K-C-DaCosta

Convert pngs to mp4

This FFmpeg command reads images named frame_[4 char digit].png and converts it to an mp4 using the h264 encoding which Twitter accepts. The bitrate is set to 5M to reduce blocking as much as possible while keeping the size small.

ffmpeg -framerate 10 -i frame_%04d.png -c:v h264_qsv -b:v 5M video.mp4

Convert and scale an existing mp4 to 1080:

ffmpeg -i input.mp4 -c:v h264_qsv -vf: scale=1080:-1 -b:v 5M output.mp4

Profiling performance

Using perf:

$ perf record -g binary
$ perf script | stackcollapse-perf.pl | rust-unmangle | flamegraph.pl > flame.svg

NOTE: See @GabrielMajeri's comments below about the -g option.

	#!/usr/bin/env zsh -f
	# Purpose: get the RSS feed for a YouTube page
	# Inspired By: https://eggfreckles.net/notes/youtube-rss/
	# Gist: https://gist.github.com/tjluoma/fdbc63ceb78a2aecd3d638fd18b6ec6e
	#
	# From: Timothy J. Luoma
	# Mail: luomat at gmail dot com
	# Date: 2020-01-17; updated 2021-01-10

	# 2021-01-10 YouTube currently has both 'rssUrl' and

	/*
	A Minimal Capture Program

	This program opens an audio interface for capture, configures it for
	stereo, 16 bit, 44.1kHz, interleaved conventional read/write
	access. Then its reads a chunk of random data from it, and exits. It
	isn't meant to be a real program.

	From on Paul David's tutorial : http://equalarea.com/paul/alsa-audio.html