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• ffmpeg - duration usage in input text file

  12 mai 2018, par Voicu

  I am trying to use ffmpeg to concatenate video segments with some black screen. To do that I’ve first generated a blank 10-second video (no audio track) with :

  $ ffmpeg -f lavfi -i color=black:s=320x240:r=1 -f lavfi -i anullsrc -t 10 -vcodec libvpx -an blank.mkv

  I then created the simplest possible scenario within input.txt file (contents below) in order to have three seconds of black screen followed by some video (no audio track) :

  file 'blank.mkv'
  
  duration 3
  
  file 'video_example.mkv'

  And, finally, ran the following ffmpeg command to concat the contents of that input file :

  $ ffmpeg -f concat -i input.txt -codec:v copy -codec:a copy output.mkv

  The issue that I have is that the duration 3 is not considered, so the final video still has ten seconds of black frames (instead of three) followed by my video. And also "Non-monotonous DTS in output stream 0:0 ..." message is shown when using duration x in the file. If I remove duration the warnings are gone and getting the 10-second black screen first output as well.

  Full output of the ffmpeg concat command :

  $ ffmpeg -hide_banner -f concat -i input.txt -codec:v copy -codec:a copy output.mkv
  
  Input #0, concat, from 'input.txt':
  
    Duration: N/A, start: 0.000000, bitrate: N/A
  
      Stream #0:0: Video: vp8, yuv420p(progressive), 320x240, SAR 1:1 DAR 4:3, 1 fps, 1 tbr, 1k tbn, 1k tbc
  
      Metadata:
  
        ENCODER         : Lavc57.107.100 libvpx
  
        DURATION        : 00:00:10.000000000
  
  File 'output.mkv' already exists. Overwrite ? [y/N] y
  
  Output #0, matroska, to 'output.mkv':
  
    Metadata:
  
      encoder         : Lavf57.83.100
  
      Stream #0:0: Video: vp8 (VP80 / 0x30385056), yuv420p(progressive), 320x240 [SAR 1:1 DAR 4:3], q=2-31, 1 fps, 1 tbr, 1k tbn, 1k tbc
  
      Metadata:
  
        ENCODER         : Lavc57.107.100 libvpx
  
        DURATION        : 00:00:10.000000000
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
  Press [q] to stop, [?] for help
  
  [concat @ 000000000031a440] DTS 3000 < 9000 out of order
  
  [matroska @ 0000000000328420] Non-monotonous DTS in output stream 0:0; previous: 9000, current: 3000; changing to 9000. This may result in incorrect timestamps in the output file.
  
  [matroska @ 0000000000328420] Non-monotonous DTS in output stream 0:0; previous: 9000, current: 4001; changing to 9000. This may result in incorrect timestamps in the output file.
  
  [matroska @ 0000000000328420] Non-monotonous DTS in output stream 0:0; previous: 9000, current: 4998; changing to 9000. This may result in incorrect timestamps in the output file.
  
  [matroska @ 0000000000328420] Non-monotonous DTS in output stream 0:0; previous: 9000, current: 6004; changing to 9000. This may result in incorrect timestamps in the output file.
  
  [matroska @ 0000000000328420] Non-monotonous DTS in output stream 0:0; previous: 9000, current: 7002; changing to 9000. This may result in incorrect timestamps in the output file.
  
  [matroska @ 0000000000328420] Non-monotonous DTS in output stream 0:0; previous: 9000, current: 8005; changing to 9000. This may result in incorrect timestamps in the output file.
  
  frame= 5794 fps=0.0 q=-1.0 Lsize=    7109kB time=01:37:09.70 bitrate=  10.0kbits/s speed=5.16e+004x
  
  video:7043kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.926229%

  Any idea what am I doing wrong ? The warning seems to hint towards the issue here.

