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• cannot locate symbol "avpriv_pix_fmt_bps_avi"

  14 mars 2017, par S. Le Galloudec

  I’m developping an android application using ffmpeg. I’m trying to decode a rtsp stream, and i have a problem with a symbol.
  After i finally compiled ffmpeg with this tuto :
  https://github.com/WritingMinds/ffmpeg-android

  I used a code i found here : Receiving RTSP stream using FFMPEG library

  But i have a problem when i run my program. I got this error :

  java.lang.UnsatisfiedLinkError : dlopen failed : cannot locate symbol "avpriv_pix_fmt_bps_avi" referenced by "/data/app/com.example.local.test_ffmpeg-2/lib/arm/libnative-lib.so"...

  The thing is that i checked into my .a to see if i had the symbol so i did :

  nm libavcodec.a | grep avpriv_pix

  It returned :

  00000060 R avpriv_pix_fmt_bps_avi
  
  00000000 R avpriv_pix_fmt_bps_mov
  
           U avpriv_pix_fmt_bps_avi
  
           U avpriv_pix_fmt_bps_mov

  So it looks like i have the symbol, but the U after means undefined, so i’m really confused. I’m not sure if my compilation failed somewhere or if the problem comes from my program.

  I’m using ndk 14, if someone has some ideas, that would be great :)

  Best regards

• lavc : drop a confusing message about "thread emulation"

  23 mars 2022, par Anton Khirnov

  lavc : drop a confusing message about "thread emulation"
  There is no such thing.
  

  • [DH] libavcodec/avcodec.c

• FFmpeg stream giving me "Alsa" errors

  14 mars 2019, par Sherman B.

  Of late I have been trying different ways of telling my Raspberry Pi to send video to YouTube live stream. One of the things I wanted to be able to do is boot the Pi up, and it automatically starts the live stream on its own. The advantages to this are huge (won’t have to tote around keyboard/mouse to start the stream, or have to ssh into the Pi to start the stream).

  Now what I did to accomplish this was to make a Python program that pipes the stream from my encoder(FFmpeg) directly to the stream. My goal was to make the program work, and then, set it to run automatically. But every time I run the file in my terminal this is my result :

  Traceback (most recent call last):
  
    File "stream.py", line 22, in <module>
  
      stream.stdin.close() 
  
  NameError: name 'stream' is not defined
  
  [h264 @ 0x19ed450] Could not find codec parameters for stream 0 (Video: h264, none): unspecified size
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  pi@raspberrypi:~ $ Input #0, h264, from 'pipe:':
  
    Duration: N/A, bitrate: N/A
  
      Stream #0:0: Video: h264, none, 25 tbr, 1200k tbn, 50 tbc
  
  Unknown input format: 'alsa'
  
  </module>

  Now I think I can fix I can fix some of those errors, but the biggest thing that worries me there is : the fact that "alsa" is unknown. I installed "libsasound" which is supposed to make Alsa usable, but that clearly did not help.

  I am using Python 3.

  This is my syntax for this program :

  import subprocess 
  
  import picamera 
  
  import time 
  
  YOUTUBE="rtmp://a.rtmp.youtube.com/live2/" 
  
  KEY = ("MY PERSONAL ENCODER KEY") 
  
  stream_cmd = 'ffmpeg -f h264 -r 25 -i - -itsoffset 5.5 -fflags nobuffer -f alsa -ac 1 -i hw:1,0 -vcodec copy -acodec aac -ac 1 -ar 8000 -ab 32k -map 0:0 -map 1:0 -strict experimental -f flv ' + YOUTUBE + KEY 
  
  stream_pipe = subprocess.Popen(stream_cmd, shell=True, stdin=subprocess.PIPE) 
  
  camera = picamera.PiCamera(resolution=(640, 480), framerate=25) 
  
  try: 
  
    now = time.strftime("%Y-%m-%d-%H:%M:%S") 
  
    camera.framerate = 25 
  
    camera.vflip = True 
  
    camera.hflip = True 
  
    camera.start_recording(stream.stdin, format='h264', bitrate = 2000000) 
  
    while True: 
  
       camera.wait_recording(1) 
  
  except KeyboardInterrupt: 
  
       camera.stop_recording() 
  
  finally: 
  
    camera.close()
  
    stream.stdin.close() 
  
    stream.wait() 
  
    print("Camera safely shut down") 
  
    print("Good bye") 

  Now maybe I am missing something simple here, but I don’t know what. I have tried many ideas (e.g. replacing Alsa with some other input, naming the "stream" function.) I have no idea.