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• 4xm : Check that the read track value is non-negative

  3 septembre 2013, par Martin Storsjö

  4xm : Check that the read track value is non-negative
  Reported-by : Mateusz "j00ru" Jurczyk and Gynvael Coldwind
  
  CC : libav-stable@libav.org
  
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavformat/4xm.c

• Split h.264 stream into multiple parts in python

  31 janvier 2023, par BillPlayz

  My objective is to split an h.264 stream into multiple parts, meaning while reading the stream from a pipe i would like to save it into x second long packages (in my case 10).

  


  I am using a libcamera-vid subprocess on my Raspberry Pi that outputs the h.264 stream into stdout.
  
Might be irrelevant, depends : libcamera-vid outputs a message every frame and I am able to locate it at isFrameStopLine
To convert the stream, I use an ffmpeg subprocess, as you can see in the code below.

  


  Imagine it like that :
  
Stream is running...
  
- Start recording to a file
  
- Sleep x seconds
  
- Finish recording to file
  
- Start recording a new file
  
- Sleep x seconds
  
- Finish recording the new file
  
- and so on...

  


  Here is my current code, however upon running the first export succeeds, and after the second or third the ffmpeg-subprocess is terminating with the error :
  
pipe:: Invalid data found when processing input
  
And shortly after, the python process, because of the ffmpeg termination i believe.
Traceback (most recent call last):   File "/home/survpi-camera/main.py", line 56, in <module>     processStreamLine(readData)   File "/home/survpi-camera/main.py", line 16, in processStreamLine     streamInfo["process"].stdin.write(data) BrokenPipeError: [Errno 32] Broken pipe</module>

  


  recentStreamProcesses = []
streamInfo = {
    "lastStreamStart": -1,
    "process": None
}

def processStreamLine(data):
    isInfoLine = ((data.startswith(b"[") and (b"INFO" in data)) or (data == b"Preview window unavailable"))
    isFrameStopLine = (data.startswith(b"#") and (b" fps) exp" in data))
    if ((not isInfoLine) and (not isFrameStopLine)):
        streamInfo["process"].stdin.write(data)
    
    if (isFrameStopLine):
        if (time.time() - streamInfo["lastStreamStart"] >= 10):
            print("10 seconds passed, exporting...")
            exportStream()
            createNewStream()

def createNewStream():
    streamInfo["lastStreamStart"] = time.time()
    streamInfo["process"] = subprocess.Popen([
        "ffmpeg",
        "-r","30",
        "-i","-",
        "-c","copy",("/home/survpi-camera/" + str(round(time.time())) + ".mp4")
    ],stdin=subprocess.PIPE,stderr=subprocess.STDOUT)
    print("Created new streamProcess.")

def exportStream():
    print("Exporting...")
    streamInfo["process"].stdin.close()
    recentStreamProcesses.append(streamInfo["process"])


cameraProcess = subprocess.Popen([
    "libcamera-vid",
    "-t","0",
    "--width","1920",
    "--height","1080",
    "--codec","h264",
    "--inline",
    "--listen",
    "-o","-"
],stdout=subprocess.PIPE,stdin=subprocess.PIPE,stderr=subprocess.STDOUT)

createNewStream()

while True:
    readData = cameraProcess.stdout.readline()
    
    processStreamLine(readData)


  


  Thank you in advance !

  


• avformat/4xm : Check for duplicate track ids

  7 décembre 2021, par Michael Niedermayer

  avformat/4xm : Check for duplicate track ids
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/4xm.c