如何監視ffmpeg的進度？

Question

我有這個使用Rails的ffmpeg視頻編碼器，我需要向用戶報告ffmpeg進度。 如果我正在使用Linux，那該怎麼做？

Answer 1

這是我到了解決方案：

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 

Answer 2

謝謝你的帖子，我修改了一些。我正在使用ffmpeg版本0.10.2。這是我的版本：

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