The document outlines a new live ingest protocol for streaming media, particularly focusing on the Compatibility of CMAF and DASH profiles. It highlights the need for a standardized interface to address deficiencies of existing protocols like RTMP, detailing two defined interfaces for live media ingest: one for CMAF and another for DASH/HLS. It emphasizes optimizing for low latency, fault tolerance, and ad insertion while aiming to encourage industry convergence and broader adoption of these standards.

1. Live Ingest Protocol
Summary of the CMAF and DASH profile of the live ingest protocol (DASH-
IF)
Rufael Mekuria (PhD), Senior R&D Engineer, Unified Streaming
Demuxed The Conference for Video Engineers
October 2019
San Francisco California

2. Streaming at Scale: some moving parts
- A. Contribution/broadcast encoders
- B. Live ABR encoders
- C. Just in Time Packagers/origin servers/content stitching
- D. Content delivery networks
- E. Ad insertion (optional)
- F. Players
Standardization is more than just a player format

3. Live OTT at Scale Beyond the ABR encoder
Media
Source
(Live) ABR
encoder
Packager/
Origin Server
Server
Stitching
CDN
Ad
insertion
Player
Live ABR ingestSource ingest
CDN Ingest/
Streaming protocol DASH/HLS
I1 I2
Goal: bring industry together and define interface for point I1 and optionally I2!
https://dashif-documents.azurewebsites.net/Ingest/master/DASH-IF-Ingest.html
A B C
D
E
F

4. Why a new protocol for live ingest ?
- RTMP/Smooth becoming deprecated (no HEVC, VVC, HDR, CMAF, MPEG-
H)
- Fmp4/CMAF becoming the dominant media segment format for OTT
-> CMAF ingest makes sense
- Push Based DASH and HLS are common but under specified -> spec
needed
- Timed metadata & content splice information -> enable JITP & ad Insertion
- Fault tolerance, low latency and redundancy for large scale streaming
- Industry Convergence, document current best practices

5. Pull versus Push in streaming
(Live) ABR
encoder
Origin
Serverhttp post a.mpd
http post rep1/rep1.init
http post rep1/seg1.mp4
GET rep1/rep1.init
DASH Ingest
Pull Based
DASH
Client
GET a.mpd
(Live) ABR
encoder
Smart
Server
http post moov
http post moof + mdat
http post moof
.....
Fmp4 Ingest DASH
Client
Just in Time
Packager
GET rep1/seg1.mp4
GET rep1/rep1.init
GET a.mpd
GET rep1/seg1.mp4
Common
but
Underspecified
Common
but
needs
Update
to
CMAF
Push Based

6. DASH-IF Live Media Ingest Spec.
Supporting companies (initial):

7. Project timeline
Interop AWS,
BBC, Unified,
Harmonic,
MediaExcel
Informal IETF
draft
DASH-IF TF
created
Document for
Community Review
Aug 2019
Target
publication
July 2019Okt. 2018May 2018
Okt
2017

8. Two interfaces defined for live media ingest
1. Interface 1: CMAF Ingest -> for push no manifest is needed and it is
created later
2. Interface 2: DASH/HLS Ingest -> manifest is also pushed, care needs to be
taken
Live ABR
Encoder
Origin
Packager
Stitching
CDN
CMAF ingest (I1) DASH/HLS ingest (I2)
All are HTTP POST (or HTTP PUT) based

9. CMAF Ingest simplified (I1)
Origin
Packager
ABR
Encoder
HTTP POST Video1.cmfv
HTTP POST Video2.cmfv
HTTP POST audio1.cmfa
HTTP POST subt1.cmft
HTTP POST meta.cmfm
DASH/HLS/Smooth
Long running POST (1 POST command per track)
or short running POST (1 HTTP Post per fragment)
Fragment boundary trigggers receiver, not POST command, at least one CMAF fragment
http://pub_point/channel1

10. CMAF Ingest: basics (I1)
- CMAF tracks: video, audio, timed text, subtitle, timed metadata
- One TCP connection per track, short running fixed length post or
chunked transfer encoding
- Continuity + increasing fragment timestamp and or sequence number
- Fmp4/CMAF fragment boundaries for retransmission and identification
- New optional boxes introduced in CMAF and DASH
- Support for Low Latency and Ad insertion based workflows

11. On sending CMAF Boxes
styp prft emsgftyp moof mdatmoov
tfdt
tfhd
Continuously increasing
sequence number and
BaseMediaDecodeTime
optional boxes
Defined in CMAF/DASH
moof mdat
CMAF header CMAF fragment CMAF fragment with optional boxes
CMAF Track

12. CMAF Ingest security and network
- HTTPS, TLS client certificates, Basic authentication, Digest Auth
- Harmonized error response codes over HTTP with the other ingest interface for
DASH/HLS
- Typically the source resends the CMAF header and last fragment in case of failure
- The protocol is kept simple as a design requirement, however many aspects that
SHOULD be supported are included

