Andy Furniss wrote:
Andy Furniss wrote:
Strange, unless there is something in the pngs that causes a
different viewer to produce different output.
I looked again (display from ancient imagemagic) and can't see any
difference - psnr/ssim agree.
The pngs are not the same md5sum wise
md5sum frame1-yuv-709.png frame1-master.png
1c086ed015ebe05aa1cfc66d9fe754a3 frame1-yuv-709.png
91ab580b1db4361fcceadaffd24930bd frame1-master.png
The obvious difference between the pngs is master is bigger by 60 bytes
and it has extra info in it, I can see with ffmpeg -i ... that SAR and
DAR are shown - nothing about 709 but maybe that's in there as well?
I tried making another png from yuv using out_color_matrix as well as
in_color_matrix, but it produced the same file (md5sum) as just
in_color_matrix.
I found the difference using identify from ImageMagick - I don't know
why display doesn't seem to show it for me but ...
identify -verbose frame1-yuv-709.png > idout-709
identify -verbose frame1-master.png > idout-master
diff idout-master idout-709
1c1
< Image: frame1-master.png
---
> Image: frame1-yuv-709.png
5,6d4
< Resolution: 1x1
< Print size: 1920x1080
47c45
< Gamma: 0.50994
---
> Gamma: 0.454545
65,68c63,64
< date:create: 2016-01-04T21:52:55+00:00
< date:modify: 2016-01-04T21:52:55+00:00
< png:cHRM : chunk was found (see Chromaticity, above)
< png:gAMA : gamma=0.45454544 (See Gamma, above)
---
> date:create: 2016-01-04T22:04:11+00:00
> date:modify: 2016-01-04T22:04:11+00:00
73c69
< png:pHYs : x_res=1, y_res=1, units=0
---
> png:pHYs : x_res=0, y_res=1, units=0
76c72
< filename: frame1-master.png
---
> filename: frame1-yuv-709.png
82,83c78,79
< User time: 0.050u
< Elapsed time: 0:01.060
---
> User time: 0.060u
> Elapsed time: 0:01.059
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