In Compression, we reduce the size of our data to achieve high efficiency and easy storage. It is quite cumbersome to transfer files having large size so we need to compress it. Compressed file takes less time for data transmission and reduce the cost of storage.
Compression Ratio = B1 / B2
B1 = Total Numbers of bits required to represent a data before compression
B2 = Total Numbers of bits required to represent a data after compression
There are 2 main types of compression:
- Inter Frame Compression
- Intra Frame Compression
Difference between Inter and Intra Frame Compression :
|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
4. AVCHD-A variant of H.264 AVC
5. XDCAM-Sony’s baby
6. XAVC-Sony’s new baby
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