Recherche avancée

Sur d’autres sites (5765)

• H264 decoder in opencv for real time video transmission

  30 mai 2019, par Narendra

  I am writing a client-server application which does real time video transmission from an android based phone to a server. The captured video from the phone camera is encoded using the android provided h264 encoder and transmitted via UDP socket. The frames are not RTP encapsulated. I need it to reduce the overhead and hence the delay.
  On the receiver, I need to decode the incoming encoded frame. The data being sent on the UDP socket not only contains the encoded frame but some other information related to the frame as a part of its header. Each frame is encoded as an nal unit.

  I am able to retrieve the frames from the received packet as a byte array. I can save this byte array as raw h264 file and playback using vlc and everything works fine.
  However, I need to do some processing on this frame and hence need to use it with opencv.
  Can anyone help me with decoding a raw h264 byte array in opencv ?
  Can ffmpeg be used for this ?

• Anomalie #3266 (Fermé) : création d’un auteur et pipeline pre et post edition

  11 octobre 2014, par cedric -

  les piplines pre_insertion et post_insertion te permettent de reperer la creation d’un auteur et d’agir en consequence. A la rigueur tu peux meme modifier le statut à la creation via pre_insertion mais Attention ! Le choix du statut 5poubelle est délibéré : un auteur ne doit pas pouvoir se connecter dans qu’il n’est pas fini d’initialiser, et si on met ’0’ par défaut à la place on a toujours le risque d’avoir un auteur qui reste dans ce statut là et possède des droits inapropriés (’0’ peut être interprété comme ’0minirezo’)

• Run FFMPEG in an Async Subprocess then Kill after condition complete ?

  16 janvier 2021, par Robert

  I am struggling to get this correct. I have a sample piece of code here :

  


  import asyncio
import signal
import os
from subprocess import PIPE, Popen


async def recScreen():
    cmd = 'ffmpeg -f gdigrab -framerate 30 -i desktop output.mkv'
    process = Popen(cmd)
    await asyncio.sleep(15)
    print("Done sleep")
    process.terminate()
    return 0

loop = asyncio.get_event_loop()
loop.run_until_complete(recScreen())
loop.close()



  


  The whole idea is that, after a condition is met (e.g. sleeping after 15 seconds), we can tell ffmpeg to gracefully stop recording and close.

  


  However, I have yet to find a method that does that. In this example, and most examples using process.terminate() and process.kill(), the process ends abruptly without letting ffmpeg do a clean exit. Attempting to add await to process throws an error since it cannot be awaited.

  


  Using a sample piece like :

  


      process = await asyncio.create_subprocess_shell(
        command, stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.PIPE
    )


  


  and then

  


  await process.terminate()


  


  Throws a NotImplementedError.

  


  I am confused and not sure how I should go about. Does anyone have a solution ?