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• mandelbrot : more interresting zoom coordinates borrowed from wikipedia.

  12 novembre 2011, par Michael Niedermayer

  mandelbrot : more interresting zoom coordinates borrowed from wikipedia.

• How to make old 4:3 video content into 16:9 with crop/zoom and slight stretch ?

  9 août 2020, par Daniel Iversen

  I have old video cam footage in 4:3 format that I'd like to have play better on modern 16:9 screens, specifically I'd like to :

  


  

  • Crop/"Zoom" the video "a little" (cutting a tiny bit, maybe 10-15%, of the top and bottom of the video off)

  


  • Stretch the video "a tiny bit" (maybe 10%) - this will of course can ruin the footage so would like to only stretch the video a tiny bit

  


  • Still keep a bit of a border on the sides (since I don't want to stretch or crop the video too much)

  


  


  I'll still keep the original files too, but would like a version that just plays slightly nicer natively in 16:9. And I'd like to use free software like ffmpeg or Handbrake.

  


  I've found guides on how to crop and how to stretch the videos independently but I'm fearing having to re-encode the videos twice loses quality and takes a lot of time, so I'd like to do it all in one go.

  


  Does anyone have any ideas on how to do this ?

  


• Crop and pinch zoom image with FFMPEG

  27 septembre 2022, par hugger

  I am working on a simple photo editor component for a mobile app which requires the user to be able to pan and scale (zoom) an image to be cropped. S/O to @kesh for the help so far !

  


  With the pinch zoom value which ranges from 1-5, I wish to use this in my FFMPEG execution along with the crop command :

  


    cropSelected() {
    this.setState({ isCropping: true });

    const diff =
      this.props.videoHeight / (this.state.aspectRatio * deviceWidth);
    const offsetDiff = this.state.offsetTopTranslate * diff;

    var filterPathPostCrop =
      this.props.type === 'photo'
        ? RNFS.DocumentDirectoryPath + '/afterCrop.png'
        : this.props.type === 'gif'
        ? RNFS.DocumentDirectoryPath + '/afterCrop.gif'
        : RNFS.DocumentDirectoryPath + '/afterCrop.mp4';
    //hardcoded zoom at 1.2x for example!
    FFmpegKit.execute(
      `-y -i ${this.state.mediaSource} -vf "crop=iw/1.2:ih/1.2:0:${offsetDiff},scale=iw:-1" -qscale 0 -frames:v 1 ${filterPathPostCrop}`
    ).then(async (session) => {
      const returnCode = await session.getReturnCode();
      if (ReturnCode.isSuccess(returnCode)) {
        // SUCCESS

        Animated.spring(this._pinchScale, {
          toValue: 1,
          useNativeDriver: true,
        }).start();

        this.setState(
          {
            mediaSource: filterPathPostCrop,
            videoSourcePreview: `${filterPathPostCrop}?${new Date().getTime()}`,
            ffMPEGinProgress: null,
            aspectRatio: 1080 / 1080,
            videoTime: 0,
            isPlayingVideo: false,
            isCropping: false,
            filterOutputIsAlt: !this.state.filterOutputIsAlt,
            wasCropped: true,
          });
      } else if (ReturnCode.isCancel(returnCode)) {
        // CANCEL
      } else {
        // ERROR
        alert('error');
      }
    });
  }


  


  I drew this to illustrate what I am trying to achieve here.

  


  

  


  I hope this helps !