About Sunac Stream

Your phone is the monitor.

Sunac Stream turns any iPhone, iPad, or Android phone into a wireless RTMP receiver with a clean HDMI output. Push a feed from a drone, a camera, a laptop, or a switcher — preview it on the phone, and send a full-bleed video signal to any HDMI display. No cloud, no account, no subscription.

See use cases How it works
What it is

A phone-as-destination video receiver

Most streaming apps turn a phone into a source — they capture from the camera and push a stream out. Sunac Stream is the opposite. It's a tiny, on-device RTMP server that listens for a stream someone pushes to the phone, decodes it live, and pipes the video out to the phone screen and, optionally, to an attached HDMI display.

Think of it as a Blackmagic Video Assistant or an Atomos monitor — except it's an app, it's free, and it runs on hardware you already own.

How it works

From encoder to display in five seconds

  1. Open Sunac Stream. It displays a URL like rtmp://192.168.1.42:1935/live/stream the moment it detects your LAN IP.
  2. Point any encoder at that URL. OBS Studio, Larix Broadcaster, a DJI drone, a Blackmagic ATEM, an HDMI encoder box, FFmpeg — anything that speaks RTMP works.
  3. The phone receives the stream on its local network through an embedded node-media-server running in a native Node thread. No data leaves the LAN.
  4. The phone decodes the feed using VLC with hardware acceleration (VideoToolbox on iOS, MediaCodec on Android).
  5. The video appears in the 16:9 preview on the phone. Plug a USB-C-to-HDMI adapter in, and a clean, full-bleed version of the same video also lights up on the connected display — with zero UI on top.

Typical end-to-end latency: ~150–300 ms over a healthy Wi-Fi 6 network with low-latency mode enabled.

Use cases

Who actually uses this, and for what

Sunac Stream started as “wireless HDMI from a laptop to a TV” and kept sprouting new scenarios. The big ones:

RTMP → HDMI monitor

Push from OBS on a laptop to the phone, plug the phone into any HDMI TV or projector. Instant wireless HDMI without buying a dedicated receiver or a Chromecast.

DJI drones

DJI Mini 4 Pro / Avata / RC Pro units that support RTMP can push their live feed to Stream Hero. Use the pilot's phone for flight and a second phone + HDMI monitor for the spotter or director to review framing in real time.

Switcher program monitor

Take the program output of a Blackmagic ATEM Mini / OBS Studio / vMix multi-source switcher and route it into Sunac Stream. Director sees the clean program feed on any HDMI monitor without running long SDI/HDMI cables from the switcher.

Church & conference directors

A pastor or speaker's assistant can see the live program output on a confidence monitor using just a phone and an HDMI cable — no capture card, no extra laptop, no subscription.

Classroom & training

A teacher can stream a laptop via OBS to Sunac Stream on a phone plugged into the classroom projector. Students on the same Wi-Fi never see a Wi-Fi Direct dialog, a Miracast dropout, or an unknown-display-receiver error.

Indie film sets

Pair a Teradek or HDMI-to-RTMP encoder with a camera; feed it into a director's monitor that's just an iPad on an articulating arm. Cheaper than a wireless video village, with less radio contention than proprietary UHF kits.

Gaming capture review

Route the OBS “Gaming” scene to Sunac Stream on a second phone or tablet as a soft-cam preview for the streamer, so they can watch the output without overlaying a source-preview window on the main screen.

Wedding & event videographers

A roving videographer feeds from an HDMI-to-RTMP box; the client sees a live preview on a phone-to-HDMI setup at the reception table without a laptop on the cake table.

Remote production monitor

Producer on one side of the venue, encoder on the other. As long as both are on the same Wi-Fi or hotspot, the producer has a full-resolution preview in their hand — with zero extra cloud hops.

Encoder latency & QC

Want to know how low your encoder really goes? Push to Sunac Stream and read live bitrate, resolution, fps, and codec on the phone. Useful for tuning x264 presets or checking keyframe intervals before going live to a real platform.

Under the hood

Feature highlights

Zero-config start

Open the app. The LAN URL is visible before the splash finishes dismissing. Tap to copy. Done.

Clean HDMI output, always

External-display routing sends the decoded video, and only the video, to the connected HDMI display — full-bleed, no HUD, no overlays, no watermark. The phone screen keeps its own UI for stats and controls.

HDMI priority & preview toggle

When a display is plugged in, Sunac Stream automatically skips the phone-side decode to save roughly 40–60% CPU at 1080p60. You can also manually turn the preview off at any time with a one-tap toggle under the preview frame.

Live network switching

The displayed IP refreshes in about five seconds. Flip Personal Hotspot on your iPhone, switch from Wi-Fi to hotspot mid-shoot, or plug into Ethernet via USB-C — the URL just keeps working because the RTMP listener is bound to every interface.

Hardware decode

VLC is invoked with VideoToolbox on iOS and MediaCodec on Android so H.264/H.265 decoding runs on the SoC's video engine rather than on the main CPU cores.

Live stats

Resolution, framerate, codec, and live bitrate update at 1 Hz with no layout shift, rendered in a typography-forward mono HUD.

Keep-awake when live

While a stream is being received, the phone screen stays awake even in HDMI-priority mode, so the director can glance at stats without unlocking the device.

iPad split layout

On tablets and landscape-wide phones, the preview sits on the left and the information column (URL card, stats, server status) sits on the right — YouTube-style — rather than stacked.

Android background mode

An opt-in foreground service keeps the RTMP listener alive when the app is not on screen on Android. iOS suspends networking apps; we don't pretend otherwise.

Why

Why we built this

Wireless HDMI is either dongle hardware that costs more than a phone, or it's Chromecast / AirPlay, which require your content to pass through Google or Apple infrastructure and make no promises about latency. For people who already own phones and already know how to push RTMP — the creator economy, basically — there was no reason that gap existed.

Sunac Stream is what happens when you take “the phone is the destination” seriously and build the rest of the UX around it. No accounts. No cloud. No servers to run out of free tier.

Compatibility

Compatibility & encoders

Devices

  • iOS 15.1+ iPhone 8 / SE 2 and newer; all iPads that support iPadOS 15.1.
  • Android 8.0+ (API 26); arm64, 32-bit ARM, and x86_64.
  • HDMI output requires USB-C DisplayPort Alt Mode (most 2020+ Android phones, all iPads with USB-C, iPhone 15+), Lightning-to-HDMI (MFi adapter), or an equivalent docking hub.

Encoders we've tested with

  • OBS Studio, vMix, XSplit, Wirecast.
  • Larix Broadcaster, Streamlabs Mobile.
  • DJI RC Pro, DJI Fly on supported drones (Mini 4 Pro, Avata 2, Mavic 3 Pro).
  • Blackmagic ATEM Mini Pro with the “Stream” output set to RTMP.
  • HDMI-to-RTMP hardware boxes (Magewell Pro Convert, generic H.264 encoders).
  • FFmpeg (ffmpeg -re -i input.mkv -c copy -f flv rtmp://…).

Codecs

Video: H.264 is universally supported. H.265 works on devices with hardware HEVC decode.
Audio: AAC-LC is universally supported.

At a glance

At a glance

Price
Free, forever.

Accounts
None. Ever.

Ads
None.

Cloud
None — LAN only.

Protocol
RTMP on port 1935 (configurable).

Latency
~150–300 ms end-to-end.

Platforms
iOS 15.1+, Android 8.0+.

HDMI
Clean, full-bleed, no overlays.