LiveWrk

livewrk is a load-testing tool for WHIP/WHEP endpoints, named after wrk, the HTTP benchmarking tool. It drives many concurrent publish or subscribe sessions against a Live777 instance and reports session, traffic, and RTCP feedback statistics.

Use cases

• Stress-test a Live777 instance with hundreds of concurrent WHIP publishers.
• Exercise the SFU fan-out path with many WHEP subscribers on one stream.
• Continuously verify that media stays decodable while the system is under load (rotating decode verification).

Build

# The whip subcommand and WHEP decode verification require FFmpeg
# development libraries (rsmpeg)
cargo build --bin livewrk --features rsmpeg

Without the rsmpeg feature only the whep subcommand (without --verify-window) is available; the whip subcommand explains how to rebuild when invoked.

Usage

Publish 100 synthetic streams (load-0 .. load-99) for 60 seconds:

livewrk whip --whip http://localhost:7777/whip/load --sessions 100 --duration 60

Subscribe 100 sessions to one already-published stream:

livewrk whep --whep http://localhost:7777/whep/load-0 --sessions 100 --duration 60

The whip subcommand appends -N to the last path segment of the URL, so each session publishes its own stream. Point whep at one of those streams (e.g. load-0) or at any other published stream.

Ready-made recipes are available in the justfile:

just livewrk-whip 100 60
just livewrk-whep 100 60 load-0

Common options

Both subcommands share these options:

Option	Default	Description
-w, --whip / --whep	required	WHIP/WHEP endpoint URL
-t, --token	none	Bearer token for authentication
--sessions	100	Number of concurrent sessions
--ramp-ms	10	Milliseconds between spawning each session (ramp-up)
--duration	60	Overall run duration in seconds; sessions stop afterwards
-v, -vv, -vvv	warn	Log verbosity: info, debug, trace

whip options

The whip subcommand publishes synthetic test patterns generated in-process (same engine as WhipSynth), no external encoder needed.

Option	Default	Description
--vcodec	vp8	Video codec: vp8, vp9, h264, h265, av1
--acodec	none	Audio codec: opus, g722 (omit for no audio)
--width	640	Video width in pixels
--height	480	Video height in pixels
--fps	30	Video frame rate
--stun-server	stun:stun.l.google.com:19302	STUN server for ICE gathering (empty string disables STUN)

whep options

Option	Default	Description
--verify-window	none	Enable rotating decode verification (seconds per window)
--verify-tolerant	false	Report verification failures without failing the whole run

Rotating decode verification

With --verify-window N, a single verifier decodes one session at a time for N seconds, then rotates to the next active session. Decode cost stays constant regardless of the session count, so even large runs verify that the SFU keeps forwarding decodable media. Windows cut short by shutdown do not count; a run with zero completed windows, or with any failed window, exits non-zero unless --verify-tolerant is set. Codecs without a decoder in the build are reported in the verification note instead of failing.

Output

At the end of a run livewrk prints a summary:

══════════════════════════════════════════════
  whep loadtest results
  Sessions: 100 total, 100 connected, 0 failed, 0 cancelled, 0 aborted
  Packets: 152340, bytes: 52428800 (52.43 MB)
  Avg connected duration: 58.9s
══════════════════════════════════════════════

Media write errors and RTCP feedback (NACK/PLI) are shown when non-zero; whip runs report sent packets, whep runs received ones.

Exit code

• 0: run completed (or interrupted by the first Ctrl-C, after graceful shutdown) with at least one connected session and no failed verification.
• 1: an error occurred, every session failed, or decode verification failed without --verify-tolerant.
• 130: a second Ctrl-C forced an immediate quit during shutdown.