Neural Network Weight Training for Bitrate-Aware Compression

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Solution Overview

Problem

Existing neural network compression methods, such as NNC, face challenges in optimizing the rate-performance trade-off due to the sensitivity of quantization indices and entropy coding, leading to inefficient storage and transmission of neural networks, especially in resource-constrained environments.

Innovation Solution

A bitrate-and quantization-aware training method that integrates performance loss and bitrate considerations through a combined loss function, using simulated quantization and straight-through estimation to update neural network weights, optimizing the compression efficiency by approximating bitrates based on quantization indices and entropy coding contexts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If quantization and entropy coding are applied to compress neural networks, then the bitrate is reduced, but the performance loss increases due to sensitivity of quantization indices

Engineering Contradiction:
ImprovebitrateVSAvoidperformance
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by performing quantization-aware training before the actual compression process. The neural network weights are pre-optimized to be more robust to quantization effects, and the training process itself is made aware of the upcoming quantization and entropy coding operations. This preliminary preparation reduces the performance loss that would otherwise occur during compression.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes parameters by making the training process bitrate-aware and quantization-aware. The loss function is modified to include bitrate estimation terms, and the training dynamically adjusts to account for the discrete nature of quantization indices. This parameter change allows the model to learn weight distributions that are more amenable to compression while maintaining performance.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If standard quantization and DeepCABAC entropy coding are used, then compression is achieved, but the rate-performance trade-off is suboptimal due to lack of bitrate awareness in training

Engineering Contradiction:
Improvecompression ratioVSAvoidcoding efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The patent implements feedback by creating a closed-loop training system where the bitrate estimation from entropy coding is fed back into the loss function during training. The training process continuously adjusts the weights based on both performance metrics and estimated bitrate, creating a feedback mechanism that optimizes the rate-performance trade-off. This feedback loop allows the model to learn from the actual compression outcomes.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies universality by creating a unified training framework that simultaneously optimizes for both performance and compression efficiency. The combined loss function serves multiple purposes: it maintains accuracy while also considering bitrate, making the training process multi-functional rather than requiring separate optimization steps for performance and compression.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If quantization levels are increased to maintain performance, then the bitrate increases, but storage and transmission efficiency decreases

Engineering Contradiction:
ImproveperformanceVSAvoidbitrate
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent changes parameters by modifying the loss function to include bitrate estimation terms that penalize excessive bitrate usage. This parameter change in the optimization objective allows the system to find a balance point where performance is maintained at acceptable levels while bitrate is minimized, rather than monotonically increasing bitrate to maintain performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by making different parts of the neural network weights have different properties suitable for their specific compression needs. The training process optimizes local weight distributions to be more amenable to quantization, and the bitrate-aware loss function applies different pressures to different weight regions based on their contribution to both performance and bitrate.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS20250378315A1Apparatus and method for determining a neural network representation
Publication Date: 2025.12.11 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • US20250378315A1 patent drawing
  • US20250378315A1 patent drawing
  • US20250378315A1 patent drawing

AI summary

For neural network representation determination, forward-passes are cyclically performed using a quantized version of weights of a neural network or using the weights of a neural network, and a weights-to-bitrate or weights-to-bitlength function is determined by determining, for each of a plurality of entropy coding contexts, a probability estimate depending on statistics of binary strings obtained from quantization indices of quantization levels of the weights or the quantization indices, and a discrete function mapping the quantization levels or the quantization indices onto bitrates by determining bit lengths for binary strings which comprise one or more context-adaptive entropy coded bins using a bin-wise summation over a logarithmized version of the probability estimate of the entropy coding context. The weights-to-bitrate or weights-to-bitlength function is formed by a summation of, for each of the weights, an approximation function approximating the discrete function and a combined loss function based on a performance loss function of the forward-passes and the weights-to-bitrate or weights-to-bitlength function. Finally, for each weight, a gradient of the combined loss function is determined and used to update the respective weight for a next cycle.