feat: unlock 1080P+ on Android via DASH streaming

- getPlayUrl uses fnval=16 (DASH) on Android, keeping fnval=0/html5 for iOS/web - New utils/dash.ts builds a valid DASH MPD from Bilibili's segmentBase ranges and returns it as a data: URI for ExoPlayer consumption - NativeVideoPlayer selects DASH path (type='mpd') or durl fallback automatically - Extend PlayUrlResponse types with DashVideoItem/DashAudioItem/DashSegmentBase
2026-07-07 23:18:38 +08:00 · 2026-03-10 20:04:48 +08:00
parent 4dbb3cb3d6
commit 5bb6a3cd68
8 changed files with 453 additions and 113 deletions
--- a/docs/superpowers/plans/2026-03-10-dash-1080p.md
+++ b/docs/superpowers/plans/2026-03-10-dash-1080p.md
@@ -0,0 +1,276 @@
+# DASH 1080P Playback Implementation Plan
+
+> **For agentic workers:** REQUIRED: Use superpowers:subagent-driven-development (if subagents available) or superpowers:executing-plans to implement this plan. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** 在 Android 上解锁 1080P+ 画质，通过切换至 DASH 格式并生成合法 MPD data URI 传给 ExoPlayer。
+
+**Architecture:** `getPlayUrl` 按平台分叉——Android 使用 `fnval=16` 获取 DASH JSON（含分离的 video/audio 流及 segmentBase 范围）；iOS/Web 保持 `fnval=0,platform=html5`（720P MP4）。DASH 数据在 `utils/dash.ts` 中组装成标准 MPD XML，经 `btoa` 编码为 `data:` URI，传给 `react-native-video` 的 ExoPlayer 播放。
+
+**Tech Stack:** React Native 0.83, Expo SDK 55, react-native-video 6.x (ExoPlayer on Android), TypeScript
+
+---
+
+## File Map
+
+| 文件 | 操作 | 说明 |
+|---|---|---|
+| `services/types.ts` | Modify | 扩展 dash video/audio 条目类型，加 segmentBase/width/height/mimeType/frameRate |
+| `services/bilibili.ts` | Modify | `getPlayUrl` 按 Platform.OS 分叉 fnval |
+| `utils/dash.ts` | **Create** | `buildDashDataUri(playData, qn): string` |
+| `components/NativeVideoPlayer.tsx` | Modify | 有 dash 时用 data URI + `type="mpd"`，否则走原 durl 路径 |
+
+---
+
+## Task 1: 扩展 PlayUrlResponse 类型
+
+**Files:**
+- Modify: `services/types.ts`
+
+- [ ] **Step 1: 更新 dash video/audio 条目类型，加入 B 站实际返回字段**
+
+```typescript
+// services/types.ts — 替换现有 PlayUrlResponse
+
+export interface DashSegmentBase {
+  Initialization: string;  // e.g. "0-938"
+  indexRange: string;       // e.g. "939-2694"
+}
+
+export interface DashVideoItem {
+  id: number;
+  baseUrl: string;
+  bandwidth: number;
+  mimeType: string;         // "video/mp4"
+  codecs: string;           // "avc1.640028"
+  width: number;
+  height: number;
+  frameRate: string;        // "25" or "25000/1000"
+  segmentBase: DashSegmentBase;
+}
+
+export interface DashAudioItem {
+  id: number;
+  baseUrl: string;
+  bandwidth: number;
+  mimeType: string;         // "audio/mp4"
+  codecs: string;           // "mp4a.40.2"
+  segmentBase: DashSegmentBase;
+}
+
+export interface PlayUrlResponse {
+  durl?: Array<{
+    url: string;
+    length: number;
+    size: number;
+  }>;
+  dash?: {
+    duration: number;
+    video: DashVideoItem[];
+    audio: DashAudioItem[];
+  };
+  quality: number;
+  accept_quality: number[];
+  accept_description: string[];
+}
+```
+
+- [ ] **Step 2: 验证 TypeScript 无报错**
+
+```bash
+cd C:/claude-code-studly/reactBilibiliApp && npx tsc --noEmit 2>&1 | head -30
+```
+
+- [ ] **Step 3: Commit**
+
+```bash
+git add services/types.ts
+git commit -m "feat: extend PlayUrlResponse types for DASH segmentBase fields"
+```
+
+---
+
+## Task 2: getPlayUrl 按平台分叉
+
+**Files:**
+- Modify: `services/bilibili.ts` (line 97–102)
+
+- [ ] **Step 1: 修改 `getPlayUrl` 函数**
+
+将现有函数替换为：
+
+```typescript
+export async function getPlayUrl(bvid: string, cid: number, qn = 64): Promise<PlayUrlResponse> {
+  const isAndroid = Platform.OS === 'android';
+  const params = isAndroid
+    ? { bvid, cid, qn, fnval: 16, fourk: 1 }
+    : { bvid, cid, qn, fnval: 0, platform: 'html5', fourk: 1 };
+  const res = await api.get('/x/player/playurl', { params });
+  return res.data.data as PlayUrlResponse;
+}
+```
+
+注：`Platform` 已在文件顶部从 `react-native` 导入（第 3 行），无需新增 import。
+
+- [ ] **Step 2: 验证 TypeScript 无报错**
+
+```bash
+cd C:/claude-code-studly/reactBilibiliApp && npx tsc --noEmit 2>&1 | head -30
+```
+
+- [ ] **Step 3: Commit**
+
+```bash
+git add services/bilibili.ts
