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• How to receive byte-stream by using gstreamer with python subprocess module or gst-launch-1.0 command ?

  21 avril 2022, par yuniversi

  I want to receive byte-stream by using gstreamer with python subprocess module.
Now I can successfully use ffmpeg to pull the byte-stream. As shown below.

  


  import cv2
import subprocess as sp


height = 714
width = 420
rtsp_url = 'rtsp://127.0.0.1:8554/video'

# command
command = ['ffmpeg',
            '-i', rtsp_url,
            '-f', 'rawvideo',
            '-s',str(width)+'*'+str(height),
            '-pix_fmt', 'bgr24',
            '-fflags', 'nobuffer',
            '-']

p = sp.Popen(command, stdout=sp.PIPE, bufsize=10**8)

while True:
    raw_image = p.stdout.read(width*height*3)
    image =  np.fromstring(raw_image, dtype='uint8')
    image = image.reshape((height,width,3)).copy()
    cv2.imshow('image', image)
    key = cv2.waitKey(20)


  


  I want to use gstreamer command instead of ffmpeg. So far, I have realized writing byte-stream to a file by using gstreamer command line.

  


  gst-launch-1.0 rtspsrc location=rtsp://127.0.0.1:8554/video latency=0 drop-on-latency=true ! rtph264depay ! video/x-h264, stream-format='byte-stream' ! filesink location=/home/name/stdout


  


  But it can't output byte-stream to pipe, so the terminal dosen't display byte-stream, not like ffmpeg command. How to change this command to output byte-stream through pipe so I can read from pipe.
Thank you for taking the time to answer for me !

  


  This is RTSP streaming code.

  


  import cv2
import time
import subprocess as sp
import numpy as np


rtsp_url = 'rtsp://127.0.0.1:8554/video'
video_path = r'test.mp4'
cap = cv2.VideoCapture(video_path)

# Get video information
fps = int(cap.get(cv2.CAP_PROP_FPS))
width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
print('fps={}'.format(fps))

# command
command = ['ffmpeg',
            '-re',
            '-y',
            '-stream_loop', '-1',
            '-f', 'rawvideo',
            '-vcodec', 'rawvideo',
            '-pix_fmt', 'bgr24',
            '-s', "{}x{}".format(width, height),
            '-r', str(fps),
            '-i', '-',
            '-c:v', 'libx264',
            '-pix_fmt', 'yuv420p',
            '-preset', 'ultrafast',
            # '-flags2', 'local_header',
            '-bsf:v', "'dump_extra=freq=k'", 
            '-keyint_min', '60',
            '-g', '60',
            '-sc_threshold', '0', 
            '-f', 'rtsp',
            '-rtsp_transport', 'tcp',
            '-muxdelay', '0.1', 
            rtsp_url]

p = sp.Popen(command, stdin=sp.PIPE)

cnt = 0
t_start = time.time()
while (cap.isOpened()):
    t_cur = time.time()-t_start

    ret, frame = cap.read()
    if not ret:
        cnt += 1
        print("count: {}".format(cnt))
        cap = cv2.VideoCapture(video_path)
        continue

    p.stdin.write(frame.tobytes())

    cv2.imshow('real_time', frame)

    key = cv2.waitKey(20)
    if key == 27:
        p.terminate()
        break


  


• avformat/movenc : sidx earliest_presentation_time is applied after editlist

  29 mars 2022, par Zhao Zhili

  avformat/movenc : sidx earliest_presentation_time is applied after editlist
  Fix #8334
  Signed-off-by : Zhao Zhili <zhilizhao@tencent.com>
  

  • [DH] libavformat/movenc.c
  • [DH] tests/ref/fate/movenc

• ffbuild/common : Fix CPPFLAGS applied for compiling C++ files

  12 mai 2022, par Andreas Rheinhardt

  ffbuild/common : Fix CPPFLAGS applied for compiling C++ files
  Currently, $(CPPFLAGS) and $(CFLAGS) are prepended to CXXFLAGS
  
  (the flags for compiling C++) like this :
  
  CXXFLAGS := $(CPPFLAGS) $(CFLAGS) $(CXXFLAGS)
  
  Using " :=" creates a simply expanded variable, i.e. the values
  
  of the variable at the time of assignment are used and later
  
  modifications to them are ignored (using a recursively expanding
  
  variable (i.e. "=" instead of " :=") is not really possible here,
  
  as there would be an infinite loop when evaluating CXXFLAGS).
  Yet we perform later additions to CPPFLAGS : HAVE_AV_CONFIG_H and
  
  BUILDING_libfoo are defined. These do not reach C++ compilations.
  To fix this a trick is employed to prepend to a recursively
  
  expanded variable while keeping it recursively expanded.
  There are two practical consequences of this : C++ files now no longer
  
  include the version.h header, but only the version_major.h header
  
  of their library, saving some recompilations. Furthermore, they
  
  now get some optimized math functions (namely the ones from
  
  lavu/intmath.h instead of the ones from lavu/common.h).
  
  (av_parity() is the only one for which it makes a difference.)
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] ffbuild/common.mak