摘要:
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. In accordance with each of the recording methods of the present invention the rotational rate of the digital VTRs headwheel is the same for both standard and long play modes of VTR operation. In addiction, the present invention is directed to several methods of reading data from a tape at a reduced data rate.
摘要:
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.
摘要:
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. When frame pictures are received one of a plurality of numerous described methods of mapping frame pictures into a single field of a pair of field pictures are used to convert the frame picture into a single field of a pair of field pictures. A plurality of methods for reducing the amount of data required to represent the single field of the pair of field pictures are also described.
摘要:
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.
摘要:
Digital video tape recorder apparatus that generates commands to instruct a television receiver to perform special processing, e.g., processing designed to enhance image quality, on video data received from the digital video tape recorder during trick play operation is disclosed. The commands from the video tape recorder inform the television receiver that the video tape recorder is operating in trick play mode and that video processing not performed on normal play video data output by the video tape recorder during normal play operation should be performed on the trick play video data which is output during trick play operation. The video data output during trick play operation is a subset of the normal play video data. The video processing commands output during trick play operation instruct a receiver to perform video processing intended to compensate for normal play data intentionally omitted by the video tape recorder from the trick play video data because of, e.g., data limitations resulting from the limited amount of data that can be accurately read from a tape during trick play operation. Method of generating the video processing commands which are output to a receiver during trick play video tape recorder operation are also disclosed.
摘要:
A method for reducing noise in a reference frame of video information by determining the mean absolute difference, MAD.sub.o, between each block in the reference frame and identically located blocks in adjacent frames. If MAD.sub.o is A, a search is made for a block in the adjacent frame that matches the block in the reference frame. This is labelled MAD.sub.min. If MAD.sub.o for the block in the adjacent frame is
摘要:
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. In accordance with each of the recording methods of the present invention the rotational rate of the digital VTRs headwheel is the same for both standard and long play modes of VTR operation. In addition, the present invention is directed to several methods of reading data from a tape at a reduced data rate.
摘要:
Methods of operating a digital video recording and playback device, such as a video tape recorder, to arrange trick play data into one or more groups, to generate error correction bits for each group of trick play data, e.g., a group of trick play data blocks, and to correct the data after being read back using the error correction bits is disclosed. The trick play data blocks are made to be smaller than normal play data blocks with multiple trick play data blocks being equal in size to a single normal play data block. By making a group of trick play data blocks equal in size to a single normal play data block, the group of trick play data blocks may be processed as a unit by the same error correction circuitry and in the same manner used to process individual normal play data blocks. In accordance with one embodiment, the error correction bits for a group of trick play data blocks are calculated treating the data in the group of trick play data blocks as a single unit. The error correction bits are appended to the last data block in the group of trick play data blocks. During trick play operation the trick play data blocks are read back and combined according to trick play data groups. Each group of trick play blocks is then processed using the same error correction circuitry used to process a normal play data block.
摘要:
A complete User Datagram Protocol (CUDP) is disclosed that reduces packet loss. Channel frame error information is used with a packet level forward error correction (FEC) coding technique to accommodate wireless multimedia traffic. Each packet, as well as the channel frame error information, is forwarded to a given application. The CUDP protocol further assists the FEC decoding process by forwarding the locations of corrupted frames to the FEC decoder. Maximal Distance Separable (MDS) codes can be applied to a group of packets, to achieve additional robustness. An MDS decoder utilizes the frame error information to recognize the erasures within each packet. The error information can be represented as a set of LTU error indicators associated with each packet (for FEC decoders requiring an erasure indicator). The error indicators point to the starting and ending location of the erroneous data. The error information can also be represented as a reformatted packet (for FEC decoders Recognizing Erasures). The frame (LTU) error information from the lower layers is incorporated in the packet payload. An FEC encoder is also disclosed that encodes multimedia packets utilizing a packet-coding scheme, such as a Vertical Packet Coding (VPC) scheme or a Long Vertical Packet Coding (LVPC) scheme.