Posted: December 2006

Related pages on www.mikekohn.net: Naken Web, Linux PTZ Control, j2me ipcamview, Axis DBus

Introduction

Naken Web is both a tiny web server capable of serving static web pages with built in ability to serve out live and prerecorded video in MJPEG format from capture devices such as webcams and AVI files. Naken Web is small enough (22k to 32k) to run on embedded platforms and has been tested on the Gumstix embedded computer, a Linksys WRT54GL router running OpenWrt, and a Neuros OSD. Naken Web can be configured to serve out video from URLs similar to commercial IP cameras like Axis.

I also have a sample plugin for Naken Web that shows it doing motor control similar to what a commercial PTZ IP camera would have here: Atmel Motor Control. I'm using it to control the motors on a Linksys Helicopter.

News

July 26, 2008 - Fixed a bug that caused plugins to not work :(. I have a video on YouTube of Naken Web being used on a Linksys router to communicate with an Atmel ATmega168 to control a servo motor here: https://www.youtube.com/watch?v=0KdkPXHDsVw.

July 23, 2008 - I started working on a module for this web server that can do motor control on an embedded computer, much the way Axis has their PTZ control. I have a project page here for anyone interested: atmel_motor_control.php.

February 27, 2008 - I added binaries for the Atmel's avr32. It's compiled for their network gateway demo board which I hope to use to interface over rs232 with an Atmel ATmega168 microcontroller using Naken Web as human interface. I'll post more info as this project continues.

July 18, 2007 - I have the server working with a Logitech Pro 5000 now using the Linux uvc driver. There is also a new plugin interface with a simple example. The plugin allows the server to alias a URL to a function inside a shared object library. Could be useful for interfacing another program to a web frontend without a CGI. So far only the GET method works.

History

A couple years ago I modified my Naken Chat chat server so that would act like a web server and serve out JPEG images out of an AVI file. Pressing the refresh button on a web browser to grab a new image would display the next image in the video based on the time that the web server was started. In other words, the video would play at normal speed in the browser. If you wait 5 seconds before pressing refresh and the avi plays at 30 frames a second, 150 frames are skipped so the time in the video is always accurate.

Anyway, I recently started up development of this program again and it currently has the following features:

• Serve out AVI files as if they were a live webcam
• Serve out static html web content like any other webserver
• Executable size is currently around 22k (32k with video4linux compiled in)
• Small/fast enough to run on embedded platforms such as Gumstix
• Alias URL strings of commerical IP cameras
• Video4Linux support for live video (early stages.. but working with bttv and sn9c102 based video)
• No dependencies unless video4linux is compiled in (libjpeg is needed then)
• Client Pull/Server Push for MJPEG video
• Username/Password Basic-Authentication
• Runs on both Unix/Linux and Microsoft Windows platforms

Compiling

If you downloaded the source code instead of the binaries, you can build it by typing:

./configure
make

from the command line. If you'd like to compile in video4linux2 support you can configure it with ./configure --enable-v4l2. Typing ./configure --help will print out a list of options. Naken Web compiles on Unix/Linux platforms as well as Windows under MingW

Starting with the January 02, 2007 version, I added a --with-mmap option. This will force Naken Web to mmap() (or on Windows, map a file) the avi videos to try and reduce i/o loads. I haven't had a chance to test this yet under a loaded system, but I'm thinking it will reduce the i/o significantly on computers with harddrives. It probably won't be a good thing to do embedded systems, but I haven't had a chance to test it yet.

Basic Configuration

Basically, you can define up to 100 avi videos in the nakenweb.conf file. They are defined with the filename option and are numbered in order they are put in the file. The first defined AVI is video #0, the second is video #1, etc. After defining videos, maxconn is set to the max number of webclients that can connect to the server at one time. max_idle_time is set to how long a client can be connected to the server without sending any data before being booted. port tells the server which port to bind to. If you have no other web server, you'll probably want to set this to 80.

An example nakenweb.conf file could look like this:

filename /storage/videos/blah.avi
filename /storage/videos/testing.avi
filename /storage/videos/asdf.avi
minconn 10
maxconn 50
max_idle_time 3
port 80

# If not defined, non-builtin web pages will 404. It's completely okay not to define htdocs_dir.
htdocs_dir /var/www/htdocs

#if username and password are not defined, password protection is turned off
username mike
password pencil

To start the server type:

./nakenweb -f nakenweb.conf

This will start the server using nakenwebcam.conf as the configuration file. If you want more help with compiling or starting the server, you can read the documentation for Naken Chat. The docs there should be very similar, if not the same.

After the sever is started, you can test connecting to the server by typing: http://localhost/0 into your webbrowser. This should give you the current video frame from blah.avi. Alternatively you could type: http://localhost/1 to get the current frame from the testing.avi or http://localhost/2 to get the current frame from asdf.avi. By refreshing the webbrowser, the newest frame will show up. It'd be pretty easy to write a web client that constantly grabs the newest frames from the videos to create full motion video.

