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• Revision bea691b5c9 : Merge "Add dynamic range comment to hadamard_8x8()"

  12 juin 2015, par Jingning Han

  Merge "Add dynamic range comment to hadamard_8x8()"

• FFmpeg crop portrait video 1:1 from the top based on dynamic value

  8 avril 2022, par hugger

  I am replacing my video editing component with FFmpeg. So far it has been smooth until getting to this point where I need to crop my vertical (portrait) video to 1080x1080 with a dynamic value.

  


  Essentially, I built a custom component to do the cropping, where I can pan a square box over the video. the Y value for the pan is where I wish to cut the top part of the video.

  


  Here is the code I have tried, which works but is not cropping to my desired specs note : offsetDiff is the space I wish to remove from the top (pan px value) :

  


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

    var path =
      this.props.type === 'photo'
        ? RNFS.DocumentDirectoryPath + '/after.png'
        : RNFS.DocumentDirectoryPath + '/after.mp4';

    var filterPath =
      this.props.type === 'photo'
        ? RNFS.DocumentDirectoryPath + '/afterFilter.png'
        : RNFS.DocumentDirectoryPath + '/afterFilter.mp4';

    FFmpegKit.execute(
      `-y -i ${path} -vf "crop=iw:1080:0:${offsetDiff}, scale=1080:1080" -qscale 0 ${filterPath}`,
    ).then(async session => {
      const returnCode = await session.getReturnCode();
      if (ReturnCode.isSuccess(returnCode)) {
        // SUCCESS
        this.setState({
          mediaSource:
            this.props.type === 'video'
              ? `file://${filterPath}?${new Date().getTime()}`
              : filterPath,
          isOpen: !this.state.isOpen,
          ffMPEGinProgress: null,
          aspectRatio: 1080 / 1080,
        });
      } else if (ReturnCode.isCancel(returnCode)) {
        // CANCEL
      } else {
        // ERROR
        alert('error');
      }
    });
  }


  


  Basically here I am trying to tell FFmpeg to keep the width (1080), make the height 1080, ignore X value, crop dynamic amount from the top.

  


  Here is what my cropper component looks like to get an idea.

  


  

  


  I appreciate any help I can get here folks, cheers !

  


• avcodec/mpegaudio_tablegen : more dynamic table creation speedups

  28 novembre 2015, par Ganesh Ajjanagadde

  avcodec/mpegaudio_tablegen : more dynamic table creation speedups
  This further speeds up runtime initialization, with identical generated tables.
  Sample benchmark (x86-64, Haswell, GNU/Linux) :
  old :
  
  34441423 decicycles in mpegaudio_tableinit,    8192 runs,      0 skips
  new :
  
  10776291 decicycles in mpegaudio_tableinit,    8192 runs,      0 skips
  Most low hanging fruit is taken care of here. For some idea, note that
  
  83,064 array elements totalling 233,722 bytes need to be initialized.
  
  Thus, with this patch, we average 12.9 cycles per element or 4.6
  
  cycles per byte.
  Reviewed-by : Derek Buitenhuis <derek.buitenhuis@gmail.com>
  
  Signed-off-by : Ganesh Ajjanagadde <gajjanagadde@gmail.com>
  

  • [DH] libavcodec/mpegaudio_tablegen.h