miniav_tools_web 0.5.0

WebCodecs/MediaStreamTrack-backed codecs for miniav_tools (browser).

miniav_tools_web

WebCodecs/MediaStream backend for miniav_tools — browser only.
Wraps the browser's native VideoEncoder, VideoDecoder, AudioEncoder, and AudioDecoder APIs, with a MediaRecorderCapture fallback for browsers that lack WebCodecs.
Self-registers with the miniav_tools_platform_interface registry on import.

Importing package:miniav_tools_web/miniav_tools_web.dart is enough. Once registered, MiniAVTools.createEncoder(...) will use this backend at priority 80 — browser-native encoding is preferred over wasm/software paths.

What it provides

• WebCodecsBackend — MiniAVToolsBackend implementation backed by the browser VideoEncoder / VideoDecoder / AudioEncoder / AudioDecoder APIs.
• MediaRecorderCapture — MediaStream-based fallback for browsers that do not yet ship WebCodecs (or when the codec/config is unsupported).
• WebCapability — runtime feature detection helpers: WebCapability.hasVideoEncoder, WebCapability.hasWebGPU, etc.

Automatic degradation

Runtime capability	Behaviour
WebGPU + WebCodecs available	GPU effects (WGSL via minigpu_web) + WebCodecs encoding
No WebGPU, WebCodecs available	GPU effects skipped; WebCodecs encoding still works
No WebCodecs	Use MediaRecorderCapture directly as a fallback

Check WebCapability.hasVideoEncoder and WebCapability.hasWebGPU at runtime to branch between paths.

Usage

import 'package:miniav_tools/miniav_tools.dart';
import 'package:miniav_tools_web/miniav_tools_web.dart'; // self-registers

final encoder = await MiniAVTools.createEncoder(EncoderConfig(
  codec: VideoCodec.h264,
  width: 1280, height: 720,
  bitrateBps: 4_000_000,
));

MediaRecorder fallback

import 'package:miniav_tools_web/miniav_tools_web.dart';

if (!WebCapability.hasVideoEncoder) {
  final capture = MediaRecorderCapture(
    stream: videoElement.captureStream(),
    mimeType: 'video/webm;codecs=vp9',
  );
  await capture.start();
  // ...
  final blob = await capture.stop();
}

Supported codecs

WebCodecs codec coverage varies by browser. The following are broadly available in Chromium-based browsers:

Codec	Encode	Decode
H.264 / AVC	✅	✅
VP8	✅	✅
VP9	✅	✅
AV1	✅ (Chrome 113+)	✅
HEVC	✅ (Chrome 106+, macOS/Windows)	✅
Opus	✅	✅
AAC	✅	✅

Dependencies

• web — dart:js_interop Web API bindings
• miniav_tools_platform_interface
• minigpu_platform_interface — optional GPU interop

See also

• miniav_tools — user-facing facade
• miniav_tools_ffmpeg — FFmpeg backend (native)
• miniav_tools_minigpu — GPU compute backend
• Design doc