livesim2 - the second generation DASH Live Source Simulator

July 23, 2026 · View on GitHub

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livesim2 - the second generation DASH Live Source Simulator

livesim2 is a new and improved version of the DASH-IF live source simulator.

Test it at https://livesim2.dashif.org or set up your own server using your own DASH content or test content available at livesim-content. See the wiki for more info.

As the original simulator (livesim1), the output is a wall-clock (UTC) synchronized infinite linear stream of segments. This achieved by looping input VoD DASH assets, and changing time stamps so that an infinite "live" stream is available. The synchronization is done modulo asset duration, for example: a 1-hour asset restarts every hour on full hours, and a 30s asset restarts every 30s on full and half minutes. If there is a clock display in the video, and the length is full minutes or similar, it is therefore easy to directly see how long the system delay is from publishing to screen presentation. The very short example assets bundled with the code are only 8s long, which means that they restart every time the UTC time is a multiple of 8s, relative to the Epoch start 1970-01-01:00:00:00Z.

To provide full UTC time stamps on-screen and the possibility to test subtitles, livesim2 has a new feature for generating subtitles for any number of languages. This is done by a URL parameter like /timesubsstpp_en,sv which will result in two stpp (segmented TTML) subtitle tracks with with language codes "en" and "sv", respectively. There is a corresponding setting for wvtt (segmented WebVTT) subtitles using /timesubswvtt_en,sv.

For in-band closed captions, /timecc608_CC1-eng injects a CTA-608 (CEA-608) caption into the AVC/HEVC video itself, showing a ticking UTC clock and the segment number on channel CC1, and advertises it with a CEA-608 Accessibility descriptor. The value is <channel>-<lang> (only CC1 is supported so far). It cannot be combined with encryption and is rejected for assets that already carry captions.

The new livesim2 software is written in Go instead of Python and designed to handle content in a more flexible and versatile way. It is intended to be very easy to install and deploy locally since it is compiled into a single binary that serves the content via a built-in performant HTTP/2 server. There is also a very simple way of setting up HTTPS using Let´s Encrypt.

Similarly to livesim1, the output is highly configurable by adding parameters inside the URLs. These parameters are included not only in the MPD requests, but in all segment requests allowing the server to be stateless, and be able to generate streams with a huge number of parameter variations. Currently, not all parameters of livesim1 are implemented, but there are also new parameters like the generated subtitles mentioned above.

The URL wiki page lists what is available and the served page /urlgen makes it easy to construct URLs to play the content with specific parameters set.

Beside livesim2 there is a tool called dashfetcher in this repo. That tool can be used to download the MPD and all segments of a DASH VoD asset.

livesim2 server

The server is configured in one or more ways in increasing priority:

  1. Default values
  2. In a config file
  3. Via command-line parameters
  4. With environment variables

Major values to configure are:

  • the top directory vodroot for searching for VoD assets to be used
  • the HTTPS domains if Let's Encrypt automatic certificates are used
    • certpath and keypath if HTTPS is used with manually downloaded certificates
    • the HTTP/HTTPS port if domains is not being used (default: 8888)

Once the server is started, it will scan the file tree starting from vodroot and gather metadata about all DASH VoD assets it finds. Currently, only source VoD assets using SegmentTimeline with $Time$ and SegmentTemplate with $Number$ are supported.

Command-line parameters

A complete list of parameters, and their access via the command line looks like:

