Hi Folks,
I'm exploring the lagfun filter and think I may have some fundamental
misunderstanding as I'm not getting the results I expect.
I have a video of green lasers on glassware in the dark and wish to make the
laser flashes persist.
My attempts so far seem to result in the green flashes persisting as white,
however.
I tried this command which I think should do this:
Take the YUV input video, split it into RGB, run lagfun on only the green
content, save resulting output.
ffmpeg -i IMG_1685.MOV -q:v 0 -vcodec h264 -acodec aac -strict -2 -filter:v
format=pix_fmts=rgb24,lagfun=decay=0.999 greenlagtest.mp4
Input file is here: http://www.robinbussell.co.uk/mov/IMG_1685.MOV (far too
much camera movement, I know!)
Output here: http://www.robinbussell.co.uk/mov/greenlagtest.mp4
Console output is:
ffmpeg version 4.2.2-1build1~18.04.sav0 Copyright (c) 2000-2019 the FFmpeg
developers
built with gcc 7 (Ubuntu 7.4.0-1ubuntu1~18.04.1)
configuration: --prefix=/usr --extra-version='1build1~18.04.sav0'
--toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu
--incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl
--disable-stripping --enable-avresample --disable-filter=resample
--enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom
--enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca
--enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig
--enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm
--enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg
--enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg
--enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr
--enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame
--enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack
--enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid
--enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal
--enable-opencl --enable-opengl --enable-sdl2 --enable-libdc1394
--enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r
--enable-libx264 --enable-shared
libavutil 56. 31.100 / 56. 31.100
libavcodec 58. 54.100 / 58. 54.100
libavformat 58. 29.100 / 58. 29.100
libavdevice 58. 8.100 / 58. 8.100
libavfilter 7. 57.100 / 7. 57.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 5.100 / 5. 5.100
libswresample 3. 5.100 / 3. 5.100
libpostproc 55. 5.100 / 55. 5.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'IMG_1685.MOV':
Metadata:
major_brand : qt
minor_version : 0
compatible_brands: qt
creation_time : 2020-03-28T12:20:59.000000Z
Duration: 00:00:18.53, start: 0.000000, bitrate: 3829 kb/s
Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv,
bt709), 1280x720, 3823 kb/s, 60.01 fps, 60 tbr, 600 tbn, 1200 tbc (default)
Metadata:
creation_time : 2020-03-28T12:20:59.000000Z
handler_name : Core Media Video
encoder : H.264
Stream #0:1(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
Metadata:
creation_time : 2020-03-28T12:20:59.000000Z
handler_name : Core Media Metadata
Stream #0:2(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
Metadata:
creation_time : 2020-03-28T12:20:59.000000Z
handler_name : Core Media Metadata
Stream mapping:
Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
Press [q] to stop, [?] for help
[libx264 @ 0x55a16881aec0] using cpu capabilities: MMX2 SSE2Fast SSSE3
SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x55a16881aec0] profile High 4:4:4 Predictive, level 3.2, 4:4:4
8-bit
[libx264 @ 0x55a16881aec0] 264 - core 155 r2917 0a84d98 - H.264/MPEG-4 AVC
codec - Copyleft 2003-2018 - http://www.videolan.org/x264.html - options:
cabac=1 ref=3 deblock=1:0:0 analyse=0x1:0x111 me=hex subme=7 psy=1
psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=0
cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=4 threads=12
lookahead_threads=2 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, mp4, to 'greenlagtest.mp4':
Metadata:
major_brand : qt
minor_version : 0
compatible_brands: qt
encoder : Lavf58.29.100
Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv444p,
1280x720, q=-1--1, 60 fps, 15360 tbn, 60 tbc (default)
Metadata:
creation_time : 2020-03-28T12:20:59.000000Z
handler_name : Core Media Video
encoder : Lavc58.54.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
frame= 1112 fps= 50 q=-1.0 Lsize= 6912kB time=00:00:18.48
bitrate=3063.4kbits/s speed=0.833x
video:6905kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: 0.101704%
[libx264 @ 0x55a16881aec0] frame I:5 Avg QP:22.29 size: 50576
[libx264 @ 0x55a16881aec0] frame P:968 Avg QP:25.09 size: 6873
[libx264 @ 0x55a16881aec0] frame B:139 Avg QP:24.68 size: 1178
[libx264 @ 0x55a16881aec0] consecutive B-frames: 81.5% 4.1% 4.3% 10.1%
[libx264 @ 0x55a16881aec0] mb I I16..4: 54.6% 0.0% 45.4%
[libx264 @ 0x55a16881aec0] mb P I16..4: 4.5% 0.0% 0.7% P16..4: 36.1%
6.4% 5.3% 0.0% 0.0% skip:46.9%
[libx264 @ 0x55a16881aec0] mb B I16..4: 0.6% 0.0% 0.0% B16..8: 25.8%
0.6% 0.2% direct: 0.3% skip:72.4% L0:29.9% L1:69.0% BI: 1.1%
[libx264 @ 0x55a16881aec0] coded y,u,v intra: 12.4% 1.8% 1.2% inter: 7.0%
1.6% 0.7%
[libx264 @ 0x55a16881aec0] i16 v,h,dc,p: 51% 26% 18% 5%
[libx264 @ 0x55a16881aec0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 18% 19% 32% 5%
6% 5% 6% 4% 5%
[libx264 @ 0x55a16881aec0] Weighted P-Frames: Y:2.9% UV:0.7%
[libx264 @ 0x55a16881aec0] ref P L0: 39.8% 52.2% 5.6% 2.3% 0.1%
[libx264 @ 0x55a16881aec0] ref B L0: 88.5% 9.1% 2.4%
[libx264 @ 0x55a16881aec0] ref B L1: 97.8% 2.2%
[libx264 @ 0x55a16881aec0] kb/s:3051.71
I can cheat by putting a colorbalance section afterwards:
ffmpeg -i IMG_1685.MOV -q:v 0 -vcodec h264 -acodec aac -strict -2
-filter:v
format=pix_fmts=rgb24,lagfun=decay=0.999:planes=1,colorlevels=romax=0.6:bomax=0.6
greenlag2.mp4
which leads to this output http://www.robinbussell.co.uk/mov/greenlag2.mp4
but that feels like cheating!
Can anyone help explain what's going on? I was expecting green trails but
got white. There are Blue trails too, however, from the blue LEDs in the
scene, am I getting the concept of planes mixed up somewhere? maybe
something to do with the very high contrast input?
Many thanks,
Robin.
--
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