MRD Streaming Format

MRD data can be stored and streamed in binary format or as NDJSON.

MRD uses Yardl to generate C++, Python, and MATLAB code for reading and writing MRD streams.

Binary

The MRD binary format is the primary format for streaming raw MR data.

Examples of reading and writing MRD streams are provided in the MRD repository:

• C++:
  • cpp/mrd-tools/mrd_phantom.cc
  • cpp/mrd-tools/mrd_stream_recon.cc
  • cpp/mrd-tools/mrd_image_stream_to_png.cc
• Python:
  • python/mrd/tools/phantom.py
  • python/mrd/tools/stream_recon.py
  • python/mrd/tools/export_png_images.py
• MATLAB:
  • matlab/toolbox/examples/generate_phantom.m
  • matlab/toolbox/examples/stream_recon.m
  • matlab/toolbox/examples/export_png_images.m

See also:

• Quick Start Guides for Python, C++, and MATLAB
• Yardl Binary Encoding Reference

NDJSON

The NDJSON serialization format is great for debugging and interoperability with other tools (like jq) but it is much less efficient than the binary format.

The C++ and Python SDKs are both capable of reading and writing NDJSON.

To use MRD NDJSON readers/writers, substitute ndjson for binary in the constructor. For example, in Python

import mrd

header = mrd.Header()

with mrd.BinaryMrdWriter("phantom.bin") as w:    
with mrd.NDJsonMrdWriter("phantom.bin") as w:    
    w.write_header(h)
    w.write_data(generate_data())