STEM与日常科技·英语30篇（3）

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视频GOP结构与关键帧的作用

Every video you stream uses a group of pictures, or GOP, to reduce file size efficiently.
A GOP starts with an I-frame, which stores full image data without referencing other frames.
P-frames and B-frames then store only the differences from nearby I- or P-frames.
This inter-frame compression saves huge amounts of bandwidth while maintaining acceptable quality.
If your internet drops mid-GOP, playback may freeze until the next I-frame arrives.
Keyframes act like visual bookmarks, letting players seek quickly to any point in the video.
Longer GOPs improve compression but increase latency and error recovery time.
Modern encoders adjust GOP length dynamically based on motion complexity and network conditions.
Without keyframes, editing software couldn’t cut video precisely at arbitrary timestamps.
Understanding GOP helps explain why paused videos sometimes show blurry or frozen artifacts.