(evince:22792): EggSMClient-WARNING **: Failed to connect to the session manager: None of the authentication protocols specified are supported
(evince:22792): Gtk-WARNING **: Attempting to read the recently used resources file at `/home/lenfers/.recently-used.xbel', but the parser failed: Datei »/home/lenfers/.recently-used.xbel« konnte nicht geöffnet werden: Permission denied.
** (evince:22792): WARNING **: Error creating last_settings file: Fehler beim Öffnen der Datei »/home/lenfers/.gnome2/evince/last_settings«: No such file or directory

As I found out, that is caused by AppArmor, a surely useful innovation to secure your computer, but new enough that I haven’t took the time to get to know it. AppArmor is activated by default on Ubunut 10.04 (and IIRC 9.10 and maybe 9.04 as well) and restricts access of programs on certain files. Due to the change of my home directory, evince tried to access files which for AppArmor are in /data/home/lenfers/ and consequently disallowed access to them.

The solution to this is easy, after I found it: Make your new location for home directories known to AppArmor: Add the path of your home direcories to the HOMEDIRs var in  /etc/apparmor.d/tunables/home. Now the line looks like that for me:

@{HOMEDIRS}=/home/ /data/home/

Now back to work.

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Download the current version directly through the plugins menu or from wordpress.org.

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My hack I will be using for the world cup the next four weeks is the following: I described how to stream the world cup at your office for all your colleagues a few days ago. I will do that at home too, and then just play that stream, in which the video and the audio are really in sync, at least for my ear. I have to play the stream, because the VDR still has control over the DVB devices and VLC couldn’t open them. And the VLC on my VDR is quite ancient, since I’m using an older version of c’t-vdr.

So, on one computer I start VLC with the following options (all in one line):

cvlc  http://vdr:3000/S19.2E-1-1101-28106  ":sout=#rtp{dst=226.42.42.42,port=5004,mux=ts}"

You can get the URL for each channel from your vdr at http://vdr:3000/channels.html.

And on all the computers that are supposed to view the stream, VLC has to be started with the following command:

vlc rtp://@226.42.42.42:5004/

Sure there is now a slightly higher delay (two streams), but I don’t mind those three seconds when we can watch the games with synced audio. You can get a bit more information about streaming in my world cup streaming post and a lot more in the VLC streaming documentation.

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Mehr Infos und Bilder auf Googles Seite zur Google Maps Navigation.

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Um bei der Verlosung mitzumachen, hinterlasst doch einfach einen Kommentar. (Mit richtiger E-Mail-Adresse, wird nicht angezeigt, aber ich brauche sie zum Verschicken des Invites.)

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Behold, there might be restrictions in your country, that prohibit even this personal use, please check before deploying this somewhere!

Prerequisite

• A spare computer with Linux,Windows or I presume OSX. It doesn’t even need to be spare one: Since we don’t want to transcode, it uses virtually no resources.
• a DVB card supported by your operating system (I’m using DVB-T in my example)
• VLC

Setting up the stream

Setting up the stream consists of two parts: You need the source and the stream settings. For the source settings with DVB-T you’ll need to know the frequency of the channel you want to stream. Here in Bremen, Germany for example the frequency for ARD is 482000Khz. You can use the tool scan to generate a channels.conf when running linux (found in the package dvb-apps in Ubuntu) and probably OSX. I don’t know how to get a channels.con or the frequencies on a windows box, but maybe you can find a channels.conf for your region in the VDR Wiki. An entry in the channels.conf looks like that:

Das Erste:482000:I999B8C23D12M16T8G4Y0:T:27500:261:262:267:0:160:8468:3329:0

The red number in the second field is the frequency we need, here 482000Khz. You can try it out by opening VLC and choosing Media=>Open Capture Device (or Ctrl+C). The capture mode has to be set to DVB (DVB Directshow on Windows), you need to fill in your frequency, ignore the advanced options and hit Play. You should be able to see a channel, but not necessarily the one you wanted. There are usually three to four channels on one frequency, so you might need to tune manually to the channel you wanted in Playback=>Program. (The SID of the channel (160) is marked in green in the example above, we’ll use it later to tune to that channel automaticly.)

When that worked we can start setting up the stream. VLC can stream anything it can play, you could stream video files, webcams and a lot of other media. We’ll set the stream up as a multicast stream for a local network with RTP, so it will not work through internet connections. If you want to set a stream over the internet up, please refer to the VLC streaming documentation, but don’t forget that you might need a lot of bandwidth for multiple clients. The advantage of multicast over unicast streaming is that we need to send the data only once into the network and not to every client. The client either ignores the traffic or subscribes to it and receives it.

