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CASTZERO DOCUMENTATION & WEBRTC GUIDES

Learn how CastZero uses WebRTC & UDP transport to achieve sub-50ms latency in OBS Studio, and how to connect DJI drones, GoPro cameras, and smartphone rigs.

RECOMMENDED INGEST ARCHITECTURE

WHY WEBRTC BROWSER LINKS GIVE LOWEST LATENCY (~30MS)

Traditional RTMP playback via Media Source introduces TCP buffering queues (100ms - 300ms delay). CastZero features an integrated MediaMTX WebRTC Bridge that automatically re-muxes incoming camera feeds into HTML5 WebRTC streams over UDP (Port 8189).

When added as an OBS Browser Source (e.g. http://localhost:8889/live), OBS decodes frames directly in real-time with zero queuing — resulting in near-instantaneous ~30ms latency.

WEBRTC BROWSER LINK: http://localhost:8889/[streamkey]

GET STREAMING IN 4 STEPS

Complete setup in under 3 minutes

1

SIGN UP & DOWNLOAD FROM ACCOUNT

Visit castzero.in, sign up for a free account, and click the download link inside your Account Page to get the installer or portable archive.

Publish URL: rtmp://[YOUR_IP]:1935/live
2

START CAMERA STREAM

In your DJI Fly app, GoPro Quik, or mobile app, enter the RTMP publish URL and start live broadcast.

Stream Key: live (or custom key)
3

ADD OBS BROWSER SOURCE

In OBS Studio, add a new Browser Source. Set URL to http://localhost:8889/live, Width: 1920, Height: 1080.

WebRTC WebLink: http://localhost:8889/live
4

SUB-50MS INSTANT PLAYBACK

CastZero's embedded HTML5 WebRTC player loads instantly in OBS Studio with ~30ms real-time latency.

Sub-50ms WebRTC Real-Time Active
METHOD 1 — RECOMMENDED (#1)

OBS STUDIO: WEBRTC BROWSER SOURCE SETUP (~30MS LATENCY)

This is the fastest, lowest-latency ingest method for OBS Studio:

STEP 01
Add Browser Source in OBS

In OBS Studio, navigate to the Sources panel → click + → Browser. Name it CastZero WebRTC Stream.

STEP 02
Enter WebRTC WebLink Address

In the URL field, paste your local WebRTC stream link:

http://localhost:8889/[streamkey]  (e.g. http://localhost:8889/live)
STEP 03
Configure Dimensions & Audio

Set Width: 1920 and Height: 1080. Check Control audio via OBS and check Shutdown source when not visible. Click OK.

METHOD 2 — ALTERNATIVE

METHOD 2 — RTMP MEDIA SOURCE FALLBACK (~100MS LATENCY)

Use this alternative method if you prefer using OBS's native Media Source plugin:

STEP 01
Add Media Source in OBS

In OBS Studio, navigate to Sources → click + → Media Source. Uncheck Local File inside properties.

STEP 02
Enter RTMP Input & 0 MB Buffer

In Input, paste: rtmp://127.0.0.1:1935/live/[streamkey]. Set Network Buffering to 0 MB and check Use Hardware Decoding.

HARDWARE GUIDE

DJI DRONE WIRELESS RTMP GUIDE

Supports all DJI drones equipped with custom RTMP output (Mavic 3, Air 3S, Air 2S, Mini 4 Pro, Mini 3 Pro):

STEP 01
Connect Controller to Wi-Fi Network

Connect your DJI Smart Controller or mobile phone to the same Wi-Fi router network as your CastZero PC.

STEP 02
Configure DJI Fly App RTMP Address

Open DJI Fly App → tap ... (Settings) → Transmission tab → select RTMP. Enter:

rtmp://YOUR_PC_IP:1935/live/dji_drone
STEP 03
Start Broadcast & View in OBS

Set Resolution & Bitrate: For DJI RC 2, select 720p resolution at 3-4 Mbps (capped by DJI RC 2 firmware). For DJI RC Pro / Mobile, select 1080p at 6-8 Mbps. Tap Start Live Streaming and ingest in OBS via http://localhost:8889/dji_drone.

