EXR Format Supported and Unsupported Features

[brianpopow]

This is a tracking issue for EXR features which are currently supported and which are not.

Supported pixel types:

• Half: 16-bit floating-point numbers
• Float: 32-bit IEEE-754 floating-point numbers
• Uint: 32-bit unsigned integers;

Supported compression's for decoding:

• NO_COMPRESSION: pixel data is not compressed
• RLE_COMPRESSION: run length encoding
• ZIPS_COMPRESSION: zlib compression, one scan line at a time
• ZIP_COMPRESSION: zlib compression, in blocks of 16 scan lines
• B44_COMPRESSION: lossy 4-by-4 pixel block compression, fixed compression rate
• B44A_COMPRESSION: lossy 4-by-4 pixel block compression, flat fields are compressed more
• DWAA_COMPRESSION: lossy DCT based compression, in blocks of 32 scanlines. More efficient for partial buffer access.
• DWAB_COMPRESSION: lossy DCT based compression, in blocks of 256 scanlines. More efficient space-wise and faster to decode full frames than DWAA_COMPRESSION.
• PIZ_COMPRESSION: piz-based wavelet compression
• PXR24_COMPRESSION: lossy 24-bit float compression
• HTJ2K256_COMPRESSION: JPEG 2000 lossless coding, in blocks of 256 scanlines and using the High-Throughput block coder specified in Rec. ITU-T T.814 and ISO/IEC 15444-15. The compressor offers both speed and high coding efficiency.
• HTJ2K32_COMPRESSION: Same as HTJ2K256_COMPRESSION, but in blocks of 32 scanlines, More efficient for partial buffer access, but slightly less efficient space-wise.

Other EXR image features:

• Tiled images
• Multi-part EXR files

The EXR specification can be found here: https://openexr.com/en/latest/index.html