  --certpath string      path to TLS certificate file (for HTTPS). Use domains instead if possible
  --cfg string           path to a JSON config file
  --domains string       One or more DNS domains (comma-separated) for auto certificate from Lets Encrypt
  --host string          full scheme://host used in MPD Location/BaseURL. If empty, auto-detected from the request (honors X-Forwarded-Proto)
  --keypath string       path to TLS private key file (for HTTPS). Use domains instead if possible.
  --livewindow int       default live window (seconds) (default 300)
  --logformat string     log format [text, json, pretty, discard] (default "text")
  --loglevel string      log level [DEBUG, INFO, WARN, ERROR] (default "INFO")
  --maxrequests int      max nr of request per IP address per 24 hours
  --playurl string       URL template to play mpd. %s will be replaced by MPD URL (default "https://reference.dashif.org/dash.js/nightly/samples/dash-if-reference-player/index.html?mpd=%s&autoLoad=true&muted=true")
  --port int             HTTP port (default 8888)
  --repdataroot string   Representation metadata root directory. "+" copies vodroot value. "-" disables usage. (default "+")
  --reqlimitint int      interval for request limit i seconds (only used if maxrequests > 0) (default 86400)
  --reqlimitlog string   path to request limit log file (only written if maxrequests > 0)
  --timeout int          timeout for all requests (seconds) (default 60)
  --vodroot string       VoD root directory (default "./vod")
  --writemissingrepdata  Write representation metadata only if missing (does not override existing)
  --writerepdata         (Re)generate and write representation metadata, overwriting any existing files

Quicker load by using metadata files

For assets with many segments, the scanning process can take a considerable time. The possibility to generate and read extra representation metadata files has therefore been added. For representation repX, the corresponding metadata file is repX_data.json.gz. As the file extensions indicates, these files are gzipped JSON files. To generate such files, turn on writerepdata (always (re)generates and overwrites the files) or writemissingrepdata (writes only the files that are missing, leaving existing ones untouched). The root directory for such files is by default the same as the VoD root directory, meaning that the metadata files will be in the same directories as the corresponding MPDs. However, it is possible to use another path, by specifying repdataroot.

Once the server has started, it is possible to find out information about the server and the assets using the root HTTP endpoint

  • /

that in turn points to:

  • /urlgen
  • /assets
  • /config
  • /healthz
  • /metrics

and links to the Wiki page for more information.

It is also possible to explore the file tree and play Vod assets by starting at

  • /vod/...

Finally, any VoD MPD like /vod/cfhd/stream.mpd is available as a live stream by replacing /vod/ with livesim2 e.g. /livesim2/cfhd/stream.mpd.

Backwards compatibility with livesim

For backwards compatibility with the first version of livesim where /livesim was used as a prefix for simulated live output, and /dash/vod was the path to the VoD assets, these two paths are redirected by the server with an HTTP 302 response as:

/livesim/* -> /livesim2/*
/dash/vod/* -> /vod/*

MPD Restrictions

The following restrictions apply to the VoD manifest to be used with livesim2

  • live-profile (separate segments)
  • one Period with all representations of "same" duration
  • no BaseURL elements
  • no Location elements
  • initialization and media attributes in SegmentTemplate on AdaptationSet level

Special Time Test Parameter nowMS

The query string parameter ?nowMS=... can be used in any request to set the wall-clock time that livesim2 uses as reference time. The time is measured with respect to the 1970 Epoch start, and makes it possible to test time-dependent requests in a deterministic way.

Get Started

Install Go 1.25 or later.

Then run

> go mod tidy

to fetch and install all dependencies.

To build dashfetcher and livesim2 you can use the Makefile like

> make build

to create binaries in the /out directory with embedded version numbers.

During development it may be easier to use the usual go commands:

> cd cmd/dashfetcher
> go build .
> cd ../../cmd/livesim2
> go build .

or compile and run directly with go run ..

HTTPS with automatic certificates

To enable HTTPS in an easy manner, make sure that you have DNS pointing to your machine, and that ports 80 and 443 are forwarded. Then use the parameter --domains=your.domain.com,second.domain.com to automatically fetch TLS certificates from Let's Encrypt for your domains to this machine. The certificates are automatically renewed before they expire.

HTTPS with manual certificates

The old-fashioned way of using manually acquired TLS certificates is also supported. Use the two parameters certpath and keypath to point to the respective files, and set the port to 443.`

Content

The content must be a DASH VoD asset in isoff-live format (individual segment files) with either SegmentTimeline with $Time$ or SegmentTemplate with $Number$. The video segments duration must have an exact average duration so that the total duration is the number of segments time that average. The total duration must be an integral number of milliseconds. For example, an asset with alternating segment duration sof 8s and 4s, is fine as long as there are an equal number of each leading so that the avererage duration is 6s. The segment duration is not allowed to vary more than 50% compared to that average duration in order for livesim2 to be able to generate MPDs with SegmentTemplate with $Number$.

