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• How to merge videos and add audio in a single command using ffmpeg ?

  9 janvier 2017, par harishkumar329

  I use the following commands to concat audio-less video files to one and add audio to it,

  To concat individual videos,

  ffmpeg  -i 1.mp4 -i 2.mp4 -i 3.mp4 -i 4.mp4 -i 5.mp4 -filter_complex 'concat=n=5:v=1:a=0[out]'  -map '[out]' -strict -2 -y video_withoutaudio.mp4

  To add audio,

  ffmpeg -i video_withoutaudio.mp4 -i audio.mp4 -c:v copy -c:a aac -strict -2 video_withaudio.mp4

  is there a way to combine these two commands to one ?

  My requirement is to optimise the commands as I have 1000+ commands taking a lot of time to complete, hoping combining these two to one will save some time.

  Thanks in advance !

• ffserver "dimensions not set" when loading stream

  29 mai 2013, par GreenGiant

  I am live streaming a webcam from my raspberry pi using avconv (ffmpeg "replacement")

  avconv -f video4linux2 -v debug -r 5 -s 176x144 -i /dev/video0 -vcodec mjpeg http://192.168.0.3:8090/feed1.ffm

  to my local network OSX machine (for testing) running ffserver

  Port 8090
  
  BindAddress 0.0.0.0
  
  MaxHTTPConnections 2000
  
  MaxClients 1000
  
  MaxBandwidth 10000
  
  CustomLog -
  
  NoDaemon
  
  
  
  <feed>
  
     File feed1.ffm
  
     FileMaxSize 20M
  
     ACL allow 192.168.0.10
  
  </feed>
  
  
  
  <stream>
  
     Feed feed1.ffm
  
     Format mjpeg
  
     NoAudio
  
     VideoQMin 1
  
     VideoQMax 10
  
     VideoSize 176x144
  
     VideoFrameRate 5
  
  </stream>

  When I start avconv it appears to be streaming to ffserver fine :

  Output #0, ffm, to 'http://192.168.0.3:8090/feed1.ffm':
  
    Metadata:
  
      encoder         : Lavf55.0.1
  
      Stream #0.0, 0, 1/1000000: Video: mjpeg, yuvj420p, 320x240, 1/5, q=2-31, 200 kb/s, 1000k tbn, 5 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (rawvideo -> mjpeg)
  
  Press ctrl-c to stop encoding
  
  frame=  108 fps= 18 q=21.7 size=     688kB time=21.60 bitrate= 260.9kbits/s 

  And the ffserver status page shows the stream

  

  However when I load http://localhost:8090/test.mjpeg in VLC it doesn't play and ffserver spits out :

  Sat May 25 17:25:34 2013 dimensions not set
  
  Sat May 25 17:25:34 2013 Error writing output header
  
  Sat May 25 17:25:34 2013 127.0.0.1 - - [GET] "/test.mjpeg HTTP/1.1" 200 66

  I've tried so many different configurations and settings, I'm at a loss to what is causing that error !

  Thank you

• How to seek by msec with ffmpeg ?

  26 mai 2014, par Srv19

  I am trying to seek in video by milliseconds with ffmpeg. I have been trying to use code from this question, which uses avformat_seek_file (i use it with -1 for stream number and AVSEEK_FLAG_ANY flag).

  After that is called, i try to read next frames, that is :

  if (av_read_frame(fmt_ctx, &pkt) >= 0)
  
  {
  
      int ret = 0;
  
  
  
      if (pkt.stream_index == video_stream_idx) {
  
          /* decode video frame */
  
          ret = avcodec_decode_video2(video_dec_ctx, frame, got_frame, &pkt);
  
          if (ret < 0) {
  
              fprintf(stderr, "Error decoding video frame\n");
  
              return ret;
  
          }
  
  //do something with frame
  
  }

  However, the frame->pts of retrieved frame always holds the time of the frame that was immediatly after last frame that was read before seeking.

  Edit : In spite of frame->pts forming unbroken sequence, seeking does occur. For some bizarre reason next frame i read is the first one. In fact, after i run :

     int got_frame = 0;
  
     do
  
     if (av_read_frame(fmt_ctx, &pkt) >= 0) {
  
         decode_packet_ro(&got_frame, 0);
  
         av_free_packet(&pkt);
  
     }
  
     else
  
     {
  
         read_cache = true;
  
         pkt.data = NULL;
  
         pkt.size = 0;
  
         break;
  
     }
  
     while(!got_frame || this->frame->pts*av_q2d(video_dec_ctx->time_base) * 1000 < tsms);

  next frame i read is always the first one.