Recherche avancée

Sur d’autres sites (5848)

• How can I simply do color interpolation on this image and then save the image ? With RGBA channels as example

  24 août 2020, par karl-police

  So I got this GIF here :

  


  

  


  As you can see, it has Red, Green and Blue in it. And it also has a full transparency in it. This was composed together with FFMPEG out of images that looked exactly like that.

  


   

  


  Then, with FFMPEG I "decomposed" the RGB and Alpha channels using the filter "extractplanes".

  


  The gallery of that, in correct order starting from up to down, can be found here :

  


  https://imgur.com/a/WN0aGuW

  


  I am not sure if this actually helps me or if I'm supposed to decompose them. Because apperantly now, after decomposing them, I'm supposed to modify them, but I'm not really sure how. It's like how do I modify the red channel that only has black and white, so all at the end, will match to the specified HEX color that I want it to be to.

  


   

  


  Now, my question is. How do I exactly make the color changing happen ? Can I do this simply with JavaScript ? Is it possible to do with FFMPEG, if possible without ImageMagicks ? Maybe a programming language where not much installation is needed to do that ?

  


  What I understood is that. These channels basically contain values from 0 to 255 with black and white. I think the "brightness" is that what 0 and 255. So something inbetween, would be like grey.

  


  So basically, like we do (255,0,0) for red. In these channels, if I want red somewhere I need to put one fully white pixel on the red channel and on all the other channels, there has to be a fully black pixel.

  


  That's the concept. Now is the question, how can I do this ?

  


   

  


  At the end I want to make it look like this one as example :

  


  

  


  This is from a game. So basically that's how it looks like in the game. And the game files only use these RGBA template sprites.

  


   

  


  I asked a similar question here : How to change colors of an image using RGBA and more channels independently of their color

  


  But somehow, I might didn't seem to explain it that well.

  


   

  


  I made a thing here to test around with things. I guess that's nearly close, but the lines are kinda weird. jsfiddle.net/qsgazubk

  


• FFmpeg command to draw text hindi font is working fine in windows command prompt but Batch script and simple CPP program in NOT working

  1er juillet 2022, par Abdullah Farweez

  Below ffmpeg command in working fine in command prompt

  


  ffmpeg -i video.mp4 -filter_complex "drawtext=fontfile=Khula-regular.ttf:fontsize=60:fontcolor=blue:text=अगला एपिसोड देखने के लिए जल्दी से फॉलो करें:x=30:y=200" output.mp4


  


  giving expected result


  


  But if we run it as a bat file, it is not giving the expected output

  


      ::bat script start 
    @echo off
    ffmpeg -i video.mp4 -filter_complex "drawtext=fontfile=Khula-Regular.ttf:fontsize=60:fontcolor=blue:text=अगला एपिसोड देखने के लिए जल्दी से फॉलो करें:x=30:y=200" output.mp4
:: bat script end


  


  This the CPP program which calling the ffmpeg command via system method

  


  #include <iostream>&#xA;#include <cstring>&#xA;#include &#xA;&#xA;using namespace std;&#xA;&#xA;int main()&#xA;{&#xA;  string command = "ffmpeg.exe -i video.mp4 -filter_complex \"drawtext=fontfile=Khula-Regular.ttf:fontsize=60:fontcolor=yellow:text=अगला एपिसोड देखने के लिए जल्दी से फॉलो करें:x=30:y=200\" output.mp4";&#xA;  system(command.c_str());&#xA;  return 0;&#xA;}&#xA;</cstring></iostream>

  


  same behavior as bat script.

  


  screenshot of the output video.


  


  Here is the additional information for the references

  


  Folder structure

  


  .
|-- Khula-Regular.ttf
|-- cpp_program.exe
|-- command.cpp
|-- ffmpeg.exe
|-- ffplay.exe
|-- ffprobe.exe
|-- output.mp4
|-- run.bat
`-- video.mp4

C:\bin


  


  FFmpeg info

  


