Apparatus for receiving motion picture
AssigneeLG Electronics Inc.
InventorsEung Tae Kim, Jin Gyeong Kim, Seung Jong Choi
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Abstract
An apparatus for receiving motion pictures is disclosed. The present invention reduces an external memory in an MPEG-2 decoding chip, which is a standard device in the field of digital video transmission. Particularly, a data processing structure is disclosed for compressing video-decoded data in an ADPCM method and storing the same in an external memory so as to ease compensation for motion in a macro-block unit of the MPEG-2 standard device as well as to maintain motion pictures of high definition.
Claims18
An apparatus for receiving motion pictures having an external memory and a video decoder for restoring original pixel values after a variable length decoding process, an inverse quantization, an IDCT process, and a motion compensation process of video bit stream in a macro-block units, comprising:
- a compression unit which divides a decoded macro-block into a plurality of sub-blocks, and compresses decoded pixel values in each sub-block to store in said external memory;
- a decompression unit which reads the compressed pixel value from said external memory and restores the compressed pixel values to an original pixel value in a macro-block units;
- and
- a memory control unit which controls compression and reconstruction of pixel values, and controls storage of said pixel values in said external memory,
- wherein said compression unit comprises:
- a deviation calculation unit which calculates a standard deviation of the decoded pixel values for each sub-block;
- a buffer which temporarily stores the decoded pixel values in a macro-block unit and outputs the decoded pixels in sub-block units;
- an ADPCM compression unit which outputs first rows of each sub-block output from said buffer as original pixel values without compression, codes a difference between a prediction value and a current pixel value with respect to each remaining rows of each sub-block, and adjusts a quantization interval using the standard deviation when performing the coding;
- and
- a write FIFO which temporarily stores an output of said ADPCM compression unit, and conforms the video decoder to a data rate of said external memory.
An apparatus for receiving motion pictures comprising:
- a transport decoder which selects a program signal from a plurality of programs included in a channel, and separates the selected program signal into audio bit stream and video bit stream;
- a video decoder which receives the video bit stream through a data bus and eliminates overheads from the video stream, said video decoder also variable length decoding, inverse quantizing, IDCT, and motion compensating the video bit steam to restore pixel values of the an original image;
- a video display processor which either re-sorts or outputs data of the restored pixel values in accordance with a picture type;
- an external memory which temporarily stores a bit stream for decoding, for motion compensation, and for displaying decoded data;
- and
- a memory reduction unit which calculates a standard deviation for each macro-block of a restored image, compresses and stores each macro-block in a buffer using the standard deviation σ, and when said buffer is filled, stores the compressed data in the external memory,
- wherein the memory reduction unit comprises:
- an adder which receives and adds IDCT data with motion compensated data from the video decoder;
- a deviation computing unit which computes a standard deviation from the output of the adder;
- a STR buffer which stores the output of the adder in macro-block units;
- an ADPCM encoder which compresses data within each macro-block stored in the STR buffer by ADPCM method based upon the standard deviation;
- a PCM buffer which stores the data compressed by the ADPCM encoder;
- and
- a write FIFO which reads and stores in the external memory the data compressed and stored in the PCM buffer, when the PCM buffer is filled.
A memory reduction unit for an apparatus which receives motion pictures comprising:
- an adder which receives and adds IDCT data with motion compensated data from a video decoder;
- a deviation computing unit which computes a standard deviation from the output of the adder;
- a STR buffer which stores the output of the adder in macro-block units;
- an ADPCM encoder which compresses data within sub-blocks of each macro-block stored in the STR buffer by ADPCM method based upon the standard deviation;
- a PCM buffer which stores the data compressed by the ADPCM encoder;
- and
- a write FIFO which reads and stores in an external memory the data compressed and stored in the PCM buffer, when the PCM buffer is filled.
Dependencies are inferred from the claim text.