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• ffmpeg : scaling the video without changing the actual width and height

  23 février 2021, par YusifJaim

  I want to scale a video with ffmpeg.

  


  This is a picture of what I'm trying to achieve :

  


  a picture of what I'm trying to achieve

  


  I don't want the actual width and height to be affected, I just want to scale the video a little bit smaller to give a space to write something above and below it.

  


• How to replace timestamps in MP4 video with FFmpeg ?

  12 février 2021, par user15180344

  I have a fragmented MP4 video which has incorrect timestamps. I was told that I can calculate the correct timestamps using the MPD manifest of that video (taking data from <segmenttimeline></segmenttimeline> tag).

  


  Could you please give me hints on how to actually calculate these timestamps, and, what's more important, how to replace the timestamps in video segments with the correct values ?

  


• How to access builtin webcam from a docker container using ffmpeg ?

  1er novembre 2020, par philippos

  I have wrote my code that captures videos by my builtin webcam of my MAC using ffmpeg.

  On local machine, the code works fine. However, I built a docker container of my code, and tried to run it, but I got the following error :

  


  error: Command failed: ffmpeg -f avfoundation -framerate 30 -i "0" -target pal-vcd -vf scale=640x480 -flags +global_header -f segment -segment_time 10 -segment_list ../out.csv -segment_format_options movflags=+faststart -reset_timestamps 1 -strftime 1 %Y%m%d-%H%M%S.mp4
ffmpeg version git-2016-05-25-9591ca7 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 4.8 (Ubuntu 4.8.4-2ubuntu1~14.04.3)
  configuration: --extra-libs=-ldl --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree --enable-openssl
  libavutil      55. 24.100 / 55. 24.100
  libavcodec     57. 43.100 / 57. 43.100
  libavformat    57. 37.100 / 57. 37.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 46.100 /  6. 46.100
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
Unknown input format: 'avfoundation'


  


  

  1. as far as what I understood from this log, is that the docker
container doesn't have access to local devices.
     According to
this discussion Docker - a way to give access to a host USB or
serial device ? , I need to use the --device flag to pass my
device's location.
     However, according to this answer,
that is not possible ?

  


  2. In addition to what I've mentioned
above, I couldn't get my webcam's path at the first place. what is
a correct path for macbook webcam

  


  


  My question is : How to access my MAC's builtin camera to record from a docker container ?