IONCANNON » software http://www.ioncannon.net Thoughts on Software Development and Engineering Tue, 03 Jan 2012 13:59:08 +0000 en hourly 1 Streaming Video Between QuickTime Broadcaster and VLC http://www.ioncannon.net/software/478/streaming-video-between-quicktime-broadcaster-and-vlc/ http://www.ioncannon.net/software/478/streaming-video-between-quicktime-broadcaster-and-vlc/#comments Sat, 04 Jul 2009 00:19:58 +0000 carson http://www.ioncannon.net/?p=478 In my attempt to stream live video to my iPhone I ran into an issue with the USB QuickCam I have. Instead of fighting the problem I decided to turn to the iSight camera on a macbook but I quickly found that there isn't a great way to get the video stream to another machine. The best way that I have found to stream from the iSight to a second machine is to use a combination of QuickTime Broadcaster and VLC. In this post I detail how I got it set up and working.

Step 1: Install QuickTime Broadcaster

The first step is to install QuickTime Broadcaster. It doesn't have a lot of requirements so it should work on most macs. The QuickTime Broadcaster will be the source of the video and the destination of the video in my case is a second machine with VLC installed on it although you could run VLC on the source machine if you wanted to.

An important note at this point is to make sure the destination machine doesn't have a firewall turned on or if it does that it isn't blocking ports 5432 and 5434.

Step 2: Configure QuickTime Broadcaster for Streaming

Navigate to the Applications folder and launch QuickTime broadcaster. Click on the network tab and select "Custom" from the "Preset" list. For "Transmission" select the "Manual Unicast" option. The "Address" field contains the IP for your target machine, the one that you are streaming to. When you are finished, your settings should look something like this:

QuickTime Broadcast Network Setup for Streaming Video to VLC

Now the configuration is ready and it is time to create an export for use in VLC. To export go to File -> Export -> SDP menu option. For this example I'm calling the file stream01.sdp.

QuickTime Broadcaster Export SDP

You should transfer this file to the machine you are going to run VLC on at this point. If you are interested you can actually view the contents of the SDP file. Here is the one generated for me from the above:

v=0
o=- 0 3702455757 IN IP4 127.0.0.0
s=QuickTime
t=0 0
a=range:npt=now-
a=isma-compliance:2,2.0,2
m=audio 5432 RTP/AVP 96
c=IN IP4 192.168.132.100
b=AS:125
a=rtpmap:96 mpeg4-generic/44100/2
a=fmtp:96 profile-level-id=15;mode=AAC-hbr;sizelength=13;indexlength=3;indexdeltalength=3;config=1210
a=mpeg4-esid:101
m=video 5434 RTP/AVP 97
c=IN IP4 192.168.132.100
b=AS:1372
a=rtpmap:97 H264/90000
a=fmtp:97 packetization-mode=1;profile-level-id=4D401E;sprop-parameter-sets=J01AHqkYFAe2ANQYBBrbCte98BA=,KN4JF6A=
a=mpeg4-esid:201
a=cliprect:0,0,480,640
a=framesize:97 640-480



Step 3: Play the Video Stream with VLC

Once the SDP file is on the destination machine you can start VLC and open it. In VLC go to File -> Open File then select the SDP file that was exported earlier.

VLC Open File

VLC is now ready to stream from QuickTime Broadcaster. In QuickTime Broadcaster click the Broadcast button and then in VLC click the play button. At this point you should start seeing the stream in VLC. The order you start broadcasting between QuickTime Broadcaster and VLC doesn't seem to matter. There were a few times that I had VLC start for a second then freeze but I was using a wireless network so I'll blame that for the freezes. In general it worked well once it was all set up.

