ERROR while decoding TS: 21 since v.2.2.09

[richard-vd]

When running examples/multicast/ts_scte_parser.py I only see ERROR while decoding TS: 21 for each SCTE-35 packet, using v.2.2.25 on Python 3.6. The latest working release is v.2.2.01, v.2.2.09 is the first release with this error.

[futzu]

I think I see the issue. I'll let you know shortly.

[futzu]

This is the previous multicast example from 2.2.01

it calls Stream.decode(func = foundit)
instead of Stream.decode_next()

2.2.01

Does this work correctly for you?

[futzu]

I had another guy have a similar issue today, I just pushed a new pip build, 2.2.29,
he's testing it now.

[richard-vd]

No difference with either 2.2.29 or 2.2.31 with the latest or old (2.2.01) multicast example, the same error appears in all cases. What can I do to help find what's happening?

[futzu]

Richard,
Do you have a lot of programs in the stream?
Can you run ffprobe for me and post the output?
With that info, I should be able to offer a solution.
Don't worry man, this won't take long.

[futzu]

Don't use 239.0.0.1, try 239.255.0.1

[futzu]

What is serving the multicast stream and what OS are you using?

[futzu]

I tested the script below with 2.2.33 tonight.
I've run it dozens of times without any issues.

I subclassed Stream so that the video pts is
displayed in the terminal so you can see progress..

import io
import socket
import struct
import threefive


def foundit(cue):
    print("""\n\t\tthis function was passed into Stream.decode
            it gets called with the cue instance as an arg
            for custom handling when a SCTE-35 packet is found\n""")
            
    print(f'\nCue methods can be called\n\tcue.get_command() returns:\n\t\t\t {cue.get_command()}')
    print(f'\nCue vars can be read.\n\t cue.command.name\n\t\t\t {cue.command.name}')

class StreamFu(threefive.Stream):
    '''
    StreamFu is a subclass of threefive.Stream.
    the _parse_pts method is modified so
    that the video PTS is displayed at the
    bottom of the screen to show progress
    '''
    def _parse_pts(self, pkt, pid):
        """
        parse pts with output
        """
        pts = ((pkt[13] >> 1) & 7) << 30
        pts |= ((pkt[14] << 7) | (pkt[15] >> 1)) << 15
        pts |= (pkt[16] << 7) | (pkt[17] >> 1)
        pts /= 90000.0
        ppp = self._pid_prog[pid]
        self._prog_pts[ppp] = pts
        print(f'PTS: \033[92m{round(pts,3)}\033[0m',end='\r\r\r')
    
class MCastParser():
    def __init__(self, mcast_ip, if_ip="0.0.0.0", hostname="0.0.0.0", port=9000):
        self.HOST = hostname
        self.PORT = port
        self.MCAST_IP = mcast_ip
        self.IF_IP = if_ip

    def do(self):
        with socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP) as sock:
            self.set_socket_options(sock)
            sock.bind((self.HOST, self.PORT))
            with sock.makefile(mode="rb") as socket_file:
                ts = StreamFu(socket_file)
                ts.decode() # without a function being passed in.

                # other method call examples

                # ts.decode(func=foundit)   # with a function passed in.
                
                # ts.show()   # will display stream types by program.

    def set_socket_options(self, sock):
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, socket.inet_aton(self.MCAST_IP)+socket.inet_aton(self.HOST))


if __name__ == "__main__":
    MCastParser(mcast_ip="239.255.0.1").do()

[futzu]

Richard,
you have figured out more than you realize.
I like your fix, but shouldn't it be
The issue you're describing shouldn't be able to happen,
but obviously is happening.
No I see what I broke.
in Stream._parser, I added returns after each if conditional,
that prevented the packets from also being checked for pts.
I added the returns in 2.2.1.
Nice work man.

If want to commit directly to this repo,
I'll add you.

[futzu]

I am adding you to the repo, I want you on the team.

All I ask is that you commit early and often,
and use black to format code.

[richard-vd]

Thanks for adding me!

In case of video and SCTE-35 in the same PID there will always be PTS. However in many cases the SCTE-35 data is on a separate PID without PTS and that's also normal. We could perhaps also try to read the PCR timestamps.