[FFmpeg-user] Strange PNG overlay issue
Paul B Mahol
onemda at gmail.com
Fri May 12 14:49:26 EEST 2023
On Fri, May 12, 2023 at 1:36 PM Bouke / Videotoolshed <
bouke at videotoolshed.com> wrote:
> Trying to compare video files to find differences.
> I have two very identical files, same codec, but one has a slight color
> correction.
> Using the difference matting I’m able to find that.
>
> But, I would also like to be able to mask out certain parts, in case there
> is BITC or a bug in the image.
> For that I use a PNG file with alpha.
>
> That does not work as expected:
>
> Please compare the two lines, and note the PNG is TOTALLY EMPTY, alpha set
> to fully transparent:
>
> Without the overlay:
>
> FFmpeg -ss 19.126 -i /Volumes/Data/!BoukeWatch/Filemail/altered.mov -ss
> 19.126 -i /Volumes/Data/!BoukeWatch/Filemail/orig.mov -t 0.04 -shortest
> -filter_complex
> [0:v]scale=640:360[v0];[1:v]scale=640:360[v1];[v0][v1]blend=all_mode=difference
> -pix_fmt gray -c:v png -start_number 459
> /Volumes/Data/!BoukeWatch/Filemail/altered_vs_orig/%06d.png -y
>
> Output is as expected, a very dark image, but with the image as greyscale
>
> FFmpeg -ss 19.126 -i /Volumes/Data/!BoukeWatch/Filemail/altered.mov -ss
> 19.126 -i /Volumes/Data/!BoukeWatch/Filemail/orig.mov -t 0.04 -i
> /Users/bouke/Library/Application
> Support/DifferenceFinder/presets/scaled.png -t 0.04 -shortest
> -filter_complex
> [0:v]scale=640:360[tmp1];[tmp1][2:v]overlay=0:0[v0];[1:v]scale=640:360[tmp2];[tmp2][2:v]overlay=0:0[v1];[v0][v1]blend=all_mode=difference
> -pix_fmt gray -c:v png -start_number 459
> /Volumes/Data/!BoukeWatch/Filemail/altered_vs_orig/%06d.png -y
>
> This results in a pure black image, where I would expect the output to be
> the same as in the first line...
> What am I missing here?
>
By default, overlay use yuv420p format, and also limited range, so if
values in above case are <= 16 than conversion of limited range difference
of yuv420p inputs with such values will give pure 0 output.
Alternatively could use grainextract blend mode, this one maps differences
from 128 up and down from that value. In such case conversion to gray
format will not middle values.
Alternatively use extractplanes=y after blend filter, this should not crush
low values when converted to gray format in PNG.
>
> Bouke
>
> videotoolshed.com
> Van Oldenbarneveltstraat 33
> 6512 AS Nijmegen, the Netherlands
> +31 6 21817248
> If you want to send me large files, please use:
> https://videotoolshed.wetransfer.com/
> Test without overlay:
> FFmpeg -ss 19.12686868686866 -i
> /Volumes/Data/!BoukeWatch/Filemail/altered.mov -ss 19.12686868686866 -i
> /Volumes/Data/!BoukeWatch/Filemail/orig.mov -t 0.04 -shortest
> -filter_complex
> [0:v]scale=640:360[v0];[1:v]scale=640:360[v1];[v0][v1]blend=all_mode=difference
> -pix_fmt gray -c:v png -start_number 459
> /Volumes/Data/!BoukeWatch/Filemail/altered_vs_orig/%06d.png -y
>
> ffmpeg version 6.0-tessus https://evermeet.cx/ffmpeg/ Copyright (c)
> 2000-2023 the FFmpeg developers
> built with Apple clang version 11.0.0 (clang-1100.0.33.17)
> configuration: --cc=/usr/bin/clang --prefix=/opt/ffmpeg
