LOLA: Low Latency Audio Visual Streaming System LOLA Low Latency Audio Visual Streaming System Installation & User's Manual © 2005-2014 - Conservatorio di musica G. Tartini – Trieste, Italy version 1.3.0 http://www.conts.it/artistica/lola-project lola-project@conts.
LOLA: Low Latency Audio Visual Streaming System 1. Introduction Lola is an Audio Visual Streaming System developed by “Conservatorio di Musica G. Tartini”, Trieste, Italy, in collaboration with GARR, the Italian Academic and Research Network. LOLA goal is to provide a tool for real-time audio/video “natural” distance human interaction. It was originally conceived for distance music performances, education and production, but can be used for any other scenario where real-time interaction is required.
LOLA: Low Latency Audio Visual Streaming System the – BitFlow ALTA-AN1 grabber with SDK 5.60 drivers which supports both analog b/w and color cameras. A possible camera for LOLA for b/w service is the – Sony HR50 b/w analog. In case of color video acquisition the video camera must provide component analog color output (RGB or YpbPr). For color operation the PC running LOLA should provide enough CPU performance to deal with data processing, i.e. an i5/i7 CPU based workstation is recommended.
LOLA: Low Latency Audio Visual Streaming System – 1Gbit LAN port (LOLA supports only 1 LAN port at present, but it will support more LAN ports in the future versions for higher video resolution and multiple node support). See section 2.8 for important information regarding NIC performance. – Integrated graphic adapter should be enough, however a PCI-Express Video Adapter (e.g., Nvidia GeForce cards) is strongly recommended, specially for color video processing and for incoming gpu-accelerated features.
LOLA: Low Latency Audio Visual Streaming System LOLA should not run behind a Firewall, and should run with a public IPv4 address (no NAT). IPv6 addresses are currently not yet supported. Traffic Shapers and other devices which inspect/act deeply on network performances must also be avoided.
LOLA: Low Latency Audio Visual Streaming System 2.7. LOLA v1.3.x backward compatibility Due to some newly introduced features, this version of LOLA is NOT backward compatible with all previous versions. If you are upgrading from v1.2.x, keep this older version in a separate folder, in order to be able to connect with those who do not have yet v1.3.x 2.8.
LOLA: Low Latency Audio Visual Streaming System 3. System Setup 3.1. Install required libraries and drivers 3.1.1 WinPcap (version 4.1.2 or later) LOLA relies on the WinPcap windows packet capture library, which has to be installed on the PC. The installer can be found at the following address: http://www.winpcap.org Note: Lola requires WinPcap version 4.1.2 or later. 3.1.2 BitFlow (SDK version 5.
LOLA: Low Latency Audio Visual Streaming System 3.2. Audio hardware Setup Update/install the drivers first! (see section 3.1). Before using the software, it is highly recommended to check if there is any board setup panel providing latency settings on which the software applications have no control. The RME driver usually provides a DSP Setting Panel as the one shown in Fig. 1 (a link to it is usually available in the bottom-right tool bar in Windows 7/XP).
LOLA: Low Latency Audio Visual Streaming System tools to affect the system configuration in Windows 7, they must be “run as Administrator”). It is useful to also install test camera files which can generate synthetic video with a wide range of frame rate and resolution characteristics. You should install the camera files for the video camera(s) you intend to use with LOLA.
LOLA: Low Latency Audio Visual Streaming System When LOLA is launched, it will check for all available video BitFlow devices (if none is available, the program will provide a warning and run without video support). It will be possible to select the desired video camera, among the ones configured with the BitFlow SysReg.exe utility, from the Audio Video Setup dialog window, available in the Tools menu (Fig. 3) 3.4.
LOLA: Low Latency Audio Visual Streaming System LOLA initial default audio setup is for 2 stereo channels, collecting audio input from the first two channels of the RME audio card; e.g. setting the “AudioInputOffset” to 0. LOLA will also remember these settings until you change them again. If your activation code includes LOLA audio multichannel services, you will also have the possibility to select the “N.
LOLA: Low Latency Audio Visual Streaming System 3.6. TCP/UDP ports used by LOLA LOLA will use by default ports TCP 7000, UDP 19788 and UDP 19798 for service communication and audio/video streaming. It is thus required that no restrictions apply for these ports (e.g. due to network or Windows firewall settings or local network administration policies).
LOLA: Low Latency Audio Visual Streaming System 4. Running LOLA The LOLA user interface (Fig. 4) is intended to be as simple as possible: a remote address to call (IP address), a “Check” button to make a quick and simple pre-connection test, a “Connect” and a “Disconnect” button. A “Session name” box allows you to assign a specific name to a setup configuration for easier identification and you can also “Save” this configuration from the “File menu”.
