Consti10 / LiveVideo10ms

Real time video decoding on android
GNU Lesser General Public License v3.0
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android cpp decoding latency live-streaming mediacodec rtp-streaming udp wifibroadcast

Live Video 10ms Android

Release android_build_windows_workflow Consti10

Description \ Library for live video playback with ultra low latency (below 10ms) on android devices. Supports playback of .h264 encoded live video data transmitted via UDP encapsulated in RAW or RTP and simple file playback. \ Latency data (see example for more information)

Device Encoder avgTotalDecodingTime
Galaxy s9+ rpi cam 8.0ms
Galaxy s9+ x264 11.5ms
Pixel 3 rpi cam 11.2ms
Pixel 3 x264 10.5ms
HTC U11 rpi cam 8.6ms
HTC U11 x264 10.1ms

Example App \ ExampleMain

This library has been optimized for low latency and tested on a wide variety of devices, including those running FPV-VR for wifibroadcast. The example library also contains test cases that can be executed on the 'gooogle firebase test lab'. These tests include feeding the decoder with faulty NALUs, created by a lossy connection. (e.g. wifibroadcast).

The 2 most important factors for low latency are

  1. HW-accelerated decoding via the MediaCodec api
  2. Receiving,Parsing and decoding is done in cpp code (multi-threaded). This decouples it from the java runtime, which increases performance and makes latency more consistent ( garbage collection halts all java threads, for example).

However, all native code needed for creating, starting and stopping the decoding process are exposed via the JNI, so you can use the lib without writing c/c++ code. The VideoPlayer class purposely has no pause/resume functions,since this library is for live video playback. Playback works on a 'best effort' principle, e.g. as soon as a receiver is created nalus are forwarded to the LowLagDecoder, but no frames can be decoded until enough I-frame data was received. Make sure to use a low enough I-frame interval with your h264 encoder. When receiving corrupted data (e.g from a lossy connection) the decoder will still generate frames if possible.

Structure:

Setup Dependencies\ There are 2 ways to use VideoCore in your Project \ 1 Declaring Dependency via Jitpack: jitpack.io \ :heavy_plus_sign: Easy \ :heavy_minus_sign: cannot browse native libraries \ Gradle example:

    allprojects {
        repositories {
            jcenter()
            maven { url "https://jitpack.io" }
        }
   }
   dependencies {
        implementation 'com.github.Consti10:LiveVideo10ms:v1.1'
   }

2 Forking the repo and including sources manually: \ :heavy_plus_sign: browse native libraries \ :heavy_plus_sign: modify code