ubuntu


Compile ffmpeg with video stabilization (vidstab) support on Ubuntu 20.04 LTS

Below are the commands to build vid.stab and ffmpeg on Ubuntu 20.04LTS. (We did not include libaom).

sudo apt-get install build-essential cmake nasm libx264-dev libx265-dev libnuma-dev libvpx-dev libfdk-aac-dev libmp3lame-dev libopus-dev libunistring-dev
mkdir ~/ffmpeg_sources ~/ffmpeg_build ~/bin
cd ~/ffmpeg_sources
wget -O https://github.com/georgmartius/vid.stab/archive/master.zip
unzip master.zip
cd vid.stab-master
cmake -DCMAKE_INSTALL_PREFIX:PATH=~/ffmpeg_build .
make
make install
sudo apt-get update -qq && sudo apt-get -y install \
autoconf \
automake \
build-essential \
cmake \
git-core \
libass-dev \
libfreetype6-dev \
libgnutls28-dev \
libsdl2-dev \
libtool \
libva-dev \
libvdpau-dev \
libvorbis-dev \
libxcb1-dev \
libxcb-shm0-dev \
libxcb-xfixes0-dev \
pkg-config \
texinfo \
wget \
yasm \
zlib1g-dev
wget -O ffmpeg-snapshot.tar.bz2 https://ffmpeg.org/releases/ffmpeg-snapshot.tar.bz2 && \
tar xjvf ffmpeg-snapshot.tar.bz2 && \
cd ffmpeg && \
PATH="$HOME/bin:$PATH" PKG_CONFIG_PATH="$HOME/ffmpeg_build/lib/pkgconfig" ./configure \
--prefix="$HOME/ffmpeg_build" \
--pkg-config-flags="--static" \
--extra-cflags="-I$HOME/ffmpeg_build/include" \
--extra-ldflags="-L$HOME/ffmpeg_build/lib" \
--extra-libs="-lpthread -lm" \
--bindir="$HOME/bin" \
--enable-gpl \
--enable-gnutls \
--disable-libaom \
--enable-libass \
--enable-libfdk-aac \
--enable-libfreetype \
--enable-libmp3lame \
--enable-libopus \
--enable-libvorbis \
--enable-libvpx \
--enable-libx264 \
--enable-libx265 \
--enable-nonfree \
--enable-libvidstab && \
PATH="$HOME/bin:$PATH" make && \
make install && \
hash -r
source ~/.profile

https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu

Using vid.stab with default parameters and two step process.

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:~/ffmpeg_build/lib
ffmpeg -i input.mp4 -vf vidstabdetect -f null -;
ffmpeg -i input.mp4 -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 output.vid.stab.mp4;

https://github.com/georgmartius/vid.stab#usage-instructions

Using deshake filter for comparison.

ffmpeg -i input.mp4 -vf deshake output.deshake.mp4

https://ffmpeg.org/ffmpeg-filters.html#deshake


Ubuntu 18.04 and VOSK Speech Recognition API

Just some quick notes on how to install and use VOSK on Ubuntu 18.04 LTS.

  1. Install using: pip3 install vosk
  2. Get samples from https://github.com/alphacep/vosk-api/tree/master/python/example
  3. Using ffmpeg create input audio files ffmpeg -i video.mkv -c:a pcm_s16le -ac 1 output.wav
    It will create a file of the following type output.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, mono 48000 Hz
  4. Export text to JSON python3 ./test_simple.py output.wav


Host or domain name not found. Name service error for name=smtp.gmail.com type=AAAA: Host not found, try again

Recently, a postfix mail server running on Ubuntu gave us the following error while trying to send an email to Bob:

Jun 16 17:02:03 gateway postfix/smtp[23522]: ED3799A0D27: to=[email protected], relay=none, delay=0.02, delays=0.01/0.01/0/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=smtp.gmail.com type=AAAA: Host not found, try again)

After several attempts like changing the protocol (inet_protocols) to IPv4 (since AAAA is an IPv6 A-record) in /etc/postfix/main.cf and so on we could not get it running.. We restored the configuration file to its original and then we restarted the service:

sudo service postfix restart;

It worked!…. no idea why..