threefive is better than you.

June 18, 2026 · View on GitHub

Latest version is v3.0.93 Released 06/11/2026
Decodes SCTE-35 from MPEGTS✔ Base64✔ Bytes✔ DASH✔ Hex ✔ HLS✔ Integers✔ JSON✔ XML✔ XML+Binary✔
Encodes SCTE-35 to MPEGTS✔ Base64✔ Bytes✔ Hex✔ Integers✔ JSON✔ XML✔ XML+Binary✔

A Lot of Examples | Tip of the Week | Cheap Tricks

[ Issues ]

I maintain threefive by myself, so mistakes are possible.
I know a lot of folks on github will punish you for opening an issue, but if you're cool, I'll be cool.
I won't answer general SCTE-35 questions, but I will answer threefive questions and if you find a bug I'll fix it.

[ Documentation ]

Need to inject SCTE-35 into HLS? X9k3.

web based SCTE-35 tools - threefive and friends over http.
install
quick start
SCTE-35 on the command line
- the threefive cli tool _If you work with SCTE-35, this is as cool as it gets.
other included tools
- scte35bump adjust SCTE-35 PTS in MPEGTS streams
- scte35fix ffmpeg changes scte-35 streams into bin data, scte35fix changes them back.
- scte35inject scte35inject inject scte-35 into mpegts.
- gums gums is a multicast sender(server) for video
the threefive library cool code for the cool kids.
- Using the threefive.Cue class
- Using the threefive library decode SCTE-35 with less than ten lines of code
- - threefive Classes threefive is OO, made to subclass
    - Cue Class this class you'll use often
    - Stream Class this is the class for parsing MPEGTS
SCTE-35 Sidecar Files threefive supports SCTE-35 sidecar files
SCTE-35 HLS parse SCTE-35 in HLS_
SCTE-35 XML and More XML threefive can parse and encode SCTE-35 xml
Encode SCTE-35 threefive can encode SCTE-35 in every SCTE-35 format
Make your threefive script an executable with cython threefive is compatible with all python tools

[Install]

threefive is curretnly tested on python-3.11, python-3.14, python-3.14t, pypy-7.3.11 and pypy-7.3.22
threefive is some of the fastest code you'll see on python3.
python3 via pip

python3 -mpip install threefive

threefive runs five times faster on pypy3,
threefive on pypy3 can parse mpegts at over 1.5 GigaBytes a second, single-threaded.
pypy3 via pip

pypy3 -mpip install threefive

To add SRT support

python3 -m pip install srtfu

To add Automatic AES decryption

python3 -mpip install pyaes

From the git repo

git clone https://github.com/superkabuki/scte35.git
cd threefive
make install

I've jazzed up the makefile to make it easier to install for different python versions and pypy3

git clone https://github.com/superkabuki/scte35.git
cd threefive

make install py3=pypy3

# OR

make install py3=python3.14

# works for any python in your path or use a full path if needed.

⇧

[ CLI ]

The threefive cli tool parses these SCTE-35 formats.
- Base64
- Hex
- HLS
- Integers
- JSON
- MPEGTS
- XML
- XMLBinary.
Formats are auto-detected.

Parse SCTE-35 Cues
- SCTE-35 Inputs: base64, hex, int, JSON,int,xml,and xmlbin.
- SCTE-35 Outputs: base64, bytes, hex, int,JSON, xml, and xmlbin.
- Any Input can be used with Any Output
- The default output is JSON

Here are several examples.

