Abstract: Techniques for identifying blocks of pixels, referred to as constant block regions, having approximately the same intensity in terms of luminance values, are discussed. High contrast vertical and/or horizontal edges will cause significant prediction errors in images generated by reduced resolution decoders under certain conditions. Methods for assessing when such conditions exist and a significant prediction error is likely to occur are described. In addition methods and apparatus for minimizing the effect of such prediction errors in downsampling decoders are also described. One specific embodiment is directed to a new video decoder which decodes portions of a single image, e.g., frame, at different resolutions. Areas of the image along high contrast vertical or horizontal edges are decoded at full resolution while other portions of the same image are decoded at reduced resolution.

Abstract: Methods and apparatus for implementing a reduced cost HDTV/SDTV video decoder are disclosed. The described joint video decoder is capable of decoding HDTV pictures at approximately the resolution of standard definition television pictures and can be used to decode HDTV and/or SDTV pictures. The described video decoder may be used as part of a picture-in-picture decoder circuit for providing picture-in-picture capability without providing multiple full resolution video decoders. The reduction in decoder circuit complexity is achieved through the use of a plurality of data reduction techniques including the use of a preparser, downsampling, and truncating pixel values.

Abstract: Methods and apparatus for implementing a reduced cost HDTV/SDTV video decoder are disclosed. The described joint video decoder is capable of decoding HDTV pictures at approximately the resolution of standard definition television pictures and can be used to decode HDTV and/or SDTV pictures. The described video decoder may be used as part of a picture-in-picture decoder circuit for providing picture-in-picture capability without providing multiple full resolution video decoders. The reduction in decoder circuit complexity is achieved through the use of a plurality of data reduction techniques including the use of a preparser, downsampling, and truncating pixel values.

Abstract: Plurality of encoding methods and apparatus for encoding video data in a manner that makes it well suited for decoding by either regular or downconverting decoders are described. In one embodiment, the selection and/or generation of motion vectors by an encoder is controlled so that only motion vectors having a size that corresponds to an integer multiple of a downsampling rate expected to be used by a downconverting decoder are generated and/or selected. In another embodiment, motion vectors having a size which corresponds to an integer multiple of an expected downsampling rate are preferred over other motion vectors. In various additional encoder embodiments feedback circuitry which models a downconverting decoder, and/or which provides feedback information on downconverted images generated by decoding the compressed video data generated by the encoder using a downconverting decoder, are incorporated into the encoder of the present invention.

Abstract: An implementation efficient video decoder suitable for use as a picture in picture decoder is described. In one embodiment, the video decoder receives primary and secondary bitstreams with the secondary bitstream including the video data intended to be displayed as inset pictures. The decoder uses many of the same circuit components on a time shared basis to decode both the main and inset pictures reducing the amount of circuitry required to implement the decoder. In one embodiment a preparser discards the majority of DCT coefficients in the secondary bitstream and the remaining data is variable length decoded and then variable length encoded using a non-MPEG compliant coding scheme prior to storing the inset picture data in a coded data buffer. Re-encoding of the selected inset picture data in this manner greatly reduces data storage requirements and simplifies the circuitry required to subsequently decode the inset picture data.

Abstract: An implementation efficient video decoder suitable for use as a picture in picture decoder is described. In one embodiment, the video decoder receives primary and secondary bitstreams with the secondary bitstream including the video data intended to be displayed as inset pictures. The decoder uses many of the same circuit components on a time shared basis to decode both the main and inset pictures reducing the amount of circuitry required to implement the decoder. In one embodiment a preparser discards the majority of DCT coefficients in the secondary bitstream and the remaining data is variable length decoded and then variable length encoded using a non-MPEG compliant coding scheme prior to storing the inset picture data in a coded data buffer. Re-encoding of the selected inset picture data in this manner greatly reduces data storage requirements and simplifies the circuitry required to subsequently decode the inset picture data.

Abstract: Plurality of encoding methods and apparatus for encoding video data in a manner that makes it well suited for decoding by either regular or downconverting decoders are described. In one embodiment, the selection and/or generation of motion vectors by an encoder is controlled so that only motion vectors having a size that corresponds to an integer multiple of a downsampling rate expected to be used by a downconverting decoder are generated and/or selected. In another embodiment, motion vectors having a size which corresponds to an integer multiple of an expected downsampling rate are preferred over other motion vectors. In various additional encoder embodiments feedback circuitry which models a downconverting decoder, and/or which provides feedback information on downconverted images generated by decoding the compressed video data generated by the encoder using a downconverting decoder, are incorporated into the encoder of the present invention.

