DavidEGrayson

ffprobe foo.mp4   # Make sure the audio stream is aac.
ffmpeg -i foo.mp4 -vn -acodec copy foo.aac
ffmpeg -i foo.aac -acodec pcm_s16le foo.wav
# Edit foo.wav with audacity, save to foo_edited.wav.
ffmpeg -i foo_edited.wav -acodec aac foo_edited.aac
ffmpeg -i foo.mp4 -codec copy -an foo_silent.mp4
ffmpeg -i foo_silent.mp4  -i foo_edited.aac -shortest -c:v copy -c:a aac foo_edited.mp4

# Reduce file size and remove sounds
ffmpeg -i foo.mp4 -vcodec libx264 -crf 28 -an foo_out.mp4

DavidEGrayson

Building a mingw-w64 GCC cross-compiler with nixcrpkgs: instructions for Terry, October 2018

1. Install Nix, the functional package manager. You'll need Linux (but macOS might work too).
2. Make sure you have at least 4 GB of free space available for /tmp and a few GB of free space available for /nix.
3. To get my recipes, run: git clone https://github.com/DavidEGrayson/nixcrpkgs && cd nixcrpkgs && git checkout 4f7b11d That commit is the current tip of the dev/david/2019 branch.
4. To build a i686-w64-mingw32 C/C++ cross-compiling toolchain and a hello world program, run: nix-build -A win32.hello
5. To build Qt and its examples, run: nix-build -A win32.qt.examples
6. To just build the toolchain itself, run: nix-build -A win32.gcc

DavidEGrayson

[root@alderaan gradual]# pacman -Sy archlinux-keyring
:: Synchronizing package databases...
 core is up to date
 extra is up to date
 community is up to date
warning: archlinux-keyring-20180108-1 is up to date -- reinstalling
resolving dependencies...
looking for conflicting packages...

Packages (1) archlinux-keyring-20180108-1

DavidEGrayson

$ clang-format --version
clang-format version 5.0.0 (tags/RELEASE_500/final)

$ cat .clang-format 
AllowShortBlocksOnASingleLine: true

$ cat test.cpp
int foo(int x)
{
  if (x == 0) { return 1; }

DavidEGrayson

$ cat somefile.h
struct a;

struct a *init();
void setd(struct a*p, int dd);
int getd(struct a*p);
void cleanup(struct a*p);


$ cat somefile.c

DavidEGrayson

$ cat test.sh
#!/bin/sh

for a in 0; do
    echo b=$(echo "c-d" | tr - _)
done

$ . test.sh
b=c_d

DavidEGrayson

$ cat test.c
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char ** argv)
{
    for(int i = 0; i < argc; i ++)
    {
        printf("%d = %s\n", i, argv[i]);
    }

DavidEGrayson

$ cat /dev/bus/usb/001/002 | head -c18 | hexdump
0000000 0112 0110 0000 0800 80ee 0021 0100 0301
0000010 0100                                   
0000012
$ lsusb
Bus 001 Device 002: ID 80ee:0021 VirtualBox USB Tablet
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

DavidEGrayson

# Given an array of dependencies and a block for retrieving dependencies of an
# dependency, returns an array of dependencies with three guarantees:
#
# 1) Contains all the listed dependencies.
# 2) Has no duplicates.
# 3) For any dependency in the list, all of its dependencies appear before it.
#
# Guarantee 3 only holds if the underlying graph has no circul dependencies.  If
# there is a circular dependency, it will not be detected, but it will not cause
# an infinite loop either.

DavidEGrayson

set -ue

pacman -S --needed "${MINGW_PACKAGE_PREFIX}-qt5-static"

if [ ! -d qt ]; then
  wget https://download.qt.io/official_releases/qt/5.8/5.8.0/submodules/qtbase-opensource-src-5.8.0.tar.xz -O qt.tar.xz
  tar -xf qt.tar.xz
  mv qtbase-opensource-src-5.8.0 qt
fi