SCTE-35 Input	SCTE-35 Output	Command
base64	JSON	threefive '/DAWAAAAAAAAAP/wBQb+AKmKxwAACzuu2Q=='
.	bytes	threefive '/DAWAAAAAAAAAP/wBQb+AKmKxwAACzuu2Q==' bytes
.	hex	threefive '/DAWAAAAAAAAAP/wBQb+AKmKxwAACzuu2Q==' hex
.	xml	threefive '/DAWAAAAAAAAAP/wBQb+AKmKxwAACzuu2Q==' xml
hex	JSON	threefive 0xfc301600000000000000fff00506fe00a98ac700000b3baed9
.	base64	threefive 0xfc301600000000000000fff00506fe00a98ac700000b3baed9 base64
.	int	threefive 0xfc301600000000000000fff00506fe00a98ac700000b3baed9 int
.	xmlbin	threefive 0xfc301600000000000000fff00506fe00a98ac700000b3baed9 xmlbin
int	JSON	threefive 1583008701074197245727019716796221242036302348025116111908569
.	hex	threefive 1583008701074197245727019716796221242036302348025116111908569 hex
.	xml	threefive 1583008701074197245727019716796221242036302348025116111908569 xml
JSON	base64	threefive < json.json base64
.	bytes	threefive < json.json bytes
.	xml	threefive < json.json xml
xml	JSON	threefive < xml.xml
xmlbin	int	threefive < xmlbin.xml int

Parse SCTE-35 from HLS

threefive https://example.com/master.m3u8

Parse SCTE-35 from MPEGTS
- SCTE-35 can be parsed from MPEGTS over a variety of protocols.
- SCTE-35 Input: MPEGTS
- Protocols: pipes, files, stdin, http(s), multicast,SRT and UDP.
- SCTE-35 Output: JSON (default) base64, bytes, hex, int, xml, and xmlbin.

SCTE-35 Input	Protocol	SCTE-35 Output	Command
MPEGTS	file	JSON	threefive video.ts
.	https	base64	threefive https://example.com/video.ts base64
.	multicast	bytes	threefive udp://@235.3.5:3535 bytes
.	SRT	hex	threefive srt://1.2.3.4:4201 hex
.	UDP	int	threefive udp://10.10.10.10:1011 int
.	Pipe	xml	cat video.ts \| threefive xml
.	stdin	xml+bin	threefive xmlbin < video.ts

⇧

[Additional functionality]
- threefive has several additional features, mostly related to MPEGTS streams.
- threefive has built in help, just type threefive help
- This table shows how to use them.

Description	How To Use
Inject SCTE35 packets	threefive inject -i in.video -s sidecar.txt -o out.ts
Show raw SCTE35 packets	threefive packets udp://@235.35.3.5:3535
Copy MPEGTS stream to stdout at realtime speed	threefive rt input.ts
Create SCTE35 sidecar file	threefive sidecar video.ts
Show streams in mpegts stream	threefive show https://example.com/video.ts
Show iframes in mpegts stream	threefive iframes srt://10.10.1.3:9000
Show PTS values from mpegts stream	threefive pts udp://192.168.1.10:9000
Proxy the mpegts stream to stdout	threefive proxy https://wexample.com/video.ts

⇧

Other tools

threefive also comes with:

scte35bump

bump adjusts SCTE-35 PTS in an MPEGTS stream

$ scte35bump -h
usage: scte35bump [-h] [-i INFILE] [-o OUTFILE] [-s SECS]

options:
  -h, --help            show this help message and exit
  -i INFILE, --infile INFILE
                        Input source, stdin, file, http(s), udp, or multicast
                        mpegts [default: sys.stdin.buffer]
  -o OUTFILE, --outfile OUTFILE
                        Output file [default: sys.stdout.buffer]
  -s SECS, --secs SECS  Adjustment to apply to SCTE-35 Cues. [default: 0.0]

scte35bump is part of threefive.

⇧

gums

the Grande Udp Multicast Server

$ gums -h
usage: gums [-h] [-i INPUT] [-a ADDR] [-b BIND_ADDR] [-t TTL]

options:
  -h, --help            show this help message and exit
  -i INPUT, --input INPUT
                        like "/home/a/vid.ts" or "https://futzu.com/xaa.ts"
                        [default: sys.stdin.buffer]
  -a ADDR, --addr ADDR  Destination IP:Port [default: 235.35.3.5:3535]
  -b BIND_ADDR, --bind_addr BIND_ADDR
                        Local IP to bind [default: 0.0.0.0]
  -t TTL, --ttl TTL     Multicast TTL (1 - 255) [default: 32]

gums is part of threefive.

