Sebastian Gassner sepastian

## dvgrab_ffmpeg.sh
# Grab video from a camcorder using dvgrap,
# convert to h.265 encoded video using ffmpeg.
#
# https://trac.ffmpeg.org/wiki/Encode/H.265
# https://regx.dgswa.com/html/content/dvgrab-ffmpeg-capture-compression

dvgrab --format dv1 --rewind - \
  | ffmpeg -f dv -i - \
    -vf yadif \
    -c:v libx265 -crf 26 \

## DEPRECATED_pip_install_in_coderpad.py
# DEPRECATED:
# In addition to running Python code, the coderpad console allows
# to pip install packages as well:
#
# >>> pip install sortedcontainers
#
# Using the code below is not required.
# It will be kept here for reference, as it shows how to access
# the Coderpad environment.

## main.cpp
#include <set>
#include <iostream>
#include <vector>

/*
 * How to order a set<vector<A>::iterator>.
 */

struct A
{

## meson_ninja.sh
# https://germandiagogomez.medium.com/getting-started-with-meson-build-system-and-c-83270f444bee

# Create project directory.
mkdir new_project
cd new_project

# Create source file.
echo "int main() {};" >> main.cpp

# Init meson, setup meson.

## v4l2_set_camera_zoom_level.md

      
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                sepastian
                / v4l2_set_camera_zoom_level.md
            
            
              Last active
              June 29, 2023 07:58
            
              
                V4L2 set camera zoom level
              
          
    Environment

$ uname -a
Linux x220 6.3.0-1-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.3.7-1 (2023-06-12) x86_64 GNU/Linux

List Cameras


## raw_to_ppm_to_jpg.sh
#!/bin/bash

set -euo pipefail

# Convert (Nikon/NEF) RAW images to PPM using dcraw;
# write results to stdout with -c;
# convert stdin to JPG using Imagemagick's convert;
# specify format of input image with 'ppm:-'.
find /path/to/sdcard/ -name '*.NEF' \
  | parallel 'dcraw -c {} \

## ext4_fs_tuning.md

      
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                sepastian
                / ext4_fs_tuning.md
            
            
              Last active
              March 10, 2023 16:36
            
              
                ext4 file system tuning
              
          
    From: https://cromwell-intl.com/open-source/performance-tuning/file-systems.html.
Mount Parameters

Disable recording of access times when mounting the FS.
For example, find with access times enabled would upate the access time of every file found.
# /etc/fstab

  
## record_left_monitor.zsh
# Oh-My-ZSH custom function to record left monitor from CLI.
#
# Place in $ZSH/.oh-my-zsh/custom.
#
# Two monitors at screen 0, the left one connected at DP-1:
#
#     xrandr
#     Screen 0: minimum 320 x 200, current 3840 x 1200, maximum 16384 x 16384
#     DP-1 connected primary 1920x1200+1920+0 (normal left inverted right x axis y axis) 518mm x 324mm
#       1920x1200     59.95*+

## compress_pdf.zsh
# Place in $ZSH/.oh-my-zsh/custom.
#
# The following ZSH function uses GhostScript's `gs` command to reduce the file size of a PDF file.
# The result of compressing `test.pdf` will be written to `test.compressed.pdf`.
# If `test.compressed.pdf` exists, it will only be overwritten after confirmation.
#
# Now, restart/open a new shell and compress PDFs with:
#
#     compress_pdf test.pdf
#     File exists: test.compressed.pdf, overwrite (Y/n)?

## determine_dpi.sh
# Based on https://apple.stackexchange.com/a/389067/453491

# In order to calculate DPI, determine units and resolution first.
identify -verbose warc2corpus@2x_300dpi.png | grep -E -i "resolution|units"
#  Resolution: 118.11x118.11
#  Units: PixelsPerCentimeter
#    png:pHYs: x_res=11811, y_res=11811, units=1

# 1 PixelsPerCentimeter corresponds to 2.54 DPI.
# Calculate DPI using the following command.
	# Grab video from a camcorder using dvgrap,
	# convert to h.265 encoded video using ffmpeg.
	#
	# https://trac.ffmpeg.org/wiki/Encode/H.265
	# https://regx.dgswa.com/html/content/dvgrab-ffmpeg-capture-compression

	dvgrab --format dv1 --rewind - \
	\| ffmpeg -f dv -i - \
	-vf yadif \
	-c:v libx265 -crf 26 \
	# DEPRECATED:
	# In addition to running Python code, the coderpad console allows
	# to pip install packages as well:
	#
	# >>> pip install sortedcontainers
	#
	# Using the code below is not required.
	# It will be kept here for reference, as it shows how to access
	# the Coderpad environment.
	#include <set>
	#include <iostream>
	#include <vector>

	/*
	* How to order a set<vector<A>::iterator>.
	*/

	struct A
	{
	# https://germandiagogomez.medium.com/getting-started-with-meson-build-system-and-c-83270f444bee

	# Create project directory.
	mkdir new_project
	cd new_project

	# Create source file.
	echo "int main() {};" >> main.cpp

	# Init meson, setup meson.
	#!/bin/bash

	set -euo pipefail

	# Convert (Nikon/NEF) RAW images to PPM using dcraw;
	# write results to stdout with -c;
	# convert stdin to JPG using Imagemagick's convert;
	# specify format of input image with 'ppm:-'.
	find /path/to/sdcard/ -name '*.NEF' \
	\| parallel 'dcraw -c {} \
	# Oh-My-ZSH custom function to record left monitor from CLI.
	#
	# Place in $ZSH/.oh-my-zsh/custom.
	#
	# Two monitors at screen 0, the left one connected at DP-1:
	#
	# xrandr
	# Screen 0: minimum 320 x 200, current 3840 x 1200, maximum 16384 x 16384
	# DP-1 connected primary 1920x1200+1920+0 (normal left inverted right x axis y axis) 518mm x 324mm
	# 1920x1200 59.95*+
	# Place in $ZSH/.oh-my-zsh/custom.
	#
	# The following ZSH function uses GhostScript's `gs` command to reduce the file size of a PDF file.
	# The result of compressing `test.pdf` will be written to `test.compressed.pdf`.
	# If `test.compressed.pdf` exists, it will only be overwritten after confirmation.
	#
	# Now, restart/open a new shell and compress PDFs with:
	#
	# compress_pdf test.pdf
	# File exists: test.compressed.pdf, overwrite (Y/n)?
	# Based on https://apple.stackexchange.com/a/389067/453491

	# In order to calculate DPI, determine units and resolution first.
	identify -verbose warc2corpus@2x_300dpi.png \| grep -E -i "resolution\|units"
	# Resolution: 118.11x118.11
	# Units: PixelsPerCentimeter
	# png:pHYs: x_res=11811, y_res=11811, units=1

	# 1 PixelsPerCentimeter corresponds to 2.54 DPI.
	# Calculate DPI using the following command.