Abstract: A video decoder capable of downsampling full resolution images on a block by block basis regardless of the downsampling rate is disclosed. When the applied downsampling rate does not divide evenly into the number of pixel values included in a block in the dimension being downsampled, the decoder generates a partial pixel value. A partial pixel value represents a portion of the information used to represent a pixel of an image. In contrast, a full or complete pixel value is a value represents all the information used to represent a pixel of an image. The generated partial pixel value is stored and then added to another partial pixel value generated by downsampling another block of pixel values corresponding to a portion of a full resolution image. Numerous drift reduction processing techniques applicable to downsampling decoders are disclosed. Many of these processing techniques are applicable to decoders which perform full order IDCTs as well as reduced order IDCTs.

Abstract: Methods and apparatus for inserting data into an encoded data stream are disclosed. In accordance with the disclosed methods data is inserted into an encoded data stream while maintaining MPEG-2 compliance. The disclosed methods achieve data reduction required to make room for the data to be added by removing certain data elements of an encoded data stream, such as high frequency discrete cosine transform coefficients, which can be removed with minimal impact on picture quality and without disturbing the data stream's compliance with MPEG 2. In a first embodiment, data reduction to make room for the data to be inserted is performed by depacketizing the encoded data, performing a data reduction operation thereon, and then re-packetizing the encoded data. The reduced rate data stream is then multiplexed with the data to be inserted. In a second embodiment data reduction is performed by combining the contents of two or more consecutive transport data packets, e.g.

Abstract: Methods and apparatus for processing digital video data to reduce the amount of video data required to represent a video frame by representing a frame or pair of field pictures into a single field of a pair of field picture are described. To prevent the second field of the field picture from being displayed a DSM byte associated with the field picture is set so that only the field representing the video frame is displayed. A field, e.g., a transparent predictively coded field is used as the field picture which is not displayed. In this manner, very little data is required to represent the field picture that is not displayed. When the received frames are represented as pairs of field pictures a single field of the pair of field pictures is selected to represent the video frame with the other field picture being replaced with a field which requires very little data.

Abstract: Method for increasing the recording time of a digital video tape recorder ("VTR") and for supporting multiple normal play modes of digital VTR operation, e.g., a standard play mode of operation and one or more long play modes of operation. To achieve long play mode operation data reduction is performed on a received full rate video data stream to generate a reduced rate video data stream. Data reduction is performed using data prioritization and selection, requantization of full rate data stream, and/or by selecting data to be included in the reduced rate data stream as a function of what portion of a video frame the data represents. The reduced rate data stream is generated to be compliant with the data format of the full rate data stream. During long play mode recording operation the data in the reduced rate data stream is recorded on a tape at the same tape data density as used during standard mode VTR operation.

Abstract: A video decoder capable of downsampling full resolution images on a block by block basis regardless of the downsampling rate is disclosed. When the applied downsampling rate does not divide evenly into the number of pixel values included in a block in the dimension being downsampled, the decoder generates a partial pixel value. A partial pixel value represents a portion of the information used to represent a pixel of an image. In contrast, a full or complete pixel value is a value represents all the information used to represent a pixel of an image. The generated partial pixel value is stored and then added to another partial pixel value generated by downsampling another block of pixel values corresponding to a portion of a full resolution image. Numerous drift reduction processing techniques applicable to downsampling decoders are disclosed. Many of these processing techniques are applicable to decoders which perform full order IDCTs as well as reduced order IDCTs.

Abstract: Methods and apparatus for implementing a reduced cost HDTV/SDTV video decoder are disclosed. The described joint video decoder is capable of decoding HDTV pictures at approximately the resolution of standard definition television pictures and can be used to decode HDTV and/or SDTV pictures. The described video decoder may be used as part of a picture-in-picture decoder circuit for providing picture-in-picture capability without providing multiple full resolution video decoders. The reduction in decoder circuit complexity is achieved through the use of a plurality of data reduction techniques including the use of a preparser, downsampling, and truncating pixel values.

