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Revolution of Open-source and film making towards open film making
6 octobre 2011, par
Mis à jour : Juillet 2013
Langue : English
Type : Texte
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Sur d’autres sites (4452)
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Prevent ffmpeg from changing the intensity of colors while downscaling the resolution of the video
29 août 2022, par dravitI have a use case where I need to downscale a
716x1280
mp4 video to358x640
(half of the original). Command that I used is

ffmpeg -i ./input.mp4 -vf "scale=640:640:force_original_aspect_ratio=decrease,pad=ceil(iw/2)*2:ceil(ih/2)*2" ./output.mp4



Out of 10 sample videos, 2 of the them suffered impact on colors. Below I have attached a comparison from the one which was impacted the most.




NOTE : The one on the right is a frame from the original video and the frame on the left is the one from the processed (down scaled) video. Notice the colors red and green in the image (even the skin color and hair color were changed).


What I am looking for is


- 

- Is there any way I can prevent changes like these happening ? Probably some flag on saturation, brightness, contrast or any other parameter.
- I am assuming that ffmpeg uses some default settings while downscaling a video. What made ffmpeg change colors only for these two videos ? If it made similar changes for the rest of the videos as well, how to predict this behaviour before hand ?






EDIT :


What I already have Tried ?


- 

-crf
with values 0 and 18.-preset veryslow
as mentioned here






None helped


Mediainfo input V/S output







 param 

input 

output 







 color range 

Limited 

NA (attribute not in description) 




 color primaries 

BT.2020 

NA (attribute not in description) 




 transfer characteristics 

HLG 

NA (attribute not in description) 




 matrix coefficients 

BT.2020 non-constant 

NA (attribute not in description) 




 bit deapth 

8 

8 









Logs of the ffmpeg command


ffmpeg -i ./input.mp4 -vf "scale=640:640:force_original_aspect_ratio=decrease,pad=ceil(iw/2)*2:ceil(ih/2)*2" -movflags +faststart ./output.mp4
ffmpeg version 4.3.1 Copyright (c) 2000-2020 the FFmpeg developers
 built with Apple clang version 12.0.0 (clang-1200.0.32.28)
 configuration: --prefix=/usr/local/Cellar/ffmpeg/4.3.1_9 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-videotoolbox --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack
 libavutil 56. 51.100 / 56. 51.100
 libavcodec 58. 91.100 / 58. 91.100
 libavformat 58. 45.100 / 58. 45.100
 libavdevice 58. 10.100 / 58. 10.100
 libavfilter 7. 85.100 / 7. 85.100
 libavresample 4. 0. 0 / 4. 0. 0
 libswscale 5. 7.100 / 5. 7.100
 libswresample 3. 7.100 / 3. 7.100
 libpostproc 55. 7.100 / 55. 7.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from './input.mp4':
 Metadata:
 major_brand : isom
 minor_version : 512
 compatible_brands: isomiso2avc1mp41
 encoder : Lavf58.45.100
 Duration: 00:00:30.05, start: 0.000000, bitrate: 10366 kb/s
 Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt2020nc/bt2020/arib-std-b67), 716x1280, 10116 kb/s, 30 fps, 30 tbr, 19200 tbn, 38400 tbc (default)
 Metadata:
 handler_name : Core Media Video
 Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 245 kb/s (default)
 Metadata:
 handler_name : Core Media Audio
Stream mapping:
 Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
 Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
[libx264 @ 0x7faab4808800] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 0x7faab4808800] profile High, level 3.0, 4:2:0, 8-bit
[libx264 @ 0x7faab4808800] 264 - core 161 r3027 4121277 - H.264/MPEG-4 AVC codec - Copyleft 2003-2020 - 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=-2 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 './output.mp4':
 Metadata:
 major_brand : isom
 minor_version : 512
 compatible_brands: isomiso2avc1mp41
 encoder : Lavf58.45.100
 Stream #0:0(und): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 358x640, q=-1--1, 30 fps, 15360 tbn, 30 tbc (default)
 Metadata:
 handler_name : Core Media Video
 encoder : Lavc58.91.100 libx264
 Side data:
 cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
 Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)
 Metadata:
 handler_name : Core Media Audio
 encoder : Lavc58.91.100 aac
[mp4 @ 0x7faab5808800] Starting second pass: moving the moov atom to the beginning of the file
frame= 901 fps=210 q=-1.0 Lsize= 3438kB time=00:00:30.02 bitrate= 938.0kbits/s speed=7.01x
video:2933kB audio:472kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.974633%
[libx264 @ 0x7faab4808800] frame I:6 Avg QP:22.60 size: 20769
[libx264 @ 0x7faab4808800] frame P:228 Avg QP:24.84 size: 7657
[libx264 @ 0x7faab4808800] frame B:667 Avg QP:27.59 size: 1697
[libx264 @ 0x7faab4808800] consecutive B-frames: 0.9% 0.9% 1.0% 97.2%
[libx264 @ 0x7faab4808800] mb I I16..4: 9.5% 64.6% 26.0%
[libx264 @ 0x7faab4808800] mb P I16..4: 2.5% 12.2% 2.5% P16..4: 37.2% 20.6% 11.2% 0.0% 0.0% skip:13.7%
[libx264 @ 0x7faab4808800] mb B I16..4: 0.4% 2.1% 0.2% B16..8: 42.2% 7.1% 1.2% direct: 1.8% skip:44.9% L0:39.4% L1:52.8% BI: 7.8%
[libx264 @ 0x7faab4808800] 8x8 transform intra:72.2% inter:74.2%
[libx264 @ 0x7faab4808800] coded y,uvDC,uvAC intra: 61.8% 67.2% 20.2% inter: 16.7% 13.9% 1.3%
[libx264 @ 0x7faab4808800] i16 v,h,dc,p: 24% 19% 7% 50%
[libx264 @ 0x7faab4808800] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 21% 16% 15% 6% 9% 11% 7% 10% 6%
[libx264 @ 0x7faab4808800] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 25% 16% 13% 7% 9% 10% 7% 9% 4%
[libx264 @ 0x7faab4808800] i8c dc,h,v,p: 53% 16% 26% 5%
[libx264 @ 0x7faab4808800] Weighted P-Frames: Y:3.9% UV:1.8%
[libx264 @ 0x7faab4808800] ref P L0: 57.8% 19.5% 14.8% 7.8% 0.1%
[libx264 @ 0x7faab4808800] ref B L0: 90.7% 7.2% 2.1%
[libx264 @ 0x7faab4808800] ref B L1: 95.3% 4.7%
[libx264 @ 0x7faab4808800] kb/s:799.80
[aac @ 0x7faab2036a00] Qavg: 189.523