The input audio segment do not need to follow the duration of the video segments, although it is beneficial if they are the same, as for example 1.92s segments for 50fps video and 48kHz AAC audio. If the audio segment duration is not identical to the corresponding video segment, the audio will be resegmented as to follow the video segments as far as possible. Every audio segment will start less than one audio frame after the video segment starts.

There are multiple ways to get content to the livesim2 server.

  1. Use the bundled test content (only 8s or 12s long)
  2. Fetch content that was used with livesim1 from github at livesim-content
  3. Use the dashfetcher tool to download a DASH asset
  4. Use an existing VoD asset in isoff-live profile

livesim2 will scan all the segments of all representations and store metadata about each segments timing in memory.

To avoid doing this at every startup, livesim2 supports storing and reading such representation data from a file. The generation of such data is controlled via the writerepdata, writemissingrepdata and repdataroot configuration parameters.

If such files are detected at startup, they will be used instead of scanning the files, unless the writerepdata parameter is set, which forces a re-scan and overwrites the files. Use writemissingrepdata instead to generate only the files that are missing without overwriting (and still use any existing files).

Bundled test streams with the livesim2 server

A few very short (8s) test assets are bundled with the code. These makes it possible to start the server and get live output by running

> cd cmd/livesim2
> ./livesim2 --vodroot=app/testdata/assets

The log will list the available assets and the port where the server runs.

They can then be streamed via URLs like:

http://localhost:8888/livesim2/WAVE/vectors/cfhd_sets/12.5_25_50/t3/2022-10-17/stream.mpd
http://localhost:8888/livesim2/testpic_2s/Manifest_thumbs.mpd
http://localhost:8888/livesim2/testpic_8s/Manifest.mpd

The default pattern provides MPDs with SegmentTemplate using $Number$. To stream with SegmentTimeline with $Time$, one should add the parameter /segtimeline_1 between livesim2 and the start of the asset path. For SegmentTimeline with $Number$, use /segtimelinenr_1 instead. Other parameters are added in a similar way.

Adding longer assets somewhere under the vodroot results in longer loops. All sources are NTP synchronized (using the host machine clock) with a initial start time given by availabilityStartTime and wrap every sequence duration after that.

Edit lists

CMAF allows two types of edit lists.

  1. Time-shift for audio priming in audio streams
  2. Time-shift for video to initial zero-valued presentation time

There are two test assets included for these cases

  1. WAVE/av/combined.mpod has shifted audio where the first two frames are used for priming. This is seen in the MPD which has a shorter initial segment. This is reflected in the livesim2 MPD where all segments are shifted by this amount
  2. bbb_hevc_ac3_8s/manifest.mpd has an edit list for video which shifts all composition time offsets so that the first presentation time is zero. This shift is kept in the MPD and in the sidx boxes of the output from livesim2

livesim-content at Github

In the repo livesim-content, the content that was used for the livesim1 online service is being gathered to make it easy to reproduce the same use cases.

All content and features are not yet (2023-08-08) in place, but should be so before end of October 2023.

To download and use that content, run

git clone https://github.com/Dash-Industry-Forum/livesim-content.git

and then set --vodroot to the livesim-content top directory or include that in a bigger file tree.

dashfetcher tool

The tool dashfetcher fetches DASH VoD assets via HTTP given an MPD URLs. Currently it supports MPDs with SegmentTimeline with $Time$ and SegmentTemplate with $Number$. The assets must have no explicit <BaseURL> elements to work properly. With the -a/--auto option, the path to the asset is preserved as much as possible and adapted to the local path.

