GNU Radio 3.9.0.0

By Marcus Müller | January 17, 2021

Release 3.9.0.0

The future is not set, there is no fate but what we make for ourselves. In this very spirit, GNU Radio 3.9 packs a whole bunch of power when it comes to transforming the way GNU Radio and its ecosytem can be developed in the future.

You’ll find the release tags and signed tarballs now on github, and later on https://www.gnuradio.org/releases/gnuradio/.

Not only did we have great progressions from old dependencies that proved to be all too problematic (SWIG, Python2), but also did we see an incredibly influx of people actively working on how maintainable this code base is. This will nurture the project for years to come.

All in all, the main breaking change for pure GRC users will consist in a few changed blocks – an incredible feat, considering the amount of shift under the hood. Mentioning large shifts, the work that went into the PyBind binding, the CMake modernization, the C++ cleanup, the bug-fixing and the CI infrastructure is worthy of explicit call out; I especially thank

  • Josh Morman
  • Thomas Habets
  • Jacob Gilbert
  • Andrej Rode
  • Ryan Volz

here.

For developers of OOTs, I’m sure PyBind11 will pose a surprise. If you’re used to SWIG, yes, that’s more code to write yourself. But in effect, it’s less code that breaks, and when it breaks, it breaks in much more understandable ways. Josh has put a lot of effort into automating as much of that as possible. There’s certainly no shortage of demand for that! The ecosystem (remember GNU Radio’s tagline?) is in a steady upwind. We’ve seen more, and more stable, contributions from OOT maintainers. That’s great!

For in-tree development, newer dependencies and removal of anachronisms will make sure things move much smoother. Our CI is getting – lately literally every day – better, which means we not only catch bugs earlier, but also allow for much quicker review cycles.

One central change:

If you’re contributing code upstream, we no longer need you to submit a CLA; instead, we ask you to just certify, yourself, that you’re allowed to contribute that code (and not, e.g. misappropriating someone else’s code).

That’s what the DCO (Developer Certificate of Origin) is: Just a quick, “hey, this code is actually for me to contribute under the project’s license”; nothing more.

Which means that our infrastructure will refuse to let your code into the tree if you didn’t add a

Signed-off-by: Maxime Example <maxime@example.com>

to your commit message. Luckily, git can do that for you: git commit -s.

Changed

Project Scope

  • We now require commits to be signed off (DCO); this means you have to attach -s to your git commit command line
  • License headers now SPDX format
  • C++14
  • use C++11 facilities in a lot of places where Boost was still used, especially smart pointers, range loops
  • lambdas where boost::bind was used
  • C11
  • Dependency versions:
    • Python 3.6.5
    • numpy 1.13.3
    • VOLK 2.4.1
    • CMake 3.10.2
    • Boost 1.65
    • Mako 1.0.7
    • PyBind11 2.4.3
  • Compiler options:
    • GCC 8.3.0
    • Clang 11.0.0 / Apple Clang 1100
    • MSVC 1910 (Microsoft VS 2017 15.0)
  • VOLK now “regular” dependency, not in-tree submodule
  • numpy now also a CMake-checked hard dependency for Python support
  • Exception Handling: throw by value, catch by reference (clang-tidy check)
  • C++11: Emplace in vectors where you can; brings performance boni, but not included in clang-tidy-checks
  • Further clang-tidy based code optimizations:
  • empty() instead of size() == 0
  • override where overriding virtual functions (which we do a lot)
  • Logging: removed all std::cerr and fprintf(stderr,…) by GNU Radio logging
  • Logging: Changed logging format for many multiline error logs
  • purged snprintf, printf logging
  • There were a lot of places where a malloc’ed object was used internally, where that was inappropriate. Using simple instance-holding fields now.
  • const for members that were only set at construction time is now desired, and implemented in most places
  • const -> constexp in a lot of places.
  • assert -> static_assert
  • An exception-throwing block will now terminate the flow graph process, configurable through top_block
  • gr-utils cleanup, folder restructuring
  • config version checks installed CMake file will accept “at least this version” now
  • PyBind11 replaces SWIG
    • Full tree conversion from SWIG to Pybind11 bindings
  • Doxygen now uses MathJax, full LaTeX installation no longer required

NOTE: Most of the changes above change the generally preferred coding style in a lot of situations.