You can start VLC from the command line and point it directly to the stream file if you want. To do that use this command:

vlc stream01.sdp

or if you want fancy logging:

vlc -vvv –color –file-logging –logfile vlc-log.html –logmode html stream01.sdp



Step 4: VLC Streaming

This is actually what I would call re-streaming since my need is to get the iSight stream to FFMpeg. In the perfect world I would be able to stream directly from QuickTime Broadcaster to FFMpeg but the limitations of QuickTime Broadcaster don't allow that to happen, at least from what I could find.

To re-stream the iSight stream follow these steps:

  1. Go to Media -> Streaming

    VLC Streaming Menu Option

    Enter the SDP file in the file window and hit the Stream button.

  2. After you click the Stream button a window will pop up where you have the option to select a Destination:

    VLC Stream Output Destinations HTTP Add

    Select "Display locally" if you want to see the video as it is re-streamed.

    Select HTTP from the "New destination" drop down list and click the Add button. I have picked HTTP here because it is what works the best for me but there are other options you can use if you want to try different streaming protocols. I was able to leave the defaults as they were for the HTTP stream.

  3. Select a transcoding profile. Here I've selected the "Video – Theora + Vorbis (OGG)" profile for streaming. It seems to work the best for me:

    VLC Stream Output Destinations Setup

    Click the Stream button at the bottom to start streaming.

  4. Test the stream with something like mplayer or ffplay. Because I'm using HTTP to do the stream I can run the following command to test:
    mplayer http://192.168.132.100:8080/

    Just as the playback can be done from the command line the re-streaming can too:

    vlc stream01.sdp –sout '#transcode{vcodec=theo,vb=800,scale=1,acodec=vorb,ab=128,channels=2,samplerate=44100}:duplicate{dst=std{access=http,mux=ogg,dst=0.0.0.0:8080},dst=display}'

    If you want to drop the local display:

    vlc stream01.sdp –sout '#transcode{vcodec=theo,vb=800,scale=1,acodec=vorb,ab=128,channels=2,samplerate=44100}:duplicate{dst=std{access=http,mux=ogg,dst=0.0.0.0:8080}}'
]]> http://www.ioncannon.net/software/478/streaming-video-between-quicktime-broadcaster-and-vlc/feed/ 6 Running Lotus Notes 8 on Linux with newer xulrunner http://www.ioncannon.net/linux/316/running-lotus-notes-8-on-linux-with-newer-xulrunner/ http://www.ioncannon.net/linux/316/running-lotus-notes-8-on-linux-with-newer-xulrunner/#comments Mon, 02 Mar 2009 11:49:01 +0000 carson http://www.ioncannon.net/?p=316 I recently got tired of running Lotus Notes under wine because I kept getting meeting invites that I couldn't accept. So I ventured out because I had heard that Notes now had a Linux client and sure enough it does. The install is huge but it went very smooth up until the point that I first launched to read my mail. At the point where it should have shown me the start screen I got an error dialog with the error "JVM terminated. Exit code=160" and a big stack trace.

Lotus Notes error message
(Click the image to see a larger version)

After digging around a little I found that the Eclipse framework/SWT expected an older version of xulrunner to be installed. The simple fix to get Notes running was to move the xulrunner libraries out of the way:

mv /usr/lib/xulrunner-1.9/ /tmp/
mv /tmp/xulrunner-1.9/ /usr/lib/

Now when I started Notes I was able to get all the way in and see the following error on the start page:

Lotus Notes start page error
(Click the image to see a larger version)

Now the key to getting Notes into a usable state is to close the "Getting Started" tab. If you don't do this you can never move xulrunner back into place. Once you have closed the tab exit out of Notes and then put the xulrunner libraries back where they belong.

Now you can start Notes without an issue, just make sure not to open anything that requires a web browser.

Lotus Notes home page
(Click the image to see a larger version)

After going through this someone pointed me towards the latest 8.5 beta 2 release of Lotus Notes for Linux and after installing that I can report that it actually has fixed the issue. So whenever 8.5 comes out this should be fixed until another incompatible version of xulrunner comes out.

