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• FFMPEG add text frames to the start of video

  12 février 2016, par Ryan

  I have some videos either in mp4 or webm format, and I’d like to use ffmpeg to add 4 seconds to the start of each video to display some text in the center with no sound.

  Some other requirements :

  • try to avoid re-encoding the video
  • need to maintain the quality (resolution, bitrate, etc)
  • (optional) to make the text fade in/out

  I am new to ffmpeg and any help will be appreciated.

  thanks in advance

  Example ffprobe information for mp4 below :

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
  
    Metadata:
  
      major_brand : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      encoder         : Lavf55.33.100
  
    Duration: 00:00:03.84, start: 0.042667, bitrate: 1117 kb/s
  
  Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720, 1021 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
  
  Metadata:
  
    handler_name    : VideoHandler
  
  Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 140 kb/s (default)
  
  Metadata:
  
    handler_name    : SoundHandler

  Example webm

  Input #0, matroska,webm, from 'input.webm':
  
    Metadata:
  
    encoder         : Lavf55.33.100
  
   Duration: 00:00:03.80, start: 0.000000, bitrate: 1060 kb/s
  
     Stream #0:0(eng): Video: vp8, yuv420p, 1280x720, SAR 1:1 DAR 16:9, 30 fps, 30 tbr, 1k tbn, 1k tbc (default)
  
     Stream #0:1(eng): Audio: vorbis, 48000 Hz, stereo, fltp (default)

  Screenshot from joined.mp4

  Screenshot for step 3 console

• Processing Camera stream in Opencv, pushing it over RTMP (NGINX RTMP Module) using FFMPEG

  19 avril 2016, par Asymptote

  Output video :
  https://youtu.be/VxfoBQjoY6E

  Explanation :

  I want to : Process camera stream in Opencv and push it over to RTMP server. I already have NGINX (RTMP module) set up and I have tested streaming videos with both RTMP (Flash Player) and HLS.

  I am reading the frames in a loop and using ’subprocess’ in python to execute ffmpeg command. Here’s the command I am using :

  command = [ffmpeg,
  
      '-y',
  
      '-f', 'rawvideo',
  
      '-vcodec','rawvideo',
  
      '-pix_fmt', 'bgr24',
  
      '-s', dimension,
  
      '-i', '-',
  
      '-c:v', 'libx264',
  
      '-pix_fmt', 'yuv420p',
  
      '-preset', 'ultrafast',
  
      '-f', 'flv',
  
      'rtmp://10.10.10.80/live/mystream']
  
  
  
  
  
  import subprocess as sp
  
  ...
  
  proc = sp.Popen(command, stdin=sp.PIPE,shell=False)
  
  ...
  
  proc.stdin.write(frame.tostring()) #frame is read using opencv

  Problem :

  I can see the stream fine but it freezes and resumes frequently. Here’s the output of FFMPEG terminal log :

  Stream mapping:
  
    Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
  
  frame=  117 fps= 16 q=22.0 size=     344kB time=00:00:04.04 bitrate= 697.8kbits/s speed=0.543x   

  It mentions speed at the end. I believe it should be close to 1x. I am not sure how to achieve that.

  And I am on the same network as server, I can post my python code if required. Need some ffmpeg guru to give me some advise.

  EDIT

  My input fps is actually 3.
  With '-use_wallclock_as_timestamps', '1' I can see in the log that speed is close to 1x.
  But HLS is not streaming live there’s 2 min delay, it halts and . Chris’s advise partially worked. I am not sure where exactly is the problem, I am starting to believe it has something to do with nginx-rtmp module.

  Here’s the final output, on left it’s flash and on right it’s hls. I am showing the ffmpeg options at the end.
  https://youtu.be/jsm6XNFOUE4

• videoshow npm module not working fine

  14 avril 2016, par Anshul

  I have used videoshow NPM module for creating a video using images but it is not working fine for me it is running twice or thrice and creating multiple videos for same images sometimes. If i am changing the value of loop in the code to ’1’ it is running fine but the slide duration is only one second.

  Here is my code :-

  var images = [
  
      'public/images/1.png',
  
      'public/images/2.png',
  
      'public/images/3.png',
  
      'public/images/4.png',
  
      'public/images/5.png',
  
      'public/images/6.png',
  
      'public/images/7.png',
  
      'public/images/8.png',
  
      'public/images/9.png'
  
  ]
  
  
  
  var videoOptions = {
  
      fps: 25,
  
      loop: 3, // seconds
  
      transition: true,
  
      transitionDuration: 1, // seconds
  
      videoBitrate: 1024,
  
      videoCodec: 'libx264',
  
      size: '640x480',
  
      audioBitrate: '128k',
  
      audioChannels: 2,
  
      format: 'mp4'
  
  }
  
  
  
  var videoPath = 'public/video/test.mp4';
  
  
  
  videoshow(images, videoOptions)
  
  .audio('public/audio/1.mp3')
  
  .save(videoPath)
  
  .on('start', function (command) {
  
      console.log('ffmpeg process started:', command)
  
  })
  
  .on('error', function (err, stdout, stderr) {
  
      res.send({status : false, message: 'Something went wrong. Please try again.'});
  
      res.end();
  
      return;
  
  })
  
  .on('end', function (output) {
  
      res.send({status : true, message: ''});
  
      res.end();
  
      return;
  
  });