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• HTML Video Exporting Using MediaRecorder vs ffmpeg.js

  3 octobre 2020, par Owen Ovadoz

  TLDR

  


  Imagine I have one video and one image. I want to create another video that overlays the image (e.g. watermark) at the center for 2 seconds in the beginning of the video and export it as the final video. I need to do this on the client-side only. Is it possible to use MediaRecorder + Canvas or should I resort to using ffmpeg.js ?

  


  Context

  


  I am making a browser-based video editor where the user can upload videos and images and combine them. So far, I implemented this by embedding the video and images inside a canvas element appropriately. The data representation looks somewhat like this :

  


  video: {
  url: 'https://archive.com/video.mp4',
  duration: 34,
},
images: [{
  url: 'https://archive.com/img1.jpg',
  start_time: 0,
  end_time: 2,
  top: 30,
  left: 20,
  width: 50,
  height: 50,
}]


  


  Attempts

  


  

  1. I play the video and show/hide images in the canvas. Then, I can use the MediaRecorder to capture the canvas' stream and export it as a data blob at the end. The final output is as expected, but the problem with this approach is I need to play the video from the beginning to the end for me to capture the stream from the canvas. If the video is 60 seconds, exporting it also takes 60 seconds.

  


  


  


  


  function record(canvas) {
  return new Promise(function (res, rej) {
    const stream = canvas.captureStream();
    const mediaRecorder = new MediaRecorder(stream);
    const recordedData = [];

    // Register recorder events
    mediaRecorder.ondataavailable = function (event) {
      recordedData.push(event.data);
    };
    mediaRecorder.onstop = function (event) {
      var blob = new Blob(recordedData, {
        type: "video/webm",
      });
      var url = URL.createObjectURL(blob);
      res(url);
    };

    // Start the video and start recording
    videoRef.current.currentTime = 0;
    videoRef.current.addEventListener(
      "play",
      (e) => {
        mediaRecorder.start();
      },
      {
        once: true,
      }
    );
    videoRef.current.addEventListener(
      "ended",
      (e) => {
        mediaRecorder.stop();
      },
      {
        once: true,
      }
    );
    videoRef.current.play();
  });
}

  


  


  



  

  2. I can use ffmpeg.js to encode the video. I haven't tried this method yet as I will have to convert my image representation into ffmpeg args (I wonder how much work that is).

  


  


• avcodec : add external enc libvvenc for H266/VVC

  5 juin 2024, par Thomas Siedel

  avcodec : add external enc libvvenc for H266/VVC
  Add external encoder VVenC for H266/VVC encoding.
  
  Register new encoder libvvenc.
  
  Add libvvenc to wrap the vvenc interface.
  
  libvvenc implements encoder option : preset,qp,qpa,period,
  
  passlogfile,stats,vvenc-params,level,tier.
  
  Enable encoder by adding —enable-libvvenc in configure step.
  Co-authored-by : Christian Bartnik chris10317h5@gmail.com
  
  Signed-off-by : Thomas Siedel <thomas.ff@spin-digital.com>
  

  • [DH] Changelog
  • [DH] configure
  • [DH] doc/encoders.texi
  • [DH] fftools/ffmpeg_mux_init.c
  • [DH] libavcodec/Makefile
  • [DH] libavcodec/allcodecs.c
  • [DH] libavcodec/libvvenc.c
  • [DH] libavcodec/version.h

• ffmpeg audio output in iOS

  19 septembre 2015, par user3249421

  Good day,

  I have own project which using iFrameExtraktor (https://github.com/lajos/iFrameExtractor). I modified initWithVideo method to :

  -(id)initWithVideo:(NSString *)moviePath imgView: (UIImageView *)imgView {
  
  if (!(self=[super init])) return nil;
  
  
  
  AVCodec         *pCodec;
  
  AVCodec         *aCodec;
  
  
  
  // Register all formats and codecs
  
  avcodec_register_all();
  
  av_register_all();
  
  
  
  imageView = imgView;
  
  
  
  // Open video file
  
  if(avformat_open_input(&pFormatCtx, [moviePath cStringUsingEncoding:NSASCIIStringEncoding], NULL, NULL) != 0) {
  
      av_log(NULL, AV_LOG_ERROR, "Couldn't open file\n");
  
      goto initError;
  
  }
  
  
  
  // Retrieve stream information
  
  if(avformat_find_stream_info(pFormatCtx,NULL) < 0) {
  
      av_log(NULL, AV_LOG_ERROR, "Couldn't find stream information\n");
  
      goto initError;
  
  }
  
  
  
  // Find the first video stream
  
  if ((videoStream =  av_find_best_stream(pFormatCtx, AVMEDIA_TYPE_VIDEO, -1, -1, &pCodec, 0)) < 0) {
  
      av_log(NULL, AV_LOG_ERROR, "Cannot find a video stream in the input file\n");
  
      goto initError;
  
  }
  
  
  
  if((audioStream = av_find_best_stream(pFormatCtx, AVMEDIA_TYPE_AUDIO, -1, -1, &aCodec, 0)) < 0 ){
  
      av_log(NULL, AV_LOG_ERROR, "Cannot find a audio stream in the input file\n");
  
      goto initError;
  
  }
  
  
  
  // Get a pointer to the codec context for the video stream
  
  pCodecCtx = pFormatCtx->streams[videoStream]->codec;
  
  aCodecCtx = pFormatCtx->streams[audioStream]->codec;
  
  
  
  // Find the decoder for the video stream
  
  pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
  
  if(pCodec == NULL) {
  
      av_log(NULL, AV_LOG_ERROR, "Unsupported video codec!\n");
  
      goto initError;
  
  }
  
  
  
  aCodec = avcodec_find_decoder(aCodecCtx->codec_id);
  
  if(aCodec == NULL) {
  
      av_log(NULL, AV_LOG_ERROR, "Unsupported audio codec!\n");
  
      goto initError;
  
  }
  
  
  
  // Open codec
  
  if(avcodec_open2(pCodecCtx, pCodec, NULL) < 0) {
  
      av_log(NULL, AV_LOG_ERROR, "Cannot open video decoder\n");
  
      goto initError;
  
  }
  
  
  
  if(avcodec_open2(aCodecCtx, aCodec, NULL) < 0){
  
      av_log(NULL, AV_LOG_ERROR, "Cannot open audio decoder\n");
  
      goto initError;
  
  }
  
  
  
  // Allocate video frame
  
  pFrame = av_frame_alloc();
  
  
  
  outputWidth = pCodecCtx->width;
  
  self.outputHeight = pCodecCtx->height;
  
  
  
  lastFrameTime = -1;
  
  [self seekTime:0.0];
  
  
  
  return self;
  
  
  
  initError:
  
      //[self release];
  
      return nil;
  
  }

  Video rendering works fine, but I don’t know how play audio to device output.

  Thanks for any tips.