+git commit -m "feat: use DASH (fnval=16) on Android for getPlayUrl"
+```
+
+---
+
+## Task 3: 新建 utils/dash.ts
+
+**Files:**
+- Create: `utils/dash.ts`
+
+- [ ] **Step 1: 创建文件，实现 `buildDashDataUri`**
+
+```typescript
+// utils/dash.ts
+import type { PlayUrlResponse } from '../services/types';
+
+/**
+ * 从 Bilibili DASH 响应生成 MPD data URI。
+ * 选取 id === qn 的视频流（找不到则取第一条），带宽最高的音频流。
+ * 返回 "data:application/dash+xml;base64,..." 供 react-native-video 使用。
+ */
+export function buildDashDataUri(playData: PlayUrlResponse, qn: number): string {
+  const dash = playData.dash!;
+
+  const video =
+    dash.video.find(v => v.id === qn) ?? dash.video[0];
+  const audio = dash.audio.reduce((best, a) =>
+    a.bandwidth > best.bandwidth ? a : best
+  );
+
+  const dur = dash.duration;
+
+  const xml = `<?xml version="1.0" encoding="UTF-8"?>
+<MPD xmlns="urn:mpeg:dash:schema:mpd:2011"
+     profiles="urn:mpeg:dash:profile:isoff-on-demand:2011"
+     type="static"
+     mediaPresentationDuration="PT${dur}S">
+  <Period duration="PT${dur}S">
+    <AdaptationSet id="1" mimeType="${video.mimeType}" codecs="${video.codecs}" startWithSAP="1" subsegmentAlignment="true">
+      <Representation id="v1" bandwidth="${video.bandwidth}" width="${video.width}" height="${video.height}" frameRate="${video.frameRate}">
+        <BaseURL>${escapeXml(video.baseUrl)}</BaseURL>
+        <SegmentBase indexRange="${video.segmentBase.indexRange}">
+          <Initialization range="${video.segmentBase.Initialization}"/>
+        </SegmentBase>
+      </Representation>
+    </AdaptationSet>
+    <AdaptationSet id="2" mimeType="${audio.mimeType}" codecs="${audio.codecs}" startWithSAP="1" subsegmentAlignment="true">
+      <Representation id="a1" bandwidth="${audio.bandwidth}">
+        <BaseURL>${escapeXml(audio.baseUrl)}</BaseURL>
+        <SegmentBase indexRange="${audio.segmentBase.indexRange}">
+          <Initialization range="${audio.segmentBase.Initialization}"/>
+        </SegmentBase>
+      </Representation>
+    </AdaptationSet>
+  </Period>
+</MPD>`;
+
+  // btoa is available in React Native's Hermes JS engine
+  return `data:application/dash+xml;base64,${btoa(xml)}`;
+}
+
+function escapeXml(s: string): string {
+  return s.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');
+}
+```
+
+- [ ] **Step 2: 验证 TypeScript 无报错**
+
+```bash
+cd C:/claude-code-studly/reactBilibiliApp && npx tsc --noEmit 2>&1 | head -30
+```
+
+- [ ] **Step 3: Commit**
+
+```bash
+git add utils/dash.ts
+git commit -m "feat: add buildDashDataUri utility for DASH MPD generation"
+```
+
+---
+
+## Task 4: 更新 NativeVideoPlayer 使用 DASH data URI
+
+**Files:**
+- Modify: `components/NativeVideoPlayer.tsx`
+
+- [ ] **Step 1: 导入 `buildDashDataUri`，更新 url 选取逻辑**
+
+在文件顶部 import 区域添加：
+```typescript
+import { buildDashDataUri } from '../utils/dash';
+```
+
+将第 34 行的 url 计算替换为（在组件函数体内）：
+
+```typescript
+// 优先使用 DASH data URI（Android），降级使用 durl MP4（iOS）
+const url = playData?.dash
+  ? buildDashDataUri(playData, currentQn)
+  : playData?.durl?.[0]?.url;
+```
+
+将 `<Video>` 组件的 `source` prop 更新，DASH 时传入 `type` hint：
+
+```tsx
+<Video
+  ref={videoRef}
+  source={
+    playData?.dash
+      ? { uri: url!, type: 'mpd', headers: BILIBILI_HEADERS }
+      : { uri: url!, headers: BILIBILI_HEADERS }
+  }
+  style={styles.video}
+  resizeMode="contain"
+  controls
+  paused={false}
+/>
+```
+
+- [ ] **Step 2: 验证 TypeScript 无报错**
+
+```bash
+cd C:/claude-code-studly/reactBilibiliApp && npx tsc --noEmit 2>&1 | head -30
+```
+
+- [ ] **Step 3: 手动测试清单**
+
+在 Android 设备 / 模拟器上：
+1. `expo run:android`（需要 dev build，react-native-video 是 native 模块）
+2. 打开任意视频详情页
+3. 确认播放器加载且**有声音有画面**
+4. 点击右上角清晰度按钮，检查可选项是否包含 1080P（80）或更高
+5. 切换清晰度，确认切换后正常播放
+6. （可选）登录后重新打开视频，确认 `accept_quality` 中出现更高画质选项
+
+在 iOS（如有设备）：
+1. 确认退化到 720P MP4 durl 路径，视频正常播放无报错
+
+- [ ] **Step 4: Commit**
+
+```bash
+git add components/NativeVideoPlayer.tsx
+git commit -m "feat: play DASH streams on Android for 1080P+ quality"
+```
+
+---
+
+## 完成标志
+
+- [ ] Android 上视频清晰度列表出现 1080P（qn=80）及以上选项
+- [ ] 切换清晰度后视频带音频正常播放
+- [ ] iOS 仍可正常播放（720P durl 路径）
+- [ ] `npx tsc --noEmit` 无类型错误