⇧

HLS

parse HLS for SCTE-35. Supports all HLS SCTE-35 tags.

$ threefive hls help


[ Input ]

A m3u8 URI as input.

[what is supported]

    M3U8 formats: master, rendition
    Segment types: AAC, AC3, MPEGTS
    Video codecs: mpeg2, h.264, h.265
	Audio codecs: mpeg2, aac, ac3, mp3
    Protocols: File, Http(s), Multicast, SRT, Stdin, UDP
    Encryption: AES-128 (automatic)

[ SCTE-35 ]

  SCTE-35 Embedded Cues as well as all SCTE-35 HLS Tags can be parsed.

  [ Supported HLS Tags ]

	* #EXT-OATCLS-SCTE35
    * #EXT-X-CUE-OUT-CONT
    * #EXT-X-DATERANGE
    * #EXT-X-SCTE35
    * #EXT-X-CUE-IN
    * #EXT-X-CUE-OUT

[ SCTE-35 Parsing Profiles ]

    SCTE-35 parsing can be fine tuned by setting a parsing profile.

    running the command:  threefive hls profile

    will generate a default profile and write a file named hls.profile
    in the current working directory.

    a@fu:~$ cat hls.profile

    expand_cues = False
    parse_segments = False
    parse_manifests = True
    hls_tags = #EXT-OATCLS-SCTE35,#EXT-X-CUE-OUT-CONT,
    #EXT-X-DATERANGE,#EXT-X-SCTE35,#EXT-X-CUE-IN,#EXT-X-CUE-OUT
    command_types = 0x6,0x5
    descriptor_tags = 0x2
    starts = 0x22,0x30,0x32,0x34,0x36,0x44,0x46

    ( Integers are show in hex (base 16),
      base 10 unsigned integers can also be used in .35rc )

    * expand_cues:       set to True to show cues fully expanded as JSON
    * parse_segments:    set to true to enable parsing SCTE-35 from MPEGTS.
    * parse_manifests:   set to true to parse the m3u8 file for SCTE-35 HLS Tags.
    * hls_tags:          set which SCTE-35 HLS Tags to parse.
    * command_types:     set which Splice Commands to parse.
    * descriptor_tags:   set which Splice Descriptor Tags to parse.
    * starts:            set which Segmentation Type IDs to use to start breaks.

    Edit the file as needed and then run threefive hls.

[ Profile Formatting Rules ]

    * Values do not need to be quoted.
    * Multiple values are separated by a commas.
    * No partial line comments. Comments must be on a separate lines.
    * Comments can be started with a # or //
    * Integers can be base 10 or base 16

[ Output Files ]
	scte35 hls creates a few output files.

	* Profile rules applied to the output:

		* hls.m3u8  - live playable rewrite of the m3u8 with the profile SCTE-35 rules.
        * hls.sidecar - list of ( pts, HLS SCTE-35 tag ) pairs

	* Profile rules not applied to the output:

		* hlsflat.m3u8  - hls live streams are flattened out into a vod playlist.
                     When the live m3u8  first loads, every line is written to hlsflat.m3u8
                     Wnen a live m3u8 is reloaded, everything except the headers
                    is appended to hlsflat.m3u8. This give you a VOD style m3u8
                    so you can fast forward or rewind while playing.
                    GREAT for debugging SCTE-35 live hls.

[ Cool Features ]

    * threefive hls can resume when started in the middle of an ad break.

