In mobile video calls, the main issues are lifecycle and token management. Without proper configuration, you get resource leaks, session drops, and wasted licenses. Our experience with 30+ projects using the Agora SDK has led to a reliable approach.
Why Agora SDK is the Best Choice for Video Calls
Agora SDK is a managed real-time video and audio service that handles WebRTC under the hood, its own transport network SD-RTN, adaptive bitrate, and codecs. Compared to raw WebRTC: Agora speeds up video call development by 12x(Agora documentation), but requires proper token management. Correct integration can reduce infrastructure costs by up to 40% by utilizing SD-RTN, saving approximately $300–$500 per month for small teams.
Steps to Integrate Agora SDK
- Create an Agora account and create a project in the console to obtain App ID.
- Generate a token using the Agora Token Builder on your backend.
- Initialize the engine once at app launch (see code examples below).
- Join a channel with the token and channel name.
- Set up local and remote video rendering.
- Handle token renewal via delegate callbacks.
- Test with various scenarios (network drop, incoming call).
Properly Configuring Tokens to Avoid Errors
Agora works with an App ID + Token model. App ID is a public identifier from the console. Token is a short-lived JWT that your backend generates via the Agora Token Builder and passes to the client when joining a channel. The most common production errors are tokenExpired (109) and invalidToken (110). The token has a limited TTL (from 24 hours down to 1 hour). We implement handling via the tokenPrivilegeWillExpire delegate method — get a new token from the backend and call renewToken() without breaking the connection.
A typical mistake: the token is generated with UID 0 on the backend, but after joinChannel the client gets a specific UID from Agora — and then on the next renewToken it passes a token for the wrong UID. Solution: save the UID from didJoinChannel and use it when requesting a new token.
| Scenario |
TTL |
Recommendation |
| Standard |
24 hours |
Balance of security and refresh frequency |
| High load |
1 hour |
Reduces token compromise risk |
Engine Initialization
Initialize the engine once at app launch:
let config = AgoraRtcEngineConfig()
config.appId = "YOUR_APP_ID"
agoraKit = AgoraRtcEngineKit.sharedEngine(with: config, delegate: self)
val config = RtcEngineConfig()
config.mContext = context
config.mAppId = "YOUR_APP_ID"
config.mEventHandler = handler
rtcEngine = RtcEngine.create(config)
Do not recreate the engine for each call. sharedEngine is a singleton; calling it again with the same App ID returns the existing instance. On Android, RtcEngine.create() creates a new instance each time; you must destroy the previous one via RtcEngine.destroy(). Otherwise, native resource leaks appear after 3–5 calls. Use LifecycleObserver to automatically destroy the engine when the activity finishes.
Joining a Channel and Handling Video
let option = AgoraRtcChannelMediaOptions()
option.clientRoleType = .broadcaster
option.channelProfile = .communication
agoraKit.joinChannel(
byToken: token,
channelId: channelName,
uid: 0,
mediaOptions: option
)
uid: 0 — Agora assigns the UID itself. If you need user binding, pass a deterministic numeric ID (UInt32).
Local video is rendered via AgoraRtcVideoCanvas with setupLocalVideo(). Remote video via setupRemoteVideo() in the didJoinedOfUid delegate method. Important: call setupRemoteVideo() on the main thread, otherwise EXC_BAD_ACCESS occurs with rapid join/leave of participants.
func rtcEngine(_ engine: AgoraRtcEngineKit, didJoinedOfUid uid: UInt, elapsed: Int) {
DispatchQueue.main.async {
let canvas = AgoraRtcVideoCanvas()
canvas.uid = uid
canvas.renderMode = .hidden
canvas.view = self.remoteVideoView
self.agoraKit.setupRemoteVideo(canvas)
}
}
Video Quality Settings
Agora provides AgoraVideoEncoderConfiguration presets and custom parameters:
let config = AgoraVideoEncoderConfiguration(
size: CGSize(width: 640, height: 360),
frameRate: .fps15,
bitrate: AgoraVideoBitrateStandard,
orientationMode: .adaptative,
mirrorMode: .auto
)
agoraKit.setVideoEncoderConfiguration(config)
For a mobile app, 360p/15fps is a reasonable balance of quality and battery drain. 720p/30fps for tablets or when quality is critical. 1080p is not suitable for mobile: it consumes a lot of power and resources, and the perceptual difference between 720p and 1080p is negligible.
| Resolution |
fps |
Bitrate |
Battery Load |
| 360p |
15 |
Standard |
Low |
| 720p |
30 |
Standard |
Medium |
| 1080p |
30 |
High |
High |
Handling Interruptions and Lifecycle
On iOS, AVAudioSession.routeChangeNotification and AVAudioSession.interruptionNotification — Agora SDK handles them automatically with the correct AgoraAudioScenario. The .meeting scenario is optimal for video calls: enables AEC, ANS, AGC.
