长 GOPLong GOP
交付 · Delivery
长 GOP 是 H.264 / H.265 这类编码的帧间压缩结构——体积小、兼容性好，代价是剪辑时拖动和调色更卡。
- 帧间压缩：体积小、兼容性最好——H.264 拿来看正是这个原因。
- 卡的根源：每一帧都不能独立解码，拖动、调色都要前后一起算——时间线卡顿先留意长 GOP 结构。
- 最大的坑：痕迹多、经不起二次调整；把交付格式当素材调，画质必崩。
- 解法：剪辑先生成代理（见 代理），别拿交付格式当工作素材。
Long GOP is the inter-frame compression structure of H.264 / H.265 — small files, great compatibility, paid for with laggy scrubbing and grading.
- Inter-frame compression: small size, best compatibility — exactly why H.264 is made for viewing.
- Why it lags: no frame decodes independently; scrubbing and grading compute frames together — when the timeline stutters, check the long-GOP structure first.
- The biggest trap: heavy artefacts, no tolerance for a second pass; grading a delivery format as if it were source material is where pictures fall apart.
- The fix: generate proxies before editing (see Proxy) — never treat a delivery format as working media.