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• Is there a way if a video file has pixelation in FFmpeg ?

  14 novembre 2019, par A Person

  I am trying to identify if a video file has pixelation or not,

  Currently, I have a watch folder where videos are dropped, I have a trigger every 120 seconds that check the folder to see if there are any video files.
  If there is a file, it uses MediaInfo command-line to extract the encoding of the video and audio.
  I also use ffprobe on a video to see if it throws out an error like moov atom not found to know if the video is corrupted.

  However, I want to be able to tell if a video file has a pixelation. I know that I can use str, std, to print out the debug logs.

  However, I am finding it difficult to find documentation on how to detect pixelation.

  Do you guys know if there a way to tell that a video file may have pixelation, even through a log output of the video ?

  I am already running a script that reads a log and finds information on the log to tell me about packet drops in a stream, so if you know how I output such log that tells if there is pixelation, or if the debug log has certain information that tells this, please let me know.

• Cannot Play RTSP Streams From the Internet

  17 avril 2023, par jnnks

  I am trying to receive an rtsp :// stream from the internet. There are many example streams running, but I cannot receive any of them.
ffplay and VLC both fail to receive data. I tried both UDP and TCP with various urls with no success.
Streaming from a local rtsp server with aler9/rtsp-simple-server Docker container works fine.

  


  This is the command I use to watch the stream :

  


  ffplay rtsp://rtsp.stream/pattern


  


  VLC fails with :

  


  [00007f58640015f0] satip stream error: Failed to connect to RTSP server rtsp.stream:554
[00007f58640015f0] access_realrtsp stream error: cannot connect to rtsp.stream:554


  


  What else can I try ?

  


• How to read stream data as chunk ?

  5 juillet 2022, par imagesck

  I try to lean, how to read chunk of stream data. It almost works, it likes i misunderstanding implement allocate buffer size in pause event of stdout. the video that i use is https://www.youtube.com/watch?v=oiNkumxPVzU. 480p. ffmpeg freeze to encode at 03:53, no error, just freeze likes missing require bytes. the video length exactly is 03:55.

  


  const { spawn } = require('child_process');
const path = require('path');

const decArgs = [
    '-i', path.join(__dirname + '/public/future.mkv'),
    '-an',
    '-pix_fmt', 'rgb32',
    '-f', 'rawvideo',
    '-'
];

const decode = spawn('ffmpeg', decArgs, {
    stdio: [
        'ignore',
        'pipe',
        'ignore'
    ] 
});

// Encode section
const width = 854;
const height = 480;
const channels = 4;
const fps = 29.97002997002997.toString();
const colorsLength = width*height*channels;


const encArgs = [
    '-pix_fmt', 'rgb32',
    '-f', 'rawvideo',
    '-s', `${width}x${height}`,
    '-r', fps,
    '-i', '-',
    '-c:v', 'libx264',
    '-preset', 'ultrafast',
    '-crf', '30',
    '-pix_fmt', 'yuv420p',
    '-r', fps,
    '-y',
    path.join(__dirname + '/public/output.mp4')
];

const encode = spawn('ffmpeg', encArgs, {
    stdio: [
        'pipe',
        'ignore',
        'pipe'
    ]
});

// colors RGBA
let buffer = Buffer.alloc(0);
decode.stdout.on('data', data => {
    const allocSize = buffer.length + data.length;
    buffer = Buffer.concat([buffer, data], allocSize);
    
    if (buffer.length > colorsLength) decode.stdout.pause();
});

decode.stdout.on('pause', () => {
    // Create new buffer with size of colors length
    const bufferData = Buffer.alloc(colorsLength);
    buffer.copy(bufferData, 0, 0, colorsLength);
    // after manipulate the buffer send it to encode
    encode.stdin.write(bufferData);
    
    // Create new buffer to take out left buffer. cause stream length cant be predict.
    const leftBuffer = Buffer.alloc(buffer.length - bufferData.length);
    buffer.copy(leftBuffer, 0, buffer.length - bufferData.length, buffer.length);
    buffer = leftBuffer;

    decode.stdout.resume()
});

decode.stdout.on('end', () => {
    if (buffer.length) encode.stdin.write(buffer);
})

encode.stderr.on('data', data => {
    console.log(data.toString())
})