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• FFMpeg Muxer Internal Buffering

  7 mars 2016, par rkrishnan2012

  I am using libFFmpeg to mux h264 and aac packets into an flv container and streaming that via rtmp.

  I want to be able to detect when frames are being sent to the server or the size of the internal buffer, in order to detect the network lag and apply variable bit-rate. However, when I clock the time it takes for av_write_frame, it is much too fast for it to be syncronous (so we can’t use this to detect network speed).

  I already tried calling av_write_frame with a null parameter (to flush data) every frame, and also directly calling avio_flush but the bitrate is still too high. So, I am wondering if there is another buffer that I am missing (such as a socket-level buffer).

  I also tried to print the AVIOContext->buf_end, buffer_size, and buf_ptr values but none of those are indicative of my network speed getting throttled (when I limit the bandwidth on my router, I would expect the buffer size to increase).

  tl ;dr - I would like to know how to properly detect packets being sent to the server, or the network speed lagging compared to my av_write_frame calls.

  If it makes a difference, this is being run on an arm-v7a Android device.

• I am calling ffmpeg from Python. Getting thread.error and repeated attempts to connect to audio stream

  16 février 2016, par user2192778

  I have some code which calls ffmpeg at a particular time of the day to record a web stream. First, the function that calls ffmpeg...

  def record_stream(): 
  
      ffmpegEXE = "C:/pathtoffmpeg/ffmpeg.exe"
  
      subprocess.call([ffmpegEXE, '-i', http://streamurl.mp3, output.mp3], shell=True)

  Then, the function which schedules record_stream according to the clock...

  def sched ():
  
      i = 0
  
      while True:
  
  
  
      x = datetime.today()
  
      y=x.replace(day=x.day+1, hour=i, minute= start_minute, second=0, microsecond=0) 
  
      delta_t=y-x
  
      secs=delta_t.seconds+1
  
      t = Timer(secs,stream_record)
  
      t.start()
  
      i = (i + 1) % 24

  When I launch the .py program an error reads :

  Traceback <most recent="recent" call="call" last="last">
  
  ... line X, in <module>
  
  sched ()
  
  ... line Y, in sched ()
  
  t.start()
  
  ... line Z, in start
  
  _start_new_thread(self.__bootstrap,())
  
  thread.error: can't start new thread
  
  </module></most>

  Despite the error, the program runs.

  When it runs, however, ffmpeg initializes over and over again. It connects to the stream, then connects to the stream again (this time saying "output.mp3 already exists. Overwrite ? Y/N" It will do this ten or so times until it finally just records the stream in a normal way.

  How do I fix these errors ? How do I stop this issue with ffmpeg connecting repeatedly ?

• microbench : Add fallback to gettimeofday()

  3 février 2016, par Dave Yeo

  microbench : Add fallback to gettimeofday()
  Some operating systems such as OS/2 don’t have any of the CLOCK* API
  
  functions so add gettimeofday() as a fallback.
  Signed-off-by : Dave Yeo <dave.r.yeo@gmail.com>
  
  Signed-off-by : Erik de Castro Lopo <erikd@mega-nerd.com>
  

  • [DH] configure.ac
  • [DH] microbench/util.c