Abstract: A procedure for selecting and storing data elements communicated from a common database to users of the database utilizing a communication link between each transmitter and a concomitant receiver accessible by the user. The transmitted information is augmented with attributes which are used at the receiver to select and then store locally only that information of interest to each receiver's user, wherein the attributes and the user selection pattern determine the criteria for storing information locally. Attributes include: utility of each data element in time; interest categories and level of interest for each of the categories determined for the collective users; repeat time to the data element; and a hyperlink to associated data elements.

Abstract: Methods and apparatus for implementing a reduced cost HDTV/SDTV video decoder are disclosed. The described joint video decoder is capable of decoding HDTV pictures at approximately the resolution of standard definition television pictures and can be used to decode HDTV and/or SDTV pictures. The described video decoder may be used as part of a picture-in-picture decoder circuit for providing picture-in-picture capability without providing multiple full resolution video decoders. The reduction in decoder circuit complexity is achieved through the use of a plurality of data reduction techniques including the use of a preparser, downsampling, and truncating pixel values.

Abstract: Methods and apparatus for reducing the complexity of decoder circuitry and video decoder memory requirements are disclosed. The described video decoders are capable of decoding HDTV pictures at approximately the resolution of standard definition television pictures and can be used to decode HDTV and/or SDTV pictures. The described video decoder may be used as part of a picture-in-picture decoder circuit for providing picture-in-picture capability without providing multiple full resolution video decoders. The reduction in decoder circuit complexity is achieved through the use of a plurality of data reduction techniques including the use of a preparser, downsampling, and truncating pixel values.

Abstract: Methods and apparatus for processing digital video data to reduce the amount of video data required to represent a video frame by representing a frame or pair of field pictures into a single field of a pair of field picture are described. To prevent the second field of the field picture from being displayed a DSM byte associated with the field picture is set so that only the field representing the video frame is displayed. In accordance with the present invention, a field, e.g., a transparent predictively coded field is used as the field picture which is not displayed. In this manner, very little data is required to represent the field picture that is not displayed. When the received frames are represented as pairs of field pictures a single field of the pair of field pictures is selected to represent the video frame with the other field picture being replaced with a field which requires very little data.

Abstract: A method and apparatus for controlling the display of progressively refreshed decoded compressed image representative data is disclosed. Subframes of intracoded video signals, and subframes of intercoded video signals based on the intracoded video signals of successive video frames are used to construct a reference video frame. Refresh descriptor data is provided indicating the number of video frames necessary for acquiring intracoded video signals to form the reference video frame. The display of video frames is inhibited based on the refresh descriptor data until a suitable video frame of intracoded video signals and intercoded video signals based thereon is constructed. In another embodiment of the invention, at least one array of memory elements is provided for storing data corresponding to the subframes of a video frame. Each subframe of a video frame corresponds to one element of the memory array.

Abstract: Method for increasing the recording time of a digital video tape recorder ("VTR") and for supporting multiple normal play modes of digital VTR operation, e.g., a standard play mode of operation and one or more long play modes of operation. To achieve long play mode operation data reduction is performed on a received full rate video data stream to generate a reduced rate video data stream. Data reduction is performed using data prioritization and selection, requantization of full rate data stream, and/or by selecting data to be included in the reduced rate data stream as a function of what portion of a video frame the data represents. The reduced rate data stream is generated to be compliant with the data format of the full rate data stream. During long play mode recording operation the data in the reduced rate data stream is recorded on a tape at the same tape data density as used during standard mode VTR operation.

Abstract: Method for increasing the recording time of a digital video tape recorder ("VTR") and for supporting multiple normal play modes of digital VTR operation, e.g., a standard play mode of operation and one or more long play modes of operation. To achieve long play mode operation data reduction is performed on a received full rate video data stream to generate a reduced rate video data stream. Data reduction is performed using data prioritization and selection, requantization of full rate data stream, and/or by selecting data to be included in the reduced rate data stream as a function of what portion of a video frame the data represents. The reduced rate data stream is generated to be compliant with the data format of the full rate data stream. During long play mode recording operation the data in the reduced rate data stream is recorded on a tape at the same tape data density as used during standard mode VTR operation.