Files already downloaded will not be downloaded again, unless -f/--force is used. As an example, to download a CTA-WAVE asset one can run

dashfetcher --auto https://dash.akamaized.net/WAVE/vectors/cfhd_sets/12.5_25_50/t3/2022-10-17/stream.mpd

which will result in a locally stored DASH VoD asset in the directory

./vod/WAVE/vectors/cfhd_sets/12.5_25_0t3/2022-10-17/

with an MPD called stream.mpd and the segments stored in subdirectories named after their relative URLs. The download URL is added to a file mpdlist.json which is read by livesim2, to provide information about the asset.

One can have multiple MPDs in the same asset directory and they may share some representations. That is an easy way to have variants with different representation combinations.

Running dashfetcher

dashfetcher was created to facilitate download of DASH assets with lots of small segment files. One particular such source was the CTA-WAVE test content. However, that content is now also available as zip-files, so it is more efficient to download an unzip these files instead of making individual downloads of the segments.

For example, the asset above is also available at https://dash.akamaized.net/WAVE/vectors/cfhd_sets/12.5_25_50/t3/2022-10-17/t3.zip.

The dashfetcher binary can be found as out/dashfetcher after make build.

> dashfetcher --help

will provide a long help text that explains how to use it and will also provide an example URL to CTA-WAVE content.

CMAF Ingest Support

livesim2 includes CMAF Ingest support (version 1.1), allowing it to act as a CMAF ingest source that pushes live segments to a configurable destination. This is useful for testing CMAF ingest receivers and validating ingest workflows.

The CMAF ingest functionality converts livesim2's VoD-based live streams into CMAF segments and sends them via HTTP PUT requests to a destination URL in real-time.

CMAF Ingest REST API

The REST API is available at /api/cmaf-ingests and supports the following operations:

POST /api/cmaf-ingests - Create and start a CMAF ingest session

Request body:

{
  "destRoot": "http://receiver-server.com/upload",
  "destName": "channel_name",
  "livesimURL": "/livesim2/testpic_2s/Manifest.mpd",
  "user": "optional_username",
  "password": "optional_password",
  "duration": 60,
  "testNowMS": null,
  "streamsURLs": false
}

Fields:

  • destRoot (required): Destination URL root where segments will be sent
  • destName (required): Destination channel/asset name
  • livesimURL (required): Full livesim2 URL path to an MPD (without scheme/host)
  • user (optional): Username for basic authentication
  • password (optional): Password for basic authentication
  • duration (optional): Duration in seconds to send segments (0 = infinite)
  • testNowMS (optional): Test mode start time (ms since epoch) for step-wise testing
  • streamsURLs (optional): Use Streams(track.cmfv) format instead of numbered segments

GET /api/cmaf-ingests/{id} - Get status and report of an active ingest session

GET /api/cmaf-ingests/{id}/step - Step to next segment (only in test mode with testNowMS)

DELETE /api/cmaf-ingests/{id} - Stop an ingest session

cmaf-ingest-receiver Tool

A standalone receiver tool is included at cmd/cmaf-ingest-receiver/ for testing CMAF ingest. It receives CMAF segments sent by livesim2 (or other CMAF sources) and stores them locally, generating MPD manifests automatically.

Build with:

make build

The binary will be at out/cmaf-ingest-receiver.

Run with:

out/cmaf-ingest-receiver -port 8080 -storage ./segments -prefix /upload

Key options:

-port 8080           # HTTP receiver port
-storage "./storage" # Storage root directory
-prefix "/upload"    # URL prefix for ingest endpoints
-tsbd 90             # TimeShiftBufferDepth in seconds
-loglevel "info"     # Log level (debug, info, warn)
-config ""           # Path to JSON config file

The receiver creates a directory structure like:

storage/
└── channel/
    ├── manifest.mpd             # Auto-generated MPD with $Number$
    ├── manifest_timeline_nr.mpd # Auto-generated MPD with SegmentTimeline
    └── track/
        ├── init.cmfv     # Init segment
        ├── nr.cmfv       # Media segment nr
        └── ...

