LOLA - MCT-master/portal GitHub Wiki

The existing hardware problem of the Lola machines has been fixed. Several audio-video configuration had been tested. Recommended software settings are detailed here.

Lola video is at the time not working on the Trondheim side, due to issues with the camera and cpu. No reported problems with the camera on the Oslo side, except for bad quality and weird colours. Lola audio is working fine, and from now on we will continue on with the combo of using Lola for audio and Zoom for video.

Read the LOLA User Manual

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. A special attention has been paid to the optimization of the signal processing and transmission in order to keep the system latency as low as possible, below the human delay perception threshold. Both Standard Definition video (SD) and High Definition video (HD) modes are supported from version 1.4.x

The system is based on high performance audio/video acquisition hardware, and on the integration and optimization of audio/video stream acquisition, presentation and transmission. The LOLA system also requires very high performance Wide Area and Local Area Networks: 1 Gigabit per second end-to-end connection is the minimum suggested configuration when running the system with uncompressed video signals; lower bandwidth can be used when running the LOLA system with video compression on. (From the Lola Manual)

The Lola system requires very specific hardware to be able to work. Here we will list audio/video hardware that works with Lola.

• RME HDSPe-AIO (PCI-Express internal card)
• RME Hammerfall HDSP 9632 (PCI internal card)
• RME Multiface II (PCI/PCIe host card + external ADC/DAC box)

• Imperx: CXP-B1410C, CXP-B1411C and ICX-B1410C (old Gen 1 model)
• Ximea xiQ line: MQ013CG-E2
• Grasshopper3 series: GS3-U3-41C6C (Color camera) and GS3-U3-41C6M (Monochrome camera) – Flea3 series: FL3-U3-13S2C-CS (Color camera)

Use a fast LCD monitor with real low latency/response time (equal to or less than 2 or 3 milliseconds) or an old style, but faster, CRT monitor/projector.

The way you connect the monitor to the PC may also cause additional latency. Use VGA, DVI-D or RGB connectors, avoid HDMI.

The following LOLA audio setup was tested on 28.08: Stereo setup with two Genelec monitors placed in line with an C414 XLS microphone from AKG.

The microphone polar pattern was set to figure-of-eight. Low sensitivity to sounds arriving 90 degrees of axis allows to cancel out the sound from the speakers placed in line with the microphone. The figure-of-eight pattern was used to avoid the microphone-speaker feedback of the signal sent back and forth between Oslo and Trondheim.

The microphone-speaker setup was placed approximately 1m away from a sound absorbing surface (wall draped with heavy curtains) to counter the high rear sensitivity of the figure-of-eight polar pattern.

A slight low-frequency cut-off at 80 Hz was introduced to avoid “muddy” and bass-heavy signal and increase speech intelligibility. Attenuation level was set to 0 dB.

More info about Oslo network setup (requires login)

It is crucial that ports 19788, 19798, 7000 are open both directions (in and out) on both TCP and UDP.

There is a running LOLA machine at Uninett (the Norwegian internet provider for universities), which can best tested on the IP 158.38.100.101 (mm-echo.uninett.no). It runs with LOLA version 1.5, with sampling rate 48khz and compressed video.

The audio settings on the NTNU and UiO machines must be identical (except for the soundcard-specific Clock Source) The video settings can be different. The following settings has been tested, providing a reliable and good quality Audio/Video link.

open from System Tray – bottom right next to the clock The system works also setting both buffer sizes to 64 (32 is preferred, any other value is not compatible with LOLA). Wrong clock sources will determine significant distortions (clicking audio) in the received/transmitted stream.

open from System Tray - bottom right next to the clock The meters show the peak audio signal peak values (numerical and/or graphical). Ensure that there is no overload (shown in red) on the Analog Inputs, otherwise the other side will hear significant distortion due to digital clipping. Mind that the Software Playback levels shown (UiO) are related to the currently-selected hardware output (in the screenshot Analog ½ is the selected output, which is the RME soundcard output connected to the MIDAS mixer).

open from icon on Desktop

Ensure that the LolaGUI process priority is set to Normal

open from Options -> Lola Setup

These settings must be changed when disconnected. Restarting Lola or Rebooting may be necessary if the link is not working (rare but it may happen). With 25 FpS, the UiO LOLA machine fails to stream the compressed video to NTNU (uncompressed is fine). Higher values are necessary. 26 FpS is the minimum value for a working video link (higher values increase the CPU and Network load, and determines a brightness flickering of UiO’s video). The compression quality can be changed. Lower values determine worst image quality, but less CPU and Network load. With values above 90 the audio link was not stable.

These settings can also be changed when the connection is up and running.

open from Tools -> A/V B. Tuning

After changing the settings, wait a few seconds for the new buffer size to stabilize. Increasing the buffer size helps to cope with jitter in packets arrival rate, but it also introduces additional latency. The video does not require buffering (values can be set to 0 or to 1 at most, each unit refers to one frame). The audio requires at least a value of 10 (recommended range is 10 to 40). Each unit refers to a buffer of 32 (or 64) samples (depending on Hamerfall DSP settings). Increase this value if/when the audio consistently presents audible clicks.

open from Tools -> Digital Cameras HW Color Correction

This panel allows to adjust the color, the brightness and the luminosity (often required).

Select Compression “NONE” and Camera Settings “1280x 1028-Mono8”. This will stream a grayscale uncompressed video (requires more bandwidth), where color will be restored by the Bayer Decoder (already auto enabled in the options). This setting delivers a better image quality (no compression) but poorer color fidelity (it can be partially recovered working on the HW Color Correction panel).

Uncompressed full resolution RGB24 video is currently not supported because of bandwidth limitations from NTNU side (required about 850 Mbps, available up to 550 Mbps).

Hardware: In case of NO sound:

• Checking the input and output fiber cable (ADAT connections) to make sure the connections are right (NTNU only).
• Checking the Analog In and Analog out connections, between the RME Soundcard and Mixer.

Software: In case of NO sound:

• Checking the LOLA’s offset in Options/LOLA Settings. It should be set to 6 for NTNU and 0 for UiO
• Checking the sample rate (should be 44100 Hz).
• Checking the TotalMix Hardware Inputs to see if the signal is going into the system from the mixer and interface, then checking the Hardware outputs (Sending)
• Checking the Software Playback to see if the signal is coming in from LOLA, going into the interface and mixer (Receiving)
• Checking the Hardware output levels to see if they match the Software Playback levels
• Going into the Matrix mode to check the routing of Hardware Output. Sending the vertical outputs in order to ADAT1/2 / ADAT 3/4 / ADAT 5/6 / ADAT 7/8. (NTNU only)

In the case of clicking sound:

• Send a test signal and in the case of rhythmic clicks, check the clock source of the interface in the Hammerfall DSP and set it to ADAT in (NTNU) and Internal (UiO)
• Increasing the audio buffer, and trying to disable the DirectX acceleration (right click on both video windows and select the corresponding option).
• Checking the Dropped Packets and Realigned Buffers in the Network Monitor.
• Adjusting the latency and matching it at the both sides.
• Monitor the send and receive to make sure of the stabilization of the network (Task manager => Performance tab => Ethernet)
• Compressing the video to free some bandwidth for Audio.
• Right clicking on the video window and checking the Window Info and matching it with the settings.
• Check the levels in Totalmix to see if there are any distortions due to saturation/overload of the analog inputs.