Sur d’autres sites (11678)

• Inconsistent crop and overflay ffmpeg result with drawImage canvas

  21 juin 2022, par yuno saga

  i try to encode the video block frame to specific pattern order, then in front-end it decode back to normal. I test it in back-end by decode back with same function, it back to normal. but in front-end with canvas the order of block not in right position. if you look into front-end function. it have same pattern. i try to check output from for generate, it equal to for in backend overlay builder command.
  
whats wrong with this ?

  


  ffmpeg config

  


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

function hflip(width) {
    const sizeBlock = 16;
    let filterCommands = '';
    const length = Math.floor(width / sizeBlock);

    for (let i=0; i < length; i++) { 
        filterCommands += `[0]crop=${sizeBlock}:480:${(i*sizeBlock)}:0[c${i}];`;
    }
    
    for (let i=0; i < length; i++) {
        if (i == 0) filterCommands += '[0]';
        if (i != 0) filterCommands += `[o${i}]`;
    
        filterCommands += `[c${i}]overlay=x=${(width - sizeBlock)-(i*sizeBlock)}:y=0`;
    
        if (i != (length - 1)) filterCommands += `[o${i+1}];`;
    }

    return filterCommands;
}

const crops = spawn('ffmpeg', [
    '-i',
    'C:/Software Development/project/blackpink.mp4',
    '-filter_complex',
    hflip(854),
    '-c:a',
    'copy',
    '-c:v',
    'libx264',
    '-crf',
    '30',
    '-preset',
    'ultrafast',
    '-pix_fmt',
    'yuv420p',
    'C:/Software Development/project/hflip.mp4',
    '-y'
], {
    cwd: 'C:/Software Development/ffmpeg'
})


  


  front-end

  


  


  


  &#xA;&#xA;    &#xA;    &#xA;        <button>play</button>&#xA;        <code class="echappe-js">&lt;script&gt;&amp;#xA;            const canvas = document.createElement(&amp;#x27;canvas&amp;#x27;);&amp;#xA;            document.body.appendChild(canvas)&amp;#xA;            const context = canvas.getContext(&amp;#x27;2d&amp;#x27;);&amp;#xA;            const video = document.createElement(&amp;#x27;video&amp;#x27;);&amp;#xA;            video.src = &amp;#x27;https://drive.google.com/uc?export=download&amp;amp;id=1Z0aFg_N3kP0SUO_xOFB0UBjTRH6_mSmb&amp;amp;confirm=t&amp;#x27;&amp;#xA;&amp;#xA;&amp;#xA;            function hflip(video) {&amp;#xA;                const widthBlock = 16;&amp;#xA;                const heightBlock = 480;&amp;#xA;                const length = Math.floor(video.videoWidth / widthBlock);&amp;#xA;&amp;#xA;                for (let i=0; i &lt; length; i&amp;#x2B;&amp;#x2B;) {&amp;#xA;                    console.log({&amp;#xA;                        cX: (i*widthBlock),&amp;#xA;                        oX: (video.videoWidth - widthBlock) - (i*widthBlock)&amp;#xA;                    });&amp;#xA;&amp;#xA;                    context.drawImage(video, (i*widthBlock), 0, widthBlock, heightBlock,  (video.videoWidth - widthBlock) - (i*widthBlock), 0, widthBlock, heightBlock)&amp;#xA;                }&amp;#xA;            }&amp;#xA;&amp;#xA;            video.onloadedmetadata = () =&gt; {&amp;#xA;                context.canvas.width = video.videoWidth;&amp;#xA;                context.canvas.height = video.videoHeight;&amp;#xA;            }&amp;#xA;&amp;#xA;            video.onplay = () =&gt; {&amp;#xA;                const updateCanvas = () =&gt; {&amp;#xA;                    hflip(video);            &amp;#xA;&amp;#xA;                    video.requestVideoFrameCallback(updateCanvas);&amp;#xA;                }&amp;#xA;&amp;#xA;                updateCanvas();&amp;#xA;            }&amp;#xA;&amp;#xA;            function play() { video.play() }&amp;#xA;        &lt;/script&gt;&#xA;    &#xA;

  


  


  



• ffmpeg android porting help me

  13 février 2018, par Mr.Han

  My development environment is Windows10 - 64bit .
  It is set to Android development environment
  I am trying to compile ffmpeg.
  I installed cygwin and installed cygwin.
  gcc related all, dos2unix, make, automake.
  ffmpeg version is 3-2.10.

