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• OpenCV videowriter H264 codec (ffmpeg)

  18 juin 2019, par alcon

  I want to save a video with opencv with lossless compresion so I don’t lose any details of the frames. Everything works with the xvid codec but offcourse this is not a lossless compression so I found that the x264 codec is suitable. However it doesn’t work, I tried the following sample code but while running I get the following error : "could not find encoder for codec id 28 : encoder not found."

  cv::VideoWriter makeVideo;
  
  makeVideo.open("makevideo//newVideo.mp4", CV_FOURCC('X','2','6','4'), 30, cv::Size(1600,1200), true);
  
  cv::Mat image = imread("makevideo//frames//111.png");
  
  
  
  for(int i = 0; i < 200; i++)
  
      makeVideo << image;
  
  
  
  makeVideo.release();

  I found that for this to work, I need to have ffmpeg support. I’m currently using opencv2.4.6 and in this discussion (how can I use the openCV FFMPEG video I/O rather than the DirectShow one in Windows ?) someone mentioned that in opencv2.4 ffmpeg is automatically included. But its not working....

  Here (How to compile OpenCV 2.3 with ffmpeg support with Visual Studio 2010) I found how to compile opencv and ffmpeg yourself on windows. I followed all the steps sucessfully but still I get the same error....

• What video codecs work on Google Chromebook

  3 mars 2019, par MonkeyDLuffy

  I’m trying to put a show on my friends Google Chromebook but the mp4 files show up black when trying to watch them on said Chromebook, audio works fine. I found out that it is a video encoding problem but I cannot find a list of video formats that work on the Chromebook. I have ffmpeg and handbrake to try and test some things, but if someone could tell me a ffmpeg code that will convert the video files into a format that works on a Google Chromebook that would help a lot.

  What I’ve tried :

  ffmpeg -i "Game of Thrones S02E01 The North Remembers.mkv" codec mpeg "Game of Thrones S02E01 The North Remembers.mp4"

  Which gives error :

  [NULL @ 00000177196ea500] Unable to find a suitable output format for
  ’codec’ codec : Invalid argument

• Cannot convert video file to audio file inside AWS lambda function using Node js

  21 février 2019, par Arun

  I cannot convert a video file into an audio file inside AWS lambda function using Node JS. While running my lambda function it doesn’t throw any error it executes without any error. But the audio file size is still 0 MB size. I am not able to find bugs or any issues in my code.

  Here is my code,

  const fs = require('fs');
  
  const childProcess = require('child_process');
  
  const AWS = require('aws-sdk');
  
  const path = require('path');
  
  AWS.config.update({
  
      region : 'us-east-2'
  
  });
  
  const s3 = new AWS.S3({apiVersion: '2006-03-01'});
  
  
  
  
  
  exports.handler = (event, context, callback) => {
  
      process.env.PATH = process.env.PATH + ':/tmp/';
  
      process.env['FFMPEG_PATH'] = '/tmp/ffmpeg';
  
      const BIN_PATH = process.env['LAMBDA_TASK_ROOT'];
  
      process.env['PATH'] = process.env['PATH'] + ':' + BIN_PATH;
  
  
  
      childProcess.exec(
  
          'cp /var/task/ffmpeg /tmp/.; chmod 755 /tmp/ffmpeg;',
  
          function (error, stdout, stderr) {
  
              if (error) {
  
                  console.log('Error occured',error);
  
              } else {
  
                  var ffmpeg = '/tmp/ffmpeg';
  
                  var createStream = fs.createWriteStream("/tmp/video.mp3");
  
                  createStream.end();
  
                  var params = {
  
                      Bucket: "test-bucket",
  
                      Key: event.Records[0].s3.object.key
  
                  };
  
                  s3.getObject(params, function(err, data) {
  
                      if (err) {
  
                          console.log("Error", err);
  
                      }
  
                      fs.writeFile("/tmp/vid.mp4", data.Body, function (err) {
  
                          if (err) console.log(err.code, "-", err.message);
  
                          return callback(err);
  
                      }, function() {
  
                          try {
  
                              var stats = fs.statSync("/tmp/vid.mp4");
  
                              console.log("size of the file1 ", stats["size"]);
  
                              try {
  
                                  console.log("Yeah");
  
                                  const inputFilename = "/tmp/vid.mp4";
  
                                  const mp3Filename = "/tmp/video.mp3";
  
                                  // // Convert the FLV file to an MP3 file using ffmpeg.
  
                                  const ffmpegArgs = [
  
                                      '-i', inputFilename,
  
                                      '-vn', // Disable the video stream in the output.
  
                                      '-acodec', 'libmp3lame', // Use Lame for the mp3 encoding.
  
                                      '-ac', '2', // Set 2 audio channels.
  
                                      '-q:a', '6', // Set the quality to be roughly 128 kb/s.
  
                                      mp3Filename,
  
                                  ];
  
                                  try {
  
                                      const process = childProcess.spawnSync(ffmpeg, ffmpegArgs);
  
                                      console.log("stdout ", process.stdout);
  
                                      console.log("stderr ", process.stderr);
  
                                      console.log("tmp files ");
  
                                      fs.readdir('/tmp/', (err, files) => {
  
                                          files.forEach(file => {
  
                                              var stats = fs.statSync(`/tmp/${file}`);
  
                                              console.log("size of the file2 ", stats["size"]);
  
                                            console.log(file);
  
                                          });
  
                                        });
  
  
  
                                  } catch (e) {
  
                                      console.log("error while converting video to audio ", e);
  
                                  }
  
  
  
                                  // return process;
  
                              } catch (e) {
  
                                  console.log(e);
  
                              }
  
                          } catch (e) {
  
                              console.log("file is not complete", e);
  
                          }
  
                      }, function () {
  
                          console.log("checking ");
  
                          var stats = fs.statSync("/tmp/video.mp3");
  
                          console.log("size of the file2 ", stats["size"]);
  
                      });
  
  
  
                      return callback(err);
  
                  });
  
              }
  
          }
  
      )
  
  }

  Code workflow

  First of all, I have downloaded ffmpeg binary exec file and put into my project directory. After that, I compressed my project and put it into the lambda function. This lambda function will be triggered whenever the new files are uploaded into an S3 bucket. I have checked /tmp/ storage files and the audio file .mp3 present but the size is 0 MB.

  Note

  And also, in my code the below is not calling or this part is not reaching. When I look into Cloudwatch logs I can’t see this console log messages. I don’t know why this function is not calling.

  function () {
  
          console.log("checking ");
  
          var stats = fs.statSync("/tmp/video.mp3");
  
          console.log("size of the file2 ", stats["size"]);
  
      });

  Please help me to find the solution of this issue. I have spent a lot of times to figure out this issue. But I am not able to find the solution. Any suggestions are welcome !!
  Thanks,