摘要:
A video encoder and decoder are provided for encoding and decoding video signal data for an image block and a particular reference picture index to predict the image block, where the encoder includes a reference picture weighting factor selector having an output indicative of a weighting factor corresponding to the particular reference picture index, a multiplier in signal communication with the reference picture weighting factor selector for providing a weighted version of the reference picture, and a motion estimator in signal communication with the multiplier for providing motion vectors corresponding to the weighted version of the reference picture; and the corresponding decoder a reference picture weighting factor unit having an output for determining a weighting factor corresponding to the particular reference picture index.
摘要:
There are provided video encoders and corresponding methods for performing fast mode decision of B-frames. A video encoder for encoding video data for a B slice that is divisible into macroblocks includes an encoder (OO) for performing mode selection when encoding a current macroblock in the B slice by counting a number of neighboring macroblocks in the B slice coded in a DIRECT mode, and only checking one of the DIRECT MODE or a 16×16 mode for the current macroblock when the number of neighboring macroblocks coded in the DIRECT mode exceeds a predetermined threshold.
摘要:
There is provided a video encoder, video decoder and corresponding encoding and decoding methods for respectively encoding and decoding video signal data for an image slice. The video encoder includes a slice prediction residual downsampler for downsampling a prediction residual of at least a portion of the image slice prior to transformation and quantization of the prediction residual. The video decoder includes a prediction residual upsampler for upsampling a prediction residual of the image slice.
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:
Reverse jog play can be provided quickly and simply in a player that plays a recorded stream of inter-frame encoded digital video by storing, in intra-coded frame format, frames that were previously decoded by the player and are in the vicinity of the frame currently being displayed. The intra-frame encoded versions of the decoded frames may be digitally stored in random access memory (RAM) or in some other storage medium that is easily accessible. The number of previously decoded frames may be a fixed number essentially independent of the frame structure of the video stream. Alternatively, the player stores each decoded frame from a predetermined, e.g., the most recently or next to most recently decoded, intra-coded frame (I-frame) until the current frame. Thus, the number of useable stored frames is a function of the video stream structure, the design choices of the user, and the current frame being displayed. Optionally, when using reverse jog play, an additional series of frames is decoded and stored upon reaching a point near the I-frame toward which the display is moving. Advantageously, by using I-frame format for storing the previously decoded frames for possible use in reverse jog play, the storage requirement for such frames is reduced while conventional available components may be used to implement the system.
摘要:
In order to transmit an inter-frame coded video signal, such as an MPEG-coded video signal, over a packet-based network such as the Internet, the video signal associated with at least one video frame, is split (102, 402) into a high priority partition and a low priority partition. A systematic forward error erasure/correction (FEC) code (108), such as a Reed Solomon (n,k) code, is then applied to bytes in the high priority partition. The forward error/erasure corrected high priority partition bytes and the low priority partition bytes are then combined (110) into n packets for transmission over the packet network to a receiver/decoder. Each of the n transmitted packets contains a combination of both high priority partition data bytes and low priority partition information bytes. In k of those packets the high priority partition data bytes are all high priority partition information bytes and in n−k of those packets all the high priority partition data byte are parity bytes produced by the FEC coding. More specifically, for each high priority partition byte position within the n packets, the forward error/erasure correction code is applied using one high priority partition information byte from the same byte position in each of those k packets to determine n−k parity bytes, which are arranged, one byte per packet, in the n−k packets containing high priority partition parity bytes. If up to n−k packets are lost in transmission over the packet network to the receiver (500, 600), then the high priority partition bytes in such lost packets can be recovered to applying FEC decoding (506) to the high partition bytes in the received packets. The most visually significant information is thus protected against packet loss over the network.
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:
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. To reduce frame memory requirements inset picture data is downsampled, stored and then upsampled prior to display thereby reducing inset picture frame memory buffer requirements.
摘要:
A device for transmitting digital packetized video and audio data is disclosed. The transmitter includes a video encoder, a prioritizer, and a packetizer. The video encoder receives video signals and encodes the video signals into a digital video data stream including codewords. The video encoder also generates motion vectors and fully intra-coded video frames for use by a video tape recorder during trick play operation. The prioritizer is coupled to the video encoder. The prioritizer receives the digital video data stream and prioritizes the video data according to a preselected prioritization scheme optimized for identifying data useful to video tape recorder trick play operation. The preselected prioritization scheme assigns the video codewords in the video data stream to a priority level according to the utility of each video codeword for video tape recorder recording and playback operation and outputs both the video codewords and a priority level signal. The video codewords and the priority level signal are supplied to a transport packetizer which packetizes the video codewords and associates a header with each packet. The headers contain information identifying the assigned priority level of the codewords in each packet. This makes it possible for a video tape recorder receiving the video packets to determine the utility of the codewords in a given packet from the priority level information in the packet headers.
摘要:
Methods and apparatus for converting digital signals having a variable data rate to fixed data rate signals suitable for recording on a tape by a digital video tape recorder are disclosed. The methods include buffering of the received variable rate data, measuring the data rate of the received data for a fixed period of time and processing the buffered data to converted it into a fixed rate data stream. This processes is repeated for each of the fixed periods of time. Methods 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., recording modes for recording SDTV and HDTV are also disclosed. To generate fixed data rate signals from variable data rate signals one or more of data padding and/or data reduction techniques are used. The same data reduction techniques used to generate the fixed rate data stream are used, in accordance with various embodiment of the invention, to reduce the amount of data required to represent a video frame.