]]> http://www.ioncannon.net/linux/316/running-lotus-notes-8-on-linux-with-newer-xulrunner/feed/ 4 PowerDNS Makes Custom DNS Backends Easy http://www.ioncannon.net/system-administration/135/powerdns-custom-dns-backend/ http://www.ioncannon.net/system-administration/135/powerdns-custom-dns-backend/#comments Sun, 14 Sep 2008 22:55:41 +0000 carson http://www.ioncannon.net/?p=135 I ran into PowerDNS recently when I needed to find a DNS server that would allow me to produce custom responses to domain queries. I needed to have a request for a DNS entry return a different IP depending on some factors in a database and I needed that data to always be accurate (not cached locally). I found that PowerDNS allows for a lot of customization and I ended up using its piped backend for dynamic queries feature.

With this level of customization you can do things like write your own DNS black list, track who is making DNS requests, give out IP addresses based on a servers availability or use geographic information to return a different IP.

The following is an overview of how to set up your own PowerDNS piped backend process. To start out it may help to read the overview of the PowerDNS backend.

Here is an example program that is run directly by PowerDNS using pipes:

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class PowerDNSPipeTest
{
  public static void main(String[] args) throws Exception
  {
    BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

    readIntro(reader);

    String line;
    while((line = reader.readLine()) != null)
    {
      processLine(line);
    }
  }

  private static void processLine(String line)
  {
    String values[] = line.split("\t");

    if(values.length == 6)
    {
      // Testing any a response to the ANY or A record request
      if("ANY".equalsIgnoreCase(values[3]) || "A".equalsIgnoreCase(values[3]))
      {
        System.out.println("DATA\t" + values[1] + "\tIN\tA\t0\t1800\t127.0.0.5");
      }
    }
    else
    {
      System.out.println("LOG\tPowerDNS sent unpareable string");
      System.out.println("FAIL");
    }

    System.out.println("END");
    System.out.flush();
  }

  private static void readIntro(BufferedReader reader) throws IOException
  {
    String line = reader.readLine();
    if(line != null)
    {
      String values[] = line.split("\t");
      if(values.length == 2 && "HELO".equals(values[0]) && "1".equals(values[1]))
      {
        System.out.println("OK\tBackend starting");
        return;
      }
    }

    System.out.println("FAIL");
    System.out.flush();
    System.exit(-1);
  }
}

I found that for some reason PowerDNS didn't want to run the java command directly so I copied that class to /tmp and wrapped the command in a small shell script like this to see if that would fix the problem:

#!/bin/sh
/usr/local/java/bin/java -cp /tmp/ PowerDNSPipeTest

In the configuration file I then added:

launch=pipe
pipe-command=/tmp/powerdns.sh

This works fine but PowerDNS spawns multiple backend processes to run the piped application and with java that seemed like a bad idea since it would create an entire JVM instance each time. So I decided to modify their sample perl program to send the requests to a long running java background process that would then just use threads.

#!/usr/bin/perl -w

use strict;

$|=1;                                   # no buffering

my $line=<>;
chomp($line);

unless($line eq "HELO\t1")
{
        print "FAIL\n";
        print STDERR "Recevied '$line'\n";
        <>;
        exit;
}
print "OK       Sample backend firing up\n";    # print our banner

while(<>)
{
        print STDERR "$$ Received: $_\n";
        chomp();
        my @arr=split(/\t/);
        if(@arr<6)
        {
                print "LOG      PowerDNS sent unparseable line\n";
                print "FAIL\n";
                next;
        }

        print STDERR "$$ Sent A records\n";
        print &sendRequest($_ . "\n");

        print STDERR "$$ End of data\n";
        print "END\n";
}

sub sendRequest
{
  use Socket;
  my($sockaddr, $this, $that, $thataddr, $thisaddr, $remote, $port, $iaddr, $paddr, $proto, $line, @output);