> --extra-version=tessus --enable-avisynth --enable-fontconfig --enable-gpl
> --enable-libaom --enable-libass --enable-libbluray --enable-libdav1d
> --enable-libfreetype --enable-libgsm --enable-libmodplug
> --enable-libmp3lame --enable-libmysofa --enable-libopencore-amrnb
> --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg
> --enable-libopus --enable-librubberband --enable-libshine
> --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora
> --enable-libtwolame --enable-libvidstab --enable-libvmaf
> --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwebp
> --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid
> --enable-libzimg --enable-libzmq --enable-libzvbi --enable-version3
> --pkg-config-flags=--static --disable-ffplay
> libavutil 58. 2.100 / 58. 2.100
> libavcodec 60. 3.100 / 60. 3.100
> libavformat 60. 3.100 / 60. 3.100
> libavdevice 60. 1.100 / 60. 1.100
> libavfilter 9. 3.100 / 9. 3.100
> libswscale 7. 1.100 / 7. 1.100
> libswresample 4. 10.100 / 4. 10.100
> libpostproc 57. 1.100 / 57. 1.100
>
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from
> '/Volumes/Data/!BoukeWatch/Filemail/altered.mov':
> Metadata:
> major_brand : qt
> minor_version : 512
> compatible_brands: qt
> creation_time : 2023-05-08T18:14:44.000000Z
> encoder : Blackmagic Design DaVinci Resolve Studio
> Duration: 00:00:47.34, start: 0.000000, bitrate: 79144 kb/s
> Stream #0:0[0x1]: Video: prores (LT) (apcs / 0x73637061),
> yuv422p10le(bt709/bt709/unknown, progressive), 1920x1080, 76070 kb/s, SAR
> 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 24k tbn (default)
> Metadata:
> creation_time : 2023-05-08T18:14:44.000000Z
> handler_name : VideoHandler
> vendor_id : appl
> encoder : Apple ProRes 422 LT
> timecode : 01:00:00:00
> Stream #0:1[0x2]: Audio: pcm_s32le (lpcm / 0x6D63706C), 48000 Hz,
> stereo, s32, 3072 kb/s (default)
> Metadata:
> creation_time : 2023-05-08T18:14:44.000000Z
> handler_name :
> SoundHandler
> vendor_id : [0][0][0][0]
> Stream #0:2[0x3](eng): Data: none (tmcd / 0x64636D74)
> Metadata:
> creation_time : 2023-05-08T18:14:44.000000Z
> handler_name : TimeCodeHandler
> reel_name : Musica_WIP_graded_h264_refAudio_230502
> timecode : 01:00:00:00
>
> Input #1, mov,mp4,m4a,3gp,3g2,mj2, from
> '/Volumes/Data/!BoukeWatch/Filemail/orig.mov':
> Metadata:
> major_brand : qt
> minor_version : 512
> compatible_brands: qt
> creation_time : 2023-05-08T18:06:58.000000Z
> encoder : Blackmagic Design DaVinci Resolve Studio
> Duration: 00:00:47.34, start: 0.000000, bitrate: 79166 kb/s
> Stream #1:0[0x1]: Video: prores (LT) (apcs / 0x73637061),
> yuv422p10le(bt709/bt709/unknown, progressive), 1920x1080, 76092 kb/s, SAR
> 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 24k tbn (default)
> Metadata:
> creation_time : 2023-05-08T18:06:58.000000Z
> handler_name : VideoHandler
> vendor_id : appl
> encoder : Apple ProRes 422 LT
> timecode : 01:00:00:00
> Stream #1:1[0x2]: Audio: pcm_s32le (lpcm / 0x6D63706C), 48000 Hz,
> stereo, s32, 3072 kb/s (default)
> Metadata:
> creation_time : 2023-05-08T18:06:58.000000Z
> handler_name : SoundHandler
> vendor_id : [0][0][0][0]
> Stream #1:2[0x3](eng): Data: none (tmcd / 0x64636D74)
