Abstract: The present disclosure includes systems and techniques relating to magnetic recording devices, such as disk drives. A recording medium of a magnetic recording device can include multiple helicoid patterns arranged in multiple helicoid groups. A described technique includes receiving a waveform produced by a head operated with respect to the medium; determining, based on the waveform, first phase difference(s) corresponding to a first helicoid group; affecting an alignment of the head with respect to the medium based on the first helicoid group by compensating for the first phase difference(s) to maintain the alignment; determining, while compensating for the first phase differences, second phase difference(s) corresponding to a second helicoid group; and affecting, responsive to a switch from the first helicoid group to the second helicoid group, the alignment of the head with respect to the medium by compensating for the second phase difference(s) to maintain the alignment.

Abstract: Methods, systems, and apparatus, including computer program products are described for calibrating servos, and in some implementations, calibrating spiral servos for use in self-servo-write (SSW) processes. In one aspect, a method is provided that includes determining timing reference information on a machine readable medium, locking a clock signal to the timing reference information, detecting a spiral on the machine readable medium, determining a location of the spiral using the clock signal, and calibrating a spiral servo according to the location of the spiral.

Abstract: Methods, systems, and apparatus, including computer program products are described for calibrating servos, and in some implementations, calibrating spiral servos for use in self-servo-write SSW processes. In one aspect, a method is provide that includes rotating a machine readable medium, and detecting a spiral on the machine readable medium. Detecting a spiral on the machine readable medium includes detecting magnitudes of the spiral and a timing mark, storing a timestamp from a clock signal that corresponds to the timing mark of the spiral, determining a peak of the spiral from the magnitudes, and locking the clock signal to the peak of the spiral using the timestamp.

Abstract: A method for dynamic spiral ISR scheduling determines a dynamic delay with spiral to spiral spacing information of a disk, so as to ensure that the sum of a primary ISR time and a secondary ISR time does not exceed the wedge to wedge time. The ISR time may be scheduled to start after a delay for the sum of a static delay and the dynamic delay from an edge. A system for dynamic spiral ISR scheduling uses a dynamic delay determining unit to determine a dynamic delay, and an ISR scheduling unit to schedule the start of a secondary spiral set ISR based on a sum of the dynamic delay and a static delay.

Abstract: A servo control system includes an input that receives spiral signals generated by reading spirals that are prewritten on a magnetic medium. The servo control system further includes a control module that generates spiral correction values for the spirals based on the spiral signals and that determines positions of the spirals based on the spiral correction values.

Abstract: A recording medium can include multiple helicoid patterns arranged in multiple helicoid groups, e.g., first and second helicoid groups. Operating a disk drive can include switching between helicoid groups to maintain the alignment of the head with respect to a target track of the rotating recording medium. Enabling a switch can include receiving a waveform produced by a head operated with respect to a rotating recording medium, generating first information from one or more portions of the waveform corresponding to the helicoid patterns of the first helicoid group; generating second information from one or more portions of the waveform corresponding to the helicoid patterns of the second helicoid group; and analyzing the second information with respect to the first information to generate calibration information. The calibration information can compensate for operational differences between using the helicoid patterns of the first helicoid group and the helicoid patterns of the second helicoid group.

Abstract: Systems, methods, and apparatus for adaptively zeroing out transform coefficients utilizing a bit-stealing parameter are presented herein. A partitioning component can be configured to separate an image into blocks of video data. Further, a frequency transform component can be configured to transform pixels of a block of the blocks into transform coefficients. Furthermore, a bit-stealing quantization component configured to predefine quantization intervals. Moreover, the bit-stealing quantization component can modify a size of a quantization interval of the quantization intervals based on a variable bit-stealing parameter. Further, the bit-stealing component can quantize a transform coefficient of the transform coefficients, based on the quantization interval, to a quantized coefficient value of quantized coefficient values.

Abstract: A control system includes a write head and a control module configured to signal the write head to write a servo test track on a rotating medium at a position relative to a reference servo track on the rotating medium. The servo test track is written on the rotating medium subsequent to an interrupt event. The reference servo track having been written to the rotating medium prior to the interrupt event, detects the position of the servo test track relative to the reference servo track and signals the write head to write a new servo track on the rotating medium based on the detected position of the servo test track relative to the reference servo track.

Abstract: Methods, systems, and apparatus, including computer program products, are described for calibrating servos, and in some implementations for calibrating spiral servos for use in self-servo-write processes. In one aspect, a method is provided that includes determining a measured slope of a spiral, and calibrating radial spacing between servo tracks using the measured slope and a target slope.

Abstract: Methods, systems and computer program products for detecting an end of a reference spiral band are described. A first portion of servo information may be written on a disk using the reference spiral band. By detecting an end of a reference spiral band, a new reference spiral band may be launched. A read/write head of a hard disk drive may subsequently use the new spiral band to write the remaining portion of the servo information, which aids the writing of data tracks on the disk.

