How to create SCTE messages?

[ashiskumarsahu]

I am new to SCTE and need help on creating SCTE messages like below. I need to understand what does these string means and how I can create and use with this package.

• /DAxAAAAAAAAAP/wFAUAAABdf+/+zHRtOn4Ae6DOAAAAAAAMAQpDVUVJsZ8xMjEqLYemJQ==
• /DC+AAAAAAAAAP/wBQb+W+M4YgCoAiBDVUVJCW3YD3+fARFEcmF3aW5nRlJJMTE1V0FCQzUBAQIZQ1VFSQlONI9/nwEKVEtSUjE2MDY3QREBAQIxQ1VFSQlw1HB/nwEiUENSMV8xMjEwMjExNDU2V0FCQ0dFTkVSQUxIT1NQSVRBTBABAQI2Q1VFSQlw1HF/3wAAFJlwASJQQ1IxXzEyMTAyMTE0NTZXQUJDR0VORVJBTEhPU1BJVEFMIAEBhgjtJQ==

Note: I have copied these messages from your examples.

I am able to insert them my livestream output using this package piping with ffmpeg.

Any help is highly appriciated.

Thank You

[futzu]

You would think it would be straight forward, but like many things in computing,
making SCTE-35 Cues is ten times harder than it needs to be, and makes very little sense.

Complex cue messages

https://github.com/futzu/scte35-threefive/blob/master/Encoding.md

Simple Splice Insert

threefive.encode has some new encoding functions that I haven't announced yet,
but I use them a lot in my work.

a@debian:~/build/clean/scte35-threefive$ pypy3
Python 3.8.13 (7.3.9+dfsg-5, Oct 30 2022, 09:55:31)
[PyPy 7.3.9 with GCC 12.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>> from threefive import encode
>>>> help(encode)

Help on module threefive.encode in threefive:

NAME
    threefive.encode - encode.py

DESCRIPTION
    threefive.encode has helper functions for Cue encoding.

FUNCTIONS
    mk_splice_insert(event_id, pts, duration=None)
        mk_cue returns a Cue
        with a Splice Insert.
        
        splice_event_id = event_id
        
        If duration is NOT set,
            out_of_network_indicator   False
            time_specified_flag        False
            duration_flag              False
            splice_immediate_flag      True
        
        if duration IS set:
            out_of_network_indicator   True
            time_specified_flag        True
            duration_flag              True
            splice_immediate_flag      False
            break_auto_return          True
            break_duration             duration
            pts_time                   pts
 
    mk_splice_null()
        mk_splice_null returns a Cue
        with a Splice Null
    
    mk_time_signal(pts=None)
         mk_time_signal returns a Cue
         with a Time Signal
        
         if pts is NOT set:
             time_specified_flag   False
        
        if pts IS set:
             time_specified_flag   True
             pts_time              pts

FILE
    /home/a/build/clean/scte35-threefive/threefive/encode.py

   

Let's try one real quick.

a@debian:~/cuei$ pypy3
Python 3.8.13 (7.3.9+dfsg-5, Oct 30 2022, 09:55:31)
[PyPy 7.3.9 with GCC 12.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.

>>>> from threefive.encode import mk_splice_insert

>>>> evnt_id= 9

>>>> pts = 29053.123456

>>>> duration = 300

>>>> cue =mk_splice_insert(evnt_id,pts,duration)

mk_splice_insert returns an instance of threefive.Cue
which has the following methods

 |  
 |  encode(self)
 |      Cue.encode() converts SCTE35 data
 |      to a base64 encoded string.
 |  
 |  encode_as_hex(self)
 |      encode_as_hex returns self.bites as
 |      a hex string
 |  
 |  encode_as_int(self)
 |      encode_as_int returns self.bites as an int.
 |  

Use threefive.Cue's encoding methods to generate the cue messages

>>>> cue.encode()

'/DAlAAAAAAAAAP/wFAUAAAAJf+/+m9pkt/4Bm/zAAAkAAAAA5ftzmA=='

>>>> cue.encode_as_hex()

'0xfc302500000000000000fff01405000000097feffe9bda64b7fe019bfcc0000900000000e5fb7398'

>>>> cue.encode_as_int()
2104181392760166021170929920497819646350710275162000838308971042240028739408705486837725464851352

[ashiskumarsahu]

Hi @futzu ,
Thanks for sharing this. It helped me a lot.