>
> Metadata:
> creation_time : 2023-05-08T18:06:58.000000Z
> handler_name : TimeCodeHandler
> reel_name : Musica_WIP_graded_h264_refAudio_230502
> timecode : 01:00:00:00
>
> Stream mapping:
> Stream #0:0 (prores) -> scale:default
> Stream #1:0 (prores) -> scale:default
> blend:default -> Stream #0:0 (png)
> Press [q] to stop, [?] for help
>
> Output #0, image2, to
> '/Volumes/Data/!BoukeWatch/Filemail/altered_vs_orig/%06d.png':
> Metadata:
> major_brand : qt
> minor_version : 512
> compatible_brands: qt
> encoder : Lavf60.3.100
> Stream #0:0: Video: png, gray(pc, bt709/bt709/unknown, progressive),
> 640x360 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 23.98 fps, 23.98 tbn
> Metadata:
> encoder : Lavc60.3.100 png
> frame= 0 fps=0.0 q=0.0 size= 0kB time=-577014:32:22.77 bitrate=
> -0.0kbits/s speed=N/A
> frame= 1 fps=0.0 q=-0.0 Lsize=N/A time=00:00:00.00 bitrate=N/A speed=
> 0x
> video:69kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
> muxing overhead: unknown
>
> //////////
> Test with overlay:
>
> FFmpeg -ss 19.12686868686866 -i
> /Volumes/Data/!BoukeWatch/Filemail/altered.mov -ss 19.12686868686866 -i
> /Volumes/Data/!BoukeWatch/Filemail/orig.mov -t 0.04 -i
> /Users/bouke/Library/Application
> Support/DifferenceFinder/presets/scaled.png -t 0.04 -shortest
> -filter_complex
> [0:v]scale=640:360[tmp1];[tmp1][2:v]overlay=0:0[v0];[1:v]scale=640:360[tmp2];[tmp2][2:v]overlay=0:0[v1];[v0][v1]blend=all_mode=difference
> -pix_fmt gray -c:v png -start_number 459
> /Volumes/Data/!BoukeWatch/Filemail/altered_vs_orig/%06d.png -y
> ffmpeg version 6.0-tessus https://evermeet.cx/ffmpeg/ Copyright (c)
> 2000-2023 the FFmpeg developers
> built with Apple clang version 11.0.0 (clang-1100.0.33.17)
> configuration: --cc=/usr/bin/clang --prefix=/opt/ffmpeg
> --extra-version=tessus --enable-avisynth --enable-fontconfig --enable-gpl
> --enable-libaom --enable-libass --enable-libbluray --enable-libdav1d
> --enable-libfreetype --enable-libgsm --enable-libmodplug
> --enable-libmp3lame --enable-libmysofa --enable-libopencore-amrnb
> --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg
> --enable-libopus --enable-librubberband --enable-libshine
> --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora
> --enable-libtwolame --enable-libvidstab --enable-libvmaf
> --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwebp
> --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid
> --enable-libzimg --enable-libzmq --enable-libzvbi --enable-version3
> --pkg-config-flags=--static --disable-ffplay
> libavutil 58. 2.100 / 58. 2.100
> libavcodec 60. 3.100 / 60. 3.100
> libavformat 60. 3.100 / 60. 3.100
> libavdevice 60. 1.100 / 60. 1.100
> libavfilter 9. 3.100 / 9. 3.100
> libswscale 7. 1.100 / 7. 1.100
> libswresample 4. 10.100 / 4. 10.100
> libpostproc 57. 1.100 / 57. 1.100
>
> Input #0, mov,mp4,m4a,3gp,3g2,mj2, from
> '/Volumes/Data/!BoukeWatch/Filemail/altered.mov':
> Metadata:
> major_brand : qt
> minor_version : 512
> compatible_brands: qt
> creation_time : 2023-05-08T18:14:44.000000Z
> encoder : Blackmagic Design DaVinci Resolve Studio
> Duration: 00:00:47.34, start: 0.000000, bitrate: 79144 kb/s
