如何从ffmpeg监控进度?

这就是我达成的解决方案:

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

谢谢你的帖子,我修改了一下。我使用的是ffmpeg版本0.10.2。以下是我的版本:

def exec_ffmpeg src_path, dst_path
    cmd = "ffmpeg -i \"%s\" -acodec libfaac -ac 2 -ab 128k -vcodec libx264 -threads 0 \"%s\" 2>&1" %
                            [src_path, dst_path]

    puts "%s" % cmd.gsub(/2\>\&1$/,'')
    puts "press 'q' to quit"
    progress = nil
    dur_secs = nil
    frame_rate = nil
    frames = 0
    dur_str = '00:00:00.000'
    ostr = ''
    ffmpeg = IO.popen(cmd)
    ffmpeg.each("\r") do |line|
        if dur_secs == nil && line =~ /Duration:\s*(\d*):(\d*):(\d*\.\d*)/
            dur_str = $1.to_s + ":" + $2.to_s + ":" + $3.to_s
            dur_secs = ($3.to_f + ($2.to_i * 60).to_f + ($1.to_i * 360).to_f)
            puts "Video Duration:" + dur_str
        end
        if frame_rate == nil && line =~ /Stream.+\, (\d+\.{0,1}\d{0,3}) fps\,/
            frame_rate = $1.to_f
            frames = dur_secs * frame_rate
            puts "Total Frames: %i" % frames.to_i
            puts "Frame Rate: %.3f fps" % frame_rate
        end
        if line =~ /frame=(\s.?(\d*))/
            cframe = $1.to_i
            csecs = 0
            if line =~ /time=\s*(\d*):(\d*):(\d*\.\d*)/
                csecs = ($3.to_f + ($2.to_i * 60).to_f + ($1.to_i * 360).to_f)
                csecs_str = $1.to_s + ":" + $2.to_s + ":" + $3.to_s
            elsif line =~ /time=\s*(\d*\.\d*)/
                csecs $1.to_f
                t = Time.at(csecs).gmtime
                csecs_str = "%0.2i:%0.2i:%0.2i.%3i" % [t.hour, t.min, t.sec, t.nsec]
            end
            if line =~ /fps=\s*(\d*)/
                cfps = $1.to_i
            else
                cfps = 0
            end
            if line =~ /bitrate=\s*(\d*\.\d*kbits)/
                br = $1
            else
                br = "???"
            end
            ostr = "  %3.2f%% ( %s ) @frame:%i fps:%i bitrate:%s" % 
                [((csecs/dur_secs)*100), csecs_str, cframe, cfps, br]
            print ostr + ("\b" * (ostr.length + 4))
        end
    end
    print "\n"
end