Adaptive-selection method for memory access priority control in MPEG processor

• US 5,982,360 A
• Filed: 09/30/1997
• Issued: 11/09/1999
• Est. Priority Date: 06/28/1997
• Status: Expired due to Term

• Current Assignee: United Microelectronics Corporation
• Original Assignee: United Microelectronics Corporation
• Inventors: Pan, Jyh-Shin, Wu, Wen-Yi
• Primary Examiner(s): Chauhan, U.
• Application Number:
  US08/941,064
• Time in Patent Office: 770 Days
• Field of Search: 345/418, 345/302, 345/327, 345/330, 345/501-503, 345/520, 345/521, 345/507, 345/509, 345/202, 395/280, 395/287-296, 395/300-303, 395/731, 395/732, 710/100, 710/107-116, 710/120, 710/123
• US Class Current: 345/535
• CPC Class Codes: H04N 19/42 characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation H04N19/635 takes precedence
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 21/443 OS processes, e.g. booting an STB, implementing a Java virtual machine in an STB or power management in an STB

Abstract

An adaptive-selection method for memory access priority control in MPEG processor. The processor has functional modules that include an input interface, a CPU, an audio decoder, a video decoder, an audio processor, a video processor and a memory controller. Each of the modules gains control over the data bus via arbitration by the memory controller for accessing the memory. The access priority of the CPU to the data bus is maintained at a relatively lower level except when the CPU needs to perform parsing on the MPEG compressed data and implementing the initial decoding of the audio compressed data. The use of data bus bandwidth is therefore balanced among all the system resources thereby increasing the overall system performance.

Claims

1. An adaptive-selection method for memory access priority control in an MPEG processor that includes:

an input interface for receiving MPEG compressed audio and video data;

a central processing unit for parsing the MPEG compressed audio and video data to obtain parsed compressed audio and parsed compressed video data;

an audio decoder for decoding the parsed compressed audio data to obtain decoded audio data;

a video decoder for decoding the parsed compressed video data to obtain decoded video data;

an audio processor for generating audio output signals from the decoded audio data;

a video processor for generating video output signals from the decoded video data;

a memory controller;

a memory for storing the MPEG compressed audio and video data, the parsed compressed audio data, the parsed compressed video data, the decoded audio data, and the decoded video data; and

a data bus linking the input interface, the central processing unit, the audio decoder, the video decoder, the audio processor, the video processor, the memory controller, and the memory together for communicating therebetween, wherein the memory controller controls access to the data bus;

the adaptive-selection method comprising;

establishing an initial access priority of the central processing unit to the data bus; and

performing a continuous routine including

determining if the central processing unit is required to perform initial audio decoding;

if the central processing unit is required to perform initial audio decoding, raising the access priority of the central processing unit to the data bus, performing initial audio decoding, and lowering the raised access priority after the performing initial decoding of the audio data;

determining if the central processing unit is required to parse the MPEG compressed audio and video data; and

if the central processing unit is required to parse the MPEG compressed audio and video data, raising the access priority of the central processing unit to the data bus, implementing parsing of the MPEG compressed audio and video data by the central processing unit, and lowering the raised access priority after the implementing parsing.

2. The adaptive-selection method of claim 1, wherein the implementing parsing of the MPEG compressed audio and video data further comprises:

the central processing unit retrieving the MPEG compressed audio and video data stored in the memory via the data bus for parsing to generate the parsed compressed audio data and the parsed compressed video data;

storing the parsed compressed audio data in the memory via the data bus;

initial decoding of the parsed compressed video data to obtain the decoded video data; and

storing the decoded video data in the memory via the data bus.

3. The adaptive-selection method of claim 2, wherein the performing initial audio decoding further comprises:

the central processing unit retrieving the parsed compressed audio data stored in the memory via the data bus for initial decoding of the parsed compressed audio data to generate the decoded audio data; and

storing the decoded audio data in the memory via the data bus.

4. The adaptive-selection method of claim 3, wherein the input interface is a CD interface for receiving MPEG compressed data generated by a Video Compact Disc.

5. The adaptive-selection method of claim 3, wherein the input interface is a CD interface for receiving MPEG compressed data generated by a Digital Video Disc.

6. The adaptive-selection method of claim 4, wherein the CD interface further comprises a serial-to-parallel converter for converting the MPEG compressed data generated by the Video Compact Disc from serial format into parallel format.

7. The adaptive-selection method of claim 5, wherein the CD interface further comprises a serial-to-parallel converter for converting the MPEG compressed data generated by the Digital Video Disc from serial format into parallel format.

8. The adaptive-selection method of claim 3 wherein the input interface is a digital broadcast receiving interface for receiving compressed data generated by a digital broadcast station.

9. The adaptive-selection method of claim 3, wherein the audio processor is a PCM processor for generating PCM output as the audio output signal.

10. The adaptive-selection method of claim 3, wherein the video processor is an NTSC processor for generating NTSC output as the video output signal.

11. The adaptive-selection method of claim 3, wherein the video processor is a PAL processor for generating PAL output as the video output signal.

12. The adaptive-selection method of claim 3, wherein the video processor is a VGA processor for generating VGA output as the video output signal.

13. An adaptive-selection method for controlling a priority for gaining access to a data bus for each of various components of an MPEG processor for receiving MPEG compressed data including at least MPEG compressed audio data, the method comprising:

establishing an initial, relatively low, priority for a central processing unit to access the data bus; and

performing a continuous routine including

determining whether initial audio decoding is required to be performed on MPEG compressed audio data received by the MPEG processor;

if initial audio decoding is required, raising the priority of the central processing unit to a second, relatively high, priority, performing initial audio decoding on the MPEG compressed audio data to generate decoded compressed audio data, and lowering the second priority to a third, relatively low, priority after the performing initial audio decoding;

determining whether the MPEG compressed data received by the MPEG processor includes MPEG compressed video data in addition to MPEG compressed audio data; and

if the MPEG compressed data includes MPEG compressed video data, raising the priority of the central processing unit to a fourth, relatively high, priority, parsing the MPEG compressed audio and video data to generate parsed audio data and parsed video data, and lowering the fourth priority to a fifth, relatively low, priority after the parsing.

14. The adaptive-selection method of claim 13, wherein the parsing the MPEG compressed audio and video data further comprises:

retrieving the MPEG compressed audio and video data stored in a memory via the data bus;

storing the parsed audio data in the memory via the data bus;

initial decoding of the parsed video data to obtain decoded video data; and

storing the decoded video data in the memory via the data bus.

15. The adaptive-selection method of claim 13, wherein the performing initial audio decoding further comprises:

retrieving the MPEG compressed audio data stored in a memory via the data bus; and

storing the decoded compressed audio data in the memory via the data bus.