Ciro Santilli @cirosantilli  40

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OpenShot Updated 2025-07-16

Ubuntu 20.10 crash...:

  exceptions:ERROR Unhandled Exception
Traceback (most recent call last):
  File "/usr/bin/openshot-qt", line 11, in <module>
    load_entry_point('openshot-qt==2.5.1', 'gui_scripts', 'openshot-qt')()
  File "/usr/lib/python3/dist-packages/openshot_qt/launch.py", line 97, in main
    app = OpenShotApp(argv)
  File "/usr/lib/python3/dist-packages/openshot_qt/classes/app.py", line 218, in __init__
    from windows.main_window import MainWindow
  File "/usr/lib/python3/dist-packages/openshot_qt/windows/main_window.py", line 45, in <module>
    from windows.views.timeline_webview import TimelineWebView
  File "/usr/lib/python3/dist-packages/openshot_qt/windows/views/timeline_webview.py", line 42, in <module>
    from PyQt5.QtWebKitWidgets import QWebView
ImportError: /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5: undefined symbol: _ZN4QRhi10newSamplerEN11QRhiSampler6FilterES1_S1_NS0_11AddressModeES2_, version Qt_5_PRIVATE_API

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Codec acceleration Updated 2025-07-16

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GHDL Updated 2026-10-19

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github.com/ghdl/ghdl

Examples under vhdl.

First install GHDL. On Ubuntu:

sudo apt install verilator

Tested on Verilator 1.0.0, Ubuntu 22.04.

Run all examples, which have assertions in them:

cd vhdl
./run

Files:

Examples
- Basic
  - vhdl/hello_world_tb.vhdl: hello world
  - vhdl/min_tb.vhdl: min
  - vhdl/assert_tb.vhdl: assert
- Lexer
  - vhdl/comments_tb.vhdl: comments
  - vhdl/case_insensitive_tb.vhdl: case insensitive
  - vhdl/whitespace_tb.vhdl: whitespace
  - vhdl/literals_tb.vhdl: literals
- Flow control
  - vhdl/procedure_tb.vhdl: procedure
  - vhdl/function_tb.vhdl: function
- vhdl/operators_tb.vhdl: operators
- Types
  - vhdl/integer_types_tb.vhdl: integer types
  - vhdl/array_tb.vhdl: array
  - vhdl/record_tb.vhdl.bak: record. TODO fails with "GHDL Bug occurred" on GHDL 1.0.0
  - vhdl/generic_tb.vhdl: generic
- vhdl/package_test_tb.vhdl: Packages
  - vhdl/standard_package_tb.vhdl: standard package
  - textio
    * vhdl/write_tb.vhdl: write
    * vhdl/read_tb.vhdl: read
  - vhdl/std_logic_tb.vhdl: std_logic
- vhdl/stop_delta_tb.vhdl: --stop-delta
Applications
- Combinatoric
  - vhdl/adder.vhdl: adder
  - vhdl/sqrt8_tb.vhdl: sqrt8
- Sequential
  - vhdl/clock_tb.vhdl: clock
  - vhdl/counter.vhdl: counter
Helpers
* vhdl/template_tb.vhdl: template

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The Man From Earth (2007) Updated 2025-07-16

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Low budget.

Good theory of Jesus.

List of similar feeling films: www.youtube.com/watch?v=zwYwFoanrNg 11 Underrated Hard Sci-fi Movies by Marvelous Videos (2021)

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The best films of all time Updated 2025-07-16

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There is only a very fine difference between a very good film, and the best films of all time. Perhaps it is something to do on how epic the subject matter is? It is often very hard to tell, and switches between the categories are also possible.

