G11 · Design YouTube Video Upload & Transcode G11 · 设计 YouTube 视频上传与转码
Verified source经核实出处
YouTube architecture is well-documented; SD interview classic. Credibility A.
Architecture架构
flowchart LR U[Uploader] --> CHUNK[Chunked resumable upload] CHUNK --> BLOB[(Original blob)] BLOB --> Q[(Transcode queue)] Q --> WORK[Transcode workers] WORK --> MULTI[(Multi-resolution renditions)] MULTI --> CDN[CDN origin] WORK --> THUMB[Thumbnail + preview]
Key decisions关键决策
- **Resumable chunked upload** (tus.io pattern) with content-hash dedup.**可断点续传的分块上传**（tus.io 风格）+ 按内容哈希去重。
- **Parallel transcoding across segments**: split into 10 s chunks, transcode in parallel, reassemble.**分段并行转码**：切 10 s 块并行转码，再合并。
- **Resolution ladder**: 144p-4K; pick codecs per region (VP9, AV1).**码率梯度**：144p-4K；按地区选 codec（VP9、AV1）。
- **HLS/DASH manifests**; CDN edge caches per rendition.**HLS/DASH manifest**；CDN 边缘按码率缓存。
Follow-ups追问
- DMCA takedown mid-transcode? hash-match audio/video against fingerprint db.DMCA 在转码中？音视频指纹匹配。