Lossless Compression in HEVC with Integer-to-Integer Transforms

TL;DR

This paper investigates using integer-to-integer transforms in HEVC for lossless compression, offering a potentially more efficient alternative to traditional residual coding methods, with experimental validation showing competitive results.

Contribution

It introduces the application of integer-to-integer transforms in HEVC for lossless coding, demonstrating their effectiveness compared to existing methods.

Findings

Integer-to-integer transforms do not increase dynamic range.

Experiments show competitive compression performance.

The approach offers a viable alternative for lossless HEVC coding.

Abstract

Many approaches have been proposed to support lossless coding within video coding standards that are primarily designed for lossy coding. The simplest approach is to just skip transform and quantization and directly entropy code the prediction residual, which is used in HEVC version 1. However, this simple approach is inefficient for compression. More efficient approaches include processing the residual with DPCM prior to entropy coding. This paper explores an alternative approach based on processing the residual with integer-to-integer (i2i) transforms. I2i transforms map integers to integers, however, unlike the integer transforms used in HEVC for lossy coding, they do not increase the dynamic range at the output and can be used in lossless coding. Experiments with the HEVC reference software show competitive results.