DALI Release 0.31.0

The DALI 0.31 is not a major release, so the features, functionality, and performance might be limited.

Using DALI 0.31

To upgrade to DALI 0.31 from an older version of DALI, follow the installation and usage information in the DALI User Guide.

Note: The internal DALI C++ API used for operator’s implementation, and the C++ API that enables using DALI as a library from native code, is not yet officially supported. Hence these APIs may change in the next release without advance notice.

Key Features and Enhancements

This DALI release includes the following key features and enhancements.

  • New operators:
    • Gridmask CPU and GridMask Data Augmentation (https://arxiv.org/abs/2001.04086), which is useful for the EfficientNet pipeline (#2582).
    • ROIRandomCrop CPU, where an operator is required to perform the biased random crop in segmentation applications (#2638).
  • Added support for the variable batch size in ExternalSource (#2481, #2641).
  • Added support for the time-major layout in the following spectrogram processing operators:
    • GPU and CPU Spectrogram (#2619, #2617)
    • GPU and CPU MelFilterBank (#2620)
  • Refactored and unified the following RNG operators:
  • Reworked the custom operators documentation (#2568).
  • Applied performance improvements in the JPEG decoder (#2655, #2610).

Fixed Issues

This DALI release includes the following fixes:

  • Fixed the length that was reported by DALI firmware iterators when the DROP policy is used (#2611).
  • Provided a workaround for a compiler problem that caused an Invalid device function error. (#2656)
  • Fixed RandomBBoxCrop errors that ocurred while using the crop_shape argument (#2605)

Breaking Changes

  • There are no breaking changes in this release.

Deprecated Features

Here are the features that were deprecated in this release:
  • ops.Uniform was moved to ops.random.Uniform.
  • ops.CoinFlip was moved to ops.random.CoinFlip.

Known Issues

  • The video loader operator requires that the key frames occur, at a minimum, every 10 to 15 frames of the video stream.

    If the key frames occur at a frequency that is less than 10-15 frames, the returned frames might be out of sync.

  • The DALI TensorFlow plugin might not be compatible with TensorFlow versions 1.15.0 and later.

    To use DALI with the TensorFlow version that does not have a prebuilt plugin binary that is shipped with DALI, make sure that the compiler that is used to build TensorFlow exists on the system during the plugin installation. (Depending on the particular version, you can use GCC 4.8.4, GCC 4.8.5, or GCC 5.4.)

  • Due to some known issues with meltdown/spectra mitigations and DALI, DALI shows the best performance when running in Docker with escalated privileges, for example:
    • privileged=yes in Extra Settings for AWS data points
    • --privileged or --security-opt seccomp=unconfined for bare Docker