On Sun, 15 Mar 2020, Ted Park wrote:
I think colorkey filter can still do this. Basically you want the
converse of what color keying does right? It should work the same (that
is the opposite) way, and you just have to invert the alpha value.
I'm not quite sure what you mean by invert the alpha value. I think you
mean invert the color I'm using... ie, if want to KEEP colors very close
to e6e65c (I've refined the color since my first post), then the "invert"
of that would be 1919A3 (at least according to an "opposite color tool" I
found).
So... after some experimenting...
colorkey sort of works if I use the "invert" color and max similarity and
blend values:
colorkey=color=0x1919A3:similarity=1:blend=1
But the yellow box is pretty faint and there's still too much of the video
still visible. NOTE: this ONLY works if I use ffplay, not ffmpeg (see
below).
try using colorkey or colorhold with higher similarity values first.
colorhold does seem to work, but as Dan Bridges points out...
On Sun, 15 Mar 2020, Dan Bridges wrote:
Note, this filter will only make the discriminated stuff gray, not black
or transparent. Perhaps someone else will be able to help.
Yes... that's what I see. If I use this:
colorhold=color=0xe6e65c:similarity=0.25:blend=0.5
Then the "yellow box" stays yellow and everything else becomes gray scale...
like I'm watching a black and white video. But I don't want ANY video...
I ONLY want the yellow box floating around the screen.
Now I did find something that works (colorhold + chromakey)
colorhold=color=0xe6e65c:similarity=0.25:blend=0.0,chromakey=color=black:similarity=.1
but this ONLY works if I use ffplay, so perhaps I'm not using it
correctly.
**IF** I use ffplay, then this does (mostly) what I want:
ffplay -i test.mkv -vf
"colorhold=color=0xe6e65c:similarity=0.25:blend=0.0,chromakey=color=black:similarity=.1"
I ONLY see the yellow box (although it's a bit spotty), but pretty much
all of the rest of the video is completely black. That's what I want.
BUT, if I use ffmpeg:
ffmpeg -i test.mkv -vf
"colorhold=color=0xe6e65c:similarity=0.25:blend=0.0,chromakey=color=black:similarity=.1"
test-highlight.mkv
Then it behaves as if the chromakey filter isn't used at all. If fact,
the above produces the same output (as far as I can tell) as this:
ffmpeg -i test.mkv -vf "colorhold=color=0xe6e65c:similarity=0.25:blend=0.0"
test-highlight.mkv
How can I get the same results with ffmpeg that I see with ffplay?
I have similar results using only colorkey with the inverted color. ie,
using this (sort of) works:
ffplay -i test.mkv -vf "colorkey=color=0x1919A3:similarity=1:blend=1"
but this doesn't seem to do anything (at least visibly):
ffmpeg -i test.mkv -vf "colorkey=color=0x1919A3:similarity=1:blend=1"
test-highlight.mkv
Here's the complete output for ffmpeg colorhold,chromakey:
$ ffmpeg -i test.mkv -vf
"colorhold=color=0xe6e65c:similarity=0.25:blend=0.0,chromakey=color=black:similarity=.1"
test-highlight.mkv
ffmpeg version N-96974-g425b6a9a2c Copyright (c) 2000-2020 the FFmpeg developers
built with gcc 9 (GCC)
configuration: --enable-gpl --enable-version3 --enable-nonfree
--enable-static --disable-shared --disable-debug --enable-libass
--enable-libfdk-aac --enable-libfontconfig --enable-libfreetype
--enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis
--enable-libvpx --enable-libx264 --enable-libx265 --enable-openssl
--enable-libbluray --enable-libcdio
libavutil 56. 42.100 / 56. 42.100
libavcodec 58. 75.100 / 58. 75.100
libavformat 58. 41.100 / 58. 41.100
libavdevice 58. 9.103 / 58. 9.103
libavfilter 7. 77.100 / 7. 77.100
libswscale 5. 6.101 / 5. 6.101
libswresample 3. 6.100 / 3. 6.100
libpostproc 55. 6.100 / 55. 6.100
Input #0, matroska,webm, from 'test.mkv':
Metadata:
ENCODER : Lavf58.29.100
Duration: 00:01:27.36, start: 0.000000, bitrate: 2479 kb/s
Stream #0:0: Video: h264 (High), yuv420p(progressive), 720x480 [SAR 32:27
DAR 16:9], 30 fps, 30 tbr, 1k tbn, 60 tbc (default)
Metadata:
ENCODER : Lavc58.54.100 libx264
DURATION : 00:01:27.333000000
Stream #0:1: Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s (default)
Metadata:
ENCODER : Lavc58.54.100 ac3
DURATION : 00:01:27.356000000
Stream mapping:
Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
Stream #0:1 -> #0:1 (ac3 (native) -> vorbis (libvorbis))
Press [q] to stop, [?] for help
[swscaler @ 0x2447600] No accelerated colorspace conversion found from yuv420p
to argb.