When an incoming system call occurs, Agora does not pause automatically. We implement via CXCallObserver: when CXCall.hasConnected == true — muteLocalAudioStream(true), when the call ends — unmute.
On Android, without a ForegroundService, Android 8+ will kill the process within 5–10 minutes. We start a ForegroundService at the beginning of a call with a notification. android:foregroundServiceType="camera|microphone" in the manifest is mandatory from Android 14.
What's Included in the Work
- Requirements analysis: number of participants, quality, backend integration, budget.
- Token setup: generation, caching, expiry handling.
- UI implementation: video canvases, controls, virtual background.
- Lifecycle: ForegroundService on Android, CXCallObserver on iOS.
- Testing: 10+ scenarios (network drop, incoming call, fast reconnection).
- Documentation: README, code comments, token flow diagram.
- Access to source code and a training session for your team.
- Support: 2 weeks post-release, bug fixes.
Timelines and Cost
Basic integration (1-on-1 video call with camera control, mute, flip) — 3–5 days. With group support up to 8 participants, token management, and background mode — 1–2 weeks. Cost is determined after requirements analysis. Contact us to evaluate your project — we will provide an estimate and roadmap. Get a consultation on Agora integration or order video call implementation.
We are a certified Agora partner with 5 years of experience and 30+ successful projects. Guaranteed uptime and support.
How to Choose a Camera Approach on Mobile Platforms?
Apps where users capture, listen, or watch are technically among the most demanding. We deal with this every day. Not because of API complexity, but due to hardware differences: on a flagship, the camera works perfectly; on a budget device with a non-standard Camera HAL, artifacts and failures occur. On iOS, stabilization differs between generations. Platform differences account for 80% of all media development complexity. Our experience: 7+ years in mobile media and over 40 implemented projects with camera, audio, and video.
What are the Differences Between CameraX, Camera2, and AVFoundation?
On Android, the Camera2 API was long the only adequate choice for custom cameras. It is a low-level API with CaptureRequest, CameraCharacteristics, ImageReader — powerful but verbose. Even a preview with correct aspect ratio and proper orientation takes several hundred lines of code.
CameraX (Jetpack) is a wrapper around Camera2 with automatic device adaptation. Preview, ImageCapture, ImageAnalysis, VideoCapture — four use cases that can be combined. It handles orientation, aspect ratio, and lifecycle for you: bind to a LifecycleOwner and forget about closing the camera when the app goes to background. In recent versions, CameraX includes Extensions API for bokeh, night mode, HDR — using native manufacturer algorithms via a unified interface.
When is Camera2 needed directly?: RAW capture via ImageFormat.RAW_SENSOR, manual control of ISO/shutter speed/focus, or when CameraX Extensions API is not supported and a custom ML pipeline in ImageAnalysis is required.
On iOS, AVFoundation is the only path for a custom camera. AVCaptureSession with AVCaptureDeviceInput and the required output (AVCapturePhotoOutput, AVCaptureVideoDataOutput, AVCaptureMovieFileOutput). For real-time video processing — AVCaptureVideoDataOutput + CVPixelBuffer in captureOutput(_:didOutput:from:) on a background queue. This is where CoreML models receive frames for inference.
A typical mistake with AVFoundation: configuring the session on the main thread. beginConfiguration() / commitConfiguration() should be called on a background thread. Otherwise, the preview freezes, and the user sees a frozen UI. This mistake appears in 70% of the projects we have audited.
Why is AudioFocus Critical for Android Apps?
Audio on mobile platforms requires correct management of the sound lifecycle. AudioFocus is a coordination mechanism between apps. AudioManager.requestAudioFocus() with OnAudioFocusChangeListener. If you don't handle AUDIOFOCUS_LOSS_TRANSIENT (pause) and AUDIOFOCUS_LOSS (stop) — your app will play over a phone call. That guarantees a bad review on Google Play. Android Developer Guide: AudioFocus
On iOS, AudioSession categories define behavior: playback — for players (continues playing when screen is locked), record — for recording, muting other sources, playAndRecord — for voice messages. Wrong category — the app mutes the user's background music on start.
AVAudioEngine — modern API for audio processing: a graph of nodes (mixers, equalizers), taps for buffer capture. For real-time speech — SFSpeechRecognizer + inputNode.installTap.
On Android for recording with noise suppression — NoiseSuppressor.isAvailable() + create(audioRecord.audioSessionId). Works not on all devices, need a fallback.