  $remote = "127.0.0.1";
  $port = 4444;
  $sockaddr = 'S n a4 x8';

  if ($port =~ /\D/) { $port = getservbyname($port, 'tcp') }
  die "No port" unless $port;
  $thisaddr   = gethostbyname("localhost");
  $thataddr   = gethostbyname($remote);
  $this   = pack($sockaddr, AF_INET, 0, $thisaddr);
  $that   = pack($sockaddr, AF_INET, $port, $thataddr);

  $proto   = getprotobyname('tcp');
  socket(SOCK, PF_INET, SOCK_STREAM, $proto)  || die "socket: $!";
  bind(SOCK, $this)    || die "bind: $!";
  connect(SOCK, $that)    || die "connect: $!";
  select(SOCK); $| = 1; select(STDOUT);

  print SOCK @_;
  @output = <SOCK>;

  close (SOCK) || die "close: $!";
  @output;
}

Here is the code for the threaded java server modified from the above pipe example:

import java.net.ServerSocket;
import java.net.Socket;
import java.io.*;
import java.util.concurrent.PriorityBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

public class PowerDNSServerTest
{
  public static void main(String[] args) throws Exception
  {
    PriorityBlockingQueue<Runnable> queue = new PriorityBlockingQueue<Runnable>();
    ThreadPoolExecutor threadPool = new ThreadPoolExecutor(5, 30, 30, TimeUnit.SECONDS, queue);

    ServerSocket serverSocket = new ServerSocket(4444);

    while(true)
    {
      threadPool.execute(new PowerDNSServerClientThread(serverSocket.accept()));
    }
  }

  private static class PowerDNSServerClientThread implements Runnable
  {
    private Socket clientSocket;

    public PowerDNSServerClientThread(Socket clientSocket)
    {
      this.clientSocket = clientSocket;
    }

    public void run()
    {
      try
      {
        BufferedReader input = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        BufferedWriter output = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()));

        String command = input.readLine();
        System.err.println("[" + Thread.currentThread().getName() + "] Received: " + command);

        String values[] = command.split("\t");

        if(values.length == 6)
        {
          // Testing any a response to the ANY or A record request
          if("ANY".equalsIgnoreCase(values[3]) || "A".equalsIgnoreCase(values[3]))
          {
            output.write("DATA\t" + values[1] + "\tIN\tA\t0\t1800\t127.0.0.5\n");
          }
        }
        else
        {
          output.write("LOG\tPowerDNS sent unpareable string\n");
          output.write("FAIL\n");
        }

        output.write("END\n");
        output.flush();

        output.close();
        input.close();

        clientSocket.close();
      }
      catch (IOException e)
      {
        e.printStackTrace();
      }
    }
  }
}

In the config file I replaced the above entries with:

launch=pipe
pipe-command=/tmp/powerdns.pl

That is all there is to it. So far this is the easiest way I have found of passing requests on to an application. The configuration for PowerDNS also allows you to force a request to the backend with every query eliminating the internal cache. For me that was a needed feature since every request could potentially change from second to second and the latest IP would need to be given out. I found that there are a lot of options for small tweaks like this that are probably on the fringe of what 99% of users need but are very handy to be able to change when you need to change them.

]]> http://www.ioncannon.net/system-administration/135/powerdns-custom-dns-backend/feed/ 0 Acrobat Reader 7 and FC6 http://www.ioncannon.net/system-administration/121/acrobat-reader-7-and-fc6/ http://www.ioncannon.net/system-administration/121/acrobat-reader-7-and-fc6/#comments Wed, 14 Feb 2007 13:41:54 +0000 carson http://www.ioncannon.net/system-administration/121/acrobat-reader-7-and-fc6/ I broke down and wanted to install Adobe Acrobat Reader 7 on my FC6 box to replace xpdf. After installing it from the tar.gz version the acroread startup script bombed out with the error: expr substr 2400000000000 1