💡 DJI RC 2 Wireless Streaming Tip:
If you do not want to record voice commentary during your wireless RTMP stream, plug a cheap USB-C to 3.5mm Headphone Adapter or USB-C Dummy Audio Dongle into the controller's USB-C port. This tricks the DJI Fly app into bypassing the "No Microphone Detected" prompt for seamless wireless broadcasting. (CastZero also automatically synthesizes a silent AAC track if video-only stream is published).
PRO ACTIVATION GUIDE

HOW TO BUY & ACTIVATE CASTZERO PRO

CastZero runs in Free Evaluation mode out-of-the-box. Upgrading to CastZero Pro unlocks 24/7 unlimited continuous streaming, 0-second session cooldown, hardware GPU acceleration, and 30-day offline field access.

STEP 01
Copy License Key From Online Account

Visit castzero.in/pricing and complete checkout. Log into your Online Account Dashboard and copy your active Pro License Key (format: PRO-XXXX-XXXX-XXXX-XXXX).

STEP 02
Open Settings Panel in CastZero App

Launch the CastZero Desktop App on Windows. Navigate to Settings (or click Activate License in the top header).

STEP 03
Paste Key & Click Activate Key

Paste your license key into the Active Key input box under License & Account Management and click ACTIVATE KEY. Pro status unlocks instantly.

🔒 Single-Device Licensing Policy:
• 1 Key = 1 PC Only: Each license key is strictly bound to one single desktop PC at a time. It cannot be re-used on other desktops simultaneously.
• Transferring to a New PC: If you buy a new computer or switch laptops, click DE-LINK LICENSE FROM DEVICE inside Settings (or in your online account dashboard) to unbind your key and transfer it to your new PC.
HARDWARE SPECS

SYSTEM REQUIREMENTS

CastZero is optimized to run smoothly even on entry-level streaming laptops:

Specification Minimum Requirements Recommended Professional Setup
Operating System Windows 10 x64 (Build 19041+) Windows 11 x64
Processor (CPU) Intel Core i3 8th Gen / AMD Ryzen 3 Intel Core i7 12th Gen / AMD Ryzen 7
Graphics (GPU) Intel UHD Graphics 620 NVIDIA RTX 3060 / GTX 1660 Super (NVENC)
System RAM 4 GB DDR4 16 GB DDR4 / DDR5
Network Interface 100Mbps Wi-Fi (5GHz 802.11ac) 1Gbps Gigabit Ethernet LAN + Wi-Fi 6 Router
Network Ports TCP 1935 (RTMP), UDP 8189 (WebRTC) TCP 1935 & UDP 8189 (Unblocked in Firewall)
HELP & FAQ

TROUBLESHOOTING & FREQUENTLY ASKED QUESTIONS

Q: Why is WebRTC recommended over RTMP for OBS Studio? +
WebRTC uses UDP transport without TCP packet retransmission delays. Adding CastZero's WebLink (`http://localhost:8889/[streamkey]`) as an OBS Browser Source provides real-time ~30ms video playback compared to ~150ms over RTMP.
Q: Why is OBS showing a black screen or buffer icon? +
Ensure CastZero Desktop Client is running and that your camera (DJI Fly or GoPro) has initiated active streaming to the correct local IP address. Verify Windows Firewall is not blocking Port 1935 TCP or Port 8189 UDP.
Q: How do I find my local PC IP address for DJI Fly? +
Open Command Prompt on Windows (`cmd`) and type `ipconfig`. Look for your IPv4 Address under Wireless LAN or Ethernet (e.g. `192.168.1.105`). Enter `rtmp://192.168.1.105:1935/live/dji` in the camera app.
Q: Can I stream multiple drones or cameras simultaneously into OBS? +
Yes! CastZero supports multi-stream ingestion. Simply assign unique stream keys to each camera (e.g. `.../live/drone1`, `.../live/gopro1`) and add corresponding Browser Sources in OBS.
VIDEO WALKTHROUGH

FULL SETUP & PRO ACTIVATION TUTORIAL

VIDEO GUIDE: Stream DJI & Mobile Cameras to OBS Studio Under 50ms FULL SETUP & PRO ACTIVATION GUIDE

NEED ADDITIONAL TECHNICAL HELP?

Our engineering team provides 1-on-1 assistance for custom OBS stream configurations and commercial broadcast setups.

Chat on WhatsApp → Contact Engineering Support