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• How to set the destination folder of a Node.js fluent-ffmpeg screenshot to your AWS S3 bucket using getSignedUrl() ?

  10 juillet 2017, par Madhavi Mohoni

  I’m writing a program to generate .png thumbnails (with the same name, in the same folder) for a set of .mp4 videos in my Amazon S3 bucket. For this example, I’m going to create a /folder/file.png for a /folder/file.mp4 in the bucket. I’ve managed to set the source URL using the s3 object and getSignedUrl as follows :

  var srcurl = s3.getSignedUrl('getObject', {
  
          Bucket: 'bucket-name',
  
          Key: '/folder/file.mp4'
  
        });

  and

  new ffmpeg({ source: srcurl })
  
       .screenshots({
  
          count: 1, 
  
          filename: '%f'.substr(0, '%f'.indexOf('.')) + '.png', 
  
          /* To shorten the long string that's returned */ 
  
          folder: desturl,
  
          size: MAX_WIDTH + 'x' + MAX_HEIGHT
  
        });

  The destination URL has to be the same folder as the source. So I set it as follows :

  var desturl = s3.getSignedUrl('putObject', {
  
          Bucket: 'bucket-name',
  
          Key: '/folder/file' + '.png'
  
        });

  This combination doesn’t work - is there a way to do this correctly ?

• How can I mux a MKV and MKA file and get it to play in a browser ?

  28 juin 2017, par Robert

  I’m using ffmpeg to merge .mkv and .mka files into .mp4 files. My current command looks like this :

  ffmpeg -i video.mkv -i audio.mka output_path.mp4

  The audio and video files are pre-signed urls from Amazon S3. Even on a server with sufficient resources, this process is going very slowly. I’ve researched situations where you can tell ffmpeg to skip re-encoding each frame, but I think that in my situation it actually does need to re-encode each frame.

  I’ve downloaded 2 sample files to my macbook pro and have installed ffmpeg locally via homebrew. When I run the command

  ffmpeg -i video.mkv -i audio.mka -c copy output.mp4

  I get the following output :

  ffmpeg version 3.3.2 Copyright (c) 2000-2017 the FFmpeg developers
  
    built with Apple LLVM version 8.1.0 (clang-802.0.42)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/3.3.2 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --disable-lzma --enable-vda
  
    libavutil      55. 58.100 / 55. 58.100
  
    libavcodec     57. 89.100 / 57. 89.100
  
    libavformat    57. 71.100 / 57. 71.100
  
    libavdevice    57.  6.100 / 57.  6.100
  
    libavfilter     6. 82.100 /  6. 82.100
  
    libavresample   3.  5.  0 /  3.  5.  0
  
    libswscale      4.  6.100 /  4.  6.100
  
    libswresample   2.  7.100 /  2.  7.100
  
    libpostproc    54.  5.100 / 54.  5.100
  
  Input #0, matroska,webm, from '319_audio_1498590673766.mka':
  
    Metadata:
  
      encoder         : GStreamer matroskamux version 1.8.1.1
  
      creation_time   : 2017-06-27T19:10:58.000000Z
  
    Duration: 00:00:03.53, start: 2.831000, bitrate: 50 kb/s
  
      Stream #0:0(eng): Audio: opus, 48000 Hz, stereo, fltp (default)
  
      Metadata:
  
        title           : Audio
  
  Input #1, matroska,webm, from '319_video_1498590673766.mkv':
  
    Metadata:
  
      encoder         : GStreamer matroskamux version 1.8.1.1
  
      creation_time   : 2017-06-27T19:10:58.000000Z
  
    Duration: 00:00:03.97, start: 2.851000, bitrate: 224 kb/s
  
      Stream #1:0(eng): Video: vp8, yuv420p(progressive), 640x480, SAR 1:1 DAR 4:3, 30 tbr, 1k tbn, 1k tbc (default)
  
      Metadata:
  
        title           : Video
  
  [mp4 @ 0x7fa4f0806800] Could not find tag for codec vp8 in stream #0, codec not currently supported in container
  
  Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
  
  Stream mapping:
  
    Stream #1:0 -> #0:0 (copy)
  
    Stream #0:0 -> #0:1 (copy)
  
      Last message repeated 1 times

  So it appears that the specific encodings I’m working with are vp8 videos and opus audio files, which I believe are incompatible with the .mp4 output container. I would appreciate answers that cover ways of optimally merging vp8 and opus into .mp4 output or answers that point me in the direction of output media formats that are both compatible with vp8 & opus and are playable on web and mobile devices so that I can bypass the re-encoding step altogether.

  EDIT :

  Just wanted to provide a benchmark after following LordNeckbeard’s advice :

  4 min 41 second video transcoded locally on my mac
  
  
  
  LordNeckbeard’s approach : 15 mins 55 seconds (955 seconds)
  
  Current approach : 18 mins 49 seconds (1129 seconds)
  
  
  
  18% speed increase

• Boto3 Video Upload 0 Bytes from Heroku

  14 juillet 2017, par genghiskhan

  I have a small Flask api that takes a video and an image, overlays the image on the video and uploads the result to Amazon S3. I am using ffmpeg to do the actual overlaying. Here is that code :

  command = "ffmpeg -i {0} -i {1} -filter_complex \"overlay=0:0\" {2}".format(background_name, overlay_name, output_name)
  
  subprocess.getoutput(command)

  Then I simply upload it via Boto3 :

  s3.upload_file(output_name, VIDEO_BUCKET_NAME, output_name)

  This code works fine when I run on localhost ; however, when I test in while deployed to Heroku, it always uploads a file with 0 bytes. I suspect that it may be a problem with Heroku’s transient filesystem, but the file is being used immediately after it is created.