13. CMAF Ingest: Switching Set
constraints/signaling (I1)
Implicit (mandatory)
- CMAF Switching set constraints (implicit and mandatory)
- Defined by CMAF specification, identical boxes + content can be
used to identify tracks in switching sets
Explicit (recommended/optional)
Encoder generates switching ids for each unique switching set
- Embed switching set id in post_uri by Switching(sw_id) keyword
- Embed switching set id in kind box in udta
- schemeIdUir urn:dashif:ingest:switchingset_id value = sw_id

14. Redundancy and hot failover (I1)
Live Source 1 Live Source 2
Origin 1 Origin 2
CMAF ingestCMAF ingest
SDISDI
Clock
Sync.
Live Source 3#
new
1. Redundant ingest/cross post
2. Procedures for
starting new instance
DASH/HLS/SMOOTH DASH/HLS/SMOOTH
Contribution source

15. Timed Metadata CMAF Track (I1)
- To enable fast processing fragmented timed metadata track is defined
- ISOBMFF Samples carrying DashEventMessageBox
- Avoid timeline problem with top level DashEventMessageBoxes
- ISOBMFF metatrack + emerging mpeg specification
- Separate track with SCTE-35/id3 and other timed metadata information,
- schemeIdUri urn:scte:scte35:2013:bin (see SCTE-214)
- Id3 in DashEventMessageBox as defined in aom by Microsoft and Apple
- https://aomediacodec.github.io/av1-id3/
- Splice conditions set IDR frame at corresponding time point
- Metadata track is technology an emerging MPEG specification

16. Timed Metadata CMAF Track (I1)

17. Splice conditioning
- SCTE-35 urn:scte:scte35:2013:bin embedded in event message
track,
- Presentation time corresponds to SCTE-35 splice point
- CMAF content conditioning for splice point: insert IDR frame or fragment
boundary (splice conditioned encoding or packaging)

18. DASH/HLS Ingest (I2)
Origin/
CDN
ABR
Encoder
HTTP POST p.mpd
Clients
HTTP 200 OK
HTTP POST p/rep1v/v.init
HTTP 200 OK
HTTP POST p/rep1v/seg1.mp4v
HTTP POST p/rep1v/seg2.mp4v
HTTP POST p/rep1a/a1.init
HTTP POST p/rep1a/seg1.mp4a
Mime types/ media types in file names
HTTP POST p/rep1a/seg2.mp4a
HTTP POST p/rep1t/seg1.cmft
Segment
Numbering
and timestamp

19. DASH/HLS + CMAF Ingest (i1 + i2)=i3?
- Both interfaces combined in one (under consideration)
Origin/
CDN
ABR
Encoder
Clients
HTTP 200 OK
HTTP POST p/rep1v/v.init
HTTP 200 OK
HTTP POST p/rep1v/seg1.cmfv
HTTP POST p/rep1v/seg2.cmfv
HTTP POST p/rep1a/a1.init
HTTP POST p/rep1a/seg1.cmfa
HTTP POST p/rep1a/seg2.cmfa
HTTP POST p/rep1t/seg1.cmft
Drop relative paths
For repackaging
Fragments comply
With CMAF and i1
HTTP POST p.mpd
CMAF
DASH

20. Summary
- CMAF ingest -> CMAF + HTTP POST
- Fully aligned with CMAF specification
- No manifest is needed, feed to JITP
- Long or short running post (or in between)
- Optimized for JITP and direct archiving
- Distributed workflow (encoding, encryption + packaging)
- DASH/HLS ingest -> DASH/HLS + HTTP POST, posting both
- Possible to combine with CMAF ingest by using CMAF fragments
- Target standard CDN, but for low latency still additional features might
need to be added.
- Mighty live encoder that needs to know it all
- Receiver still needs some understanding to convert POST to GET and
understand for example chunked CMAF pass through

21. Reference Software + demo
- Live ingest of CMAF files using CMAF ingest profile
- https://github.com/unifiedstreaming/fmp4-ingest/tree/master/ingest-tools
- fmp4Ingest (ingest cmaf files using CMAF ingest)
- Tools for converting timed metadatatrack (still in progress)
- Demo with Unified origin and docker compose:
- https://github.com/unifiedstreaming/cmaf-ingest-demo

22. Next Steps
- Publish Document the final specification
- Encourage more deployment in live encoders and work with them on this
- Follow & promote the CMAF event message track in MPEG
- Formally standardize the specification of live media ingest
- Promote usage in other sectors: security camera, mobile device 5G
uplink etc…
- https://github.com/Dash-Industry-Forum/Ingest

23. Thank you for your attention!
- Questions ?
- Contact: Rufael@unified-streaming.com