Building Android App without IDE from the command line

Recently I got the source code of one particular Android App from github and I wanted to build that on my Debian Unstable latest.  I was just trying to see how I could build without installing the IDE.  This is what I did. apt-get install default-jdk From Android site I downloaded both commandlinetools and gradle.Continue reading “Building Android App without IDE from the command line”

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gstreamer pipeline to stream raw audio over network

Normally all audio pipelines use an audio codec and RTP encapsulation. I searched a lot for a raw audio pipeline, but I could not find much information. Then, I tried different options and came up with the following. gst-launch-1.0 -v filesrc location=/tmp/musicfile.mp3 ! mpegaudioparse ! mpg123audiodec ! audioconvert ! audioresample ! audio/x-raw, rate=16000, channels=1, format=S16LEContinue reading “gstreamer pipeline to stream raw audio over network”

Compiling ffmpeg and vlc from source

Both ffmpeg and vlc are two of the important applications in free software media processing. I wanted to compile both to incorporate latest codecs, x264 and libvpx for video along with aac and libopus for audio. This is what I have done on Debian unstable. For my purpose, I was compiling these codecs from source.Continue reading “Compiling ffmpeg and vlc from source”

Airtel 3G modem E1731 Linux Configuration – Complete guide

Recently I bought an Airtel 3G connection using Huawei E1731Bu-1 USB modem. As usual, I wanted to get it working in Debian GNU/Linux amd64 version. As a first step, installed the following packages using apt-get. sudo apt-get install ppp pppconfig wvdial Normally this modem is detected properly, but I was curious to know the extraContinue reading “Airtel 3G modem E1731 Linux Configuration – Complete guide”

Network File Transfer using Netcat

Netcat can be of great help in trasferring files across network, that too in a really scalable pipeline. For bear minimum usage of file transfer, only tar and netcat utilities are required. I tried different options and found the following superset pipeline. sender:$ tar cf – some_directory | gzip -9 | \ pv | gpgContinue reading “Network File Transfer using Netcat”

Spoofing Multicast packet from another interface.

This is the scenario. I have a working ethernet device eth0 with an IP address 192.168.1.x. There is one more special interface in the system, say if1 which is connected to another network. That network is mainly used for transmitting multicast data. Received multicast data has to be processed by a userland application. Due toContinue reading “Spoofing Multicast packet from another interface.”

Network throughput measurement using netcat

There are many network throughtput and performance measurement tools available. One of the most widely used one is “iperf”. But, I found “netcat” to be a very versatile and fantastic tool to do the same. The only “extra” requirement is to have shell access to both sides, so that netcat could be used. First installContinue reading “Network throughput measurement using netcat”

Taking OpenEmbedded SRC_URI from environment variable

OpenEmbedded uses SRC_URI to determine where the source code is taken from. For many projects it would be convenient to use source code from local repository due to many reasons, in order to support that, it is possible to use file URI as ‘file://’ For example, SRC_URI=”file:///path/to/local_repo/whatever_project” This can create problem because it is notContinue reading “Taking OpenEmbedded SRC_URI from environment variable”

Creating a Minimal Kernel Development Setup using KVM/Qemu

I wanted to setup a Linux kernel development system and the best choice I found was using KVM/Qemu. Both KVM and Qemu use the same virtual hardware specification, but KVM could give near native performance using special processor instructions. Since both of them use the same virtual hardware, the same virtual disk image could beContinue reading “Creating a Minimal Kernel Development Setup using KVM/Qemu”

Basic Mathematics from shell command line

It is possible to do a lot of calculations from command shell itself without using any spreadsheet applications or scripting languages like perl or python. What we require is simple un*x applications like, bc, xargs, awk etc. To sum a list of numbers There are many different ways to do that, but the best wayContinue reading “Basic Mathematics from shell command line”