Video: Playback and Streaming
ExoPlayer (Media3) — standard for Android. Supports HLS, DASH, SmoothStreaming, progressive playback. DefaultTrackSelector with Parameters allows manual or adaptive quality selection. DRM via DefaultDrmSessionManager with Widevine L1/L3.
Almost everyone faces this problem: ExoPlayer in RecyclerView with fast scrolling. Need a PlayerPool — a pool of reusable players. Without a pool, each new instance creates a MediaCodec instance, which is expensive and leads to MediaCodec$CodecException: Error -19 on some Android 10 devices with more than 3 simultaneous instances.
AVPlayer / AVPlayerViewController on iOS — for playback. For custom UI — AVPlayerLayer + custom controls. HLS works natively via AVPlayer(url:) with m3u8. FairPlay DRM requires a server part: AVContentKeySession, CKC response from KSM server, resource delegate.
For Flutter — video_player as a base layer, chewie for UI. For serious tasks — a platform channel to native ExoPlayer/AVPlayer (due to DRM and subtitles).
| Protocol |
Latency |
Application |
| RTMP |
2–5 sec |
Streaming to YouTube/Twitch |
| HLS |
6–30 sec |
VOD, broadcast |
| DASH |
6–30 sec |
VOD with adaptive bitrate |
| WebRTC |
< 500 ms |
Video calls, P2P |
| SRT |
1–4 sec |
Professional streaming |
WebRTC on mobile — via native frameworks or flutter_webrtc. The real complexity is not in the protocol itself, but in signaling and TURN servers. Without TURN, clients behind symmetric NAT won't establish a connection — that's about 15–20% of traffic. Coturn is the standard open-source server.
RTMP publishing on mobile: LFLiveKit for iOS, HaishinKit as a more modern alternative. On Android — rtmp-rtsp-stream-client-java or via FFmpeg with JNI. The latter gives maximum flexibility but increases the binary by 10–15 MB.
Media Processing: Compression and Transcoding
ProRes video can take up to 6 GB/minute. Compression is needed before upload. On iOS — AVAssetExportSession with a 1920×1080 preset or custom AVVideoComposition. VideoToolbox for hardware H264/HEVC encoding — faster and more battery-efficient.
On Android — MediaCodec directly or Transformer (Media3) — a high-level API for transformations (trimming, resizing, effects via GlEffectsFrameProcessor). For images — BitmapFactory.Options.inSampleSize for downsampling, Glide / Coil for caching. Coil on Coroutines fits well with Compose. Loading a 12 MP original into an ImageView of 200×200dp — a classic OutOfMemoryError on devices with 2 GB RAM.
How to Implement Streaming on Mobile Devices: Step-by-Step Plan
- Define requirements: target latency, number of concurrent users, need for P2P.
- Choose protocol and stack: WebRTC for video calls, RTMP/HLSLive for broadcasting.
- Set up signaling (SIP, WebSocket, MQTT) and TURN server.
- Implement publishing/viewing via native API or cross-platform plugin.
- Test on real devices with different cameras and network conditions.
- Optimize bitrate and resolution based on bandwidth.
Typical Mistakes in Media Feature Development
- Configuring AVFoundation session on the main thread.
- Missing AudioFocus Loss handling on Android.
- Ignoring
MediaCodec limitations on cheap devices.
- Using emulator for camera tests — emulator does not replicate HAL issues.
- Memory leaks when recreating media players without a pool.
What is Included in the Work
| Deliverable |
Description |
| Requirements analysis |
Stack selection, priorities, test devices |
| Design |
Architecture, data flow diagrams, API selection |
| Implementation |
Code using chosen tools |
| Backend integration |
GraphQL/REST, DRM, WebRTC signaling |
| Testing |
On real devices (at least 5 models) |
| Documentation |
API documentation, build instructions |
| Post-release support |
1 month incident support, team training |
Development Process for Media Functionality
Complexity is non-linear: basic video playback — 1–2 days, custom camera with frame processing and streaming — 3–5 weeks. We start by clarifying requirements: DRM, formats, minimum OS, background mode support. Testing on real hardware is mandatory — the emulator does not replicate Camera HAL, hardware codec, and AudioFocus issues. Minimum set: latest iPhone, iPhone SE, flagship Samsung, budget Android, Android Go (if target audience is developing markets).
Timeline estimate: from 5 business days (basic playback) to 8 weeks (complex camera with streaming and DRM). Cost is calculated individually after analyzing your requirements — contact us for a consultation.
Our service: "Mobile Media Integration" — this is our expertise. Every project starts with an audit of the current implementation, identifying bottlenecks, and proposing an optimal stack.
Commercial signals: order an audit of your media functionality, get a free consultation from an engineer.
