Recherche avancée

Sur d’autres sites (4793)

• Simultaneously map video and data streams to one subprocess pipeline in real-time

  9 février 2023, par seabass1217

  I need to process the video stream and the klvdata streams simultaneously in real-time in OpenCV/Python. I'm using FFMPEG to read the file or stream as OpenCV does not retain the klvdata. I pass the data to OpenCV with the subprocess module.

  


  My problem is I cannot figure out how to map both the video and klvdata to the same subprocess pipe simultaneously ?

  


  My code :

  


  #!/usr/bin/env python3
import sys, json, klvdata;
from subprocess import PIPE
import subprocess as sp
import cv2
import numpy

command = ['ffmpeg',
    '-i', 'DayFlight.mpg',
    '-map', '0:0',
    '-map', '0:d',        
    '-pix_fmt', 'bgr24',
    '-c:v', 'rawvideo',      
    '-an','-sn',              
    '-f', 'image2pipe', '-',
    '-c:d', 'copy',
    '-f','data',
    ]

pipe = sp.Popen(command, stdin=sp.PIPE, stdout=sp.PIPE, stderr=sp.PIPE, bufsize=10**8)

while True:
   raw_image = pipe.stdout.read(1280*720*3)
   image =  numpy.fromstring(raw_image, dtype='uint8')
   image = image.reshape((720,1280,3))          
   if image is not None:
      cv2.imshow('Video', image)
   if cv2.waitKey(1) & 0xFF == ord('q'):
      break
   for packet in klvdata.StreamParser(pipe.stdout): 
      metadata = packet.MetadataList()
      print(metadata)
pipe.stdout.flush()
cv2.destroyAllWindows()



  


  Produces the below error :

  


  Traceback (most recent call last):&#xA;  File "test_cv.py", line 32, in <module>&#xA;    metadata = packet.MetadataList()&#xA;AttributeError: &#x27;UnknownElement&#x27; object has no attribute &#x27;MetadataList&#x27;&#xA;&#xA;</module>

  


  Any help is greatly appreciated.

  


• How To Abandon The Probesize Input Buffer For Real Time RTSP Playback

  3 juin 2014, par user3051473

  As far as I know that ffmpeg need to first read probesize input buffer to analysis the codec. And the probesize data will cause realtime RTSP delay. So I’m wandering that :

  How can I make av_read_frame() to skip the probesize input buffer which has already delayed ? Thanks very much.

• Problems getting real width and height of videos

  1er mai 2022, par Eduardo

  I'm having a problem when I upload videos. The thing is that I record my videos with my cellphone in vertical way and when I download them to my computer or pass them through whatsapp they still look vertical, I can still watch them in vertical way as I recorded them, but when I try to upload them on my website using PHP and FFMPEG I always get horizontal resolutions.

  


  I use this command to get the width of my videos :

  


  $width = $video_attributes['width'] ;

  


  The variable $video_attributes is an array that comes from a FFMPEG function that returns an array with the data related to the video.

  


  Somebody could help me out with some ideas about what I'm doing wrong ?

  


  I need to get the vertical resolution so my videos will be displayed in vertical containers in my website.

  


  Thanks in advance :)