            2023-10-13T05:59:50.24Z Resuming Ad Break
            2023-10-13T05:59:50.34Z Setting Break Timer to 17.733
            2023-10-13T05:59:50.44Z Setting Break Duration to 60.067

[ Example Usage ]

	* Show this help:   scte35hls help

	* Generate a new hls.profile:   scte35hls profile

	* parse an m3u8:    scte35hls  https://example.com/out/master.m3u8

⇧

scte35fix

when ffmpeg changes a SCTE-35 stream to bin data stream, scte35fix changes it back.

$ scte35fix -h

  scte35fix checks MPEGTS for SCTE-35 Streams
  that have been change to bin data (type 0x06)
  and changes them back to SCTE-35 (type 0x86) streams.
  Output files are created in the current directory
  and prefixed with 'sixfix-'.
  Only bin data streams containing SCTE-35 will be converted.
  Multiple files can be specified on the command line.
  Wild cards work too.

  Example Usage:
        scte35fix video.ts
        scte35fix video1.ts video2.ts
        scte35fix video*.ts
        scte35fix https://example.com/video.ts
        scte35fix srt://10.10.10.13:4201
scte35fix is part of threefive.

⇧

[ Using the library ]

Let me show you how easy threefive is to use.
reading SCTE-35 xml from a file

a@fu:~/threefive$ pypy3
Python 3.9.16 (7.3.11+dfsg-2+deb12u3, Dec 30 2024, 22:36:23)
[PyPy 7.3.11 with GCC 12.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>> from threefive import reader
>>>> from threefive import Cue
>>>> data =reader('/home/a/xml.xml').read()

load it into a threefive.Cue instance

>>>> cue = Cue(data)

Show the data as JSON

>>>> cue.show()
{
    "info_section": {
        "table_id": "0xfc",
        "section_syntax_indicator": false,
        "private": false,
        "sap_type": "0x03",
        "sap_details": "No Sap Type",
        "section_length": 92,
        "protocol_version": 0,
        "encrypted_packet": false,
        "encryption_algorithm": 0,
        "pts_adjustment": 0.0,
        "cw_index": "0x00",
        "tier": "0x0fff",
        "splice_command_length": 15,
        "splice_command_type": 5,
        "descriptor_loop_length": 60,
        "crc": "0x7632935"
    },
    "command": {
        "command_length": 15,
        "command_type": 5,
        "name": "Splice Insert",
        "break_auto_return": false,
        "break_duration": 180.0,
        "splice_event_id": 1073743095,
        "splice_event_cancel_indicator": false,
        "out_of_network_indicator": true,
        "program_splice_flag": false,
        "duration_flag": true,
        "splice_immediate_flag": false,
        "event_id_compliance_flag": true,
        "unique_program_id": 1,
        "avail_num": 12,
        "avails_expected": 5
    },
    "descriptors": [
        {
            "tag": 0,
            "identifier": "CUEI",
            "name": "Avail Descriptor",
            "provider_avail_id": 12,
            "descriptor_length": 8
        },
        {
            "tag": 0,
            "identifier": "CUEI",
            "name": "Avail Descriptor",
            "provider_avail_id": 13,
            "descriptor_length": 8
        },
      

    ]
}

convert the data back to xml

>>>> print(cue.xml())
<scte35:SpliceInfoSection xmlns:scte35="https://scte.org/schemas/35"  ptsAdjustment="0" protocolVersion="0" sapType="3" tier="4095">
   <scte35:SpliceInsert spliceEventId="1073743095" spliceEventCancelIndicator="false" spliceImmediateFlag="false" eventIdComplianceFlag="true" availNum="12" availsExpected="5" outOfNetworkIndicator="true" uniqueProgramId="1">
      <scte35:BreakDuration autoReturn="false" duration="16200000"/>
   </scte35:SpliceInsert>
   <scte35:AvailDescriptor providerAvailId="12"/>
   <scte35:AvailDescriptor providerAvailId="13"/>
   <scte35:AvailDescriptor providerAvailId="14"/>
   <scte35:AvailDescriptor providerAvailId="15"/>
   <scte35:AvailDescriptor providerAvailId="16"/>
   <scte35:AvailDescriptor providerAvailId="17"/>
</scte35:SpliceInfoSection>