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Trying to scale a webm video to 50% of its resolution using FFMPEG but keep getting an error (video has transparency btw)
6 février 2021, par DistantDigitI'm trying to scale down a webm video with transparency using this line of commands (based off of an answer in this stackoverflow question @ How to keep transparency when scale webm file with ffmpeg) :


ffmpeg -c:v libvpx -i in.webm -c:v libvpx -vf scale=400:416 -auto-alt-ref 0 out.webm


but I keep getting errors (for example) :


[libvpx @ 00000128eb6123c0] Invalid sync code 310042.
[libvpx @ 00000128eb6123c0] Failed to decode frame: Bitstream not supported by this decoder
Cannot determine format of input stream 0:0 after EOF



Full log (I've removed a ton of the same exact message with "..."'s) :


ffmpeg version 2021-02-02-git-2367affc2c-full_build-www.gyan.dev Copyright (c) 2000-2021 the FFmpeg developers
 built with gcc 10.2.0 (Rev6, Built by MSYS2 project)
 configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-libsnappy --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libglslang --enable-vulkan --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
 libavutil 56. 64.100 / 56. 64.100
 libavcodec 58.120.100 / 58.120.100
 libavformat 58. 65.101 / 58. 65.101
 libavdevice 58. 11.103 / 58. 11.103
 libavfilter 7.101.100 / 7.101.100
 libswscale 5. 8.100 / 5. 8.100
 libswresample 3. 8.100 / 3. 8.100
 libpostproc 55. 8.100 / 55. 8.100
[libvpx @ 00000128eb6123c0] v1.9.0-146-gebb5ffc1d
[libvpx @ 00000128eb6123c0] Invalid sync code 310042.
[libvpx @ 00000128eb6123c0] Failed to decode frame: Bitstream not supported by this decoder
[libvpx @ 00000128eb6123c0] Invalid sync code 007a49.
[libvpx @ 00000128eb6123c0] Failed to decode frame: Bitstream not supported by this decoder
[libvpx @ 00000128eb6123c0] Invalid sync code 01f096.
[libvpx @ 00000128eb6123c0] Failed to decode frame: Bitstream not supported by this decoder
...
...
...
[libvpx @ 00000128eb6123c0] Invalid sync code 01f096.
[libvpx @ 00000128eb6123c0] Failed to decode frame: Bitstream not supported by this decoder
[libvpx @ 00000128eb6123c0] Invalid sync code 01f096.
[libvpx @ 00000128eb6123c0] Failed to decode frame: Bitstream not supported by this decoder
[libvpx @ 00000128eb6123c0] Invalid sync code 01f096.
[libvpx @ 00000128eb6123c0] Failed to decode frame: Bitstream not supported by this decoder
[libvpx @ 00000128eb6123c0] Invalid sync code 01f096.
[matroska,webm @ 00000128eb60f040] decoding for stream 0 failed
[matroska,webm @ 00000128eb60f040] Could not find codec parameters for stream 0 (Video: vp8 (libvpx), none(progressive), 800x832): unspecified pixel format
Consider increasing the value for the 'analyzeduration' (0) and 'probesize' (5000000) options
Input #0, matroska,webm, from 'in.webm':
 Metadata:
 encoder : libwebm-0.2.1.0
 creation_time : 2017-12-02T12:06:12.000000Z
 Duration: 00:00:10.00, start: 0.000000, bitrate: 2592 kb/s
 Stream #0:0(eng): Video: vp8, none(progressive), 800x832, SAR 1:1 DAR 25:26, 30 fps, 30 tbr, 1k tbn, 1k tbc (default)
