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• Audio-Video Delay When Fetching From NGINX-RTMP live-Mode

  17 novembre 2020, par Suuuehgi

  We get an RTSP-stream and mix it together with line-in over pulseaudio.

  


  This looks something like :

  


  ffmpeg \&#xA;  -use_wallclock_as_timestamps 1  -fflags &#x2B;genpts    \&#xA;  -max_delay 2000000 -thread_queue_size 1024         \&#xA;  -i "rtsp://url"           \&#xA;  -use_wallclock_as_timestamps 1  -fflags &#x2B;genpts    \&#xA;  -max_delay 2000000 -thread_queue_size 1024         \&#xA;  -itsoffset <offset>       \&#xA;  -f pulse                  \&#xA;  [...]&#xA;</offset>

  


  So far so good. This kind of works when fetching the rtsp stream directly.

  


  As soon as we route the RTSP-stream through an NGINX-RTMP loopback
(live mode) beforehand,

  


  ffmpeg -i rtsp://url -c copy -an -f flv rtmp://localhost/live&#xA;&#xA;ffmpeg \&#xA;  -use_wallclock_as_timestamps 1  -fflags &#x2B;genpts    \&#xA;  -max_delay 2000000 -thread_queue_size 1024         \&#xA;  -i "rtmp://localhost/live"                         \&#xA;  -use_wallclock_as_timestamps 1  -fflags &#x2B;genpts    \&#xA;  -max_delay 2000000 -thread_queue_size 1024         \&#xA;  -itsoffset <offset>                                \&#xA;  -f pulse                                           \&#xA;  [...]&#xA;</offset>

  


  we get a delay of close to 5 s within the output (audio-video offset).

  


  Whereat the configuration of rtmp ://localhost/live is :

  


  application live {
      live on;
      sync 10ms;
      record off;
      allow publish 127.0.0.1;
      deny publish all;
      }


  


  What causes the delay and how to get rid of it ?

  


  The RTMP-server itself does not cause a noticeable delay, I hence
assume this to be a timestamp issue but my wisdom ends with the above
written options.

  


• Streaming live video from ios [closed]

  15 février 2018, par John

  I have a need to stream video from the iPhone/iPad camera to a server. It looks like this will need to be done with AVCaptureSession but I don’t know how to best architect this.

  I found this post :

  streaming video FROM an iPhone

  But it doesn’t handle the "live" part, latency needs to be 2 or 3 seconds at most. Devices can be constrained to 4 or 4S capability if needed, and there is no requirement for HD, VGA is probably what we’ll end up with. I assume any solution would use ffmpeg, I haven’t found any more appropriate library.

  How is this best accomplished ?

• Stream to Facebook Live using OpenCV

  23 mai 2022, par Lanzy Erin

  I am planning to stream a video file to Facebook Live but I want to programmatically edit its frames like adding texts depending. My problem is that I don't know how to properly send data to Facebook Live. I tried ffmpeg but it doesn't work.

  


  Here is my code that I tried

  


  import subprocess
import cv2

rtmp_url = "rtmps://live-api-s.facebook.com:443/rtmp/FB-1081417119476224-0-AbwwMK91tFTjFy2j"

path = "7.mp4"
cap = cv2.VideoCapture(path)

# gather video info to ffmpeg
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))

# command and params for ffmpeg
command = ['ffmpeg',
           '-y',
           '-f', 'rawvideo',
           '-vcodec', 'rawvideo',
           '-pix_fmt', 'bgr24',
           '-s', f"{width}x{height}",
           '-r', str(fps),
           '-i', '-',
           '-c:v', 'libx264',
           '-pix_fmt', 'yuv420p',
           '-preset', 'ultrafast',
           '-f', 'flv',
           rtmp_url]

# using subprocess and pipe to fetch frame data
p = subprocess.Popen(command, stdin=subprocess.PIPE)

while cap.isOpened():
    ret, frame = cap.read()
    if not ret:
        print("frame read failed")
        break

    # YOUR CODE FOR PROCESSING FRAME HERE

    # write to pipe
    p.stdin.write(frame.tobytes())