On 2022-09-14T11:21:58+0200, Dan <twinbe...@skytopia.com> wrote:
> The double height version is darker than it should be. I've checked the
> resulting video in both Media Player Classic and Chrome.
>
> If you check the dark green colour on the original PNG images, using an eye
> dropper tool, they're both R=25,G=74,B=15. However, if you check the same
> colour on the output MP4s, the colour matches on the original PNG, but not
> the doubleHeight version, which is R=22,G=66,B=12.
Long time ago since I last dealt with this
<https://forum.doom9.org/showthread.php?t=170306>. It's all about BT.601
(≤576p) v.s BT.709 (>576p), so for this conversion from RGB to YUV you'll also
need a colourmatrix conversion.
I'm no expert, but these are my observations:
ffplay -f lavfi "color=0x194a0f:s=400x576,format=rgb24" -->
R=25,G=74,B=15 (0x194a0f)
ffplay -f lavfi "color=0x194a0f:s=400x576[,format=yuv420p]" -->
R=25,G=74,B=14 (0x194a0e)
ffplay -f lavfi "color=0x194a0f:s=400x576,format=yuv444p" -->
R=25,G=74,B=14 (0x194a0e)
ffplay -f lavfi "color=0x19be0f:s=400x576,format=rgb24" -->
R=25,G=190,B=15 (0x19be0f)
ffplay -f lavfi "color=0x19be0f:s=400x576[,format=yuv420p]" -->
R=25,G=190,B=16 (0x19be10)
ffplay -f lavfi "color=0x19be0f:s=400x576,format=yuv444p" -->
R=25,G=190,B=16 (0x19be10)
I know too little about this for an explanation on why Blue is off by 1.
ffplay -f lavfi "color=0x194a0f:s=400x578,format=rgb24"
--> R=25,G=74,B=15 (0x194a0f)
ffplay -f lavfi "color=0x194a0f:s=400x578[,format=yuv420p]"
--> R=22,G=65,B=12 (0x16410c)
ffplay -f lavfi "color=0x194a0f:s=400x578,format=yuv444p"
--> R=22,G=65,B=12 (0x16410c)
ffplay -f lavfi
"color=0x194a0f:s=400x578[,format=yuv420p],scale=out_color_matrix=bt709" -->
R=23,G=72,B=11 (0x17480b)
ffplay -f lavfi
"color=0x194a0f:s=400x578,format=yuv444p,scale=out_color_matrix=bt709" -->
R=25,G=74,B=15 (0x194a0f)
ffplay -f lavfi "color=0x19be0f:s=400x578,format=rgb24"
--> R=25,G=190,B=15 (0x19be0f)
ffplay -f lavfi "color=0x19be0f:s=400x578[,format=yuv420p]"
--> R=14,G=164,B=11 (0x0ea40b)
ffplay -f lavfi "color=0x19be0f:s=400x578,format=yuv444p"
--> R=14,G=164,B=11 (0x0ea40b)
ffplay -f lavfi
"color=0x19be0f:s=400x578[,format=yuv420p],scale=out_color_matrix=bt709" -->
R=23,G=189,B=14 (0x17bd0e)
ffplay -f lavfi
"color=0x19be0f:s=400x578,format=yuv444p,scale=out_color_matrix=bt709" -->
R=26,G=189,B=15 (0x1abd0f)
It's not exactly the same colour, but it's the closest you'll get.
I've also tried zscale, but with ffplay it fails with the following
error-message:
ffplay -f lavfi "color=0x194a0f:s=400x578,format=yuv444p,zscale=m=709"
[Parsed_zscale_2 @ 0359d6c0] code 3074: no path between colorspaces
With FFmpeg, creating a temp-file, zscale does work:
ffmpeg -i PLdsb.png -t 5 -vf "zscale=m=709" -c:v libx264 -crf 0
PLdsb_zscale-bt709.mp4
ffplay PLdsb_zscale-bt709.mp4 --> R=24,G=74,B=14 (0x184a0e) | R=25,G=190,B=14
(0x19be0e)
Again, not exactly the same colour, but very close.
On 2022-09-15T13:07:08+0200, Michael Koch <astroelectro...@t-online.de> wrote:
> Please try this, for me it works with VLC player, the color is exactly the
> same:
>
> ffmpeg -f lavfi -i color=0x19be0f:s=400x576 -colorspace bt709
> -color_primaries bt709 -color_trc bt709 -crf 0 -vcodec libx264 -t 5 -y
> out1.mp4
> ffmpeg -f lavfi -i color=0x19be0f:s=400x720 -colorspace bt709
> -color_primaries bt709 -color_trc bt709 -crf 0 -vcodec libx264 -t 5 -y
> out2.mp4
These are all VUI (Video Usability Information) options and, unlike the
colourmatrix conversions above, don't have a direct impact on the video-image
itself.
It's kind of like meta-data. Your media player needs to support it to display
the correct colours. MediaInfo can show you this, like for instance:
Color range : Full
Matrix coefficients : BT.709
ffmpeg -i PLdsb.png -t 5 -color_range tv -colorspace bt470bg -c:v libx264 -crf
0 PLdsb_vui-tv601.mp4
ffplay PLdsb_vui-tv601.mp4 --> R=22,G=65,B=12 (0x16410c) | R=14,G=164,B=11
(0x0ea40b)
mpc-hc PLdsb_vui-tv601.mp4 --> R=25,G=74,B=14 (0x194a0e) | R=25,G=190,B=16
(0x19be10)
If you insist on using these VUI options, then in contrast to what you might
expect (PC,BT.709) it's actually TV,BT.601 that has the expected result.
Welcome to the wonderful world of video conversions.
On 2022-09-15T11:40:10+0200, Paul B Mahol <one...@gmail.com> wrote:
> Looks like your knowledge is very limited, incorrect and completely full of
> nonsense.
On 2022-09-16T15:38:51+0200, Paul B Mahol <one...@gmail.com> wrote:
> It is evident that your knowledge is exactly 0.
On 2022-09-14T17:01:39+0200, Paul B Mahol <one...@gmail.com> wrote:
> Next time be more constructive and try it before pointlesly commenting here
> in so bold and arrogant fashion.
Do you have any idea how rude and condescending your posts are? Disgraceful!
Especially for an FFmpeg-developer.
Next time please refrain from posting unless you have actually something useful
and helpful to add!
--
Reino
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