UTD App

Digital Item Developer Guide

Every format on the UTD App marketplace, with the official playback library and a ready-to-paste snippet for Android, iOS, Web and Flutter.

Formats

Supported formats & playback libraries

Pick your platform under each format — library names link to the official repositories.

SVGA

.svga

A compact animation format exported straight from After Effects, widely used for live-streaming gifts. Plays with hardware acceleration through the SVGAPlayer family.

GiftView.kt
val parser = SVGAParser(context)
parser.decodeFromURL(URL(itemUrl)) { videoItem ->
    svgaImageView.setVideoItem(videoItem)
    svgaImageView.startAnimation()
}
GiftView.swift
let player = SVGAPlayer(frame: view.bounds)
SVGAParser().parse(with: URL(string: itemUrl)!) { entity in
    player.videoItem = entity
    player.startAnimation()
}
gift.js
import SVGA from "svgaplayerweb";

const player = new SVGA.Player("#canvas");
new SVGA.Parser().load(itemUrl, (videoItem) => {
  player.setVideoItem(videoItem);
  player.startAnimation();
});
gift_view.dart
SVGASimpleImage(resUrl: itemUrl);

WebP

.webp

Animated WebP images with full alpha transparency in a single small file. Supported natively on most platforms — little to no extra runtime needed.

AndroidGlide
GiftView.kt
// Animated WebP plays out of the box
Glide.with(context).load(itemUrl).into(imageView)
GiftView.swift
SDImageCodersManager.shared.addCoder(SDImageWebPCoder.shared)
imageView.sd_setImage(with: URL(string: itemUrl))
gift.html
<!-- Animated WebP is supported natively -->
<img src="item.webp" alt="" />
gift_view.dart
// Animated WebP is supported natively
Image.network(itemUrl);

VAP

.mp4

Tencent's Video Animation Player format: an MP4 carrying a color track plus an alpha track and a vapc config box, for pixel-perfect compositing of rich gift effects.

GiftView.kt
// AnimView from the VAP SDK
animView.setLoop(1)
animView.startPlay(File(itemPath))
GiftView.m
// QGVAPWrapView from the VAP SDK
[wrapView playHWDMP4:itemPath repeatCount:0 delegate:self];
gift.js
import Vap from "video-animation-player";

new Vap({ container, src: itemUrl, config: vapcJson }).play();
gift_view.dart
VapView();
await VapController.playPath(itemPath);

MP4 Alpha

.mp4

A regular MP4 whose frame holds the color half next to a grayscale alpha half. Your player samples both halves and composites a fully transparent animation.

GiftView.kt
// Side-by-side color/alpha video
alphaMovieView.setVideoFromUrl(itemUrl)
alphaMovieView.start()
GiftView.m
BDAlphaPlayerMetalConfiguration *config =
    [BDAlphaPlayerMetalConfiguration defaultConfiguration];
config.directory = itemDirectory;
[self.playerView playWithMetalConfiguration:config];
gift.js
// Upload each <video> frame as a texture, then in the
// fragment shader: rgb from the color half x alpha from
// the alpha half -> draw on a transparent canvas.
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA,
  gl.UNSIGNED_BYTE, video);
gift_view.dart
// Play the mp4, sample color/alpha halves in a
// custom FragmentShader and paint the composited frame.
final controller = VideoPlayerController.networkUrl(Uri.parse(itemUrl));
await controller.initialize();
controller.play();

PAG

.pag

Tencent's PAG (Portable Animated Graphics): After Effects animations in a tiny binary file, rendered by the cross-platform libpag runtime (WASM on the web).

Androidlibpag
GiftView.kt
val pagView = PAGView(context)
pagView.composition = PAGFile.Load(itemPath)
pagView.setRepeatCount(0)
pagView.play()
GiftView.swift
let pagView = PAGView()
pagView.setComposition(PAGFile.load(itemPath))
pagView.setRepeatCount(0)
pagView.play()
gift.js
import { PAGInit } from "libpag";

const PAG = await PAGInit();
const file = await PAG.PAGFile.load(buffer);
const view = await PAG.PAGView.init(file, canvas);
view.setRepeatCount(0);
await view.play();
Flutterpag
gift_view.dart
PAGView.network(
  itemUrl,
  repeatCount: PAGView.REPEAT_COUNT_LOOP,
  autoPlay: true,
);

Lottie

.json / .lottie

Airbnb's Lottie: After Effects animations exported as JSON (or a .lottie dotLottie bundle) and rendered natively on every platform.

GiftView.kt
lottieView.setAnimationFromUrl(itemUrl)
lottieView.repeatCount = LottieDrawable.INFINITE
lottieView.playAnimation()
GiftView.swift
let view = LottieAnimationView(url: URL(string: itemUrl)!) { _ in }
view.loopMode = .loop
view.play()
gift.js
import lottie from "lottie-web";

lottie.loadAnimation({
  container,
  path: itemUrl,
  renderer: "svg",
  loop: true,
  autoplay: true,
});
Flutterlottie
gift_view.dart
Lottie.network(itemUrl);

APNG

.png

Animated PNG — the standard PNG format with an animation control chunk, keeping lossless quality and full alpha. Static PNG files are rejected by the marketplace.

GiftView.kt
val drawable = APNGDrawable.fromFile(itemPath)
imageView.setImageDrawable(drawable)
GiftView.swift
// APNG plays out of the box
imageView.sd_setImage(with: URL(string: itemUrl))
gift.html
<!-- APNG is supported natively -->
<img src="item.png" alt="" />
gift_view.dart
// APNG is supported natively
Image.network(itemUrl);