Pixel Storage for HDR Frame Buffers Using Lossy Compression

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Solution Overview

Problem

Current pixel formats for High Dynamic Range (HDR) graphics systems fail to meet the requirements of packing efficiency, random access, and real-time access, making it challenging to implement a cost-effective HDR graphics system that maintains high visual quality without introducing quantization artifacts.

Innovation Solution

A lossy compression process is employed for storing pixels in HDR graphics systems, utilizing a targeted number of bits per pixel to represent statistical redundancy, which allows for efficient packing and real-time access while maintaining sufficient visual quality, using formats like RGBA10 or FP16 that balance bit usage and storage efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high bit depth (10, 12, 16, 24, 32 bits per sample) is used for HDR pixel storage, then the dynamic range and visual quality are improved, but the memory bandwidth and storage requirements increase significantly

Engineering Contradiction:
Improveluminance representation precisionVSAvoidmemory bandwidth
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The pixel data is segmented into multiple components (e.g., YCbCr color space separation) where only the luminance component requires high precision for HDR, while chrominance components can use lower precision. This segmentation allows selective application of high bit depth only where necessary for visual quality, reducing overall memory bandwidth requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter representation by using floating-point formats (e.g., FP16) instead of fixed-point integer formats. This allows dynamic allocation of precision where needed while using fewer bits overall, optimizing the balance between visual quality and memory bandwidth for HDR content.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If high bit depth pixel formats are used for HDR, then the visual quality and dynamic range are improved, but the packing efficiency and storage cost worsen

Engineering Contradiction:
Improveluminance representation precisionVSAvoidstorage cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

By segmenting pixel data into luminance and chrominance components and applying different precision levels to each, the system achieves high visual quality where needed while reducing overall storage requirements, directly lowering storage costs for HDR content.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs lossy compression techniques that discard imperceptible data details, effectively using a cheaper storage approach that maintains acceptable visual quality. This trade-off reduces storage costs while preserving the essential HDR visual experience.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If lossless compression is used for pixel storage, then the visual quality is maintained, but the compression ratio and real-time access performance worsen

Engineering Contradiction:
Improvepixel data accuracyVSAvoidreal-time access speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

Instead of applying full lossless compression to all pixel data, the patent applies partial compression by selectively discarding only the least significant bits that are imperceptible to human vision. This partial action maintains real-time access performance while preserving sufficient visual quality for HDR content.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent changes from lossless to lossy compression parameters, accepting controlled data degradation in exchange for significantly improved compression ratios and real-time access performance. This parameter change enables HDR content to be processed in real-time while maintaining acceptable visual quality.

Inventive Principle:
Principle #35Parameter changes

4Quantity of substance

If standard 8-bit per sample format is used, then the memory bandwidth and storage cost are reduced, but the dynamic range and visual quality worsen due to quantization artifacts

Engineering Contradiction:
Improvememory bandwidthVSAvoidluminance representation precision
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent transitions from the traditional 8-bit fixed-point dimension to a floating-point dimension (e.g., FP16), enabling more efficient use of memory bandwidth through dynamic precision allocation. This dimensional change allows HDR content to achieve high visual quality with reduced bandwidth requirements compared to naive 10-bit or 12-bit formats.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

By changing the data representation parameter from fixed-point integers to floating-point numbers, the system achieves better precision-to-bandwidth ratio. Floating-point formats allow the same number of bits to represent both very bright and very dark regions accurately, maintaining visual quality while reducing memory bandwidth requirements for HDR content.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS10922848B2Pixel storage for graphical frame buffers
Publication Date: 2021.02.16 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • US10922848B2 patent drawing
  • US10922848B2 patent drawing
  • US10922848B2 patent drawing

AI summary

A device implementing the subject pixel storage for graphical frame buffers may include at least one processor configured to obtain a plurality of data units containing a plurality of pixels stored in memory, each of the plurality of data units including a first pixel of the plurality of pixels packed in succession with at least a portion of a second pixel of the plurality of pixels, in which the plurality of pixels is represented by a number of bits, obtain a group of pixels from the plurality of pixels, and store the group of pixels using a targeted number of bits. A method and computer program product implementing the subject pixel storage for graphical frame buffers is also provided.