CMAF Ingest Example

Start the cmaf-ingest-receiver:

out/cmaf-ingest-receiver -port 8080 -storage ./segments -prefix /upload

Start livesim2:

out/livesim2 --vodroot=cmd/livesim2/app/testdata/assets

Create a CMAF ingest session:

curl -X POST http://localhost:8888/api/cmaf-ingests \
  -H "Content-Type: application/json" \
  -d '{
    "destRoot": "http://localhost:8080/upload",
    "destName": "test_channel",
    "livesimURL": "/livesim2/testpic_2s/Manifest.mpd",
    "duration": 60
  }'

whith should return a response like

{
  "$schema":"http://localhost:8888/api/schemas/CmafIngestDeleteResponseBody.json",
  "destRoot":"http://localhost:8080/upload",
  "destName":"test_channel",
  "livesim-url":"/livesim2/testpic_2s/Manifest.mpd",
  "id":"1"}

You can check the status by using the ingester id:

curl http://localhost:8888/api/cmaf-ingests/1

The receiver will store segments in ./segments/test_channel/ and generate playable MPD files.

Server-Guided Ad Insertion (SGAI)

livesim2 can signal Server-Guided Ad Insertion using DASH 6th-edition Alternative-MPD Replace events. The main live stream stays a single continuous-timeline presentation; an EventStream of scheme urn:mpeg:dash:event:alternativeMPD:replace:2025 marks the ad breaks and points each break at an ad-decisioning endpoint. A player resolves that endpoint during the break, plays the returned (personalized) ad pod, and then resumes the live edge. Players that do not support the event keep playing the underlying content, so it is always a graceful fallback.

Enable it with the sgai_ URL option, which schedules the breaks:

  • Fixed breaks: sgai_30:15 (one 15 s break 30 s after the availabilityStartTime), or a comma-separated list sgai_18:20,48:20,78:20.
  • Periodic breaks: sgai_p60:20 (a 20 s break at every full UTC minute, recurring forever; wall-clock anchored, so all sessions share the schedule and a late joiner lands mid-break).
  • Options are appended with ;key=val: skipafter=<s>, nojump=<0|1|2>, clip=<0|1>, once=<0|1>, resolve=<s> (earliest resolution offset), ep=<path> (ad endpoint). For example sgai_p60:20;skipafter=5.

The /urlgen/ page and the URL wiki page document the sgai_ option and its parameters.

Ad creatives and personalization

The ad creatives are ordinary Single-Period-Static DASH VoD assets placed under <vodroot>/ads/ (one directory per ad). An optional <vodroot>/ads/ads.json tags each ad with a title and interest keywords, e.g.:

{
  "train_ad":        { "title": "Train Journey",             "interests": ["travel"] },
  "gotland_runt_ad": { "title": "Gotland Runt Sailing Race", "interests": ["sailing", "boats"] }
}

Those two creatives are bundled under the test vodroot, so SGAI works out of the box. A viewer is identified and steered with two query parameters that are propagated to the ad request via Annex I: sessionId (personalization key) and interests (a comma-separated list). They can be added on the /urlgen/ page or directly on the MPD URL, for example …/Manifest.mpd?sessionId=alice&interests=travel,sailing. With no sessionId, ad decisions and impression beacons are still recorded but grouped under a single shared anon session in the monitor and API.

How the ad pod is selected

The /sgai/ads endpoint returns a personalized List MPD that imports the chosen ads as a pod. The selection follows these rules (see selectPod in sgai_ads.go):

  • Ads tagged with any requested interest come first (rotated per sessionId for variety), then the remaining ads are used as filler.
  • The pod is trimmed to fit the break duration: ads are added while the running total stays within the break, and at least the lead ad is always kept.
  • If the break is longer than the available ads, the pod is as long as the inventory allows and the remainder of the break shows the generated "AD BREAK" countdown slate (the visible "ad to be replaced") — a gapless mismatch is not padded.
  • If the break is shorter than a single ad, the lead ad is still returned and the player clamps playout to the event's maxDuration.
  • With no interests, or interests that match no creative, /sgai/ads answers 404; the player skips the break and the viewer keeps the AD BREAK slate. A clean setup — interests that match some ads and a break duration that is a multiple of the ad length (e.g. sgai_…:20 for the bundled 10 s ads, with interests=travel,sailing) — gives a gapless two-ad pod.