  $ ffmpeg
ffmpeg version N-107262-g4454142782-20220628 Copyright (c) 2000-2022 the FFmpeg developers
  built with gcc 11.2.0 (crosstool-NG 1.24.0.533_681aaef)
  configuration: --prefix=/ffbuild/prefix --pkg-config-flags=--static --pkg-config=pkg-config --cross-prefix=x86_64-w64-mingw32- --arch=x86_64 --target-os=mingw32 --enable-gpl --enable-version3 --disable-debug --disable-w32threads --enable-pthreads --enable-iconv --enable-libxml2 --enable-zlib --enable-libfreetype --enable-libfribidi --enable-gmp --enable-lzma --enable-fontconfig --enable-libvorbis --enable-opencl --disable-libpulse --enable-libvmaf --disable-libxcb --disable-xlib --enable-amf --enable-libaom --enable-libaribb24 --enable-avisynth --enable-libdav1d --enable-libdavs2 --disable-libfdk-aac --enable-ffnvcodec --enable-cuda-llvm --enable-frei0r --enable-libgme --enable-libass --enable-libbluray --enable-libjxl --enable-libmp3lame --enable-libopus --enable-librist --enable-libtheora --enable-libvpx --enable-libwebp --enable-lv2 --enable-libmfx --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopenmpt --enable-librav1e --enable-librubberband --enable-schannel --enable-sdl2 --enable-libsoxr --enable-libsrt --enable-libsvtav1 --enable-libtwolame --enable-libuavs3d --disable-libdrm --disable-vaapi --enable-libvidstab --enable-vulkan --enable-libshaderc --enable-libplacebo --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxvid --enable-libzimg --enable-libzvbi --extra-cflags=-DLIBTWOLAME_STATIC --extra-cxxflags= --extra-ldflags=-pthread --extra-ldexeflags= --extra-libs=-lgomp --extra-version=20220628
  libavutil      57. 27.100 / 57. 27.100
  libavcodec     59. 34.100 / 59. 34.100
  libavformat    59. 25.100 / 59. 25.100
  libavdevice    59.  6.100 / 59.  6.100
  libavfilter     8. 41.100 /  8. 41.100
  libswscale      6.  6.100 /  6.  6.100
  libswresample   4.  6.100 /  4.  6.100
  libpostproc    56.  5.100 / 56.  5.100
Hyper fast Audio and Video encoder
usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...

Use -h to get full help or, even better, run 'man ffmpeg'


  


  PS : FFmpeg does not showing any error while processing in bat or cpp_program, but output is not giving in the specified font instead giving in random characters in the final output.mp4

  


• unable to successfully close ffmpeg stream in node.js

  25 septembre 2022, par K. Russell Smith

  i'm trying to write a node video app that generates frames using the canvas api (via node-canvas, the project's only npm dependancy right now), and writes it to ffmpeg via a stream to generate a video :

  


  const { createCanvas } = require('canvas');
const { spawn } = require('child_process');
const fs = require('fs');
const canvas = createCanvas(1280, 720);

const ffmpeg = spawn('ffmpeg', [
    '-y',
    '-f', 'rawVideo',
    '-vcodec', 'rawVideo',
    '-pix_fmt', 'rgb24',
    '-s', `${ canvas.width }x${ canvas.height }`,
    '-r', '40',
    '-i', '-', '-f', 'mp4',
    '-q:v', '5',
    '-an', '-vcodec', 'mpeg4', 'output.mp4',
]);

const ctx = canvas.getContext('2d');
ctx.font = '30px Prime';
ctx.fillStyle = 'blue';
ctx.textAlign = 'center';
ctx.textBaseline = 'middle';
ctx.fillText('Hello Canvas', canvas.width / 2, canvas.height / 2);

for (let i = 0; i < 250; ++i)
{
    console.log(i);
    ffmpeg.stdin.write(Buffer.from(ctx.getImageData(0, 0, canvas.width, canvas.height).data));
}
ffmpeg.stdin.end();


  


  unfortunately, when i run it, the program throws this after writing the frames :

  


  node:events:368
      throw er; // Unhandled 'error' event
      ^

Error: write EPIPE
    at WriteWrap.onWriteComplete [as oncomplete] (node:internal/stream_base_commons:98:16)
Emitted 'error' event on Socket instance at:
    at emitErrorNT (node:internal/streams/destroy:164:8)
    at emitErrorCloseNT (node:internal/streams/destroy:129:3)
    at processTicksAndRejections (node:internal/process/task_queues:83:21) {
  errno: -32,
  code: 'EPIPE',
  syscall: 'write'
}

Node.js v17.1.0


  


  what am i doing wrong ?