We need a multicast address to identify our stream and we can chose in the range from 224.0.0.0 to 239.255.255.255, e.g. 226.42.42.42. To set the stream up, chose Media=>Streaming (or Ctrl+S) and select Capture Device. Set the DVB settings up like you tried out above and select Stream. Your settings are copied into the Source field in the next dialog, so you could simply click next. But you might want to copy the settings into a text file for the automation later. Next you will have the possibility to set the stream settings up: As destination chose RTP and click Add. You should get something like the following, where you should put in your multicast address, uncheck the transcoding option and leave the other options on default settings:

After a click on next you get a few options you can leave alone and, like with the source before, a string for the stream. We should copy that one too to the text file and click on stream. We are now streaming a channel to the network, even though you cannot see anything.

Connecting with a client

To see the stream, you need to connect to it. You can do that locally on your own computer too, just open a new VLC and choose Media=>Open Network Stream. Check RTP as protocol and put in your multicast address:

You can now already save a playlist file to send to your clients later on. Make sure your playlist is empty besides that stream (Ctrl+L opens it) and then save it Media=>Save Playlist to File (or Ctrl+Y).

Automating the Server

This is supposed to be a quick and dirty solution, we won’t create start scripts for this or run it as a NT service. But if you don’t want to set the server settings up every time you start the stream, you can create a batch file under windows or run it completely from the command line on linux. (Preferably in a GNU screen session.)

Linux users can run cvlc without an interface, but can also use vlc if they want the interface. You can run the following line after replacing your my settings with the ones you gathered directly in a shell (or a shell with screen) or you can put it into a .sh file and run it as a script.

cvlc dvb-t://frequency=482000000 --ts-es-id-pid --program 160 ":sout=#rtp{dst=226.42.42.42,port=5004,mux=ts}"

In windows create a .bat file with a simple text editor and replace my example with your settings (all in one line). Of course you can configure a lot more settings with the GUI and get very complex settings in the first step for this. (On 64bit Windows, you might have to replace %ProgramFiles% with “%ProgramFiles(x86)%.) Then you can just run the .bat file instead of setting the stream up every time.

"%ProgramFiles%\Videolan\vlc\vlc.exe" dvb-t://frequency=482000000 --ts-es-id-pid --program 160 :sout=#rtp{dst=226.42.42.42,port=5004,mux=ts}

The frequency is here given in Hz, not Khz, so you need to add three more zeros.

Conclusion

I hope this simple tutorial about streaming helped you to stream the word cup wherever you wanted. I wrote it, because I had some problems in the beginning, since the VLC documentation is being revised for the current 1.0 series and didn’t reflect always the current status.

I found it very impressing that I could stream a channel to three different computers in the same room and the audio was in sync, at least for my ears. I would love to see something like this to find it’s way into VDR or some other solution to stream audio (or even video!) at home…

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Oh and from a geeks point of view I found the license quite curious: Creative Commons – Deed Attribution-Noncommercial-No Derivative Works Kudos to that!

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What I for example didn’t knew before, is that he left Star Trek on his own to pursue his movie career. Since there was a big Anti Wesley Crusher Campaign during TNG, I always assumed that he was written out of the show. I have to admit, I wasn’t a Wesley fan either and wasn’t that unhappy that he left the show, even though I never would have written him a fan hate letter or something like that. But I never really thought about the fact, that it wasn’t his fault: A 16 year old boy has not that much influence with writers/directors/whatever, he had to do what the script told him.

If you are interested in a bit Star Trek history from a unique point of view or perhaps follow Wils blog, this book is surely a good read, I enjoyed it very much.

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My new mainboard for the vdr (Asus M4N78-VM) runs great so far with linux, especially at the moment yavdr: HDTV on the DVI worked out of the box. And my biggest fear that I’ll get problems with the wakeup are completely wiped out: The board woke up after setting a time with acpi-wakeup. (Well, it didn’t boot up, because there are some problems with the standby mode, but I don’t need that too bad.)

Only real bummer: The board doesn’t fit in my gorgeous Silverstone LaScala SST – LC 11M. Don’t know what to do yet, the case is really nice, but quite small. I would like to buy something where I can fit pci cards without a riser card, but that on the other hand doesn’t fit in my living room anymore.

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