How to cut mp4 using ffmpeg

Tested on Ubuntu 16.04

-ss is the starting time
-t is the duration

ffmpeg -i input.mp4 -ss 00:12:20 -t 00:2:00 -async 1 -strict -2  cut.mp4

How to Install Go 1.10 on Ubuntu16.04

Copied from  Rahul K. https://tecadmin.net/install-go-on-ubuntu/ 

 

Go is an open source programming language developed by a team at Google. It provides easy to build simple, reliable, and efficient software. This language is designed for writing servers, that’s why it is using widely these days. Go has released latest version 1.10. This tutorial will help you to install Go 1.10 on your Ubuntu 18.04 LTS, 16.04 LTS, and 14.04 LTS systems.

Step 1 – Install Go Language

Login to your Ubuntu system using ssh and upgrade to apply latest security updates there.

sudo apt-get update
sudo apt-get -y upgrade

Now download the Go language binary archive file using following link. To find and download latest version available or 32 bit version go to official download page.

wget https://dl.google.com/go/go1.10.3.linux-amd64.tar.gz

Now extract the downloaded archive and install it to the desired location on the system. For this tutorial, I am installing it under /usr/local directory. You can also put this under the home directory (for shared hosting) or other location.

sudo tar -xvf go1.10.3.linux-amd64.tar.gz
sudo mv go /usr/local

Step 2 – Setup Go Environment

Now you need to setup Go language environment variables for your project. Commonly you need to set 3 environment variables as GOROOT, GOPATH and PATH.

GOROOT is the location where Go package is installed on your system.

export GOROOT=/usr/local/go

GOPATH is the location of your work directory. For example my project directory is ~/Projects/Proj1 .

export GOPATH=$HOME/Projects/Proj1

Now set the PATH variable to access go binary system wide.

export PATH=$GOPATH/bin:$GOROOT/bin:$PATH

All above environment will be set for your current session only. To make it permanent add above commands in ~/.profile file.

Step 3 – Verify Installation

At this step, you have successfully installed and configured go language on your system. First, use the following command to check Go version.

go version

go version go1.10.3 linux/amd64

Now also verify all configured environment variables using following command.

go env

GOARCH="amd64"
GOBIN=""
GOCACHE="/root/.cache/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/root/Projects/Proj1"
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
...
...

Deploy celery on Debian 8 using upstart

Make an upstart conf file:

nano /etc/init/celery.conf

Insert in it:

description "Celery application server handling myproject"
start on runlevel [2345]
stop on runlevel [!2345]
respawn
setuid john
setgid www-data
chdir /path/to/django/proj
exec bash celery.sh

Put `celery.sh` in /path/to/django/proj

CELERY_BIN="/home/john/.projenv/bin/celery"

# App instance to use
CELERY_APP="proj"
# Where to chdir at start.
CELERYD_CHDIR="/path/to/django/proj"
# Extra command-line arguments to the worker
CELERYD_OPTS="--time-limit=300 --concurrency=1"
# %n will be replaced with the first part of the nodename.
CELERYD_LOG_FILE="/var/log/celery/%n%I.log"
CELERYD_PID_FILE="/var/run/celery/%n.pid"
# Workers should run as an unprivileged user.
#   You need to create this user manually (or you can choose
#   a user/group combination that already exists (e.g., nobody).
CELERYD_USER="john"
CELERYD_GROUP="www-data"
# If enabled pid and log directories will be created if missing,
# and owned by the userid/group configured.
CELERY_CREATE_DIRS=1
export SECRET_KEY="somekey"

Start the deamon:

service celery start

That's it!‌

How to concatenate mp4 videos using ffmpeg on Ubuntu

for f in $(ls *.mp4); do
    ffmpeg -i $f -c copy -bsf:v h264_mp4toannexb -f mpegts $f.ts
done

CONCAT=$(echo $(ls *.ts) | sed -e "s/ /|/g")

ffmpeg -i "concat:$CONCAT" -c copy -bsf:a aac_adtstoasc output.mp4

rm *.ts


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