Recherche avancée

Sur d’autres sites (4283)

• Extracting Thumbnail URL from Video URL

  29 août 2023, par Deepak Sangle

  So, I have a video URL in an Amazon S3 bucket. I must extract the thumbnail image (preview image) from the video URL. The catch is that I do not have the luxury to download or upload the complete video since it takes time. My approach is something like this.
I first created a blob object containing the first few seconds of that video using something like this.

  


    const chunkSize = 1024*1024; // 1MB
  const start = 0;
  const end = chunkSize - 1;
  const rangeHeader = `bytes=${start}-${end}`;
  
  const VideoResponse = await axios.get(url, { 
    responseType: 'arraybuffer',
    headers: { Range: rangeHeader }
  });

  const chunkData = VideoResponse.data; 
  
  const videoBlob = new Blob([chunkData], { type: 'video/mp4' });
  const videoUrl = URL.createObjectURL(videoBlob);
  console.log({chunkData, videoBlob, videoUrl});


  


  Console gives me something like this

  


  {&#xA;  chunkData: <buffer 00="00" 1c="1c" 66="66" 74="74" 79="79" 70="70" 6d="6d" 34="34" 32="32" 69="69" 73="73" 6f="6f" 61="61" 76="76" 63="63" 31="31" 02="02" bd="bd" ab="ab" 6c="6c" 68="68" 64="64" c7="c7" 1048526="1048526" more="more" bytes="bytes">,&#xA;  videoBlob: Blob { size: 1048576, type: &#x27;video/mp4&#x27; },&#xA;  videoUrl: &#x27;blob:nodedata:764fce87-792f-47e8-bc3e-15921ee5787f&#x27;&#xA;}&#xA;</buffer>

  


  Now, there are many options after this. I am trying to download this blob object by converting it into a file. After I successfully convert it into an mp4 file, I can easily take a screenshot of it using fluent-ffmpeg package. However, I couldn't convert it into a file. If I try to do something like this

  


    const BlobResponse = await axios({
    method: 'GET',
    url: videoUrl,
    responseType: 'stream'
  });

  const file = fs.createWriteStream(`video.mp4`);
  BlobResponse.data.pipe(file);
  
  file.on("error", (error) => {
    console.log(`There was an error writing the file. Details: $ {error}`);
  });

  file.on('finish', () => {
    file.close();
    console.log("File downloaded successfully");
  });


  


  But it throws me the error AxiosError: Unsupported protocol blob:

  


  I also tried to directly convert the blob object to a jpeg object but to no avail.

  


  I have searched complete StackOverflow, and I have not found a single solution working so please let me know why those are not working or if there is any new solution to do this.

  


• java.lang.NoClassDefFoundError : Could not initialize class on Linux (Works fine on Windows)

  26 décembre 2016, par Jake Miller

  I’m using a C++ FFmpeg wrapper for Java (org.bytedeco.javacpp). This works perfectly on a Windows machine (my development machine) but throws this error when ran on Linux (Amazon Web Services Elastic Beanstalk) :

  java.lang.NoClassDefFoundError: Could not initialize class org.bytedeco.javacpp.avutil
  
      at java.lang.Class.forName0(Native Method) ~[na:1.8.0_111]
  
      at java.lang.Class.forName(Class.java:348) ~[na:1.8.0_111]
  
      at org.bytedeco.javacpp.Loader.load(Loader.java:472) ~[javacpp-1.2.1.jar!/:1.2.1]
  
      at org.bytedeco.javacpp.Loader.load(Loader.java:417) ~[javacpp-1.2.1.jar!/:1.2.1]
  
      at org.bytedeco.javacpp.avformat$AVFormatContext.<clinit>(avformat.java:2819) ~[ffmpeg-3.2.1-1.3.jar!/:1.2.1]
  
      at org.bytedeco.javacv.FFmpegFrameGrabber.startUnsafe(FFmpegFrameGrabber.java:391) ~[javacv-1.3.jar!/:1.3]
  
      at org.bytedeco.javacv.FFmpegFrameGrabber.start(FFmpegFrameGrabber.java:385) ~[javacv-1.3.jar!/:1.3]
  
