NNEF Overview


Neural Network Exchange Format (NNEF)

Industry Call for Participation in a new neural network initiative

Neural network technology has seen recent explosive progress in solving pattern matching tasks in computer vision such as object recognition, face identification, image search, image to text, and is also playing a key part in enabling driver assistance and autonomous driving systems.

Convolutional Neural Networks (CNN) are computationally expensive, and so many companies are actively developing mobile and embedded processor architectures to accelerate neural net-based inferencing at high speed and low power. As a result of such rapid progress, the market for embedded neural net processing is in danger of fragmenting, creating barriers for developers seeking to configure and accelerate inferencing engines across multiple platforms.

Today, most neural net toolkits and inference engines use proprietary formats to describe the trained network parameters, making it necessary to construct many proprietary importers and exporters to enable a trained network to be executed across multiple inference engines.

The Khronos Neural Network Exchange Format (NNEF) is designed to simplify the process of using a tool to create a network and running that trained network on other toolkits or inference engines. This can reduce deployment friction and encourage a richer mix of cross-platform deep learning tools, engines and applications.

The NNEF standard encapsulates neural network structure, data formats, commonly used operations (such as convolution, pooling, normalization, etc.) and formal network semantics. This enables the essentials of a trained network to be reliably exported and imported across tools and engines. NNEF is purely a data interchange format and deliberately does not prescribe how an exported network has been trained, or how an imported network is to be executed. This ensures that the data format does not hinder innovation and competition in this rapidly evolving domain.

Neural Network Exchange Format

Khronos is coordinating its neural network activities, including NNEF and the new OpenVX Neural Network Extension. It is expected that NNEF files will be able to represent all aspects of an OpenVX neural network graph, and that OpenVX will enable import of network topologies via NNEF files through the Import/Export extension, once the NEFF format definition is complete.

More details on the OpenVX Neural Network Extension