convert to xml+binary

>>>> print(cue.xmlbin())
<scte35:Signal xmlns:scte35="https://scte.org/schemas/35">
    <scte35:Binary>/DBcAAAAAAAAAP/wDwVAAAT3f69+APcxQAABDAUAPAAIQ1VFSQAAAAwACENVRUkAAAANAAhDVUVJAAAADgAIQ1VFSQAAAA8ACENVRUkAAAAQAAhDVUVJAAAAEQdjKTU=</scte35:Binary>
</scte35:Signal>

convert to base64

>>>> print(cue.base64())
/DBcAAAAAAAAAP/wDwVAAAT3f69+APcxQAABDAUAPAAIQ1VFSQAAAAwACENVRUkAAAANAAhDVUVJAAAADgAIQ1VFSQAAAA8ACENVRUkAAAAQAAhDVUVJAAAAEQdjKTU=

convert to hex

>>>> print(cue.hex())
0xfc305c00000000000000fff00f05400004f77faf7e00f7314000010c05003c0008435545490000000c0008435545490000000d0008435545490000000e0008435545490000000f000843554549000000100008435545490000001107632935

show just the splice command

>>>> cue.command.show()
{
    "command_length": 15,
    "command_type": 5,
    "name": "Splice Insert",
    "break_auto_return": false,
    "break_duration": 180.0,
    "splice_event_id": 1073743095,
    "splice_event_cancel_indicator": false,
    "out_of_network_indicator": true,
    "program_splice_flag": false,
    "duration_flag": true,
    "splice_immediate_flag": false,
    "event_id_compliance_flag": true,
    "unique_program_id": 1,
    "avail_num": 12,
    "avails_expected": 5
}

edit the break duration

>>>> cue.command.break_duration=30
>>>> cue.command.show()
{
    "command_length": 15,
    "command_type": 5,
    "name": "Splice Insert",
    "break_auto_return": false,
    "break_duration": 30,
    "splice_event_id": 1073743095,
    "splice_event_cancel_indicator": false,
    "out_of_network_indicator": true,
    "program_splice_flag": false,
    "duration_flag": true,
    "splice_immediate_flag": false,
    "event_id_compliance_flag": true,
    "unique_program_id": 1,
    "avail_num": 12,
    "avails_expected": 5
}

re-encode to base64 with the new duration

>>>> cue.base64()
'/DBcAAAAAAAAAP/wDwVAAAT3f69+ACky4AABDAUAPAAIQ1VFSQAAAAwACENVRUkAAAANAAhDVUVJAAAADgAIQ1VFSQAAAA8ACENVRUkAAAAQAAhDVUVJAAAAEe1FB6g='

re-encode to xml with the new duration

>>>> print(cue.xml())
<scte35:SpliceInfoSection xmlns:scte35="https://scte.org/schemas/35"  ptsAdjustment="0" protocolVersion="0" sapType="3" tier="4095">
   <scte35:SpliceInsert spliceEventId="1073743095" spliceEventCancelIndicator="false" spliceImmediateFlag="false" eventIdComplianceFlag="true" availNum="12" availsExpected="5" outOfNetworkIndicator="true" uniqueProgramId="1">
      <scte35:BreakDuration autoReturn="false" duration="2700000"/>
   </scte35:SpliceInsert>
   <scte35:AvailDescriptor providerAvailId="12"/>
   <scte35:AvailDescriptor providerAvailId="13"/>
   <scte35:AvailDescriptor providerAvailId="14"/>
   <scte35:AvailDescriptor providerAvailId="15"/>
   <scte35:AvailDescriptor providerAvailId="16"/>
   <scte35:AvailDescriptor providerAvailId="17"/>
</scte35:SpliceInfoSection>