IP Camera Emulation Configuration

Setting up an alias for an IP camera should be fairly straight forward. The following 2 examples will set up a couple of aliases in Axis's VAPIX API format:

alias /axis-cgi/mjpg/video.cgi
{
  port camera
  type stream
  frame_rate fps
}

Which would allow the URL http://localhost/axis-cgi/mjpg/video.cgi?camera=1 to work. By setting up the "port camera" option, this tells the Naken Web server that if on the URL line the user adds the option camera=<some number> that it should use camera number to dictate which defined video number the user wants to look at. Note that this is video number - 1. So if the URL was video.cgi?camera=2, the user would be grabbing from Naken Web's video defined as number 1. type stream defines this as a server push video (multipart/x-mixed-replace). "frame_rate fps" tells the server that if the user adds fps=<some number> to use this frame rate for sending out video.

alias /axis-cgi/jpg/image.cgi
{
  port camera
  type single
}

This example is the same as the first example execpt it relies on a client pull. In other words, that URL will only send one image (jpeg) instead of a stream of images (mjpeg). The URL that would be used to grab an image would then be http://localhost/axis-cgi/jpg/image.cgi?camera=1

alias /oneshotimage.jpg
{
  port 0
  type single
}

The above alias will emulate the URL of a Sony IP camera. It will send a single image from Naken Web's video source number 0. In this example, all ?paramter=value's will be ignored.

You are not limited to the number of aliases you can create, altho for each one you define a few bytes of memory will be allocated and a tiny amount of CPU is used to check if the current URL matches the alias for every hit to the server. If this doesn't make sense, send me an email. I'd be glad to help :)

Video4Linux2 Configuration

To set up a Video4Linux2 device, the capture parameter is used:

capture /dev/video0
{
  size 640x480
  max_fps 5
}

This sets of a video4linux2 USB camera for use with Naken Web. Note that the capture option is counted in the same way the filename option is. In other words, if a capture options is defined first, then the capture option is defined as video #0. Capture and filename options can be intermixed so videos and cameras can be numbered how you want them.

capture /dev/video1
{
  size 352x240
  max_fps 5
  channel 1 # bttv can have 4 devices hooked up to the same chip
  format ntsc
}

This sets of a video4linux2 bttv device for use with Naken Web.

Limitations

If you'd like to serve out AVI files the AVI's need to use the MJPEG codec. If you have a video encoded with mpeg or some other fileformat/codec, you can convert it to AVI/MJPEG using ffmpeg with the following line:

ffmpeg -i myvideo.mpeg -vcodec mjpeg -b 10000 -s 352x240 -an out.avi

Obviously you need to change myvideo.mpeg to the name of your input file, out.avi to what you want the output file to be called, -b is the bitrate and will affect the size of each jpeg in the avi file along with the quality of the video. The -s option is the resolution of the video. The -an option tells ffmpeg to leave out audio.

New Features (March 2007)

The following features are implemented in the new version:

• VFW (Video For Windows) code added for webcams and capture devices on Windows (2007-03-15)
• CGI execution with php/cgi support (GET only right now) (2007-02-28).
• Huge increase in performance, especially on Windows (2007-03-15)
• mmap()'d avi's for possible added performance (2007-01-02)
• Added the ability to serve static html (html, jpeg, png, etc) from an htdocs directory
• Added URL aliasing for emulation of IP camera strings
• Video4linux for display of live real-time video
• Added server push support for MJPEG streaming
• Username/Password Basic Authentication

The following are my list of things to work on:

• Frames per second control
• Mutex issues with video4linux
• Memory allocation on jpeg compression
• Networking send failure retries
• RTSP streams (probably a bit in the future)
• Virtual Hosts
• Video4Windows support so USB webcams and such work on Microsoft Windows (Code is written and in subversion, just needs to be tested)

License: Since Naken Chat is GPL, this program is GPL also.

Download 2011-March-5
nakenweb-2011-03-05.tar.gz (Source Code)
nakenweb-2011-03-05.zip (Windows Binaries)

Note: CGI is currently compiled out of these binaries

If you need binaries for another system please email me

Java Webcam Viewer (Will be improved later)

IpCamView-2007-03-19.tar.gz
IpCamView-2007-03-19.zip

I have a J2ME IpCamView here: J2ME

Older Versions
nakenweb-2008-07-26.tar.gz (Source Code)
nakenweb-2008-07-26.zip (Windows Binaries)
nakenweb-2008-07-26-i686-linux.tar.gz (Linux Binaries)
nakenweb-2007-03-19.tar.gz (Source Code)
nakenweb-2007-03-15.tar.gz (Source Code)
nakenweb-2007-02-28.tar.gz (Source Code)

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