LOLA: Low Latency Audio Visual Streaming System 4.1. Local audio and video settings Before attempting to connect to a remote host, the user should correctly configure the local audio and video options. The Lola Setup dialog (in the Options Menu, Fig. 3) allows to select the desired ASIO audio device, the video camera file, the desired video frame rate (30 up to 60 fps, but 30 or 60 are the standard suggested values), the video compression (default NONE) and the network interface controller.
LOLA: Low Latency Audio Visual Streaming System video aspect ratio is preserved). By resizing the window, you can also select the desired interpolation algorithm (Zoom menu, Zoom Interpolation).
LOLA: Low Latency Audio Visual Streaming System - 40% = low video quality but low cpu usage and overall better performance. Incomplete frames rendering threshold: when using uncompressed video you can also select the incomplete frames rendering threshold (Fig. 3); 0% means that Lola must receive ALL video packets from the remote host in order to correctly render the entire video frame.
LOLA: Low Latency Audio Visual Streaming System Before sending a connection request, it is recommended to check if the remote host is ready for the connection. After inserting the remote host IP address, use the Check button provided in the control panel below the IP address box: LOLA will issue a “ping request” the remote host at the given IP address, and will also check if LOLA is running on it. An estimate of the network round trip time (RTT) will also be provided.
LOLA: Low Latency Audio Visual Streaming System Figure7a: Buffer tuning panel 4.4. Toggling Audio/Video and Network Monitor During a connection, the user can also gain some information on the audio and video stream through the Network Monitor panel, available in the Tools menu (Fig. 7b). This dialog box provides some information on the connection and on the traffic, as well as the possibility of selectively switching off/on each one of the inbound, outbound, audio and video streams.
LOLA: Low Latency Audio Visual Streaming System 4.5. Disconnecting from a remote host The connection can be interrupted by any of the two hosts by clicking on the Disconnect button. When the software is shutting down, the current local configuration (i.e., audio and video setup) will be saved on a .ini file located in the same directory as the executable, and will be loaded at the next start-up of the Lola application.
LOLA: Low Latency Audio Visual Streaming System Select the “network” tab, and under the “show” menu display all total (green), input (yellow) and output (red) real time traffic statistics. When everything is working fine (with uncompressed video - default) you should see something like the above picture: a very stable constant traffic flow, both in and out.
LOLA: Low Latency Audio Visual Streaming System 4.11. Audio Test signal To test the audio connection Lola can send an internally generated audio signal (689Hz, -3dBfs) to the remote host. To do so use the Send Audio Test Signal command available in the Tools menu. 4.12. Windows layout When Lola is connected to the remote host, you can decide how to automatically dispose the Local and Remote windows on the screen.
LOLA: Low Latency Audio Visual Streaming System Duplicating the remote windows is useful to organise your local video sertup, enabling scenarios where you need to handle in different ways the video coming from the remote site. For example imagine that you need to use a monitor dedicated for the users involved in the connection, and you need another different image to display to the audience on a different screen or projector.
LOLA: Low Latency Audio Visual Streaming System Appendix A – experimental digital video setup A.1 - CameraLink A CameraLink Digital (B/W and Color) video configuration was tested but for various reasons, first of all the small maximum cable length (10m) but also for the greater latency, it is abandoned. The Camera Link configuration under test was as follows: • BitFlow Neon-CL grabber with SDK 5.
LOLA: Low Latency Audio Visual Streaming System Digital color video will require a pixel depth of 32 bits per pixel (whereas B/W usually requires 8/10 bits per pixel and analog color requires 24 bits per pixel).
LOLA: Low Latency Audio Visual Streaming System Appendix B – Compatible Video Cameras Analog B/W cameras with characteristics similar to the Sony HR50 can be easily found. On the other hand, analog color cameras with frame rates > 30 fps @ 640x480 and RGB output seems to be rare on the market. A few examples of brands offering analog RGB cameras are Toshiba (e.g., IK-TF5), JAI-Pulnix (e.g. the CV-M91 series), Hitachi (e.g. KP-FD30).
LOLA: Low Latency Audio Visual Streaming System Appendix C – Cameras Cabling Guide Although you can buy appropriate cables for many of the analog cameras to be used with the BitFlow grabber cards, this short guide can help you in building your own high quality cables. In order to start, we suggest to use high quality VGA cables, which you can quite easily get anywhere. A good reference model are for example the Belkin F3H982, which comes in different lengths.
