WebGear_RTC: Once the camera stream on the browser is closed, it cannot be reloaded again on a new tab until the app is closed and restarted.

[megha-seventhsense]

Description

WebGear_RTC: Once the camera stream on the browser is closed, it cannot be reloaded again on a new tab until the app is closed and restarted.

Acknowledgment

• I have searched the issues for my issue and found nothing related or helpful.
• I have read the Documentation.
• I have read the Issue Guidelines.

Environment

• VidGear version: 0.2.2
• Branch: v0.2.2
• Python version: Python 3.7.9
• PiP version: 21.3
• Operating System and version: Ubuntu 18.04.3 LTS

Expected Behavior

Once the browser tab with camera stream is closed, it should be possible to reopen it in a new browser/tab successfully without the need to close and restart the application.

Actual Behavior

Once we close the first browser tab with camera stream and we try to reopen it again in a new tab, camera stream cannot be loaded at all.

Steps to reproduce

Tested with the below sample code from
https://abhitronix.github.io/vidgear/latest/gears/webgear_rtc/advanced/

1. Run the following sample code to view the camera stream on a browser-

#import necessary libs
import uvicorn, asyncio, cv2
from av import VideoFrame
from aiortc import VideoStreamTrack
from aiortc.mediastreams import MediaStreamError
from vidgear.gears.asyncio import WebGear_RTC
from vidgear.gears.asyncio.helper import reducer

#initialize WebGear_RTC app without any source
web = WebGear_RTC(logging=True)

#create your own Bare-Minimum Custom Media Server
class Custom_RTCServer(VideoStreamTrack):
    """
    Custom Media Server using OpenCV, an inherit-class
    to aiortc's VideoStreamTrack.
    """

    def __init__(self, source=None):

        # don't forget this line!
        super().__init__()

        # initialize global params
        self.stream = cv2.VideoCapture(source)

    async def recv(self):
        """
        A coroutine function that yields `av.frame.Frame`.
        """
        # don't forget this function!!!

        # get next timestamp
        pts, time_base = await self.next_timestamp()

        # read video frame
        (grabbed, frame) = self.stream.read()

        # if NoneType
        if not grabbed:
            return MediaStreamError

        # reducer frames size if you want more performance otherwise comment this line
        frame = await reducer(frame, percentage=30)  # reduce frame by 30%

        # contruct `av.frame.Frame` from `numpy.nd.array`
        av_frame = VideoFrame.from_ndarray(frame, format="bgr24")
        av_frame.pts = pts
        av_frame.time_base = time_base

        # return `av.frame.Frame`
        return av_frame

    def terminate(self):
        """
        Gracefully terminates VideoGear stream
        """
        # don't forget this function!!!

        # terminate
        if not (self.stream is None):
            self.stream.release()
            self.stream = None


#assign your custom media server to config with adequate source (for e.g. foo.mp4)
web.config["server"] = Custom_RTCServer(source=0)

#run this app on Uvicorn server at address http://localhost:8000/
uvicorn.run(web(), host="localhost", port=8000)

#close app safely
web.shutdown()

2. Open a browser (tested with Chrome and Firefox) and navigate to http://localhost:8000/. It should show the camera stream on the browser successfully.
3. Now close the above browser tab and open a new tab. Try to navigate to the URL http://localhost:8000/ again. Camera stream cannot be loaded at all.

Optional

[welcome]

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[abhiTronix]

@megha-seventhsense This issue is being worked on and will be resolved soon. Please stay tuned.

[abhiTronix]

Successfully resolved and merged in commit: cd481c1

[abhiTronix]

Docs for defining custom streaming class can be found here: https://abhitronix.github.io/vidgear/v0.2.4-dev/gears/webgear_rtc/advanced/#using-webgear_rtc-with-a-custom-sourceopencv