Image decoder with bus arbitration circuit
First Claim
1. An image decoder for decoding an input bit stream, the image decoder comprising:
- a memory havingan input bit stream buffer for storing the input bit stream;
an image memory region for storing a decoded image; and
an image decoding circuit coupled to the memory through a bus, the image decoding circuit havinginput bit stream buffer control means coupled to the bus for writing and reading the input bit stream to and from the input bit stream buffer;
decoding means coupled to the bus for reading the input bit stream from the input bit stream buffer to generate decoded image data, and for writing the decoded image data in the image memory region;
image output control means coupled to the bus for reading the decoded image data from the image memory region and outputting the decoded image data; and
bus arbitrating means coupled to at least one of the input bit stream buffer control means, the decoding means and the image output control means for controlling use of the bus by any one of the input bit stream buffer control means, decoding means, and image output control means, wherein the bus arbitrating means controls the bus to provide the image output control means with the highest priority to use the bus without interruption to access the memory at predetermined time intervals, and after the completion of the memory access by the image output control means, detects whether a request for access to the memory is made by the input bit stream buffer control means, and when the request is made, permits the input bit stream buffer control means to use the bus, and when both the image output control means and input bit stream buffer control means are not using the bus, permits the decoding means to use the bus to access the memory.
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Accused Products
Abstract
An image decoder has a bus arbitrating circuit for controlling the use of the bus by any one of input bit stream buffer control circuit, decoding circuit, and image output control circuit. The bus arbitrating circuit controls the bus to provide the image output control means with the highest priority to use the bus without interruption to access the memory at predetermined time intervals. After the completion of the memory access by the image output control means, the bus arbitrating circuit detects whether a request for access to the memory is made by the input bit stream buffer control circuit, and when the request is made, permits the input bit stream buffer control circuit to use the bus. When both the image output control circuit and input bit stream buffer control circuit are not using the bus, permits the decoding means to use the bus to access the memory.
69 Citations
5 Claims
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1. An image decoder for decoding an input bit stream, the image decoder comprising:
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a memory having an input bit stream buffer for storing the input bit stream; an image memory region for storing a decoded image; and an image decoding circuit coupled to the memory through a bus, the image decoding circuit having input bit stream buffer control means coupled to the bus for writing and reading the input bit stream to and from the input bit stream buffer; decoding means coupled to the bus for reading the input bit stream from the input bit stream buffer to generate decoded image data, and for writing the decoded image data in the image memory region; image output control means coupled to the bus for reading the decoded image data from the image memory region and outputting the decoded image data; and bus arbitrating means coupled to at least one of the input bit stream buffer control means, the decoding means and the image output control means for controlling use of the bus by any one of the input bit stream buffer control means, decoding means, and image output control means, wherein the bus arbitrating means controls the bus to provide the image output control means with the highest priority to use the bus without interruption to access the memory at predetermined time intervals, and after the completion of the memory access by the image output control means, detects whether a request for access to the memory is made by the input bit stream buffer control means, and when the request is made, permits the input bit stream buffer control means to use the bus, and when both the image output control means and input bit stream buffer control means are not using the bus, permits the decoding means to use the bus to access the memory. - View Dependent Claims (2)
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3. An image decoding circuit for decoding an input bit stream, operable with a memory device having an input bit stream buffer and an image memory region, the image decoding circuit coupled to the memory device via a bus, the image decoding circuit comprising:
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input bit stream buffer control means coupled to the bus for writing and reading the input bit stream to and from the input bit stream buffer; decoding means coupled to the bus for reading the input bit stream from the input bit stream buffer to generate decoded image data, and for writing the decoded image data in the image memory region; image output control means coupled to the bus for reading the decoded image data from the image memory region and outputting the decoded image data; and bus arbitrating means coupled to at least one of the input bit stream buffer control means, the decoding means and the image output control means for controlling use of the bus by any one of the input bit stream buffer control means, decoding means, and image output control means, wherein the bus arbitrating means controls the bus to provide the image output control means with the highest priority to use the bus without interruption to access the memory at predetermined time intervals, and after the completion of the memory access by the image output control means, detects whether a request for access to the memory is made by the input bit stream buffer control means, and when the request is made, permits the input bit stream buffer control means to use the bus, and when both the image output control means and input bit stream buffer control means are not using the bus, permits the decoding means to use the bus to access the memory. - View Dependent Claims (4)
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5. An image decoding circuit for decoding an input bit signal, operable with a memory device having an input bit stream buffer and an image memory, the image decoding circuit coupled to the memory device via a bus, the image decoding circuit comprising:
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an input bit stream buffer control unit coupled to the bus for writing and reading the input bit signal to and from the input bit stream buffer; a decoding unit coupled to the bus for reading the input bit signal from the input bit stream buffer to generate decoded image data, and for writing the decoded image data in the image memory; an image output control unit coupled to the bus for reading the decoded image data from the image memory and outputting the decoded image data; and a bus arbitrating unit coupled to at least one of the input bit stream buffer control means, the decoding means and the image output control means for controlling use of the bus by any one of the input bit stream buffer control unit, decoding unit, and image output control unit, wherein the bus arbitrating means controls the bus to provide the image output control unit with the highest priority to use the bus without interruption to access the memory at predetermined time intervals, and after the completion of the memory access by the image output control unit, detects whether a request for access to the memory is made by the input bit stream buffer control unit, and when the request is made, permits the input bit stream buffer control unit to use the bus, and when both the image output control unit and input bit stream buffer control unit are not using the bus, permits the decoding unit to use the bus to access the memory.
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Specification