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• Using FFMPEG command to read the frame and show using the inshow function in opencv

  28 novembre 2024, par HARSH BHATNAGAR

  I am trying to get the frame using the ffmpeg command and show using the opencv function cv2.imshow(). This snippet gives the black and white image on the RTSP Stream link . Output is given below link [ output of FFmpeg link].
I have tried the ffplay command but it gives the direct image . i am not able to access the frame or apply the image processing.

  


  Output of FFMPEG

  


  import cv2
import subprocess as sp
command = [ 'C:/ffmpeg/ffmpeg.exe',
            '-i', 'rtsp://192.168.1.12/media/video2',
            '-f', 'image2pipe',
            '-pix_fmt', 'rgb24',
            '-vcodec', 'rawvideo', '-']


import numpy
pipe = sp.Popen(command, stdout = sp.PIPE, bufsize=10**8)
while True:
    raw_image = pipe.stdout.read(420*360*3)
   # transform the byte read into a numpy array
    image =  numpy.fromstring(raw_image, dtype='uint8')
    image = image.reshape((360,420,3))
    cv2.imshow('hello',image)
    cv2.waitKey(1)
    # throw away the data in the pipe's buffer.
    pipe.stdout.flush()


  


• avcodec/dvbsubdec : Fix conditions for fallback to default resolution

  3 décembre 2021, par softworkz

  avcodec/dvbsubdec : Fix conditions for fallback to default resolution
  The previous code expected a segment of type CLUT definition to exist
  
  in order to accept a set of segments to be complete.
  
  This was an incorrect assumption as the presence of a CLUT segment
  
  is not mandatory.
  
  (version 1.6.1 of the spec is probably a bit more clear about this
  
  than earlier versions : https://www.etsi.org/deliver/etsi_en/
  
  300700_300799/300743/01.06.01_20/en_300743v010601a.pdf)
  The incorrect condition prevented proper fallback to using the default
  
  resolution for the decoding context.
  This also adds variables and moves the fallback check to the outside
  
  for better clarity.
  Signed-off-by : softworkz <softworkz@hotmail.com>
  

  • [DH] libavcodec/dvbsubdec.c

• why mpd file contain same resolution AdaptationSet

  18 mars, par Jahid Hasan Antor

  this is the code that i used. this code create a minifest.mpd file, with the same resolution AdaptationSet set

  


  const createCourse = async (req: Request, res: Response, next: NextFunction) => {
    try {
        const VIDEO_STORAGE_PATH = path.join(__dirname, "../../public/uploads").replace(/\\/g, "/");
        const videoId = req.body.videoId;
        const inputPath = path.join(VIDEO_STORAGE_PATH, "original", `${videoId}.mp4`).replace(/\\/g, "/");
        const outputDir = path.join(VIDEO_STORAGE_PATH, "dash", videoId).replace(/\\/g, "/");

        if (!fs.existsSync(outputDir)) {
            fs.mkdirSync(outputDir, { recursive: true });
        }

        if (!ffmpegStatic) {
            return next(new Error("❌ ffmpegStatic path is null"));
        }

        ffmpeg.setFfmpegPath(ffmpegStatic);

        const qualities = [
            { resolution: "1280x720", bitrate: "1800k" },
            { resolution: "854x480", bitrate: "1200k" },
            { resolution: "640x360", bitrate: "800k" },
            { resolution: "426x240", bitrate: "400k" }
        ];

        const outputMpd = path.join(outputDir, "manifest.mpd").replace(/\\/g, "/");

        // Create FFmpeg command
        let command = ffmpeg(inputPath)
            .output(outputMpd)
            .outputOptions([
                '-f dash', // Output format
                '-seg_duration 4', // Segment duration in seconds
                '-window_size 10', // Number of segments in the manifest
                '-init_seg_name init-stream$RepresentationID$.webm', // Name for initialization segments
                '-media_seg_name chunk-stream$RepresentationID$-$Number%05d$.webm', // Name for media segments
            ]);

        // Add multiple resolutions
        qualities.forEach(({ resolution, bitrate }) => {
            console.log('esolution, bitrate :>> ', resolution, bitrate);
            command
                .outputOptions([
                    `-map 0:v`, // Map the video stream
                    `-s ${resolution}`, // Set resolution
                    `-b:v ${bitrate}`, // Set bitrate
                    `-c:v libvpx-vp9`, // Use VP9 codec
                    `-c:a libopus`, // Use Opus codec
                ]);
        });

        command
            .on("end", () => {
                console.log(`🚀 Video processing complete: ${outputMpd}`);
            })
            .on("error", (err) => {
                console.error("❌ ffmpeg error:", err);
                next(err);
            })
            .run();