Patent application number | Description | Published |
20080221908 | MULTI-CHANNEL AUDIO ENCODING AND DECODING - An audio encoder and decoder use architectures and techniques that improve the efficiency of multi-channel audio coding and decoding. The described strategies include various techniques and tools, which can be used in combination or independently. For example, an audio encoder performs a pre-processing multi-channel transform on multi-channel audio data, varying the transform so as to control quality. The encoder groups multiple windows from different channels into one or more tiles and outputs tile configuration information, which allows the encoder to isolate transients that appear in a particular channel with small windows, but use large windows in other channels. Using a variety of techniques, the encoder performs flexible multi-channel transforms that effectively take advantage of inter-channel correlation. An audio decoder performs corresponding processing and decoding. In addition, the decoder performs a post-processing multi-channel transform for any of multiple different purposes. | 09-11-2008 |
20090080533 | VIDEO DECODING USING CREATED REFERENCE PICTURES - Reference pictures can be created to assist with video decoding. For example, a method for decoding video can comprise receiving an encoded video bit stream, determining that a reference picture is needed, and creating and inserting the reference picture into the encoded video bit stream. A method for decoding video can also comprise receiving an encoded video bit stream, performing bit stream parsing, determining that a reference picture is needed, selecting a representation level for the reference picture, and conveying data for the selected reference picture to a hardware accelerated graphics processing unit. Various video operations, such as creating reference pictures and related information, can be performed by central processing units, while other video decoding operations can be performed by graphics processing units. | 03-26-2009 |
20090252233 | ADAPTIVE ERROR DETECTION FOR MPEG-2 ERROR CONCEALMENT - A decoder which can detect errors in MPEG-2 coefficient blocks can identify syntactically-correct blocks which have out-of-bounds coefficients. The decoder computes coefficient bounds based on quantization scalers and quantization matrices and compares these to coefficient blocks during decoding; if a block has out-of-bounds coefficients, concealment is performed on the block. In a decoder implemented all in software, coefficient bounds checking is performed on iDCT coefficients against upper and lower bounds in a spatial domain. In a decoder which performs iDCT in hardware, DCT coefficients are compared to an upper energy bound. | 10-08-2009 |
20090323820 | Error detection, protection and recovery for video decoding - Error detecting and protection innovations for video decoders are described. For example, in a multithreaded video decoder, a picture extent discovery (PED) task detects an error in a video bitstream which corrupts a picture. The PED task then determines any PED sub-stage which have been completed for the picture, and based on this determination, performs error-handing PED operations. In another example, an entropy decoding (ED) task checks validity on a macroblock-by-macroblock basis using a redundant buffer to avoid overflows. Additionally, error recovery innovations are described which facilitate playback of a video bit stream at an arbitrary position. For example, a video decoder chooses a picture in the bit stream after the arbitrary position at which to begin decoding based on a determination of acceptable recovery time and/or acceptable picture quality. | 12-31-2009 |
20090323826 | Error concealment techniques in video decoding - Error concealment techniques for video decoding are described. For example, a video decoder after finding a corrupted picture in a bit stream, finds a suitable neighbor for the corrupted picture. For example, the video decoder favors pictures with the same parity as the corrupted picture and considers picture order count and picture corruption in choosing a neighbor. The decoder then modifies syntax elements for the encoded video in the bit stream to allow the neighbor to be used in concealing the corruption in the corrupted picture. The modification of syntax elements can depend on the particular video decoder implementation. For example, in a software-only multithreaded video decoder, a task graph is modified, while in a system utilizing video acceleration, syntax elements for reference lists are modified. | 12-31-2009 |
20090326962 | QUALITY IMPROVEMENT TECHNIQUES IN AN AUDIO ENCODER - An audio encoder implements multi-channel coding decision, band truncation, multi-channel rematrixing, and header reduction techniques to improve quality and coding efficiency. In the multi-channel coding decision technique, the audio encoder dynamically selects between joint and independent coding of a multi-channel audio signal via an open-loop decision based upon (a) energy separation between the coding channels, and (b) the disparity between excitation patterns of the separate input channels. In the band truncation technique, the audio encoder performs open-loop band truncation at a cut-off frequency based on a target perceptual quality measure. In multi-channel rematrixing technique, the audio encoder suppresses certain coefficients of a difference channel by scaling according to a scale factor, which is based on current average levels of perceptual quality, current rate control buffer fullness, coding mode, and the amount of channel separation in the source. In the header reduction technique, the audio encoder selectively modifies the quantization step size of zeroed quantization bands so as to encode in fewer frame header bits. | 12-31-2009 |
20100128778 | ADJUSTING HARDWARE ACCELERATION FOR VIDEO PLAYBACK BASED ON ERROR DETECTION - Adjustment of hardware acceleration level in a video decoder utilizing hardware acceleration is described. Errors are detected in a bitstream as it is decoded using different levels of error detection based on decoding characteristics. A statistical analysis is performed on the error values as they are detected. In one technique, if the bitstream is categorized as fitting a high error rate state in a bitstream model, then hardware acceleration is dropped. In another technique, error statistics based on run-lengths of good and bad bitstream units are kept, and compared to predetermined thresholds. If the thresholds are exceeded, the hardware acceleration level is dropped. The level is dropped in order to take advantage of superior error handing abilities of software-based decoding over hardware-accelerated decoding. | 05-27-2010 |
