Abstract: A video coding system that codes video objects as scalable video object layers. Data of each video object may be segregated into one or more layers. A base layer contains sufficient information to decode a basic representation of the video object. Enhancement layers contain supplementary data regarding the video object that, if decoded, enhance the basic representation obtained from the base layer. The present invention thus provides a coding scheme suitable for use with decoders of varying processing power. A simple decoder may decode only the base layer of video objects to obtain the basic representation. However, more powerful decoders may decode the base layer data of video objects and additional enhancement layer data to obtain improved decoded output. The coding scheme supports enhancement of both the spatial resolution and the temporal resolution of video objects.

Abstract: A method and apparatus prioritizing video information during coding and decoding. Video information is received and an element of the video information, such as a visual object, video object layer, video object plane or keyregion, is identified. A priority is assigned to the identified element and the video information is encoded into a bitstream, such as a visual bitstream encoded using the MPEG-4 standard, including an indication of the priority of the element. The priority information can then be used when decoding the bitstream to reconstruct the video information.

Abstract: A Method And Apparatus For Control of Rate-Distortion Tradeoff by Mode Selection in Video Encoders is Disclosed. The system of the present invention first selects a distortion value D near a desired distortion value. Next, the system determines a quantizer value Q using the selected distortion value D. The system then calculates a Lagrange multiplier lambda using the quantizer value Q. Using the selected Lagrange multiplier lambda and quantizer value Q, the system begins encoding pixelblocks. If the system detects a potential buffer overflow, then the system will increase the Lagrange multiplier lambda. If the Lagrange multiplier lambda exceeds a maximum lambda threshold then the system will increase the quantizer value Q. If the system detects a potential buffer underflow, then the system will decrease the Lagrange multiplier lambda. If the Lagrange multiplier lambda falls below a minimum lambda threshold then the system will decrease the quantizer value Q.

Abstract: A number of novel configurations for MPEG-4 playback, browsing and user interaction are disclosed. MPEG-4 playback systems are not simple extensions of MPEG-2 playback systems, but, due to object based nature of MPEG-4, present new opportunities and challenges in synchronized management of independent coded objects as well as scene composition and presentation. Therefore, these configurations allow significantly new and enhanced multimedia services and systems. In addition, MPEG-4 aims for an advanced functionality, called Adaptive Audio Visual Session (AAVS) or MPEG-J. Adaptive Audio Visual Session (AAVS) (i.e., MPEG-AAVS, MPEG-Java or MPEG-J) requires, in addition to the definition of configurations, a definition of an application programming interface (API) and its organization into Java packages. Also disclosed are concepts leading to definition of such a framework.

Abstract: A method and apparatus for displaying received data, analyze the quality of the displayed data formulating a media-parameter suggestion for the encoder to alter the characteristics of data to be sent to the receiver, and sending from the receiver, the formulated suggestion.

Abstract: Disclosed is a system and method of controlling a video decoder, including a reviewing channel data representing coded video data generated by an encoder to identify parameters of a hypothetical reference decoder (HRD) used by the encoder during coding operations. A parameter representing an exit data rate requirement of a coded picture buffer (CPB) of the HRD is compared against exit rate performance of the video decoder. If the exit rate performance of the video coder matches the exit rate requirement of the HRD, the coded video data is decoded, otherwise, a certain decoding degradation scheme can be applied, including disabling decoder from decoding the coded video data.

Abstract: This invention is directed to a video bit rate control method for encoding a video sequence based on a decoder buffer condition and a group of picture (GOP) size limitation of the encoded video sequence. The method includes iteratively adjusting a quantization parameter and/or a masking strength parameter and encoding the video sequence at the adjusted parameters until the buffer condition and GOP size limitation are satisfied. The method makes the above adjustments to avoid buffer underflow and GOP oversizing.

Abstract: Some embodiments of the invention provide a multi-pass encoding method that encodes several images (e.g., several frames of a video sequence). The method iteratively performs an encoding operation that encodes these images. The encoding operation is based on a nominal quantization parameter, which the method uses to compute quantization parameters for the images. During several different iterations of the encoding operation, the method uses several different nominal quantization parameters. The method stops its iterations when it reaches a terminating criterion (e.g., it identifies an acceptable encoding of the images).

Abstract: A quantizer and dequantizer for use in a video coding system that applies non linear, piece-wise linear scaling functions to video information signals based on a value of a variable quantization parameter. The quantizer and dequantizer apply different non linear, piece-wise linear scaling functions to a DC luminance signal, a DC chrominance signal and an AC chrominance signal. A code for reporting updates of the value of the quantization parameter is interpreted to require larger changes when the quantization parameter initially is large and smaller changes when the quantization parameter initially is small.

Abstract: A number of novel configurations for MPEG-4 playback, browsing and user interaction are disclosed. MPEG-4 playback systems are not simple extensions of MPEG-2 playback systems, but, due to object based nature of MPEG-4, present new opportunities and challenges in synchronized management of independent coded objects as well as scene composition and presentation. Therefore, these configurations allow significantly new and enhanced multimedia services and systems. In addition, MPEG-4 aims for an advanced functionality, called Adaptive Audio Visual Session (AAVS) or MPEG-J. Adaptive Audio Visual Session (AAVS) (i.e., MPEG-AAVS, MPEG-Java or MPEG-J) requires, in addition to the definition of configurations, a definition of an application programming interface (API) and its organization into Java packages. Also disclosed are concepts leading to definition of such a framework.

Abstract: A method and apparatus for displaying received data, analyze the quality of the displayed data formulating a media-parameter suggestion for the encoder to alter the characteristics of data to be sent to the receiver, and sending from the receiver, the formulated suggestion.

