摘要:
Efficient operations in image or video decoding. For example, a tool such as an image or video decoder receives and decodes encoded data for a picture in a bitstream. As part of the decoding, the tool adapts a multi-symbol lookup table to use in decoding of symbols then decodes the symbols using the multi-symbol lookup table, producing exactly correct results. The tool can also perform selectively truncated inverse frequency transforms. For a given block, the tool identifies upper horizontal and vertical frequencies among non-zero coefficients for the block and, based on the upper frequency values, selectively applies a simplified inverse frequency transform to transform coefficients for the block without hurting decoding quality. Using restart markers in the bitstream, the tool can organize multiple blocks of the picture as partitions. The tool decodes at least some of the partitions in parallel on a partition-by-partition basis using multiple processing cores.
摘要:
Efficient operations in image or video decoding. For example, a tool such as an image or video decoder receives and decodes encoded data for a picture in a bitstream. As part of the decoding, the tool adapts a multi-symbol lookup table to use in decoding of symbols then decodes the symbols using the multi-symbol lookup table, producing exactly correct results. The tool can also perform selectively truncated inverse frequency transforms. For a given block, the tool identifies upper horizontal and vertical frequencies among non-zero coefficients for the block and, based on the upper frequency values, selectively applies a simplified inverse frequency transform to transform coefficients for the block without hurting decoding quality. Using restart markers in the bitstream, the tool can organize multiple blocks of the picture as partitions. The tool decodes at least some of the partitions in parallel on a partition-by-partition basis using multiple processing cores.
摘要:
Multi-threaded implementations of deblock filtering improve encoding and/or decoding efficiency. For example, a video encoder or decoder partitions a video picture into multiple segments. The encoder/decoder selects between multiple different patterns for splitting operations of deblock filtering into multiple passes. The encoder/decoder organizes the deblock filtering as multiple tasks, where a given task includes the operations of one of the passes for one of the segments. The encoder/decoder then performs the tasks with multiple threads. The performance of the tasks is constrained by task dependencies which, in general, are based at least in part on which lines of the picture are in the respective segments and which deblock filtering operations are in the respective passes. The task dependencies can include a cross-pass, cross-segment dependency between a given pass of a given segment and an adjacent pass of an adjacent segment.
摘要:
Techniques and tools for reducing latency in video decoding for real-time communication applications that emphasize low delay. For example, a tool such as a video decoder selects a low-latency decoding mode. Based on the selected decoding mode, the tool adjusts output timing determination, picture boundary detection, number of pictures in flight and/or jitter buffer utilization. For low-latency decoding, the tool can use a frame count syntax element to set initial output delay for a decoded picture buffer, and the tool can use auxiliary delimiter syntax elements to detect picture boundaries. To further reduce delay in low-latency decoding, the tool can reduce number of pictures in flight for multi-threaded decoding and reduce or remove jitter buffers. The tool receives encoded data, performs decoding according to the selected decoding mode to reconstruct pictures, and outputs the pictures for display.
摘要:
Techniques and tools for reducing latency in video decoding for real-time communication applications that emphasize low delay. For example, a tool such as a video decoder selects a low-latency decoding mode. Based on the selected decoding mode, the tool adjusts output timing determination, picture boundary detection, number of pictures in flight and/or jitter buffer utilization. For low-latency decoding, the tool can use a frame count syntax element to set initial output delay for a decoded picture buffer, and the tool can use auxiliary delimiter syntax elements to detect picture boundaries. To further reduce delay in low-latency decoding, the tool can reduce number of pictures in flight for multi-threaded decoding and reduce or remove jitter buffers. The tool receives encoded data, performs decoding according to the selected decoding mode to reconstruct pictures, and outputs the pictures for display.
摘要:
Techniques and tools described herein help manage memory efficiently during video decoding, especially when multiple video clips are concurrently decoded. For example, with clip-adaptive memory usage, a decoder determines first memory usage settings expected to be sufficient for decoding of a video clip. The decoder also determines second memory usage settings known to be sufficient for decoding of the clip. During decoding, memory usage is initially set according to the first settings. Memory usage is adaptively increased during decoding, subject to theoretical limits in the second settings. With adaptive early release of side information, the decoder can release side information memory for a picture earlier than the decoder releases image plane memory for the picture. The decoder can also adapt memory usage for decoded transform coefficients depending on whether the coefficients are for intra-coded blocks or inter-coded blocks, and also exploit the relative sparseness of non-zero coefficient values.
摘要:
A battery operated device, having a display with two or more available refresh rates, has its refresh rate selected so as to match the video frame rate of video data played back on the display. This selection is made by coordinating the resources in the device that are used to process the video from its reception through to its display.
摘要:
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.
摘要:
Multi-threaded implementations of deblock filtering improve encoding and/or decoding efficiency. For example, a video encoder or decoder partitions a video picture into multiple segments. The encoder/decoder selects between multiple different patterns for splitting operations of deblock filtering into multiple passes. The encoder/decoder organizes the deblock filtering as multiple tasks, where a given task includes the operations of one of the passes for one of the segments. The encoder/decoder then performs the tasks with multiple threads. The performance of the tasks is constrained by task dependencies which, in general, are based at least in part on which lines of the picture are in the respective segments and which deblock filtering operations are in the respective passes. The task dependencies can include a cross-pass, cross-segment dependency between a given pass of a given segment and an adjacent pass of an adjacent segment.
摘要:
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.