20100195721 | LOCAL PICTURE IDENTIFIER AND COMPUTATION OF CO-LOCATED INFORMATION - Video decoding innovations for using local picture identifiers and computing co-located information are described. In one aspect, a decoder identifies reference pictures in a reference picture list of a temporal direct prediction mode macroblock that match reference pictures used by a co-located macroblock using local picture identifiers. In another aspect, a decoder determines whether reference pictures used by blocks are the same by comparing local picture identifiers during calculation of boundary strength. In yet another aspect, a decoder determines a picture type of a picture and based on the picture type selectively skips or simplifies computation of co-located information for use in reconstructing direct prediction mode macroblocks outside the picture. | 08-05-2010 |
20100318368 | QUANTIZATION AND INVERSE QUANTIZATION FOR AUDIO - An audio encoder and decoder use architectures and techniques that improve the efficiency of quantization (e.g., weighting) and inverse quantization (e.g., inverse weighting) in audio coding and decoding. The described strategies include various techniques and tools, which can be used in combination or independently. For example, an audio encoder quantizes audio data in multiple channels, applying multiple channel-specific quantizer step modifiers, which give the encoder more control over balancing reconstruction quality between channels. The encoder also applies multiple quantization matrices and varies the resolution of the quantization matrices, which allows the encoder to use more resolution if overall quality is good and use less resolution if overall quality is poor. Finally, the encoder compresses one or more quantization matrices using temporal prediction to reduce the bitrate associated with the quantization matrices. An audio decoder performs corresponding inverse processing and decoding. | 12-16-2010 |
20110013889 | IMPLEMENTING CHANNEL START AND FILE SEEK FOR DECODER - A video bit stream with pictures comprising inter-coded content can be decoded upon receiving a channel start or file seek instruction. Pictures for beginning decoding and display of the bit stream can be selected based at least in part on one or more tuning parameters that set a preference between a latency of beginning to display video and possible defects in the displayed video. In some embodiments, to implement decoding upon a channel start or file seek, one or more types of data are generated for one or more pictures. For example, picture order counts are generated for pictures after a channel start or file seek operation. As another example, a decoder generates a frame number value that triggers re-initialization of a reference picture buffer before decoding after a channel start or file seek operation. | 01-20-2011 |
20110054916 | MULTI-CHANNEL AUDIO ENCODING AND DECODING - An audio encoder and decoder use architectures and techniques that improve the efficiency of multi-channel audio coding and decoding. The described strategies include various techniques and tools, which can be used in combination or independently. For example, an audio encoder performs a pre-processing multi-channel transform on multi-channel audio data, varying the transform so as to control quality. The encoder groups multiple windows from different channels into one or more tiles and outputs tile configuration information, which allows the encoder to isolate transients that appear in a particular channel with small windows, but use large windows in other channels. Using a variety of techniques, the encoder performs flexible multi-channel transforms that effectively take advantage of inter-channel correlation. An audio decoder performs corresponding processing and decoding. In addition, the decoder performs a post-processing multi-channel transform for any of multiple different purposes. | 03-03-2011 |
20110060597 | MULTI-CHANNEL AUDIO ENCODING AND DECODING - An audio encoder and decoder use architectures and techniques that improve the efficiency of multi-channel audio coding and decoding. The described strategies include various techniques and tools, which can be used in combination or independently. For example, an audio encoder performs a pre-processing multi-channel transform on multi-channel audio data, varying the transform so as to control quality. The encoder groups multiple windows from different channels into one or more tiles and outputs tile configuration information, which allows the encoder to isolate transients that appear in a particular channel with small windows, but use large windows in other channels. Using a variety of techniques, the encoder performs flexible multi-channel transforms that effectively take advantage of inter-channel correlation. An audio decoder performs corresponding processing and decoding. In addition, the decoder performs a post-processing multi-channel transform for any of multiple different purposes. | 03-10-2011 |
20110166864 | QUANTIZATION MATRICES FOR DIGITAL AUDIO - Quantization matrices facilitate digital audio encoding and decoding. An audio encoder generates and compresses quantization matrices; an audio decoder decompresses and applies the quantization matrices. The invention includes several techniques and tools, which can be used in combination or separately. For example, the audio encoder can generate quantization matrices from critical band patterns for blocks of audio data. The encoder can compute the quantization matrices directly from the critical band patterns, which can be computed from the same audio data that is being compressed. The audio encoder/decoder can use different modes for generating/applying quantization matrices depending on the coding channel mode of multi-channel audio data. The audio encoder/decoder can use different compression/decompression modes for the quantization matrices, including a parametric compression/decompression mode. | 07-07-2011 |
20110193978 | GENERIC PLATFORM VIDEO IMAGE STABILIZATION - Video image stabilization provides better performance on a generic platform for computing devices by evaluating available multimedia digital signal processing components, and selecting the available components to utilize according to a hierarchy structure for video stabilization performance for processing parts of the video stabilization. The video stabilization has improved motion vector estimation that employs refinement motion vector searching according to a pyramid block structure relationship starting from a downsampled resolution version of the video frames. The video stabilization also improves global motion transform estimation by performing a random sample consensus approach for processing the local motion vectors, and selection criteria for motion vector reliability. The video stabilization achieves the removal of hand shakiness smoothly by real-time one-pass or off-line two-pass temporal smoothing with error detection and correction. | 08-11-2011 |