Cable-actuated systems provide an effective method for precise motion control over various distances. Motion control using such systems has traditionally focused on eliminating longitudinal resonances and disturbance. Moreover, longitudinal cable resonances are usually assumed to be at much higher frequencies compared to transverse resonances, ensuring minimal coupling between the two. However, in high-speed high-precision applications, the coupling between longitudinal and lateral cable oscillations cannot be ignored in the presence of high-inertia components. In this paper, we describe the mechanism of auto-parametric resonance in cable-pulley systems through which longitudinal vibrations can couple strongly to transverse vibrations. We model exact dynamics of coupled cable-pulley oscillations and solve them numerically to observe the intrinsic non-linear behavior. Preliminary experimental results show the effect of this coupling on pulley rotation.

Low bit-rate live encoding and streaming of video over wired or wireless channels, as utilized in place-shifting applications, need to adapt the frame rate and bit-rate according to content and channel conditions. Typical rate control schemes work with a given target frame rate and can result in irregular frame skips that are induced by buffer conditions and quantizer saturation. Prior methods proposed to address the dynamic frame-rate selection (DFS) problem work by projecting the impact of a new frame-rate from the operating frame-rate and can have slower convergence to the required frame-rate. In this paper, we propose a scheme that utilizes a given computational capacity (typical in embedded appliances) to actually assess the impact of the new frame-rate by coding at the corresponding new frame-skip (referred to as trial frames) before committing to it. The proposed scheme offers quick content-adaptive convergence to the target frame-rate and maintains a motion-adaptive frame skipping pattern to provide a subjectively pleasing spatio-temporal quality trade-off at the operating bit-rate. In addition, the scheme can work with most existing rate control methods that operate at a supplied frame-rate and is also suitable for hooking to a user controlled quality dial.

Personal computers today have 802.11 (b/a/g) -based wireless connectivity. By connecting laptops to a projector wirelessly, multiple persons could connect to the projector and present the content on their laptops. This typically requires another personal computer at the projector end that is wirelessly connected to the laptop and which receives, decodes, and renders a compressed version of what was rendered on the display of the laptop. On the laptop, the screen buffer is captured and the captured frames are compressed. The encoded stream is streamed over the WLAN to a streaming client. The article presents a low cost interface device for the projector system based on the TI TMS320DM270 image/video processor.