This chapter presents a frame memory compression method used in video coding. Frame memory compression compresses the data to be stored in the frame memory in order to reduce the external bandwidth and the related power consumption, as shown in Figure 7.1. When the pixels of a motion-compensated frame have to be written into external DRAM, the frame memory compression engine compresses those pixels. During motion estimation (ME), the frame memory compression engine decompresses the compressed pixels of previous frames and passes them to the video codec. As shown in Figure 7.2, most of the frame memory compression algorithms are composed of three stages: prediction, entropy coding and memory organization [1], which are respectively introduced in Sections 7.1, 7.2 and 7.3.

Chapter Contents:

• 7.1 Prediction
• 7.1.1 Differential pulse-code modulation
• 7.1.2 Intra-mode referenced in-block prediction
• 7.1.3 Block truncation coding
• 7.1.4 Hierarchical minimum and difference
• 7.1.5 Hierarchical average and copy
• 7.1.6 Modified Hadamard transform
• 7.1.7 Discrete cosine transform
• 7.2 Entropy coding
• 7.2.1 Coding methods in frame compression
• 7.2.2 Huffman coding
• 7.2.3 Golomb coding
• 7.2.4 SFL coding and SBT coding
• 7.3 Memory organization
• 7.3.1 Works on bandwidth efficiency
• 7.3.1.1 Address table compression and reference memory access style of IP module and ME module
• 7.3.1.2 Pixels duplication and luma–chroma correlated mapping
• 7.3.1.3 TLB addressing and fixed addressing
• 7.3.1.4 Dual-mode memory addressing (DMMA): direct block memory access (DBMA) and relative block memory access (RBMA)
• 7.3.2 Works on power consumption
• 7.3.2.1 Different-level memory mapping for VCR-LFRC (variable-compression-ratio lossless frame recompression)
• 7.3.2.2 Main memory and auxiliary memory
• 7.3.2.3 Partition group table-based compression storage
• 7.3.3 Other works
• 7.3.3.1 MB-column-based memory mapping
• References

Inspec keywords: motion estimation; video coding; motion compensation; image coding; DRAM chips; data compression; video codecs

Other keywords: high-resolution video coding; compressed pixels; Figure 7; motion-compensated frame; memory organization; frame memory compression engine compresses; entropy coding; frame memory compression algorithms; frame memory compression method

Subjects: Computer vision and image processing techniques; Semiconductor storage; Video signal processing; Optical, image and video signal processing; Memory circuits; Image and video coding