After a little searching I didn't find much help so I started looking at the script myself to see if I could track down the problem. It turns out that it wasn't that hard to fix. First off the script file was located at: /usr/bin/acroread

Open the script file and find the function named "check_gtk_ver_and_set_lib_path". This is the location of the first error you will hit. To fix the error you will need to change:

base_version=`expr substr "${base_version}0000000000" 1 $len_version`

to

blah1="${base_version}0000000000"
base_version=${blah1:1:$len_version}

You will find this two places and it needs to be changed in both. If you don't notice the 2nd place it is right after the first in a loop:

while [ $len_version -gt $len_base_version ]; do

The second problem you will have is located in the function "get_gtk_file_ver". Find this function and change the following line:

echo $mfile| sed 's/libgtk-x11-\([0-9]*\).0.so.0.\([0-9]\)00.\([0-9]*\)\|\(.*\)/\1\2\3/g'

to

echo $mfile| sed 's/libgtk-x11-\([0-9]*\).0.so.0.\([0-9]\)000.\([0-9]*\)\|\(.*\)/\1\2\3/g'

Now you should be able to run acroread without errors.

Tags: , ,

]]> http://www.ioncannon.net/system-administration/121/acrobat-reader-7-and-fc6/feed/ 4 Making screencasts with Linux http://www.ioncannon.net/linux/73/making-screencasts-with-linux/ http://www.ioncannon.net/linux/73/making-screencasts-with-linux/#comments Wed, 26 Jul 2006 10:44:35 +0000 carson http://www.ioncannon.net/linux/73/making-screencasts-with-linux/ After my post about capturing full page screenshots with firefox I started wondering if there was a way to do screencasts using Linux. It just so happens that you can. There are a couple different options if you want a pure movie of your desktop but I was more interested in a flash version. I found what I was looking for with this tutorial on how to record videos of your desktop that uses vnc2swf.

I tried the instructions on a fedora core 5 box and found that vnc2swf requires tkinter and pygame be installed but they are both packages that are easy to install with yum. You will also need some type of vnc server running on your box. If you want to do a screencast of your current desktop you will need to use x11vnc. It will allow you to let a vnc viewer connect to your current desktop. I found that using x11vnc didn't work that well. I'm not sure if it was the desktop I was using or what but the screencasts came out very choppy and for the most part unusable. I switched to using vncserver with a lightweight window manager and that fixed the issue. I think I like doing that better anyway because it gives me a fresh desktop to work from without all the normal extras. When you are doing a screencast it probably makes more sense to have less to look at anyway.

  1. Start the vnc server (here I set the size too): vncserver :1 -geometry 640×480
  2. Then you will want to start the viewer: vncviewer :1
  3. Start the recorder: python vnc2swf.py -t video -o test.swf :1
  4. Select a filename to save the screencast as
  5. Select SWF(Video) from the dropdown on the left
  6. Hit start and make your screencast using the viewer

Here is an example of the final product:



You may also only want to capture one window of your desktop. To do that you will need to run xwininfo in you vnc session and click on the window you want to capture. After clicking the window xwininfo will return the location of that window in absolute terms as well as the width and height of the window. With that information you add -C widthxheight+x+y to the recording command. For example the xterm in my previous example is at 11×29 on the screen and is 517 wide and 355 tall so the command would be:

python vnc2swf.py -t video -o test2.swf -C 517×355+11+29 :1

And that produces this:



There are a couple other utilities that come with the package. One is a player that you can use to play your screencast and the other is an editor. The editor lets you remove frames, change the framerate and shrink the screencast .I found that shrinking the screencast was mostly useless since it became unreadable quickly.

A few other options you have if you want a pure video of your desktop are: wink for linux, Istanbul for gnome and screenkast.

Tags: , , ,

]]> http://www.ioncannon.net/linux/73/making-screencasts-with-linux/feed/ 1