  1. configure file
     Before

     SLIBNAME_WITH_MAJOR=’$(SLIBNAME).$(LIBMAJOR)’
     LIB_INSTALL_EXTRA_CMD=’$$(RANLIB) "$(LIBDIR)/$(LIBNAME)"’
     SLIB_INSTALL_NAME=’$(SLIBNAME_WITH_VERSION)’
     SLIB_INSTALL_LINKS=’$(SLIBNAME_WITH_MAJOR) $(SLIBNAME)’

  After

  SLIBNAME_WITH_MAJOR='$(SLIBPREF)$(FULLNAME)-$(LIBMAJOR)$(SLIBSUF)'
  
  LIB_INSTALL_EXTRA_CMD='$$(RANLIB) "$(LIBDIR)/$(LIBNAME)"'
  
  SLIB_INSTALL_NAME='$(SLIBNAME_WITH_MAJOR)'
  
  SLIB_INSTALL_LINKS='$(SLIBNAME)'

  2. build_android.sh

      !/bin/bash

     NDK=c :/Users/storm/AppData/Local/Android/Sdk/ndk-bundle
     SYSROOT=$NDK/platforms/android-16/arch-arm/
     TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/windows-x86_64
     CUR=cygpath -m $(pwd)
     TEMPDIR=cygpath -m /tmp
     TMP=cygpath -m /tmp
     function build_one
     
     sed -i ’s/ln_s="ln -s -f"/ln_s="cp -f"/g’ ./configure
     ./configure \
     — prefix=$PREFIX \
     — enable-shared \
     — disable-static \
     — disable-doc \
     — disable-ffmpeg \
     — disable-ffplay \
     — disable-ffprobe \
     — disable-ffserver \
     — disable-avdevice \
     — disable-doc\
     — disable-symver \
     — cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
     — target-os=linux \
     — arch=arm \
     — enable-cross-compile \
     — sysroot=$SYSROOT \
     — extra-cflags="-Os -fpic $ADDI_CFLAGS" \
     — extra-ldflags="$ADDI_LDFLAGS"\
     $ADDITIONAL_CONFIGURE_FLAG
     sed -i’:a ;N ;$ !ba ;s/gcc 4.9\r/gcc 4.9/g’ ./config.h
     sed -i’:a ;N ;$ !ba ;s/gcc 4.9\r/gcc 4.9/g’ ./config.mak

     make clean

     make

     make install

     
     CPU=arm
     PREFIX=$CUR/android/$CPU
     ADDI_CFLAGS="-marm"
     build_one

  Where is the problem ?
  Please help me.

• Audio effect ( a 20ms delay between right and the left channel) using Web Audio API or any Javascript Audio Library like howler.js, tone.js ?

  15 juillet 2020, par questionare_101

  I was wondering if there any option in howler.js, tone.js or any other javascript audio library which I can use to add a 20ms delay between the right and the left channel which makes the audio listening experience more immersive.

  


  Can it be achieved using Audio sprites with howler.js ? (but I guess it can't separate the right and the left channels)
https://medium.com/game-development-stuff/how-to-create-audiosprites-to-use-with-howler-js-beed5d006ac1

  


  Is there any ?

  


  Have also asked the same quest here : https://github.com/goldfire/howler.js/issues/1374

  


  I usually enable this option under ffdshow audio processor while playing audio using MPC-HC (Mega Version) on my pc. I was wondering how can I do it using Web Audio API or howler.js ?

  


  

  


  Somewhat like this kind of effect : Just delay the either channel by 20ms
Like we do in Adobe Audition