> Stream #0:0[0x1]: Video: prores (LT) (apcs / 0x73637061),
> yuv422p10le(bt709/bt709/unknown, progressive), 1920x1080, 76070 kb/s, SAR
> 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 24k tbn (default)
> Metadata:
> creation_time : 2023-05-08T18:14:44.000000Z
> handler_name : VideoHandler
> vendor_id : appl
> encoder : Apple ProRes 422 LT
> timecode : 01:00:00:00
>
> Stream #0:1[0x2]: Audio: pcm_s32le (lpcm / 0x6D63706C), 48000 Hz,
> stereo, s32, 3072 kb/s (default)
> Metadata:
> creation_time : 2023-05-08T18:14:44.000000Z
> handler_name : SoundHandler
> vendor_id : [0][0][0][0]
> Stream #0:2[0x3](eng): Data: none (tmcd / 0x64636D74)
> Metadata:
> creation_time : 2023-05-08T18:14:44.000000Z
> handler_name : TimeCodeHandler
> reel_name : Musica_WIP_graded_h264_refAudio_230502
> timecode : 01:00:00:00
>
> Input #1, mov,mp4,m4a,3gp,3g2,mj2, from
> '/Volumes/Data/!BoukeWatch/Filemail/orig.mov':
> Metadata:
> major_brand : qt
> minor_version : 512
> compatible_brands: qt
> creation_time : 2023-05-08T18:06:58.000000Z
> encoder : Blackmagic Design DaVinci Resolve Studio
> Duration: 00:00:47.34, start: 0.000000, bitrate: 79166 kb/s
> Stream #1:0[0x1]: Video: prores (LT) (apcs / 0x73637061),
> yuv422p10le(bt709/bt709/unknown, progressive), 1920x1080, 76092 kb/s, SAR
> 1:1 DAR 16:9, 23.98 fps, 23.98 tbr, 24k tbn (default)
> Metadata:
> creation_time : 2023-05-08T18:06:58.000000Z
> handler_name : VideoHandler
> vendor_id : appl
> encoder : Apple ProRes 422 LT
> timecode : 01:00:00:00
> Stream #1:1[0x2]: Audio: pcm_s32le (lpcm / 0x6D63706C), 48000 Hz,
> stereo, s32, 3072 kb/s (default)
> Metadata:
> creation_time : 2023-05-08T18:06:58.000000Z
> handler_name : SoundHandler
> vendor_id : [0][0][0][0]
> Stream #1:2[0x3](eng): Data: none (tmcd / 0x64636D74)
> Metadata:
>
> creation_time : 2023-05-08T18:06:58.000000Z
> handler_name : TimeCodeHandler
> reel_name : Musica_WIP_graded_h264_refAudio_230502
> timecode : 01:00:00:00
>
> Input #2, png_pipe, from '/Users/bouke/Library/Application
> Support/DifferenceFinder/presets/scaled.png':
> Duration: N/A, bitrate: N/A
> Stream #2:0: Video: png, rgba(pc), 640x360 [SAR 2835:2835 DAR 16:9], 25
> fps, 25 tbr, 25 tbn
>
> Stream mapping:
> Stream #0:0 (prores) -> scale:default
> Stream #1:0 (prores) -> scale:default
> Stream #2:0 (png) -> overlay
> Stream #2:0 (png) -> overlay
> blend:default -> Stream #0:0 (png)
> Press [q] to stop, [?] for help
>
> Output #0, image2, to
> '/Volumes/Data/!BoukeWatch/Filemail/altered_vs_orig/%06d.png':
> Metadata:
> major_brand : qt
> minor_version : 512
> compatible_brands: qt
> encoder : Lavf60.3.100
> Stream #0:0: Video: png, gray(pc, bt709/bt709/unknown, progressive),
> 640x360 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 23.98 fps, 23.98 tbn
> Metadata:
> encoder : Lavc60.3.100 png
>
> frame= 0 fps=0.0 q=0.0 size= 0kB time=-577014:32:22.77 bitrate=
> -0.0kbits/s speed=N/A
> frame= 1 fps=0.0 q=-0.0 Lsize=N/A time=00:00:00.00 bitrate=N/A speed=
> 0x
> video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
> muxing overhead: unknown
>
>
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