User`s manual

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). The default is Nearest Neighbor because it's faster and has a low cpu
usage; however if you want a better image quality and you have a good core i7 processor, you can
select one of the two bilinear interpolation algorithms: Bilinear (GDI) performs better on Windows
7 or later, instead Bilinear (GDI+) performs generally better on WinXP. (Test your pc performance
with the Show Window Info command in the Options menu).
Pay attention that using a zoom bigger than 100% may consume more CPU time and
decrease the overall system performance, specially if you choose the Bilinear Interpolation; so if
you hear clicks on audio or notice “stuttering” video effects set the window zoom to 100%. Starting
from the next version (1.4.0) the local and remote windows will be fully gpu accelerated in order to
avoid this issue.
For this purpose, you can monitor the window rendering performance by using the Show
Window Info command available in the Options menu (on the Local or Remote Video window).
When you select this option, in the window titlebar you will see the real fps rendered on your
display surface; if they are slower than your fps settings it means that your cpu cannot keep up with
the current zoom percentage and/or the selected interpolation algorithm.
Figure 5: Zoom options (left) and Show Window Info (right)
Jpeg Video Compression: Starting from version 1.3.0 it is possible to send and receive jpeg
compressed video frames; this reduces the amount of transmitted/received data/packets so saving a
lot of network bandwidth.
In order to apply the compression, inside the Video section of the Lola Setup window (Fig.
3), select from the drop-down menu the “CPU-JPEG” value; after selecting this option the
compression quality drop-down menu will be available too.
Comp. Quality settings:
- 100% = high video quality but more cpu usage;
- 60% (default) = good balance between video quality and cpu performance;