Abstract: A method and apparatus for performing motion estimation in a digital video system is disclosed. Specifically, the present invention discloses a system that quickly calculates estimated motion vectors in a very efficient manner. In one embodiment, a first multiplicand is determined by multiplying a first display time difference between a first video picture and a second video picture by a power of two scale value. This step scales up a numerator for a ratio. Next, the system determines a scaled ratio by dividing that scaled numerator by a second first display time difference between said second video picture and a third video picture. The scaled ratio is then stored calculating motion vector estimations. By storing the scaled ratio, all the estimated motion vectors can be calculated quickly with good precision since the scaled ratio saves significant bits and reducing the scale is performed by simple shifts.

Abstract: An effective method for dynamically selecting the number of I, P and B frames during video coding is proposed. Short-term look-ahead analysis of a video sequence yields a variable number of B frames to be coded between any two stored pictures. The first picture of a group of frames (GOF) may be coded as a B picture. Motion speed is calculated for each picture of the GOF with respect to the first picture of the GOF. Subject to exceptions, as long as the subsequent pictures exhibit motion speeds that are similar and motion vector displacements that are co-linear with those of the first picture in the GOF, they may be coded as B pictures. When a picture is encountered having a motion speed that is not the same as that of the first picture in the GOF, the picture may be coded as a P picture.

Abstract: A method is provided for decoding a bit stream representing an image that has been encoded The method includes the steps of: performing an entropy decoding of the bit stream to form a plurality of transform coefficients and a plurality of motion vectors; performing an inverse transformation on the plurality of transform coefficients to form a plurality of error blocks; determining a plurality of predicted blocks based on bidirectional motion estimation that employs the motion vectors, wherein the bidirectional motion estimation includes a direct prediction mode and a second prediction mode; and, adding the plurality of error blocks to the plurality of predicted blocks to form the image. The second prediction mode may include forward, backward, and interpolated prediction modes.

Abstract: A method and apparatus for variable accuracy inter-picture timing specification for digital video encoding is disclosed. Specifically, the present invention discloses a system that allows the relative timing of nearby video pictures to be encoded in a very efficient manner. In one embodiment, the display time difference between a current video picture and a nearby video picture is determined. The display time difference is then encoded into a digital representation of the video picture. In a preferred embodiment, the nearby video picture is the most recently transmitted stored picture. For coding efficiency, the display time difference may be encoded using a variable length coding system or arithmetic coding. In an alternate embodiment, the display time difference is encoded as a power of two to reduce the number of bits transmitted.

Abstract: A method and apparatus for variable accuracy inter-picture timing specification for digital video encoding is disclosed. Specifically, the present invention discloses a system that allows the relative timing of nearby video pictures to be encoded in a very efficient manner. In one embodiment, the display time difference between a current video picture and a nearby video picture is determined. The display time difference is then encoded into a digital representation of the video picture. In a preferred embodiment, the nearby video picture is the most recently transmitted stored picture. For coding efficiency, the display time difference may be encoded using a variable length coding system or arithmetic coding. In an alternate embodiment, the display time difference is encoded as a power of two to reduce the number of bits transmitted.

Abstract: A method and apparatus for variable accuracy inter-picture timing specification for digital video encoding is disclosed. Specifically, the present invention discloses a system that allows the relative timing of nearby video pictures to be encoded in a very efficient manner. In one embodiment, the display time difference between a current video picture and a nearby video picture is determined. The display time difference is then encoded into a digital representation of the video picture. In a preferred embodiment, the nearby video picture is the most recently transmitted stored picture. For coding efficiency, the display time difference may be encoded using a variable length coding system or arithmetic coding. In an alternate embodiment, the display time difference is encoded as a power of two to reduce the number of bits transmitted.

Abstract: A method and apparatus for variable accuracy inter-picture timing specification for digital video encoding is disclosed. Specifically, the present invention discloses a system that allows the relative timing of nearby video pictures to be encoded in a very efficient manner. In one embodiment, the display time difference between a current video picture and a nearby video picture is determined. The display time difference is then encoded into a digital representation of the video picture. In a preferred embodiment, the nearby video picture is the most recently transmitted stored picture. For coding efficiency, the display time difference may be encoded using a variable length coding system or arithmetic coding. In an alternate embodiment, the display time difference is encoded as a power of two to reduce the number of bits transmitted.

Abstract: A method and apparatus for variable accuracy inter-picture timing specification for digital video encoding is disclosed. Specifically, the present invention discloses a system that allows the relative timing of nearby video pictures to be encoded in a very efficient manner. In one embodiment, the display time difference between a current video picture and a nearby video picture is determined. The display time difference is then encoded into a digital representation of the video picture. In a preferred embodiment, the nearby video picture is the most recently transmitted stored picture. For coding efficiency, the display time difference may be encoded using a variable length coding system or arithmetic coding. In an alternate embodiment, the display time difference is encoded as a power of two to reduce the number of bits transmitted.

Abstract: A video encoding method and apparatus is shown wherein image information is represented as a plurality of pixels, the pixels are organized into blocks, pixels transposition is performed on image information at the boundaries of the blocks, the blocks are transform coded and quantized. Pixel transposition involves transposition of alternate pixels at the boundaries of blocks with pixels of neighboring blocks found in a pre-determined direction. The pre-determined direction may be fixed by a system or may be applied on an image by image basis. In the event that the pre-determined direction is not established by a system, a pixel transposition circuit includes a transposition keyword in the output bit stream which is used by a decoded to determine the direction of pixel transposition.