Question

I have this ffmpeg video encoder using Rails and I needed to report ffmpeg progress to the user.
How can that be done provided that I am using Linux?

Answer 1

This is the solution I reached:

def execute_ffmpeg(cmd, progress)
  logger.debug "Running command #{cmd}"
  command = "#{cmd} 2>&1"
  progress = nil
  frames = nil
  fps = 25
  ffmpeg = IO.popen(command)
  ffmpeg.each("\r") do |line|
    if frames.nil? && line =~ /Duration:(\s.?(\d*):(\d*):(\d*\.\d*))/
      duration = $2.to_s + ":" + $3.to_s + ":" + $4.to_s
      frames = ($4.to_i + ($3.to_i * 60) + ($2.to_i * 60 * 60)) * fps
    end
    if line =~ /frame=(\s.?(\d*))/
      progress = $1.to_i / frames.to_i
      print "Progress: #{progress}"
    end
  end
end