CAL supports DPCM decompression of a complete image in vertical stripes (i.e. frame division mode). This feature is typically used to provide decompressed to hardware that operates in frame division mode and that has to operate from a full frame DPCM compressed buffer. Stripes can overlap to compensate to filtering overlap.
First stripe configuration:
- Configure the RD_DMA to "n" pixels per line.
- Configure one WR_DMA context to send at least 4 pixels per line to SDRAM that will be used to resume DPCM decompression on the next stripe.
- Configure one pixel processing context for DPCM decompression (normal mode).
- Configure BYS ports, video port and/or WR_DMA to send decompressed pixels to the destination.
Other stripes configuration:
- Configure the RD_DMA to "n" pixels per line and to read 4 pixels of initialization data per line.
- Configure one WR_DMA context to send at least 4 pixels per line to SDRAM that will be used to resume DPCM decompression on the next stripe (not needed for the last stripe).
- Configure one pixel processing context for DPCM decompression (resume mode).
- Configure BYS ports, video port, and/or WR_DMA to send decompressed pixels to the destination.