 Metadata:
 alpha_mode : 1
[libvpx @ 00000128eb612a40] v1.9.0-146-gebb5ffc1d
Stream mapping:
 Stream #0:0 -> #0:0 (vp8 (libvpx) -> vp8 (libvpx))
Press [q] to stop, [?] for help
[libvpx @ 00000128eb612a40] Failed to decode frame: Bitstream not supported by this decoder
Error while decoding stream #0:0: Invalid data found when processing input
[libvpx @ 00000128eb612a40] Failed to decode frame: Bitstream not supported by this decoder
Error while decoding stream #0:0: Invalid data found when processing input
[libvpx @ 00000128eb612a40] Failed to decode frame: Bitstream not supported by this decoder
...
...
...
Error while decoding stream #0:0: Invalid data found when processing input
[NULL @ 00000128eb6123c0] Invalid sync code 01f096.
[libvpx @ 00000128eb612a40] Failed to decode frame: Bitstream not supported by this decoder
Error while decoding stream #0:0: Invalid data found when processing input
[NULL @ 00000128eb6123c0] Invalid sync code 01f096.
[libvpx @ 00000128eb612a40] Failed to decode frame: Bitstream not supported by this decoder
Error while decoding stream #0:0: Invalid data found when processing input
[NULL @ 00000128eb6123c0] Invalid sync code 009c96.
[libvpx @ 00000128eb612a40] Failed to decode frame: Bitstream not supported by this decoder
Error while decoding stream #0:0: Invalid data found when processing input
Cannot determine format of input stream 0:0 after EOF
Error marking filters as finished
Conversion failed!



Log of
ffmpeg -i input.webm
:

ffmpeg version 2021-02-02-git-2367affc2c-full_build-www.gyan.dev Copyright (c) 2000-2021 the FFmpeg developers
 built with gcc 10.2.0 (Rev6, Built by MSYS2 project)
 configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-libsnappy --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libglslang --enable-vulkan --enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint
 libavutil 56. 64.100 / 56. 64.100
 libavcodec 58.120.100 / 58.120.100
 libavformat 58. 65.101 / 58. 65.101
 libavdevice 58. 11.103 / 58. 11.103
 libavfilter 7.101.100 / 7.101.100
 libswscale 5. 8.100 / 5. 8.100
 libswresample 3. 8.100 / 3. 8.100
 libpostproc 55. 8.100 / 55. 8.100
Input #0, matroska,webm, from 'input.webm':
 Metadata:
 encoder : libwebm-0.2.1.0
 creation_time : 2017-12-02T12:06:12.000000Z
 Duration: 00:00:10.00, start: 0.000000, bitrate: 2592 kb/s
 Stream #0:0(eng): Video: vp9 (Profile 0), yuv420p(tv), 800x832, SAR 1:1 DAR 25:26, 30 fps, 30 tbr, 1k tbn, 1k tbc (default)
 Metadata:
 alpha_mode : 1
At least one output file must be specified



-
Overlaying 2 videos using FFMPEG in Android Giving Low Resolution Video Output
7 janvier 2021, par mirza aliI'm overlaying 2 videos using below command
This command works perfectly but returns Low resolution Video output any change to this command which make my video resolution better ...!!?


"-i", FirstVideo, "-f","lavfi","-i","movie=" + SeconedVideo+ 
 
":loop=200,setpts=N/FRAME_RATE/TB","-filter_complex", 
 
"[1:v][0:v]scale2ref[ua][b];[ua]setsar=1,format=yuva444p,colorchannelmixer=aa=1[u];[b][u]overlay=1:1:shortest=1", OutputFilePath