Android App to view NDI®- or UVC (USB Video Class Device) Feed on an Android mobile phone.
This project was renamed from NDIMonitor to FeedWatch to avoid confusion with the official NDI® Tools app "NDI® Video Monitor" and I don't want to get in trouble with Vizrt ;)
All sources the app finds are listed on the start screen: NDI® sources from the network and UVC devices connected via USB. The list updates itself in the background, pull down to refresh it right away. Tap a source to open it.
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NDI® High Bandwidth Monitoring
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Supports NDI® High Bandwidth sources
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Since NDI® can be network-intensive, using a USB-C Ethernet adapter is strongly recommended.
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NDI® senders outside mDNS discovery can be added by their IP address in the Settings. The dot after a full block of three digits is added for you. Changes apply right away.
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NDI® HX is currently not supported. I invested some effort and implemented a working prototype. However, in order to receive NDI® HX streams for longer than 5 minutes, you need currently a NDI® Advanced SDK license. Even if I had a license - which I do not - publishing the source code would not be useful, because I would not be able to publish the license itself. Anyone who wanted to use this functionality would need to obtain the appropriate license independently.
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UVC HDMI Capture Cards
The app can capture video from UVC-compatible devices, such as USB HDMI capture cards.
This functionality was developed and tested with a low-cost UGREEN Video Capture Card (Amazon), which performed reliably.
Any supported UVC device will automatically appear as an available source.
Long-press a source and choose Set as default source to open it automatically. There can only be one default source, it is marked with a DEFAULT badge.
Once per app start, the default source opens as soon as it is available. A short countdown is shown before, tap Cancel to stay on the source list. Closing the stream returns to the list without opening the source again.
The default source can also be removed in the Settings, even while it is not available.
Tap the picture to show or hide the controls. The top bar shows the source, its tally state, resolution, frame rate and pixel format. The bottom bar switches the monitoring tools and audio.
Tap the chart icon next to the frame rate to show the stream statistics, a second tap closes them. They update twice a second:
- NDI®: duration, bandwidth, connections, received and shown frame rate, received, dropped and skipped frames, audio delay, audio buffer (filled / target), audio gaps and dropped audio frames
- UVC: duration, received and shown frame rate, data rate of the MJPEG stream, received and dropped frames and the time to decode a frame
NDI® audio is played back together with the picture, with a level meter for the left and right channel. Use the AUDIO button to mute it. Without audio, the picture is shown with the lowest latency instead of waiting for its audio.
Audio goes through a jitter buffer, so packets that Wi-Fi holds back for a moment do not cause gaps. It starts at 100 ms and grows by 50 ms each time it runs empty anyway, up to 200 ms. On a steady connection it shrinks again by 50 ms, down to 50 ms, once 30 seconds passed without gaps and the delays seen would still fit. If it runs empty again soon after, it waits twice as long before the next try, up to 8 minutes. The picture waits for its audio, so a larger buffer delays both, but they stay in sync.
Low Bandwidth Mode reduces network and CPU usage by using the NDI proxy stream instead of the full-resolution video feed. This mode is ideal when your android device is only connected to a wireless network. While image quality is reduced compared to the full NDI stream it can nevertheless be enough to check feed existence, framing or exposure.
You can enable Low Bandwidth Mode in the app’s Settings (gear icon on the source list).
Viewer Mode shows only the picture: monitoring tools, overlays and stream info are hidden, only the close and audio buttons remain. It can be enabled in the Settings.
- Displays NDI® tally information (red for program /green for preview) for NDI sources
- Simple focus peaking implementation
- Fixed sharpness sensitivity: 70%
- Edge color red, yellow or blue: long-press the PEAK button to choose it
- Exposure warning using zebra stripes
- Threshold from 50 to 100 IRE, 95 IRE by default: long-press the ZEBRA button to set it
- Small waveform monitor over the picture, turned on with the WFM button
- Luma or RGB waveform with the red, green and blue traces on top of each other: long-press the WFM button to choose
- Drag it with one finger to move it, pinch with two fingers to resize it, its place and size are remembered
- Small vectorscope over the picture, turned on with the VEC button: hue as the angle, saturation as the distance from the middle (Rec. 709)
- Targets for the 75% color bars and a skin tone line
- Long-press the VEC button to draw the trace in color or white and to zoom 1× or 2×, which spreads the low saturation of skin or log footage
- Moved and resized like the waveform monitor, both can be open at the same time
- Grid: rule of thirds or a center cross
- Frame lines for 2.39:1, 4:3 or 9:16, the picture outside of them is darkened
- Title safe area at 90%
- Guides in white, yellow or red
- Long-press the GRID button to choose them, a tap turns all guides on or off
Before building, we need to make sure that the following components are installed:
- Java Development Kit (JDK) 11
- Android SDK Platform 33
- NDI SDK for Android
This project must be built with Java 11. Newer Java versions (e.g. Java 17) may cause Gradle or NDK build failures. The reason is, that this project should be runnable on older phones. Android SDK Platform Level 33 uses Java 11.
Install Android SDK Platform 33. Instruction can be found here
Download the NDI SDK for Android from the official site
Follow the installer instructions for your platform and note the installation directory.
After installation, copy the NDI header files into the project’s C++ include directory:
cp <NDI_SDK_INSTALL_DIR>/NDI\ SDK\ for\ Android/include/* \ <PROJECT_ROOT>/FeedWatch/app/src/main/cpp/include/
Next, copy the NDI library binaries into the project’s jniLibs directory:
cp <NDI_SDK_INSTALL_DIR>/NDI\ SDK\ for\ Android/lib/* <PROJECT_ROOT>/FeedWatch/app/src/main/jniLibs/
Ensure that the copied libraries match the ABIs you intend to build for (e.g. arm64-v8a, armeabi-v7a).
./gradlew assemble
This app is in a very early development phase. Therefore it is not fully tested. It is possible that the app does not work stable and that there are some ui or- performance glitches.
NDI® is a registered trademark of Vizrt NDI AB. Also visit https://ndi.video/ for details.
This project is licensed under the APACHE License 2.0. See included LICENSE file.