIIO idiff output idiff -o ./chip-chart-yuvconvert/chip-chart-1080-noiccdiff.png ../sourceimages/chip-chart-1080-noicc.png ./chip-chart-yuvconvert/chip-chart-1080-noicc-spline444out_color_matrix.png b'Comparing "../sourceimages/chip-chart-1080-noicc.png" and "./chip-chart-yuvconvert/chip-chart-1080-noicc-spline444out_color_matrix.png" Mean error = 0.250917 RMS error = 0.500002 Peak SNR = 6.02056 Max error = 1 @ (0, 0, A) values are 0, 0, 0 vs 0, 0, 0, 1 2073600 pixels (100%) over 1e-06 2073600 pixels (100%) over 1e-06 FAILURE 'ERROR! libswscale filter + flags full-range (Match) Using the libswscale library. Seems similar to colorspace, but with image resizing, and levels built in. This also has a number of libswscale parameters. Looking at the oiio difference, this is the first one that has an identical result to the input image. ffmpeg flags to add: -sws_flags spline+accurate_rnd+full_chroma_int+full_chroma_inp -vf "scale=in_range=full:in_color_matrix=bt709:out_range=full:out_color_matrix=bt709" Full creation commandline: ffmpeg -y -r 1 -i ../sourceimages/chip-chart-1080-noicc.png -sws_flags spline+accurate_rnd+full_chroma_int+full_chroma_inp -vf "scale=in_range=full:in_color_matrix=bt709:out_range=full:out_color_matrix=bt709" -c:v libx264 -preset placebo -qp 0 -x264-params "keyint=15:no-deblock=1" -pix_fmt yuv444p10le -qscale:v 1 -color_range 2 -colorspace 1 -color_primaries 1 -color_trc 13 ./chip-chart-yuvconvert/spline444out_color_matrixfull.mp4 OIIO idiff output idiff -o ./chip-chart-yuvconvert/chip-chart-1080-noiccdiff.png ../sourceimages/chip-chart-1080-noicc.png ./chip-chart-yuvconvert/chip-chart-1080-noicc-spline444out_color_matrixfull.png b'Comparing "../sourceimages/chip-chart-1080-noicc.png" and "./chip-chart-yuvconvert/chip-chart-1080-noicc-spline444out_color_matrixfull.png" Mean error = 0.250915 RMS error = 0.500002 Peak SNR = 6.02056 Max error = 1 @ (0, 0, A) values are 0, 0, 0 vs 0, 0, 0, 1 2073600 pixels (100%) over 1e-06 2073600 pixels (100%) over 1e-06 FAILURE 'ERROR!