Sidecar Specification | Generate Sidecar Files

SCTE-35 Sidecar Files

SCTE-35 sidecar files are used to insert SCTE-35 in MPEGTS streams, DASH,or HLS.

SCTE-35 sidecar files are not part of the specification, but they fully and completely meet the specification. SCTE-35 sidecar files are just something I have used for years, and they work will really really well. threefive, sideways, x9k3, umzz, and m3ufu all support sidecar files. Right now they are partially documented across several repos, so I decided to put it all here in one place.

Why not SCTE-104?

Have you read the SCTE-104 specification?

I have. Shortly after reading the spec, I came up with SCTE-35 sidecar files.

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Specification

• Sidecar Files
• lines
• insert_pts
• cue
• Additional Details

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Sidecar files

a@fu:~/threefive$ cat ~/sidecar.txt

58000.0,/DAlAAAAAAAAAP/wFAUAAAABf+//NyLhAP4AUmXAAAEAAAAAWia/Iw==
58060.0,/DAgAAAAAAAAAP/wDwUAAAACf0//N3VGwAACAAAAAPWDDDY=
57900.0,/DAlAAAAAAAAAP/wFAUAAAABf+//NpmMwP4Bm/zAAAEAAAAAD7tCMw==

• Are text files.
• Can have comments prefixed by '#' and terminated by a new line '\n'
• Can be appended at any time.
• Are made of lines.

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Sidecar files are made of Lines.

    58100.0 , /DAlAAAAAAAAAP/wFAUAAAABf+//N6w1QP4Bm/zAAAEAAAAAASHDdA==

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Lines

• End with a new line '\n'
• Can have comments prefixed by '#' and terminated by a new line '\n'
• Can wrap if needed.
• Contain 1 insert_pts and 1 cue separated by a comma.

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Lines have an insert_pts and a cue.

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insert_pts

• Is pts in seconds.
• Has a range of 0 to 95443.717677.
  • Is the pts to insert the SCTE35 Cue.
• Is absolute, no adjustment is applied.
• If insert_pts is zero '0', the SCTE35 Cue is inserted at the next iFrame.

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cue

• is a SCTE35 cue.
• can be Base64, Hex or Integer.

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Details

1. Sidecar files are used for inserting SCTE35 into MPEGTS,DASH, or HLS.
2. Sidecar files can be appended to live.
3. Sidecar files should be checked for new information at every iFrame.
4. When lines are read from a sidecar file, the lines should be deleted from the sidecar file.
5. lines with an insert_pts older than the current pts of the video should be left in the sidecar file and ignored until they become relevant after a rollover.
6. Sidecar files do NOT have to be in chronological order.
7. The cue should be inserted at the insert_pts if an iframe is present.
8. If an iframe is NOT present at the insert_pts, then the cue should be inserted at the closest iframe to the insert_pts.
9. Setting insert_pts to 0 indicates a "splice immediate" and the cue should be inserted at the next iframe.
10. insert_pts should NOT contain a preroll.
11. __insert_pts = (Splice Comand pts_time + Splice Info Section pts_adjustment) % 95443.717677

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End of Specification

Generating sidecar files.

• You can write a sidecar file by hand or you can use one of these tools.

threefive

• If you want to extract the SCTE-35 from an existing MPEGTS stream into a sidecar file

threefive sidecar video.ts

• a sidecar file named 'sidecar.txt' will be created in the same directory.

a@fu:~/threefive$ cat sidecar.txt 
72820.9484,/DBDAAAAAyiYAP/wFAUAAAABf+//hqqjQv4ApMbEmZkBAQAeAhxDVUVJAAAAAH/AAACky4ABCDEwMTAwMDAwNAAAN7GZ7w==
72951.7791,/DAsAAAAAyiYAP/wCgUAAAABf1+ZmQEBABECD0NVRUkAAAAAf4ABADUAAC2XQZU=

• if your SCTE-35 is xml or json you can convert it and write it to a sidecar
  • in this example, 123.45678 is your insert_pts and json.json is a file containing your SCTE-35 cue in json.

printf "123.45678 %s \n" `threefive < ~/json.json base64 2>&1`  >> sidecar.txt

• the above will append this to the sidecar file.

123.45678 /DA5AAAAAyiYAP/wCgUAAAABfx+ZmQH/AB4CHENVRUkAAAAAf4AMDURPT01TdXBlckRvb201AACPN660 

• How do you that shell stuff on Windows?
  • I have no idea. If anyone wants to tell me, I will add it.

adbreak3

• adbreak3 is a command line tool for generating SCTE-35 for sidecar files

$ adbreak3 -h
usage: adbreak3 [-h] [-d DURATION] [-e EVENT_ID] [-i] [-o] [-p PTS] [-P]
                [-s SIDECAR] [-v]

options:
  -h, --help            show this help message and exit
  -d DURATION, --duration DURATION
                        Set duration of ad break. [ default: 60.0 ]
  -e EVENT_ID, --event-id EVENT_ID
                        Set event id for ad break. [ default: 1 ]
  -i, --cue-in-only     Only make a cue-in SCTE-35 cue [ default: False ]
  -o, --cue-out-only    Only make a cue-out SCTE-35 cue [ default: False ]
  -p PTS, --pts PTS     Set start pts for ad break. Not setting pts will
                        generate a Splice Immediate CUE-OUT. [ default: 0.0 ]
  -P, --preroll         Add SCTE data four seconds before splice point. Used
                        with MPEGTS. [ default: False ]
  -s SIDECAR, --sidecar SIDECAR
                        Sidecar file of SCTE-35 (pts,cue) pairs. [ default:
                        sidecar.txt ]
  -v, --version         Show version

• use adbreak3 like this

a@fu:~/Downloads$ adbreak3 --duration 60 --pts 1234.56789 --event-id 34

Writing to sidecar file: sidecar.txt

		CUE-OUT   PTS:1234.567889   Id:34   Duration: 60.0
		CUE-IN    PTS:1294.567889   Id:35

• by default adbreak3 writes to sidecar.txt.
• a different file can be specified with the -s switch.
• if the file already exists, adbreak3 will append to it.

a@fu:~/Downloads$ cat sidecar.txt
1234.56789,/DAlAAAAAAAAAP/wFAUAAAAif+/+Bp9rxv4AUmXAACIAAAAAjjSYpQ==
1294.56789,/DAgAAAAAAAAAP/wDwUAAAAjf0/+BvHRhgAjAAAAAE55tjQ=