  </clinit>

  I’ve been troubleshooting for the past 2 days and have tried the following to fix the issue :

  • upgrade to Linux to 2.4
  • downgrading javacpp to 1.2.1
  • running mvn clean
  • running mvn -U
  • deleting contents of /.m2/ and redownloading dependencies
  • various combinations of dependency versions
  • git clone on a Linux VM & running mvn install there

  When looking further into the issue, I stumbled upon documentation for avformat$AVFormatContext as it’s in the stack trace posted above (6th line). The documentation for a C++ class named AVFormatContext. Whenever I attempt to view the class in Eclipse, it says Source Not Found.

  My question : could this problem possibly be caused by the C++ libraries on my Linux VM ? None of the above solutions fixed it so this is my only hypothesis as of now.

  Here’s my other Stack Overflow question regarding this subject : Java.lang.NoClassDefFoundError caused by FFmpeg when deployed on Linux as a packaged .war (Works on development machine)

• Enabling libmp3lame for FFMPEG on elastic beanstalk

  13 octobre 2017, par Adam Sith

  I am trying to enable libmp3lame with FFMPEG in elastic beanstalk (Amazon Redhat Linux machine).

  I am able to successfully install FFMPEG in /ffmpeg.config with the following script :

  # .ebextensions/ffmpeg.config
  
  
  
  packages:
  
    yum:
  
      autoconf: []
  
      automake: []
  
      cmake: []
  
      freetype-devel: []
  
      gcc: []
  
      gcc-c++: []
  
      git: []
  
      libtool: []
  
      make: []
  
      nasm: []
  
      pkgconfig: []
  
      zlib-devel: []
  
  sources:
  
    /usr/local/src: http://ffmpeg.org/releases/ffmpeg-3.2.tar.bz2
  
  commands:
  
    ffmpeg_install:
  
        cwd: /usr/local/src/ffmpeg-3.2
  
        command: sudo ./configure --prefix=/usr && make && make install

  I need to install libmp3lame however. I’ve tried to do this with an --enable-libmp3lame flag and the directions here. The modified script :

  packages:
  
  yum:
  
      autoconf: []
  
      automake: []
  
      cmake: []
  
      freetype-devel: []
  
      gcc: []
  
      gcc-c++: []
  
      git: []
  
      libtool: []
  
      make: []
  
      nasm: []
  
      pkgconfig: []
  
      zlib-devel: []
  
  sources:
  
    /usr/local/src: http://ffmpeg.org/releases/ffmpeg-3.2.tar.bz2
  
  commands:
  
    01-install_libmp3lame:
  
        cwd: /usr/local/src/
  
        command: curl -L -O http://downloads.sourceforge.net/project/lame/lame/3.99/lame-3.99.5.tar.gz && tar xzvf lame-3.99.5.tar.gz && cd lame-3.99.5 && ./configure --prefix="$HOME/ffmpeg_build" --bindir="$HOME/bin" --disable-shared --enable-nasm && make && make install
  
    02-ffmpeg_install:
  
        cwd: /usr/local/src/ffmpeg-3.2
  
        command: sudo ./configure --enable-libmp3lame && --prefix=/usr && make && make install

  This doesn’t work. Command 01-install_libmp3lame completes. Command 02-ffmpeg_install fails because :

  [2017-10-12T20:55:19.324Z] INFO  [24606] - [Application update app-8fe3-123456_7895@111/AppDeployStage0/EbExtensionPreBuild/Infra-EmbeddedPreBuild/prebuild_3_clover_platform/Command 02-ffmpeg_install] : Activity execution failed, because: ERROR: libmp3lame >= 3.98.3 not found

  I have tried installing libmp3lame in /ffmpeg-3.2 and got the same issue.