GRC

  • start flowgraph in folder where it resides

gnuradio-runtime

  • When calculating offsets in non-integer rate FEC, lround
  • default seed for gr::random now actually as documented time-dependent
  • loggers moved from gr::block to gr::basic_block
  • PMT serialization
  • PMT dicts no longer indistinguishable from pairs
  • PMT symbol hashing no longer suffers under oddball own implementations

gr-audio

  • Increased ALSA buffer nperiods

gr-blocks

  • add, add_const VOLK’ized, templated
    • this seems to break things in other places, even if it proves to be mathematically identical
  • wavfile infrastructure: libsndfile now dependency

gr-digital

  • transcendental block: default to 32 bit float complex, not double
  • Linear equalizer: separate adaptive algorithm, allows for using e.g. trained sequences instead of the classical LMS, CMA
  • DFE: better structure for decision history

gr-dtv

  • LDPC encoder: template functions instead of #defined macros
  • LDPC encoder: smaller tables through uint16_t for index tables

gr-fec

  • API uint8_t, not char

gr-fft

  • FFT blocks/functions templatized

gr-filter

  • logging format
  • rational_resampler_base -> rational_resampler

gr-uhd

  • Required UHD version bumped to 3.9.7
  • logging format

Deprecated

gr-analog

  • sig_source: freq port will be removed in the future

gr-audio

  • audio-sink, -source: Windows audio sink/source deprecated, the portaudio sink/source works even better under windows anyway

gr-digital

  • In favor of symbol_sync, deprecate:
    • clock_recovery_mm
    • msk_timing_recovery
    • pfb_clock_sync

Added

Project Scope

  • C++ Generation all over the place
  • PyBind bindings + generator
  • Github actions
  • Reproducible builds-compatible CMake TIMESTAMP

gnuradio-runtime

  • block_gateway: set_max_output_buffer
  • GR_PREFS_PATH environment variable sensitivity to configure the path to the config file
  • gnuradio-config-info --print-all

GRC

  • option to toggle ID visibilities globally
  • Validation check for QT GUI hints
  • Python snippets

block header parsing tool

  • block header parsing tool (GSoC 2019)

gr_modtool

  • option to convert blacklisted files

gr-analog

  • sig_source: cmd port adds support for dicts, setting of frequency, amplitude, offset and phase parameters

gr-blocks

  • selector now has control message ports
  • Rotator-based freq shift convenience wrapper
  • Message-to-Variable and vice versa blocks
  • DC Spike removal
  • IQ Swap
  • Complex to interleaved char / short: scaling option
  • Delay block: control message port
  • Phase Shift block with message port
  • wavfile_sink, _source can now deal with a lot of audio formats: uncompressed WAV/AIFF, µ- and A-law compressed audio, OGG/Vorbis, FLAC, even octave files
  • Stream Demux, which demuxes streams according to lengths vector
  • rotator: phase() getter

gr-digital

  • OFDM: multiple CP lengths
  • ofdm_equalizer_simpledfe: enable_soft_output
  • Constellation Encoder
  • Constellation: normalization options

gr-fec

  • {en,de}code_rs_8, {en,de}code_rs_ccsds: Reed-Solomon en- and decoders

gr-fft

  • Windows:
    • Gaussian
    • Flat Top
    • Tukey
  • Window build() call now with default beta

gr-filter

  • GRC: File taps loader block
  • Low pass FFT filter convenience wrapper
  • ichar / ishort decimator
  • phase continuity for freq_xlating_fir_filter

gr-network

  • gr-network: a whole new networking blocks module!
    • TCP
    • UDP
  • Much better lockup/multithreading support than 3.7-era blks2 nightmare infrastructure :)

gr-qtgui

  • Azimuth/Elevation plot
  • Autocorrelation plot
  • Compass visualization
  • Dial control
  • Gauge: dial, level
  • Distance plot
  • LED-like indicator
  • Message-passing check box
  • Message-passing numeric control
  • Message-passing push button
  • Toggle Button
  • Eye sink
  • Vertical slider

gr-uhd

  • Filter API
  • UHD 4.0 support
  • Power Reference API
  • Bidirectional setting messages on both sink, source