[libx264 @ 0x21ea280] using SAR=32/27
[libx264 @ 0x21ea280] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 0x21ea280] profile High 4:4:4 Predictive, level 3.0, 4:4:4, 8-bit
[libx264 @ 0x21ea280] 264 - core 157 r2980 34c06d1 - H.264/MPEG-4 AVC codec -
Copyleft 2003-2019 - http://www.videolan.org/x264.html - options: cabac=1 ref=3
deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00
mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11
fast_pskip=1 chroma_qp_offset=4 threads=6 lookahead_threads=1 sliced_threads=0
nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3
b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2
keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf
mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, matroska, to 'test-highlight.mkv':
Metadata:
encoder : Lavf58.41.100
Stream #0:0: Video: h264 (libx264) (H264 / 0x34363248), yuv444p, 720x480
[SAR 32:27 DAR 16:9], q=-1--1, 30 fps, 1k tbn, 30 tbc (default)
Metadata:
DURATION : 00:01:27.333000000
encoder : Lavc58.75.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
Stream #0:1: Audio: vorbis (libvorbis) (oV[0][0] / 0x566F), 48000 Hz,
stereo, fltp (default)
Metadata:
DURATION : 00:01:27.356000000
encoder : Lavc58.75.100 libvorbis
frame= 2620 fps= 45 q=-1.0 Lsize= 6972kB time=00:01:27.35 bitrate= 653.9kbits/s speed= 1.5x
video:5839kB audio:1076kB subtitle:0kB other streams:0kB global headers:4kB muxing overhead: 0.828422%
[libx264 @ 0x21ea280] frame I:11 Avg QP:20.07 size: 12820
[libx264 @ 0x21ea280] frame P:665 Avg QP:23.54 size: 6011
[libx264 @ 0x21ea280] frame B:1944 Avg QP:28.26 size: 946
[libx264 @ 0x21ea280] consecutive B-frames: 0.6% 1.1% 0.6% 97.7%
[libx264 @ 0x21ea280] mb I I16..4: 6.1% 79.0% 14.9%
[libx264 @ 0x21ea280] mb P I16..4: 1.0% 3.7% 1.3% P16..4: 15.8% 11.1%
6.7% 0.0% 0.0% skip:60.4%
[libx264 @ 0x21ea280] mb B I16..4: 0.1% 0.4% 0.0% B16..8: 17.4% 2.3%
0.4% direct: 1.0% skip:78.4% L0:48.7% L1:43.0% BI: 8.3%
[libx264 @ 0x21ea280] 8x8 transform intra:66.9% inter:68.0%
[libx264 @ 0x21ea280] coded y,u,v intra: 45.1% 0.9% 0.3% inter: 8.8% 0.1% 0.0%
[libx264 @ 0x21ea280] i16 v,h,dc,p: 61% 31% 4% 4%
[libx264 @ 0x21ea280] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 31% 13% 29% 4% 4% 6%
3% 6% 4%
[libx264 @ 0x21ea280] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 29% 27% 12% 4% 6% 7%
5% 6% 4%
[libx264 @ 0x21ea280] Weighted P-Frames: Y:0.3% UV:0.2%
[libx264 @ 0x21ea280] ref P L0: 39.3% 13.3% 36.0% 11.3% 0.1%
[libx264 @ 0x21ea280] ref B L0: 68.3% 25.3% 6.4%
[libx264 @ 0x21ea280] ref B L1: 90.3% 9.7%
[libx264 @ 0x21ea280] kb/s:547.63
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