Use it!!

Click on the "Pure Data ( Webcam v4l )" or "Pure Data ( Webcam v4l2 )" icon on the desktop :

Alternatively, you can open a terminal and type the command "/usr/local/pd/bin/start-v4l" or "/usr/local/pd/bin/start-v4l2".

You should choose one application or the other depending on the model of your webcam and if it's supported by Video 4 linux or Video 4 Linux 2.

The application should start and the first thing you see is something like this :

You should also see a blank video window output like this :



You should set up this window on top, this is the window monitoring the stream.

The main window of the application is divided in 4 parts :
The upper part containing the sources input : one playlist for quicktime movies, one playlist for Ogg/Theora movies and a camera input module.
The second part is the mixing desk.
The third part is the stream configuration window.
The last part is the window for activating and monitoring the stream.

1. the first step is to configure your camera to start playing locally

The camera configuration window lets you configure your webcam or capture card :

Here you have to set a few parameters for your webcam or your capture card :

• video device: if you have several webcams or capture cards plugged in, they will be numbered video0, video1, ... .
  Here, you should choose the video device you want to use. the default is video0 and is generally the right one.
• channel: this applies only to video capture card which has more than one channel, like the ones having s-video or tuner input.
  Check the pd console to see what channels has your card. A webcam has only one channel, the channel 0 which is the default.
• width x height: this is the size of the incoming video, it should fit your hardware specification.
• freq (MHz): this applies only to a tuner input to receive some TV channels with a capture card. In other cases, it is not used.
• norm: this is the video standard used, it can be set to PAL, SECAM, ... .
  This parameter is only used for capture cards, not for webcams.

Now you can test your camera pressing the "start!" and the "preview" button.
Each video module has a "start!" and the "preview" button.
When you activate the preview, a second video window should appear showing you the camera input :

The same video input should also appear in the general stream output.

2. the next step is to mix different sources to make your program

Once you see the camera input in your streaming window, you can load video clips using one of the playlists ( quicktime movies or Ogg/Theora clips ) :

You should select a video file in the playlist and press the "start!" button so that it will appear in the streaming window.
If you activate the "preview" button, you'll also have another video window where you can monitor the clips you are playing.
If you want to play a list of clips, you should choose one of the playing modes which is one of : "loop", "random" or "continuous".
You can also adjust the speed of the player, but watch out, this can have a disatrous effect on the sound output.
If the file is playing fine, the number of frames played should increase and you should see your clip in your streaming window.

WARNING: you can play two kinds of video clips : Ogg/Theora clips but this requires a relatively good machine because the Theora decoding needs a lot of CPU power.
The other format are quicktime clips, which should be preferred, but this has some restrictions because only a few video codecs can be decoded properly.
The recommended format is quicktime clips encoded in motion jpeg ( mjpeg ).

Now that you can play some clips and that your camera is functioning, you can use the mixer module to make a mix of clips and camera :

If your camera input is too dark, you can also use the luminosity module to correct the output :

If all is working well, you should get a video monitoring window that looks like this :

3. the next step is to connect and start streaming

Once you are set with you video sources, you must configure your streaming options : .

The streaming options window is composed of 3 parts. First, you must fill the server configuration options :

In this window, you have to fill the following information fields, the one noted in red are mandatory, the stream will not work if you don't fill them :

• server: this is the name of the server you will stream to, in our case, we will use giss.tv.
• port: this is the port where you will stream to, in the case of GISS, it should be set at 8000.
• mountpoint: this is the name of your channel, it should be set for example to my_channel.ogg.
  WARNING : it should be an .ogg mountpoint here, video streaming is made in Ogg/Theora format.
• password: this is the password you received when you opened a channel on giss.tv, it should be composed of 5 characters or numbers.

WARNING: Pure Data will not show you any cursor in the field boxes, just click in the box and enter your data followed by <return>.

The second window of the stream configuration is the description of your stream :



You can describe your stream with the following information fields that will appears in players meta-data , all informations here are optional :

• title: this is the title of your program.
• artist: this is the name of the artist currently on the program.
• url: this is a website related to your stream.
• description: this is the description of your program.
• genre: this is the genre of the contents you broadcast.

WARNING: If you want to enter several words in one of these fields, you have to separate the words with underscore : _.

The last part of the stream configuration is the parameters for the quality of your stream :



You can set up parameters here to fine-tune the quality of your stream.
Each time you change one of these parameters, you will need to reconnect your stream to make it effective.
Every parameter has a default value that is an average quality for your stream ( video : 64kbps + audio : 32 kbps = 96kbps ) :

• width x height: this is the size of your video stream. The default is 320x240.
• framerate: this is the framerate of your video stream, that can be different from the input framerate.
  You can play clips of 25 frames/second but resampled to 7 frames/second which is an average value for a stream and the default value.
• video quality: this is video encoding quality for the codec. It can be set from 0 ( worse ) to 63 ( better ), default is 2.
• video bitrate: this is video bitrate of your stream. The default value is 64kbps.
• audio quality: this is audio encoding quality for the Vorbis codec. It can be set from -0.1 ( worse ) to 1.0 ( better ), default is 0.1.
• audio bitrate: this is the audio bitrate of your stream.

NOTE: The weight of your stream will be the sum of the video and of the audio bitrate. By default, it will be 64kbps + 32kbps = 96kbps.
You can use the default values for an average stream unless you want a higher quality stream, this should be tested according to your bandwidth.

Once you have set all the parameters for your stream ( the only mandatory part is the server configuration window ), you can start streaming using the connection window :

3. the next step is to check that the streaming is working

Once you have clicked in the connection window, you can check the status window.
You should see a green button and a few real time information about the stream you are emitting :



Here, you can check the state of the stream you are broadcasting, monitoring the following parameters :

• frames emitted: this is the number of frames that have been broadcasted since the beginning of your stream.
• audio stream time: this is the length in seconds of the audio stream emitted.
• video stream time: this is the length in seconds of the video stream emitted.
• reconnections: if the audio stream time differs from the video stream time of more that 30 seconds, the patch will automatically reconnects and the number of reconnections will be increased.
  Getting reconnections indicates that there is a problem of synchronization in your stream.

WARNING: When you get a big difference between your audio and your video stream time, this means that the stream is not emitted smoothly, and most probably that you have some bandwidth issues.

You should also check that your stream is not saturated looking at the VU-meter next to the connection window and try to avoid situations like this adjusting the input levels :

Optionally, you can activate the simultaneous recording of your stream at any time.
Recording is independent from streaming, you should activate it in the following window :

You have the option of recording in two formats : quicktime clip or Ogg/Theora clip, or both but don't be too demanding, this requires lots of CPU power.