gr-vocoder

  • Codec2 dev branch support
  • FreeDV: In/output rates can differ
  • FreeDV: text message output

gr-zeromq

  • C++ GRC templates
  • Tag filtering for tag-forwarding blocks

Removed

Project Scope

  • VOLK is no longer a submodule
  • Sphinx: consolidate into doxygen, or wiki-maintained block list.
  • Python 2
  • SWIG
  • gru python module

gnuradio-runtime

  • circular_file.cc
  • math/common_factor.hpp

gr-blocks

  • bin_statistics_f
  • log2_const

gr-digital

  • PFB clock sync: set_taps
  • deprecated old OFDM infrastructur
    • ofdm_frame_acquisition
    • ofdm_frame_sink
    • ofdm_insert_preamble
    • ofdm_sync_fixed
    • ofdm_sync_pn
    • ofdm_sync_pnac
    • ofdm_sync_ml
    • ofdm_receiver
  • digital_voice

gr-fft

  • malloc_float, _double: rely on VOLK
  • Goertzel: dtor superfluous

gr-filter

  • deprecated window function duplicates (use them from gr-fft!)

Fixed

Project Scope

  • CMake: Qwt, Log4Cpp detection
  • ctrlport strings unicodified
  • Freedesktop install script was not executed
  • Redundant icons installed
  • Path substitution on Windows was backslash-broken
  • YAML definitions: more than I can count
  • Cross-building: py interpreter at runtime != build time

gnuradio-runtime

  • ctrlport: unholy stored reference to stack-allocated object removed
  • Sine table generation for fixed point math
  • gr_unittest: floatAlmostEqual had a lot of false passes due abuse of all()
  • get_tags_in_range for delay < (end-start)
  • Premature tag pruning
  • release flattened flowgraph after stopping, fixes restartability/shutdown problem
  • PMT serialization portability
  • latency issue caused by setting block alias on msg block
  • Windows logging errors
  • ctrlport: Thrift >= 0.13 broke

GRC

  • Tab widget ID visibilities
  • A lot of YAML templates
  • Default setting in qtgui chooser restored
  • Boolean parameters no longer switch buttons
  • Nested namespace handling
  • Don’t rely on set ordering in tests
  • configparser import
  • input box color theme on dark themes
  • Search box typing doesn’t inadvertedly interact with the rest of GRC anymore

gr_modtool

  • Empty argument lists allowed
  • Boost UTF replaced CppUnit, this needed to be done here, too

gr-analog

  • wfm left/right, filters

gr-audio

  • portaudio: lock acquisition was improper

gr-blocks

  • Throttle now uses monotonic clock
  • Tag debug only saved last work call’s tags
  • File sink flushes on stop
  • gr_read_file_metadata.py used to lose rx_time precision
  • File source big file handling under Windows
  • file_*: fseek errors used to be ignored

gr-digital

  • map_bb: thread safety, buffer overflows
  • additive_scrambler: reset was broken
  • Constellation scalefactor wasn’t always initialized
  • long-standing qa_header_payload_demux bug addressed by waiting for both RX and TX, not only either
  • false triggers in correlate_access_code

gr-dtv

  • rate mismatch in ATSC flowgraphs

gr-fec

  • async_decoder Heap corruption
  • cc_encoder: constraint length K > 8 led to wrong output

gr-fft

  • thread safety of copy assignment/ctor
  • log power FFT Python

gr-filter

  • variable_band_pass_filter GRC complex taps input
  • RRC filter gain for alpha = 1

gr-qtgui

  • Remove copies of image data in returns by using move semantics
  • Remove bogus overriding in drawing functions of plot_raster, _waterfall
  • Edit MSG box: don’t require key to be set
  • Don’t check for Python2 libs
  • Number Sink ignored averaging setting

gr-uhd

  • UHD apps: Py3 fixes
  • USRP blocks: multichannel objects not properly populating channels

gr-video-sdl

  • YUV formats fixed

gr-zeromq

  • Don’t depend on deprecated ZMQ functionality (fix warnings, include what you use)
  • Unhandled exceptions now handled, much calmer
  • Avoid infinite blocking in tb.stop() by using ZMQ_LINGER

Contributors