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2019 redefinition of the SI base units Updated 2025-07-16

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web.archive.org/web/20181119214326/https://www.bipm.org/utils/common/pdf/CGPM-2018/26th-CGPM-Resolutions.pdf gives it in raw:

the unperturbed ground state hyperfine transition frequency of the caesium-133 atom $Δ v_{C s}$ is 9 192 631 770 Hz
the speed of light in vacuum c is 299 792 458 m/s
the Planck constant h is 6.626 070 15 × $1 0^{- 34}$ J s
the elementary charge e is 1.602 176 634 × $1 0^{- 19}$ C
the Boltzmann constant k is 1.380 649 × $1 0^{- 23}$ J/K
the Avogadro constant NA is 6.022 140 76 × $1 0^{23}$ mol
the luminous efficacy of monochromatic radiation of frequency 540 × 1012 Hz, Kcd, is 683 lm/W,

The breakdown is:

actually use some physical constant:
- the unperturbed ground state hyperfine transition frequency of the caesium-133 atom $Δ v_{C s}$ is 9 192 631 770 Hz
  Defines the second in terms of caesium-133 experiments. The beauty of this definition is that we only have to count an integer number of discrete events, which is what allows us to make things precise.
- the speed of light in vacuum c is 299 792 458 m/s
  Defines the meter in terms of speed of light experiments. We already had the second from the previous definition.
- the Planck constant h is 6.626 070 15 × $1 0^{- 34}$ J s
  Defines the kilogram in terms of the Planck constant.
- the elementary charge e is 1.602 176 634 × $1 0^{- 19}$ C
  Defines the Coulomb in terms of the electron charge.
arbitrary definitions based on the above just to match historical values as well as possible:
- the Boltzmann constant k is 1.380 649 × $1 0^{- 23}$ J/K
  Arbitrarily defines temperature from previously defined energy (J) to match historical values.
- the Avogadro constant NA is 6.022 140 76 × $1 0^{23}$ mol
  Arbitrarily defines the mol to match historical values. In particular, the kilogram is not an exact multiple of the weight of an atom of hydrogen.
- the luminous efficacy of monochromatic radiation of frequency 540 × 1012 Hz, Kcd, is 683 lm/W
  Arbitrarily defines the Candela in terms of previous values to match historical records. The most useless unit comes last as you'd expect.

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Value change dump Updated 2025-07-16

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Verilator Updated 2025-07-16

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Verilog simulator that transpiles to C++.

One very good thing about this is that it makes it easy to create test cases directly in C++. You just supply inputs and clock the simulation directly in a C++ loop, then read outputs and assert them with assert(). And you can inspect variables by printing them or with GDB. This is infinitely more convenient than doing these IO-type tasks in Verilog itself.

Some simulation examples under verilog.

First install Verilator. On Ubuntu:

sudo apt install verilator

Tested on Verilator 4.038, Ubuntu 22.04.

Run all examples, which have assertions in them:

cd verilator
make run

File structure is for example:

verilog/counter.v: Verilog file
verilog/counter.cpp: C++ loop which clocks the design and runs tests with assertions on the outputs
verilog/counter.params: gcc compilation flags for this example
verilog/counter_tb.v: Verilog version of the C++ test. Not used by Verilator. Verilator can't actually run out _tb files, because they do in Verilog IO things that we do better from C++ in Verilator, so Verilator didn't bother implementing them. This is a good thing.

Example list:

verilog/negator.v, verilog/negator.cpp: the simplest non-identity combinatorial circuit!
verilog/counter.v, verilog/counter.cpp: sequential hello world. Synchronous active high reset with active high enable signal. Adapted from: www.asic-world.com/verilog/first1.html
verilog/subleq.v, verilog/subleq.cpp: subleq one instruction set computer with separated instruction and data RAMs

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Venture capitalist Updated 2025-07-16

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Bibliography:

Something Ventured (2011) documentary

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Venture capital firm Updated 2025-07-16

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Scalable Vector Graphics Updated 2025-07-16

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Companies have been really slow to support SVG features in their browsers, and that is very saddening: medium.com/@michaelmangial1/introduction-to-scalable-vector-graphics-6450c03e8d2e

You can't drop SVG support for canvas until there's a way to run untrusted JavaScript on the browser!

SVG does have some compatibility annoyances, notably SVG fonts. But we should as a society work to standardize and implement a fix those, the benefits of SVG are just too great!

Examples: