在Compression 中，我们减少数据的大小以实现高效率和易于存储。传输较大的文件非常麻烦，因此我们需要对其进行压缩。压缩文件传输数据所需的时间更少，并降低了存储成本。
Compression Ratio = B1 / B2 在哪里，
B1 = 压缩前表示数据所需的总位数
B2 = 压缩后表示数据所需的总位数
有两种主要的压缩类型：
- 帧间压缩
- 帧内压缩
帧间和帧内压缩的区别：
| Inter Frame Compression | Intra Frame Compression |
|---|---|
| In this, Data Reduction takes place between the frames. It Exploits redundancy between successive frames. | In this, Data Reduction takes place within the frames. It exploits redundancy within the frames. |
| It is also known as Temporal redundancy where the image transition is abrupt | It is also known as Spatial redundancy where the image transition is block based. |
| It requires more Processing time because the computer needs to look at several frames. | It requires less processing time because the computer is dealing with single frame, |
| A few popular intra frame codec are: 1. MJPEG-JPEGS bunched together 2. Prores-Apple’s favorite 3. DN*HD-Avid’s baby 4. ALL-I-Found in the newer DSLRs 5. Cinema DNG-Adobe’s baby for raw image sequences. |
A few popular inter frame codec are: 1. H.264-A variant of MPEG-4 2. MPEG-4 3. MPEG-2 4. AVCHD-A variant of H.264 AVC 5. XDCAM-Sony’s baby 6. XAVC-Sony’s new baby |