القائمة
Stream video to mobile with HLS/DASH adaptive bitrate and optional DRM. Use when building or integrating a video delivery pipeline for a mobile app.
التثبيت باستخدام Codex أو Claude انسخ هذا Prompt والصقه في Codex أو Claude أو مساعد آخر ليراجع صفحة Skill ويثبّتها لك.
استنادا إلى تصنيف SOC المهني
When and how to use a Backend-for-Frontend (BFF) for mobile -- scoping, ownership, and anti-patterns. Use when deciding whether a BFF is justified or designing one.
GraphQL server design tuned for mobile -- persisted queries, batching, N+1 mitigation, and Apollo client integration. Use when building or reviewing a GraphQL API for mobile apps.
Design mobile-friendly HTTP APIs with predictable pagination, filtering, sorting, sparse/partial responses, and a consistent error envelope. Use when specifying new endpoints or reviewing existing ones for mobile use.
REST conventions tuned for mobile clients -- resources, HTTP caching, idempotency, and versioning. Use when designing or reviewing RESTful endpoints.
Server-side OAuth 2.1 + PKCE for native mobile apps -- authorization endpoint, token endpoint, refresh rotation, and device binding. Use when implementing or reviewing the auth server for mobile clients.
Model multi-device sessions on the backend with sliding vs absolute expiry, device listing, and remote logout. Use when building the session model or a "Your devices" screen.
| name | video-streaming |
| description | Stream video to mobile with HLS/DASH adaptive bitrate and optional DRM. Use when building or integrating a video delivery pipeline for a mobile app. |
Mobile video requires adaptive bitrate (ABR) streaming -- the client switches between renditions based on bandwidth. Serve HLS on iOS (mandatory) and HLS or DASH on Android (HLS is simplest cross-platform).
Source file -> transcoded into multiple renditions -> packaged as HLS/DASH -> stored on object storage -> served through a CDN.
Renditions for UGC-style content (rules of thumb):
| Resolution | Bitrate (video) | Audio |
|---|---|---|
| 240p | 250 kbps | 64 kbps |
| 360p | 500 kbps | 64 kbps |
| 480p | 1.0 Mbps | 96 kbps |
| 720p | 2.5 Mbps | 128 kbps |
| 1080p | 4.5 Mbps | 128 kbps |
upload -> transcode worker (ffmpeg / AWS MediaConvert / Mux) -> HLS/DASH output
-> object storage (media/<id>/hls/master.m3u8, media/<id>/hls/720p/*.ts)
-> CDN
ffmpeg one-shot HLS (simplified):
ffmpeg -i input.mp4 \
-filter_complex "[0:v]split=3[v1][v2][v3]; \
[v1]scale=w=854:h=480[v1out]; \
[v2]scale=w=1280:h=720[v2out]; \
[v3]scale=w=1920:h=1080[v3out]" \
-map "[v1out]" -c:v:0 libx264 -b:v:0 1000k \
-map "[v2out]" -c:v:1 libx264 -b:v:1 2500k \
-map "[v3out]" -c:v:2 libx264 -b:v:2 4500k \
-map a:0 -map a:0 -map a:0 -c:a aac -b:a 128k \
-var_stream_map "v:0,a:0 v:1,a:1 v:2,a:2" \
-f hls -hls_time 4 -hls_playlist_type vod \
-master_pl_name master.m3u8 \
-hls_segment_filename "out/%v/seg_%03d.ts" "out/%v/index.m3u8"
For production, a managed service (AWS MediaConvert, Google Transcoder API, Mux, Bitmovin) saves a huge amount of ops work.
Prefer CMAF (fragmented MP4) segments. The same fMP4 files serve both HLS and DASH manifests; you halve storage and invalidation overhead. Required for low-latency HLS and for Widevine + FairPlay + PlayReady shared DRM.
Needed for live/near-live use cases (sub-5 s). Requires partial segments, blocking playlist reload, and CDN support. Most VoD apps do not need this; live-ish apps (sports, auctions, collab) do.
iOS (AVPlayer): HLS is native; set AVPlayerItem.preferredPeakBitRate to cap on cellular:
let asset = AVURLAsset(url: URL(string: "https://cdn/media/\(id)/hls/master.m3u8")!)
let item = AVPlayerItem(asset: asset)
if networkMonitor.isCellular { item.preferredPeakBitRate = 1_500_000 }
let player = AVPlayer(playerItem: item)
Android: ExoPlayer supports HLS and DASH:
val player = ExoPlayer.Builder(context).build()
val source = HlsMediaSource.Factory(DefaultHttpDataSource.Factory())
.createMediaSource(MediaItem.fromUri("https://cdn/media/$id/hls/master.m3u8"))
player.setMediaSource(source)
player.prepare()
For Flutter / React Native, wrap the native players; do not roll your own.
Two tiers:
CMAF + CENC + multi-DRM lets one set of files serve both. License exchange happens between the player and the license server; your backend signs a short-lived license request token.
user_id + video_id + TTL.LANGUAGE tags.audio background mode; the manifest must allow extraction.