Resize video with fluent-ffmpeg and upload to S3 in lambda AWS

Question

I've written below code which(is triggered when a video is uploaded to s3) gets an image from s3, resizes it with fleunt-ffmpeg nodejs module and then uploads it to s3 bucket.

async.waterfall([
  function download(next) {
    // Download video
    s3.getObject({
      Bucket: srcBucket,
      Key: srcKey
    }, next);
  },
  function resizeBuffer(response, next) {
    // Resize
    resizeVideo(response, function (err, response, buffer){
      if(err){
        console.log(err);
        return next(err);
      }

      next(null, response, buffer);
    });
  },
  function uploadBuffer(response, buffer, next) {
    // Upload to s3
    let resizedImageName    = "resized/" + imageName;
    s3.putObject({
      Bucket: srcBucket,
      Key: resizedImageName,
      Body: buffer,
      ContentType: response.ContentType
    }, function(err, data) {
      if (err) {
        console.log(err, err.stack);
      }else{
        console.log('image resized----------------------->');
        next(null, response, buffer);
      }
    });
  }
], function (err) {
  if (err) {
    console.log('Unable to resize image.');
  } else {
    console.log('Successfully resized image.');
  }
  callback(null, "done--------------->");
});

function resizeVideo(response, callback){
  try {
    let command = ffmpeg(response.Body);
    console.log('1-------------->');
    command.size('50%');
    console.log('2-------------->');
    callback(null, response, command.pipe());
  } catch (e) {
    console.log('video resize error------------------------->');
    console.log(e);
    callback('Video resize error')
  }
}

This code works fine for images(imagemagik instead of fluent-ffmpeg) but shows error when I use ffmpeg : Error: Stream yields empty buffer