show just the descriptors

>>>> _ = [d.show() for d in cue.descriptors]
{
    "tag": 0,
    "identifier": "CUEI",
    "name": "Avail Descriptor",
    "provider_avail_id": 12,
    "descriptor_length": 8
}
{
    "tag": 0,
    "identifier": "CUEI",
    "name": "Avail Descriptor",
    "provider_avail_id": 13,
    "descriptor_length": 8
}
{
    "tag": 0,
    "identifier": "CUEI",
    "name": "Avail Descriptor",
    "provider_avail_id": 14,
    "descriptor_length": 8
}
{
    "tag": 0,
    "identifier": "CUEI",
    "name": "Avail Descriptor",
    "provider_avail_id": 15,
    "descriptor_length": 8
}
{
    "tag": 0,
    "identifier": "CUEI",
    "name": "Avail Descriptor",
    "provider_avail_id": 16,
    "descriptor_length": 8
}
{
    "tag": 0,
    "identifier": "CUEI",
    "name": "Avail Descriptor",
    "provider_avail_id": 17,
    "descriptor_length": 8
}

pop off the last descriptor and re-encode to xml


>>>> cue.descriptors.pop()
{'tag': 0, 'identifier': 'CUEI', 'name': 'Avail Descriptor', 'private_data': None, 'provider_avail_id': 17, 'descriptor_length': 8}
>>>> print(cue.xml())
<scte35:SpliceInfoSection xmlns:scte35="https://scte.org/schemas/35"  ptsAdjustment="0" protocolVersion="0" sapType="3" tier="4095">
   <scte35:SpliceInsert spliceEventId="1073743095" spliceEventCancelIndicator="false" spliceImmediateFlag="false" eventIdComplianceFlag="true" availNum="12" availsExpected="5" outOfNetworkIndicator="true" uniqueProgramId="1">
      <scte35:BreakDuration autoReturn="false" duration="2700000"/>
   </scte35:SpliceInsert>
   <scte35:AvailDescriptor providerAvailId="12"/>
   <scte35:AvailDescriptor providerAvailId="13"/>
   <scte35:AvailDescriptor providerAvailId="14"/>
   <scte35:AvailDescriptor providerAvailId="15"/>
   <scte35:AvailDescriptor providerAvailId="16"/>
</scte35:SpliceInfoSection>

⇧

[web]

threefive SCTE-35 Online Parser hosted on my server iodisco.com
Parse SCTE-35 in MPEGTS over HTTP, in your browser with Go, Wasm and Super Karate Death Car hosted om my server bigcorp.ltd
Parse SCTE-35 in MPEGTS over HTTP, in your browser with threefive.js,javascript, and a little sed just to keep things interesting. hosted om my server bigcorp.ltd
SCTE-35 Online Parser powered by threefive another online parser powered by threefive not hosted on my servers.
SCTE-35 As a Service if you can make an http request, you can parse SCTE-35, no install needed. hosted on my server iodisco.com

⇧

[XML]

XML New! updated 05/01/2025

[HLS]

Advanced Parsing of SCTE-35 in HLS with threefive All HLS SCTE-35 tags, Sidecar Files, AAC ID3 Header Timestamps, SCTE-35 filters... Who loves you baby?

⇧

[Classes]

The python built in help is always the most up to date docs for the library.


a@fu:~/build7/threefive$ pypy3

>>>> from threefive import Stream
>>>> help(Stream)

Class Structure
Cue Class Cue is the main SCTE-35 class to use.
Stream Class The Stream class handles MPEGTS SCTE-35 streams local, Http(s), UDP, and Multicast.

⇧

[threefive now supports SRT]

( You have to unmute the audio )

https://github.com/user-attachments/assets/a323ea90-867f-480f-a55f-e9339263e511

more SRT and threefive info
checkout SRTfu

⇧

[more]

Encode SCTE-35 Some encoding code examples.

⇧