Abstract: The present invention discloses how a transcoder may be used to reduce the bit rate of an MPEG-2 stream by transmitting only the visible area of the movie specified by pan-scan directives. Because the pan-scan conversion is performed prior to transmission, not immediately before display, the non-viewed portion of video does not need to be transmitted.

Abstract: An apparatus generally having a reference memory and a motion estimation circuit is disclosed. The reference memory may store reference samples used in a motion estimation of a current block beyond a boundary of a picture. The motion estimation circuit may (i) buffer the reference samples as copied from the reference memory, the reference samples as buffered residing both (a) inside the boundary and (b) inside a search window of the motion estimation, (ii) shift a sub-set of the reference samples to align with a corner of a sub-window, the sub-window being (a) completely within the search window and (b) at least partially outside of the boundary, (iii) fill an empty portion of the sub-window with copies of the reference samples within the sub-set and (iv) generate difference values by comparing the current block against the reference samples within the sub-window a plurality of times.

Abstract: An apparatus generally having a first circuit and a second circuit is disclosed. The first circuit may be configured to generate a plurality of sum values by adding a plurality of pixel difference values between a current block and a reference block, one of the sum values corresponding to each of a plurality of smallest partitions of the current block. The second circuit configured to (i) generate a plurality of intermediate values from the sum values, one of the intermediate values corresponding to each of a plurality of possible partitions of the current block, (ii) store a plurality of lowest values among the intermediate values as the current block is moved through a search window and (iii) generate a motion signal conveying at least one motion vector based on the lowest values.

Abstract: A method for implementing B-frame prediction in video compression comprising the steps of (A) setting a prediction flag (i) “off” if B-frames are used for block prediction and (ii) “on” if B-frames are not used for block prediction, (B) if the prediction flag is off, generating an output video signal in response to an input video signal by performing an inverse quantization step and an inverse transform step in accordance with a predefined coding specification and (C) if the prediction flag is on, bypassing the inverse quantization step and the inverse transform step.

Abstract: The present invention discloses a system and method for rate control of MPEG video streams to achieve a target bit rate in a transcoder at the best visual quality possible. The invention monitors video buffer fullness for selecting the amount of rate reduction necessary to achieve a target bit rate. The invention also utilizes a method for selective requantization of DCT coefficients to assure visual quality.

Abstract: The present invention discloses a motion estimation method for MPEG video sequences. The method makes use of a global motion estimation algorithm to determine a set of dominant motion components. A simultaneous Full Search Block Matching (FSBM) search is conducted utilizing each dominant component for every block in a current frame. The results of each FSBM search are then compared to determine the best motion vector.

Abstract: An apparatus comprising a first circuit and a second circuit. The first circuit may be configured to generate a plurality of signals in response to one or more of a context index and a binary symbol. The second circuit may be configured to generate a series of output bits in response to the plurality of signals. The memory may be configured to transfer the plurality of signals between the first circuit and the second circuit.

Abstract: A method for implementing non-reference frame prediction in video compression comprising the steps of (A) setting a prediction flag (i) “off” if non-reference frames are used for block prediction and (ii) “on” if non-reference frames are not used for block prediction, (B) if the prediction flag is off, generating an output video signal in response to an input video signal by performing an inverse quantization step and an inverse transform step in accordance with a predefined coding specification and (C) if the prediction flag is on, bypassing the inverse quantization step and the inverse transform step.

Abstract: An apparatus generally having a first circuit and a second circuit for motion estimation is disclosed. The first circuit may be configured to (i) generate a first motion vector for a block at an integer-pel resolution and (ii) determine a single block size associated with the first motion vector. The second circuit may be configured to (i) generate a plurality of second motion vectors at a sub-pel resolution by searching proximate the first motion vector using the single block size and (ii) determine a motion vector for the block as a particular one of the second motion vectors best matching a plurality of reference samples.

Abstract: An apparatus generally having a first circuit, a second circuit and a third circuit is disclosed. The first circuit may be configured to generate a plurality of difference values by calculating an absolute difference between each pixel from a current block and a corresponding pixel from a reference block substantially simultaneously. The second circuit may be configured to generate a plurality of sum values by adding the difference values. The third circuit may be configured to generate at least one motion vector in response to the sum values.

Abstract: An apparatus generally having a first memory and a circuit is disclosed. The first memory may be used for a motion estimation of a current block. The circuit may be configured to (i) determine if a search window for the current block is at least partially outside a boundary of a picture stored in a second memory, (ii) copy a first plurality of reference samples in the search window from the second memory to the first memory and (iii) map a plurality of reads from the first memory for a plurality of pad samples to the reference samples in the first memory, where the pad samples are determined to be outside the boundary.

Abstract: An apparatus for motion estimation generally including a memory and a circuit. The circuit may be configured to (i) search for a first motion vector for a first current block among a plurality of first reference samples, (ii) copy a plurality of second reference samples from the memory and (iii) search for a second motion vector for a second current block among the second reference samples copied from the memory and at least a portion of the first reference samples.

Abstract: The present invention discloses a motion estimation method for MPEG video sequences. The method makes use of a global motion estimation algorithm to determine a set of dominant motion components. A simultaneous Full Search Block Matching (FSBM) search is conducted utilizing each dominant component for every block in a current frame. The results of each FSBM search are then compared to determine the best motion vector.