Monitoring

Each ad fires impression and quartile callback beacons to /sgai/beacon (carrying the session and break id via Annex I). The per-session ad decisions and beacons are recorded and can be inspected live at /sgai/session_status?sid=<sessionId> or via the API at /api/sgai/sessions[/{sid}] and /api/sgai/ads (the ad catalog).

DASH Content Steering

livesim2 can be used to demonstrate and test client behavior for DASH Content Steering (ISO/IEC 23009-1 6th ed. §K.3.6, ETSI TS 103 998). A single server advertises two or more service locations ("CDNs") that all point back to itself, plus a root <ContentSteering> element referencing a steering endpoint on the same server. A DASH client (e.g. dash.js) polls that endpoint, which returns a steering manifest with a PATHWAY-PRIORITY ordering and a TTL; by changing the ordering the server makes the client switch CDN. Because every CDN points back here, the per-CDN segment requests are counted per session and can be watched live — which makes the switch observable.

Enable it with the steer_ URL option:

  • Service locations: a comma-separated list of names, at least two: steer_alpha,beta (or steer_cdnA,cdnB,cdnC).
  • Options are appended with ;key=val:
    • ttl=<seconds> — steering-manifest TTL (default 300); the client re-polls every TTL.
    • mode=rotate|trigger — trigger (default) holds the priority at the default order until a switch is triggered via the API / monitor; rotate rotates the priority one step every TTL automatically (wall-clock based, so all clients rotate in lockstep).
    • qbs=<0|1> — ContentSteering@queryBeforeStart (resolve the steering server before playback starts).
    • default=<name> — the initial top service location (default: the first one listed).

A viewer is identified with a sessionId (or sid) query parameter, as for SGAI, e.g. …/steer_alpha,beta;ttl=20/testpic_2s/Manifest.mpd?sessionId=alice. The server bakes the session id and the chosen service location into each <BaseURL> so segment requests are attributable to a (session, CDN) pair. If no sessionId is supplied, requests fall back to a single shared anon session — they still show as one bucket in the monitor and API, and the generated URLs use sid_anon and ?sessionId=anon.

Moving several clients together — groups (csid)

To switch a group of clients at once, add a csid_<group> path token before steer_, e.g. …/csid_groupA/steer_alpha,beta;ttl=20/testpic_2s/Manifest.mpd?sessionId=alice. The steering decision (the pinned priority and any manual override) is then owned by the group and shared by every member, so a single group switch moves them all on their next poll — while each member keeps its own per-CDN segment counts and _DASH_pathway verification. Give several viewers the same csid with distinct sessionIds. A stream with no csid behaves as before: a group of one that owns its own decision. (Note: in mode=rotate all clients already rotate in lockstep regardless of grouping — csid matters for mode=trigger and switches.)

Driving and monitoring the switch

The live monitor at /steering/session_status?sid=<sessionId> shows, per session, the segment request distribution across the CDNs and the current PATHWAY-PRIORITY, polled every second. It has a Switch CDN button (advance one step) and a per-CDN make top button to set the order directly — handy for driving a switch by hand and watching the client follow on its next poll. A Steering polls table below it lists each poll's reported _DASH_pathway/_DASH_throughput, the priority served back, and the verification verdict for that client message (see below).

Verifying the client's steering messages

On each poll the client appends _DASH_pathway and _DASH_throughput. These are a per-pathway measurement report — a positionally-paired list of the pathways the client has measured and their throughputs in bits/s (e.g. _DASH_pathway=beta,alpha&_DASH_throughput=802522000,647618000), in an implementation-defined order — not a declaration of the single pathway in use. livesim2 validates their format and flags:

  • a _DASH_pathway entry that is not one of the configured service locations,
  • a _DASH_throughput entry that is not a non-negative integer,
  • a _DASH_pathway/_DASH_throughput entry-count mismatch.

