Newest 'ffmpeg' Questions - Stack Overflow

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• Stitching videos side by side using java [on hold]

  9 mai 2018, par mejos2512

  how to stitch two videos side by side and make one video like in smule app using java. Any libraries/library wrappers for this ? Please help.

• FFMpeg default bitrate value

  9 mai 2018, par Rafael Lima

  What does FFMpeg do if I specify one codec to reencode and omit bitrate parameter? I tested with one video but I would like to understand

  Original:

   Duration: 00:00:10.48, start: 0.000000, bitrate: 17282 kb/s
  

  then I ran

  ffmpeg.exe -i a.mp4 -c:v h264 c.mp4
  

  Result:

  Duration: 00:00:10.50, start: 0.000000, bitrate: 4467 kb/s
  

  Where did it get 4467 from? is it a standard value for any video or it depends on something?

• Passing arguments to FFMPEG using subprocess.call()

  8 mai 2018, par Peter F

  I was working through this answer to an FFMPEG question and the command works just fine through the Windows 10 command prompt (I've only changed the input and output filenames):

  ffmpeg -i test.mp4  -filter:v "select='gt(scene,0.4)',showinfo" -f null  - 2> test.txt
  

  My Python 3 script gives arguments (as a list) to the subprocess.call() function and works fine for a number of basic FFMPEG operations, but not this one! It seems to be failing at the final null - 2> test.txt part, with the following error messages depending on how I split the arguments:

  [NULL @ 000001c7e556a3c0] [error] Unable to find a suitable output format for 'pipe:'
  [error] pipe:: Invalid argument
  
  [error] Unrecognized option '2> test.txt'.
  [fatal] Error splitting the argument list: Option not found
  
  [error] Unrecognized option '2>'.
  [fatal] Error splitting the argument list: Option not found
  

  Here's the basic list of arguments I've been trying:

  args=['C:\\Program Files\\ffmpeg\\ffmpeg.exe',
        '-i',
        'test.mp4',
        '-filter:v "select=\'gt(scene,0.4)\',showinfo"',
        '-f null',
        '-',
        '2>',
        'test.txt']
  

  Plus various permutations combining and splitting the last few elements.

  Please could somebody help me with the right syntax for running FFMPEG with these arguments through Python 3?

  Many thanks - I just can't see where I'm going wrong :(

• You can generate a video with audio and videos clip with ffmpeg

  8 mai 2018, par Jhonny Luis

  I am making an application in which I have to generate a single video clip of x duration, I was recommended to use the ffmpeg but I do not know if it could be created and if possible how the structure would be, since I understand that you need a file with a structure in which the path is established in this case videos and audio, I am working on codeigniter with php 7, I have already executed the ffmpeg to change the format of a video.

  The question is the following, from a database I bring the list of the route of the videos its duration and weight, equal with the audios, the thing is how I can do to create the video with ffmpeg from this.

• ffmpeg cannot generate thumbnail

  8 mai 2018, par rabbit

  In Windows to make a thumbnail with ffmpeg I use:

  ./ffmpeg -i 1.mp4 -ss 00:00:01 -f image2 1.jpg
  

  or:

  ./ffmpeg -ss 00:00:01 -i 1.mp4 -f image2 1.jpg
  

  But none can generate a thumbnail, it displays:

  ffmpeg -i input.mp4 -ss 1 -frames:v 1 output.jpg
  ffmpeg version N-91013-g8007a86363 Copyright (c) 2000-2018 the FFmpeg developers
    built with gcc 7.3.1 (GCC) 20180406
    configuration: 
    libavutil      56. 18.100 / 56. 18.100
    libavcodec     58. 19.101 / 58. 19.101
    libavformat    58. 13.102 / 58. 13.102
    libavdevice    58.  4.100 / 58.  4.100
    libavfilter     7. 21.100 /  7. 21.100
    libswscale      5.  2.100 /  5.  2.100
    libswresample   3.  2.100 /  3.  2.100
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
    Metadata:
      major_brand     : isom
      minor_version   : 1
      compatible_brands: isom
      creation_time   : 2017-01-11T08:30:55.000000Z
      encoder         : My MP4Box GUI 0.6.0.6 /my-mp4box-gui.zymichost.com>
    Duration: 00:03:27.93, start: 0.000000, bitrate: 9345 kb/s
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 2560x1440 [SAR 1:1 DAR 16:9], 9216 kb/s, 30 fps, 30 tbr, 90k tbn, 60 tbc (default)
      Metadata:
        creation_time   : 2016-10-14T14:16:02.000000Z
        handler_name    : videoplayback.mp4
      Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 125 kb/s (default)
      Metadata:
        creation_time   : 2017-01-11T08:30:56.000000Z
        handler_name    : videoplayback (1).m4a
  Stream mapping:
    Stream #0:0 -> #0:0 (h264 (native) -> mjpeg (native))
  Press [q] to stop, [?] for help
  [swscaler @ 0x55ad99ffe1c0] deprecated pixel format used, make sure you did set range correctly
  Output #0, image2, to 'output.jpg':
    Metadata:
      major_brand     : isom
      minor_version   : 1
      compatible_brands: isom
      encoder         : Lavf58.13.102
      Stream #0:0(und): Video: mjpeg, yuvj420p(pc), 2560x1440 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 30 fps, 30 tbn, 30 tbc (default)
      Metadata:
        creation_time   : 2016-10-14T14:16:02.000000Z
        handler_name    : videoplayback.mp4
        encoder         : Lavc58.19.101 mjpeg
      Side data:
        cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
  frame=    0 fps=0.0 q=0.0 Lsize=N/A time=00:00:00.00 bitrate=N/A speed=   0x    
  video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
  Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)
  

  and I find that the video which encoder is

   My MP4Box GUI 0.6.0.6 /my-mp4box-gui.zymichost.com>
  

  the ffmpeg cannot generate thumbnail. And how can I generate the thumbnail?