LOLA: Low Latency Audio Visual Streaming System
LOLA: Low Latency Audio Visual Streaming System Cable for Sony HR50 The VGA connector has 3 coaxial cables for video signal, but for b/w cameras you only need one; just select, for example, the "G" (green) one. Use the twisted pairs for the other signals.
LOLA: Low Latency Audio Visual Streaming System Here is a detailed table for pinout connections, if you use the Belkin F3H982 and the Hitachi: (NC) = Not Connected 15 Pin Hitachi camera Comment Belkin cable 62 Pin DIN Comment 1 R/C Output For Y/C mode Red Coaxial 23 2 tap mode? 2 G/Y Output For Y/C mode Green Coaxial 2 2 tap mode? 3 B/VBS Output Wen in Y/C mode? Blue Coaxial 1 4 WE Output Wen? Black 26 5 GND (TXD/RXD) Brown (NC) 6 Video GND Red Shield 11 7 Video GND Gree
LOLA: Low Latency Audio Visual Streaming System Cable for Toshiba IK-TF5 The cable for the Toshiba is very similar to the one for the Hitachi.
LOLA: Low Latency Audio Visual Streaming System Appendix D – Setting Cameras in External Trigger Mode This section show how to correctly set in External Trigger Mode the supported cameras. If you are using a camera not listed here, contact lola-poject@conts.it for assistance. Sony HR50 setting for external trigger mode If using the Sony HR50 B/W analog camera, the camera must be configured according to external trig/shutter mode 2 (DIP switches 6,7 set to OFF, and DIP switch 8 set to ON, see Fig. 12).
LOLA: Low Latency Audio Visual Streaming System Figure 14: Hitachi KP=FD30 rear DIP switch setting for progressive scan mode. Finally, the "shutter mode" field in the software setting menu of the camera should be set to "Ext.
LOLA: Low Latency Audio Visual Streaming System Index Menu -> shutter Menu -> Mode: E. TRG E. TRG: 1P SR TRG P.
LOLA: Low Latency Audio Visual Streaming System Appendix E – Audio Card internal Mixer settings LOLA usually adopt RME audio cards for audio in/out functions. In order to work correctly, these audio cards must be setup in the correct configuration to ensure LOLA gets the correct audio input channels, and also can output the sound from the remote host correctly. You should at first display the audio card routing matrix (see fig. 17 and 18). The top row displays the available input channels.
LOLA: Low Latency Audio Visual Streaming System Then the output routing shall be correctly configured. Fig 17 shows a correct routing example both for the analogue channels and for the ADAT channels. Fig 18 shows a configuration where only the 8 ADAT channels are routed to the output. The HDSP audio Mixer should also look like in Fig. 19 or 20. Please note that buttons link Out1 Out2 AN1 AN1 shall NOT be in red/pink color, because this means you set the audio card in local audio loop.
LOLA: Low Latency Audio Visual Streaming System Fig 20: The RME main Mixer window (8 channels out setup)
LOLA: Low Latency Audio Visual Streaming System Appendix F – Known Issues F.1 No timeout on remote partner unexpected disconnection In some rare occasions, if the remote LOLA system occurs in an unexpected disconnection (system or application problems, network disconnection, etc) and thus cannot notify the other system about its closure, the local system remains “open and active” without warning (you of course immediately see you are not receiving any more audio/video from the remote system).
LOLA: Low Latency Audio Visual Streaming System the Intel NICs described at chapter 2.8. Network Interface Cards (NICs) performances. F.6 Network Configuration on the same Virtual LAN If both LOLA systems are on the same Virtual LAN (VLAN), for example a GigaEthernet Circuit with IP addresses in the same subnet, the current LOLA IP packet generation engine can behave not correctly and you might have the systems to connect correctly, but no audio or video or both streaming flow among them.
LOLA: Low Latency Audio Visual Streaming System F.7 Video Artifacts if LOCAL and REMOTE video windows overlay on screen. If the LOCAL and the REMOTE video Windows overlay one to the other on the screen, the foreground window may display some artifacts in the area where the background window is laying behind it. This issue is still under investigation. Thus avoid to have partially overlapping LOCAL and REMOTE windows on the the screen while using LOLA.
LOLA: Low Latency Audio Visual Streaming System Acknowledgments We would like to thank Dan Nichols (NIU School of Music) for his precious work, collaboration and suggestions both for the creation of camera cables and for fine tuning of many Camera Files. We also thank Marco d'Ambrosio (Università di Cassino) for his camera power supply suggestions.
