A method and apparatus for encoding, illustratively, a video information stream to produce an encoded information stream according to a group of frames (GOF) information structure where the GOF structure and, optionally, a bit budget are modified in response to, respectively, information discontinuities and the presence of redundant information in the video information stream (due to, e.g., 3:2 pull-down processing).

Method and apparatus for encoding video information

Apparatus and method for classifying regions of an image, based on the relative “importance” of the various areas and to adaptively use the importance information to allocate processing resources and input image formation.

Method and apparatus for region-based allocation of processing resources and control of input image formation

For video compression processing, each frame in a video sequence is segmented into one or more different regions, where the macroblocks of each region are to be encoded using the same quantizer value, but the quantizer value can vary between regions in a frame. For example, for the videophone or video-conferencing paradigm of one or more “talking heads” in front of a relatively static background, each frame is segmented into a foreground region corresponding to the talking head, a background region corresponding to the static background, and an intervening transition region. An encoding complexity measure is generated for each macroblock of the previous frame using a (e.g., first-order) rate distortion model and the resulting macroblock-level encoding complexities are used to generate an average encoding complexity for each region. These region complexities are then used to select quantizer values for each region in the current frame, e.g., iteratively until the target bit rate for the frame is satisfied to within a specified tolerance range. The selected quantizer values may be modified based on spatial and/or temporal constraints to satisfy spatial requirements of the video compression algorithm and/or to provide temporal smoothness in quality, respectively.

Quantizer selection based on region complexities derived using a rate distortion model

Both distortion rate and bit-rate can be considered together when selecting a lowest cost motion estimation signal. A motion estimation signal is generated for each of the candidate motion vectors and candidate mode information vectors for a macroblock. An estimated amount of encoding bits is determined for each of the candidate motion vectors, candidate mode information vectors, and quantized coefficients. A bit-rate is computed based on the estimated amount of encoding bits. In addition, a current macroblock is reconstructed with each of the candidate vectors, and distortion measured between each of the reconstructions and the current macroblock. A sum is computed for each distortion measurement and corresponding bit-rate. The lowest sum represents the lowest cost motion estimation signal.

Optimal encoding of motion compensated video

A video apparatus consistent with certain embodiments has a receiver that receives a data stream containing video data and video overlay data, wherein the video data includes a censored region having boundaries. A video plane receives the video data in order to render a video frame for display, the video data including the censored region. A video overlay plane receives the video overlay data in order to render a frame of overlay video data for display. The overlay data has boundaries that overlay the censored region. An alpha plane defines overlay boundaries for the overlay data to determine how much of the overlay video data overlays the censored region when rendering the video frame. The alpha frame defines boundaries that are smaller than the boundaries of the overlay data and larger than the boundaries of the censored region. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Copy protection arrangement

A method and apparatus for selecting a quantizer scale for each object within a frame to optimize the coding rate are disclosed. A quantizer scale is selected for each region or "object" within each frame such that the target bit rate for the frame is achieved while maintaining a uniform visual quality over the entire frame.

Tihao Chiang

Papers

Apparatus and method for object based rate control in a coding system