  Other possibly useful info :

  $ ffprobe -hide_banner blank.mkv
  
  Input #0, matroska,webm, from 'blank.mkv':
  
    Metadata:
  
      ENCODER         : Lavf57.83.100
  
    Duration: 00:00:10.00, start: 0.000000, bitrate: 1 kb/s
  
      Stream #0:0: Video: vp8, yuv420p(progressive), 320x240, SAR 1:1 DAR 4:3, 1 fps, 1 tbr, 1k tbn, 1k tbc (default)
  
      Metadata:
  
        ENCODER         : Lavc57.107.100 libvpx
  
        DURATION        : 00:00:10.000000000
  
  
  
  $ ffprobe -hide_banner video_example.mkv
  
  Input #0, matroska,webm, from 'video_example.mkv':
  
    Metadata:
  
      encoder         : GStreamer matroskamux version 1.8.1.1
  
      creation_time   : 2018-05-04T17:57:04.000000Z
  
    Duration: 01:37:08.70, start: 15434.269000, bitrate: 9 kb/s
  
      Stream #0:0(eng): Video: vp8, yuv420p(progressive), 320x240, SAR 1:1 DAR 4:3, 1 fps, 1 tbr, 1k tbn, 1k tbc (default)
  
      Metadata:
  
        title           : Video
  
  
  
  $ ffmpeg -v
  
  ffmpeg version 3.4.2 Copyright (c) 2000-2018 the FFmpeg developers
  
    built with gcc 7.3.0 (GCC)

• Non-monotonous DTS in output stream 0:1

  4 mai 2018, par sana

  I’m using ffmpeg to get a video file on network .I get the sound live but I it get the video too late. The code I use on the receiver side is :

   ffmpeg -i rtsp://10.0.0.1:8554/test1.sdp -acodec copy -vcodec copy /home/sana/lab/mrp/test1.avi

  The code I use On the sender side is :

  cvlc -vvv /home/sana/lab/video-server1/1.avi --sout '#transcode{vcodec=h264,vb=3000,scale=Auto,acodec=mp3,ab=128,channels=2,samplerate=8000}:rtp{dst=10.0.0.2,port=1234,sdp=rtsp://10.0.0.1:8554/test1.sdp}'

  the error in the output of the ffmpeg command(on the receiver) is :

   [avi @ 0x521ba80] Non-monotonous DTS in output stream 0:1; previous: 196, current: 162; changing to 197. This may result in incorrect timestamps in the output file

  the errors in the input of the vlc command(on the sender) is :

      [0x7f6070000f58] x264 encoder warning: invalid DTS: PTS is less than DTS
  
  
  
      [0x7f608c0009b8] main input error: ES_OUT_SET_(GROUP_)PCR  is called too late (pts_delay increased to 532 ms)
  
      [0x7f608c0009b8] main input error: ES_OUT_RESET_PCR called
  
      .
  
      .
  
      [mpeg4 @ 0x7f60700075a0] header damaged
  
      [0x7f6070000b08] avcodec generic warning: cannot decode one frame (4105 bytes)
  
      [mpeg4 @ 0x7f60700075a0] header damaged
  
      [0x7f6070000b08] avcodec generic warning: cannot decode one frame (4078 bytes
  
  
  
  )

  What does this actually mean and what can I do to prevent it from happening ?

  the ffmpeg version is 4.0-static and vlc version is VLC media player 2.1.6 Rincewind (revision 2.1.6-0-gea01d28) and ubuntu version is 14.04.

• How to make ffmpeg available inside my Docker container ?

  26 août 2019, par vcamargo

  I’m currently trying to run a ffmpeg Docker image inside my own container with docker-compose using the depends_on clause. But when I try to reach ffmpeg inside my code, it seems like it’s not available system-wide and I get an error. I believe I’m misconfiguring Docker.

  My current Dockerfile is as follows :

  FROM node:9
  
  
  
  WORKDIR /usr/app
  
  
  
  COPY package*.json ./
  
  
  
  RUN npm install --quiet
  
  
  
  COPY . .

  And my docker-compose.yml :

  version: '3'
  
  services:
  
    app:
  
      build: .
  
      command: npm run dev
  
      volumes:
  
      - .:/usr/app/
  
      - /usr/app/node_modules
  
      ports:
  
        - "3000:3000"
  
      depends_on:
  
        - ffmpeg
  
    ffmpeg:
  
      image: jrottenberg/ffmpeg:3.3

  When I run docker-compose up I can see that the ffmpeg is actually working, but then my application proceeds to start and it seems that ffmpeg ceases to work.