Whether the client actually followed a steering decision is judged from its segment requests (the cdn_ token in the BaseURL it fetches through) — the ground truth — not from _DASH_pathway. Once the client has been steered to a top CDN and had a 10 s grace period to converge (measured from when it received that top on a poll, so a switch it has not yet polled for is never faulted), a segment still fetched from a different CDN marks the session off-pathway — the real "client ignored steering" signal. It clears as soon as the client fetches from the steered CDN again.

Format issues (per poll) and off-pathway episodes are rolled up into a per-session issueCount. The monitor shows a verify verdict (✓ conformant / ⚠ N) per session, an off-pathway banner, and the timeline of polls/switches/off-pathway detections; the same is exposed over the API (issueCount and offPathway on the session, issues on each event). Each session also records when it last fetched steering (lastPolledAt) and the last address (lastLocation) and segment (lastSegment) it fetched, shown in the session, group and list views.

Open the monitor with ?csid=<group> for the group view: the aggregate per-CDN distribution across all members, the member list, a Switch group button that moves every member, and the group's switch timeline. With no ?sid=/?csid= it lists active groups and sessions.

The same is available over the API:

  • GET /api/steering/sessions[/{sid}] — list sessions / one session's per-CDN counts and timeline.
  • POST /api/steering/sessions/{sid}/switch with body {"target":"next"} (advance one step) or {"target":"<name>"} (promote a service location) — pin a new priority. The client picks it up on its next steering poll (within TTL). This is how an automated dash.js test can load a stream, confirm a steady CDN, trigger a switch, and assert the client moves.
  • POST /api/steering/sessions/{sid}/clear and POST /api/steering/sessions/clear — reset.
  • GET /api/steering/groups[/{csid}] — list groups (member counts, aggregate per-CDN counts) / one group's members, shared priority, and switch timeline.
  • POST /api/steering/groups/{csid}/switch (same body as the session switch) — move the whole group at once. POST /api/steering/groups/{csid}/clear resets the group and its members.

The steering endpoint itself is GET /steering/[csid_<group>/]steer_<spec>?sessionId=<id>, returning the steering manifest as application/json; the client appends _DASH_pathway and _DASH_throughput, which are recorded for inspection. mode=trigger (the default) is best for scripted/monitor-driven switches; use mode=rotate for a hands-off "switches every TTL" demo.

Running tests

The unit tests can be run from the top directory with the usual recursive Go test command go test ./... or with the make targets for testing, linting, and coverage:

> make test
> make check
> make coverage

Deployment

Both dashfetcher and livesim2 can be compiled to single binaries on any Go compiler target platform such as Windows, MacOS, and Linux. Since the result is a single binary it is easy to start it anywhere.

On Linux, livesim2 can be run as a systemd service. More information can be found in the deployment/README.md file.

To get information about the available assets and other information access the server's root URL.

Docker

A Dockerfile is also provided. It builds a stand-alone livesim2 service. A new image is automatically built and uploaded to the Github Container Registry (ghcr.io) for each new release. To use the v1.7.0 image with a folder test_streams with VoD assets, you can use docker compose to mount test_streams in the default folder path /vod by using a compose.yml file like this:

services:
  livesim2:
    image: ghcr.io/dash-industry-forum/livesim2/livesim2:v1.7.0
    ports:
      - 8888:8888
    volumes:
      - ./test_streams:/vod/test_streams
    restart: always

List of functionality and options

The most direct information about the URL parameters and how to find them, is available via the /urlgen/ page that can be reached once the server is running. The livesim2 online page is /urlgen/.

The URL parameters are also listed on this project's Wiki page URL-parameters. Some more information about how they are working is also available on the Wiki.

Project and plan for new features/enhancement

The sponsored transition from livesim to livesim2 is covered on a wiki page. On the livesim2 project page the status of issues and proposed new ideas are listed. Draft ideas are changed into livesim2 issues if prioritized.

Sponsoring

It is possible to sponsor the project for further development. See the SPONSORING.md file for more information.

License

See LICENSE.md.