摘要:
A scene-aware auto-exposure control process stabilizes changes in a camera's auto-exposure settings so as to reduce lighting and color flicker during image capture operations. A metric, referred to as the Modified Adjusted Luminance (MAL) metric, is defined to remain relatively constant as long as the lighting of the scene being captured remains relatively constant. Thus, scene changes such as an object moving into, out of, or around in a scene do not significantly affect the MAL metric's value and do not, therefore, trigger an exposure adjustment. Once the MAL metric indicates a scene's lighting is stable, the camera's auto-exposure operation may be suppressed. As long as incoming frames indicate a stable lighting condition (based on the MAL metric), auto-exposure operation may remain suppressed. When incoming frames result in a substantially different MAL over a specified number of frames, auto-exposure operation may be restored.
摘要:
A coding technique is disclosed in which frames of a video sequence are assigned to one of a plurality of sub-channels to be transmitted to a decoder. The frames are coded according to predictive coding techniques such that ordinarily prediction references of the frames in each sub-channel only reach the reference frames that occur within the same sub-channel. Thus, if transmission errors arise with respect to one sub-channel, decoding may occur for another sub-channel until the transmission error is detected and corrected.
摘要:
A system and method using edge processing to remove blocking artifacts comprises an edge processor having an image converter for building an edge representation of a received image, a statistics analyzer for compiling a histogram containing edge intensities of the edge representation, a reference calculator for using the histogram to compute reference values corresponding to the blocking artifacts and an artifact remover for identifying and removing the blocking artifacts using the computed reference values.
摘要:
Decoding and encoding of variable length data words and data strings is accelerated by testing for and processing more than one word or string per encoding or decoding cycle. In an encoding scheme wherein fixed length data words are encoded into variable length data strings, decoding is carried out by first receiving a data stream having a plurality of encoded data strings contained therein, and then testing at least a portion of the data stream to determine whether the portion contains one of a number of selected sets of multiple data strings. If the portion of the data stream contains one of the selected sets of multiple data strings, the multiple data strings are decoded into a corresponding set of multiple data words. This decoding procedure allows a plurality of encoded data strings to be decoded in a single decoding cycle. The procedure may be implemented using either a single lookup table or a set of split-level lookup tables. The above procedure may also be applied to an encoding scheme wherein variable length data words are transformed into fixed length encoded data strings to encode the variable length data words. Furthermore, the above procedure may be applied to an encoding scheme wherein variable length data words are transformed into variable length data strings to both encode and decode the variable length data words and data strings.
摘要:
In a video coder/decoder system using variable resolution adaptation, decoder techniques provide a mechanism to changing resolution of coded lower-resolution video to a higher resolution for rendering. Coded video data of a low resolution frame may be decoded. A motion estimation search may be performed between the decoded low resolution frame and a cache of previously-stored high resolution video frames. If the motion estimation search generates one or more matches, high resolution video data of the decoded frame may generated as a derivation of matching data from the cached video frames.
摘要:
A video coder employs techniques for applying frame rate adaptation and variable resolution adaptation in response to environmental coding factors present at the coding terminal. According to such techniques, a coder may estimate a coding quality level to be applied based on the environmental coding factors. The coder may retrieve from a controller table, settings for resolution and frame rate based on the estimated quality level. Optionally, the coder further may retrieve settings identifying a range of quantization parameters that may be used during coding. Prior to coding, the coder may configure input video data to match the resolution and frame rate settings retrieved from the controller table. Thereafter, the coder may code the reconfigured input video data by motion-compensation prediction constrained, as applicable, by the retrieved quantization parameter range.
摘要:
A coding technique is disclosed in which frames of a video sequence are assigned to one of a plurality of sub-channels to be transmitted to a decoder. The frames are coded according to predictive coding techniques such that ordinarily prediction references of the frames in each sub-channel only reach the reference frames that occur within the same sub-channel. Thus, if transmission errors arise with respect to one sub-channel, decoding may occur for another sub-channel until the transmission error is detected and corrected.
摘要:
Some embodiments provide a method for allowing a first device that is in a video conference with a second mobile device to remotely control the second mobile device. The method sends images captured by a camera of the first device to the second device. The method receives images captured by a camera of the second device. The method sends a command through a communication channel of a real-time communication session to the second device. The command is for instructing the second device to perform an operation that modifies the images captured by the camera of the second device.
摘要:
Embodiments of the present invention provide a control system for video processes that selectively control the operation of motion stabilization processes. According to the present invention, motion sensor data indicative of motion of a mobile device may be received and processed. A determination may be made by comparing processed motion sensor data to a threshold. Based on the determination, motion stabilization may be suspended on select portions of a captured video sequence.
摘要:
In a video coding/decoding system, reference picture caches in a video coder and decoder may be partitioned dynamically based on camera and background motion can lead to improved coding efficiency and coding quality. When a camera is fixed and therefore exhibits low motion, a system may allocate larger portions of the reference picture cache to storage of long term reference frames. In this case, foreground elements of an image (for example, a person) may move in front of a relatively fixed background. Increasing the number of long term reference frames can increase the chances that, no matter where the foreground elements are within a frame currently being coded, the reference picture cache will contain at least one frame that provides an adequate prediction match to background elements within the new frame. Thus the background elements uncovered in the current frame can be coded at high quality with a low number of bits. When a camera exhibits high motion, the system may allocate larger portions of the reference picture cache to storage of short term reference frames.