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• Debayer video with ffmpeg

  23 février 2023, par Andrew Spence

  Looking to debayer video with ffmpeg. I can't find a way to do it without piping raw video between two instances of ffmpeg, because I can't change the pixel format of my input video "in place" from gray to bayer_gbrg8. So, this command works :

  


  ffmpeg -i fr_losslessmovie_png_codec.avi -f image2pipe -pix_fmt gray \
-vcodec rawvideo - | ffmpeg -r 25 -f rawvideo -s 2048x700 \
-pix_fmt bayer_gbrg8 -i pipe:0 -y -pix_fmt yuv420p -b:v 25000k \
fr_debayer_compressed.mp4


  


  I would have given the source movie this pixel format, but didn't realize ffmpeg suported bayered pixel formatting.

  


  Didn't see this exact question online, and have not found a way to change the pixel format with video filters etc. without ffmpeg thinking i'm trying to convert the data. I just want to change the pixel format that the already existing gray data has been assigned.

  


  Thanks in advance !

  


• C# ffmpeg how to read input from stream

  28 novembre 2022, par thiago kaique

  I'm trying to read use the pipe feature of ffmpeg to not have to write files in the disk.

  


  my inputs implementations are :

  


  public FFMPEG input(string path)
{
    parameters.Add($"-i {path}");
    return this;
}
public FFMPEG input(byte[] file)
{
    parameters.Add("-i pipe:.mp4");
    files.Add(file);
    return this;
}


  


  my output implementation is :

  


  public FFMPEG output(string format)
{
    _output = $"-f {format} -";
    return this;
}


  


  my run implementation is :

  


  public byte[] run()
{
    if (_output == "")
    {
        throw new Exception("missing output format");
    }

    var process = new Process()
    {
        StartInfo =
        {
            FileName = @"ffmpeg.exe",
            Arguments = String.Join(" ", parameters) + " " + _output,
            RedirectStandardOutput = true,
            RedirectStandardInput = true,
            UseShellExecute = false,
        }
    };

    process.Start();

    foreach (var item in files)
    {
        process.StandardInput.BaseStream.Write(item);
    }

    byte[] result;
    using(var memstream = new MemoryStream())
    {
        process.StandardOutput.BaseStream.CopyTo(memstream);
        result = memstream.ToArray();
    }
    process.WaitForExit();

    return result;
}


  


  which works perfectly if I use a file as input :

  


  var result = new FFMPEG()
.input("./assets/video.mp4")
.output("avi")
.run();


  


  but when I try to use bytes input :

  


  var result = new FFMPEG()
    .input(File.ReadAllBytes("./assets/video.mp4"))
    .output("avi")
    .run();


  


  I get the following error :

  


  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000137385a10c0] stream 1, offset 0x30: partial file
Error demuxing input file 0: Invalid data found when processing input
pipe:.mp4: Invalid data found when processing input
Cannot determine format of input stream 0:0 after EOF
Error marking filters as finished


  


• ffmpeg/ffprobe input as buffer stream, get an error always

  13 décembre 2023, par hhk

  


  Code to reproduce

  


  I attached the test.gif file on https://github.com/fluent-ffmpeg/node-fluent-ffmpeg/assets/122068264/e1f3aa31-5386-4dab-a409-9a224e0610fe

  


  
const ffprobeInstaller = require('@ffprobe-installer/ffprobe');
const ffmpeg = require('fluent-ffmpeg');
const { Readable } = require('stream');
const fs = require('fs');


(async () => {

    const buffer = fs.readFileSync('test.gif');
    let readableStream = new Readable();
    readableStream._read = () => { };
    readableStream.push(buffer);
    readableStream.push(null);

    // console.log(ffprobe.path, ffprobe.version);
    ffmpeg.setFfprobePath(ffprobeInstaller.path);
    let metadata = await get_video_meta_data(readableStream);

    async function get_video_meta_data(stream) {
        return new Promise((resolve, reject) => {
            new ffmpeg()
                .input(stream)
                .ffprobe((err, data) => {
                    // console.log(err);
                });
            resolve();
        });
    }
})();





  


  (note : if the problem only happens with some inputs, include a link to such an input file)

  


  Expected results

  


  data should include duration but empty.

  


  Observed results

  


  data is empty and err happens.
Here is error data :

  


  
  libavutil      58.  1.100 / 58.  1.100
  libavcodec     60.  2.100 / 60.  2.100
  libavformat    60.  2.100 / 60.  2.100
  libavdevice    60.  0.100 / 60.  0.100
  libavfilter     9.  1.100 /  9.  1.100
  libswscale      7.  0.100 /  7.  0.100
  libswresample   4.  9.100 /  4.  9.100
  libpostproc    57.  0.100 / 57.  0.100
pipe:0: Input/output error


  


  I only need the metadta for the input gif file. specifically, duration field.