Free SRT test signal, live 24/7
Point any SRT receiver at the address below and you get a reference picture: SMPTE bars, a burned-in UTC timecode, a monotonic frame counter, a moving bar and a 1 kHz beep locked to a visual flash. It runs permanently on our Germany and USA nodes. No account, no time limit, nothing to install.
It answers the questions you actually have before a show: does my decoder speak SRT, does my network let UDP out, how much delay am I really adding, is my audio in sync, and am I losing packets?
Pull it now
Both nodes carry the same signal, generated locally on each node — so the difference you see between them is your path to that continent, not ours.
Stream ID is required. streamid=read:beacon tells our server which stream you want. If your decoder has a separate "Stream ID" field, put read:beacon there and leave the URL as srt://de.inoutsrt.com:6999.
What is in the picture
| Element | What it proves |
|---|---|
UTC timecode HH:MM:SS:FF | End-to-end delay — compare it with a reference clock |
| Frame counter, 9 digits | Dropped frames: the counter must never skip |
| Moving bar, 2 s sweep | Judder and freezes are obvious at a glance |
| SYNC flash + 1 kHz beep | Audio/video sync: they happen on the same frame |
| SMPTE HD bars | Colour space, levels, chroma subsampling |
| Node name | Which continent you are pulling from |
Format: 1280×720, 25 fps, H.264 Main Profile, CBR ≈ 2 Mbit/s, AAC-LC 96 kbit/s, 48 kHz stereo, 2-second GOP. Deliberately modest: it has to decode on the cheapest hardware decoder you own.
Five checks in sixty seconds
- Does my receiver speak SRT at all? If the bars appear, your SRT stack, stream ID handling and caller mode all work.
- Does my network let SRT out? SRT is UDP. Corporate Wi-Fi, hotel networks and some LTE APNs silently drop it. If the bars appear, UDP egress to port 6999 is open.
- What is my real delay? See the method below — most people discover their decoder adds far more than their network.
- Is my audio in sync? The white SYNC square lights up on the exact frame the beep starts. If you hear the beep before or after the flash, the offset is yours.
- Am I losing packets? Watch the frame counter. Numbers must run without gaps; a freeze with the counter jumping means loss your latency buffer could not repair. Raise
latencyand try again.
Measure your glass-to-glass delay
- Open time.is in a browser window — it shows true UTC to the millisecond.
- Put your decoder's output window next to it on the same screen.
- Take one screenshot of both.
- Subtract:
time.is − timecode in the picture= everything between our encoder and your eyes.
That figure includes about 0.2 s of our own encoder and packaging, your SRT latency buffer (200 ms by default in the URL above) and your decoder's own buffer. Try it with latency=120 and then latency=1000 — the number moves exactly as much as you changed, which is the whole point of SRT: you choose the trade between delay and loss recovery.
The browser preview on this page is not a latency test. It is HLS, which adds 6–10 seconds by design. Use it to confirm the signal is alive, then pull the SRT URL into a real decoder.
Ready-made commands
ffplay / ffmpeg
ffplay -fflags nobuffer -flags low_delay \
"srt://de.inoutsrt.com:6999?streamid=read:beacon&latency=200"Record 20 seconds for an offline look, without re-encoding:
ffmpeg -i "srt://de.inoutsrt.com:6999?streamid=read:beacon&latency=200" \
-c copy -t 20 beacon.tsJust inspect what arrives:
ffprobe -v error -show_streams -of flat \
"srt://de.inoutsrt.com:6999?streamid=read:beacon"OBS Studio
Add a Media Source, uncheck Local File, and paste into Input:
srt://de.inoutsrt.com:6999?streamid=read:beacon&latency=200Set Input Format to mpegts, uncheck Restart playback when source becomes active, and set Network Buffering to 0 MB for the lowest delay.
vMix
Add Input → Stream/SRT → SRT Caller. Hostname de.inoutsrt.com, Port 6999, Stream ID read:beacon, Latency 200.
VLC
vlc --srt-streamid=read:beacon --srt-latency=200 srt://de.inoutsrt.com:6999mpv
mpv --profile=low-latency "srt://de.inoutsrt.com:6999?streamid=read:beacon"GStreamer
gst-launch-1.0 srtsrc uri="srt://de.inoutsrt.com:6999?streamid=read:beacon&latency=200" \
! tsdemux ! h264parse ! avdec_h264 ! autovideosinkIf nothing arrives
| Symptom | Most likely cause | Fix |
|---|---|---|
| Connection times out | UDP blocked outbound | Test from a phone hotspot; if it works, it is your network |
| "Connection rejected" / 1016 | Stream ID missing or misspelled | It must be exactly read:beacon |
| Connects, then drops after ~5 s | Latency too low for your path | Raise to latency=500, then tune down |
| Picture freezes, counter jumps | Packet loss beyond the buffer | Raise latency; if it persists, your uplink is the problem |
| Audio but no video | Decoder cannot do H.264 Main | Tell us your device — we can add a baseline variant |
House rules
Free, permanent, no registration, no SLA. Every node serves the signal to everyone at once.
One session lasts 30 minutes, then the connection is dropped. Reconnect as often as you like — the limit only stops the signal from being parked as free content delivery. Thirty minutes is far more than any decoder check needs, and if a test really needs to run longer, tell us what you are doing and we will open it.
If you need a stream that carries your video rather than our bars, that is the paid side of this service, and it starts at $5 a day.
Why we run it
We sell SRT tunnels: your encoder connects in, your receiver connects out, and we relay in between — no static IP, nothing installed. The test signal is the same network, the same nodes and the same software you get as a customer, running where you can see it. If the beacon looks clean from your venue, your show will too.
Need a tunnel that carries your own video?
IN/OUT-SRT is a hosted SRT relay in Germany and the USA. Your encoder connects in, your receiver connects out — no static IP, no port forwarding, nothing installed. Three free 30-minute sessions every day; a full production day is $5.