Abstract: This invention is a method for speeding up block matching based motion estimation for video encoder. The invention 1) calculates statistics for a candidate motion vector for a predetermined fraction of the pixels of a macroblock, 2) makes an early decision based on this preliminary cost function, and 3) terminates the block matching process without calculating the cost function for other pixels if the preliminary cost function is not less than a predetermined threshold. This early decision for goodness estimation provides an economy of processing load when a large portion of data is left untouched (i.e. unprocessed). The present invention employs feedback control to reduce the predetermined threshold for quick convergence upon each detection of a better match.

Abstract: Multiple reference frame motion estimation for video frame blocks is provided. A plurality of copies of a block list of a reference frame can be loaded into texture memory. Encoding of video blocks of the video frame can be ordered to allow concurrent encoding of the video blocks. Furthermore, motion vector prediction can be performed concurrently for independent video blocks, the motion vectors can be related to each one of the plurality of copies of the block list of the reference frame and determined for the at least a portion of the plurality of blocks ordered for concurrent encoding. Additionally, a fast motion estimation algorithm can be concurrently performed on a number of video blocks to search surrounding blocks and compute motion vectors. Further, concurrent processing of multiple slices can be performed. Such concurrent processes can leverage the parallel architecture of at least one graphical processing unit.

Abstract: A control system includes a write head that writes servo data on a rotating medium. A control module signals the write head to write a servo test track on the rotating medium and subsequent to a reference servo track. The reference servo track is written prior to an interrupt event. The control module detects a position of the servo test track relative to the reference servo track and signals the write head to write a new servo track based on the position after the interrupt event.

Abstract: Block parallel fast motion estimation for blocks of a video frame is provided where encoding of video blocks can be ordered to allow concurrent encoding thereof. Furthermore, motion vector prediction can be performed concurrently for independent video blocks where requisite blocks for calculating the prediction of a given block can be previously encoded, but not all blocks depend from each other; thus, parallel motion vector estimation is possible. Additionally, a fast motion estimation algorithm can be concurrently performed on a number of video blocks to search surrounding blocks to compute motion vectors as well. The concurrent processes can leverage the parallel architecture of one or more graphical processing units (GPU).

Abstract: GPU-based intra frame processing techniques are provided to selectively offload computation loading from a CPU to a GPU. By rearranging the 4×4 block encoding order, the process can benefit from a parallel processing mechanism available on the GPU. Block list size has an effect on speed and by using the optimal block list size for a selection, up to about two times speed improvement in intra frame processing can be achieved.

Abstract: The present invention is an improved book cover and removable reading light, the book cover having a central spine section having a longitudinal pocket therein and two outer covers each pivotally connected to opposite edges of the central spine section. An elongated reading light is removably mounted in the pocket of the central spine section, the reading light having a housing including a battery compartment for receiving batteries and a second compartment for receiving an extendable supporting arm for the reading light. The supporting arm and reading light are disposed for movement relative to the second compartment between an open position in which the supporting arm extends out of the second compartment and a closed position in which the supporting arm is disposed within the second compartment. In addition, the reading light is movably mounted relative to the supporting arm for directing light in different directions, as desired by the user.

Abstract: A servo control system includes a peak detection module that detects peak times of spiral signals generated by reading spirals prewritten on a magnetic medium. The servo control system includes a control module that determines positions of the spirals based on the peak times, stores the positions of the spirals, seeks and tracks the spirals using the positions, and writes servo on the magnetic medium based on the positions of the spirals.

Abstract: Deblock filtering for Microsoft WMV video decoders partitions the computation so that the deblock filtering operations can be performed on horizontal or vertical stripes or in one pass on oversized macroblocks.

Abstract: An interrupt controller is provided for processing interrupt requests in a system having a plurality of data processing units operable to service those interrupt requests, each interrupt request having an associated priority level. The interrupt controller comprises request logic operable to receive an indication of unserviced interrupt requests, to apply predetermined criteria to determine which of said plurality of data processing units are candidate data processing units for servicing at least one of said unserviced interrupt requests, and to issue a request signal to each said candidate data processing unit. Priority encoding logic is operable to determine a highest priority unserviced interrupt request based on the associated priority levels of the unserviced interrupt requests.

Abstract: The present invention is an improved book cover and removable reading light, the book cover having a central spine section having a longitudinal pocket therein and two outer covers each pivotally connected to opposite edges of the central spine section. An elongated reading light is removably mounted in the pocket of the central spine section, the reading light having a housing including a battery compartment for receiving batteries and a second compartment for receiving an extendable supporting arm for the reading light. The supporting arm and reading light are disposed for movement relative to the second compartment between an open position in which the supporting arm extends out of the second compartment and a closed position in which the supporting arm is disposed within the second compartment. In addition, the reading light is movably mounted relative to the supporting arm for directing light in different directions, as desired by the user.