System and method for playing compressed audio data

• US 6,377,530 B1
• Filed: 02/12/1999
• Issued: 04/23/2002
• Est. Priority Date: 02/12/1999
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Burrows, Michael
• Primary Examiner(s): Hudspeth, David
• Assistant Examiner(s): CHU, KIM KWOK
• Application Number:
  US09/249,182
• Time in Patent Office: 1,166 Days
• Field of Search: 369/54, 369/32, 369/48, 369/33, 369/47, 369/59, 369/58, 369/59.21, 369/59.23, 369/30.03, 369/32.01, 369/30.06, 369/47.1, 704/500, 704/501, 704/502, 846/09
• US Class Current: 369/59.21
• CPC Class Codes: G11B 31/003 with radio receiver
• CPC Class Codes: G11B 31/02 with automatic musical instruments

Abstract

A portable audio player stores a large amount of compressed audio data on an internal disk drive, and loads a portion of this into an internal random access memory (RAM) which requires less power and less time to access. The audio player plays the data stored in RAM and monitors the amount of unplayed data. When the amount of unplayed data falls below a threshold, additional data is copied from the disk drive into RAM. When the portable audio player is turned off, a predetermined amount of audio data is stored in a fast-access non-volatile flash memory unit. When the audio player is turned back on, and play is resumed, a suitable portion of this data can be played while data is being loaded from the disk drive into RAM, thus reducing the amount of time a user must wait before receiving data in response to a play request.

Claims

1. An audio player, comprising:

a first memory unit;

a non-volatile memory buffer;

fast-start logic for copying a predefined amount of audio data from the first memory unit into the non-volatile memory buffer under predefined conditions before the audio player is turned off, and for playing the audio data stored in the non-volatile memory buffer when the audio player is commanded to resume playing;

wherein the first memory unit has a longer data access time than a data access time associated with the non-volatile memory buffer;

whereby the fast-start logic enables the audio player to resume playing audio data within a time period corresponding to the data access time associated with the non-volatile memory buffer upon receiving a command to resume playing after the audio player has been turned off.

2. The audio player of claim 1, wherein

the audio data is compressed; and

the audio player further includes;

a compressed audio data converter for converting compressed audio data in the first memory unit into a decompressed audio signal; and

a communications port for transmitting the decompressed audio signal to a user.

3. The audio player of claim 1, wherein the first memory unit has storage capacity greater than storage capacity of the non-volatile memory buffer, and the first memory unit comprises a hard disk drive that is powered off when the audio player is turned off and the non-volatile memory buffer comprises a flash EEPROM.

4. The audio player of claim 1, wherein said first memory unit comprises a non-volatile memory unit and a volatile memory unit.

5. The audio player of claim 4 further comprising:

play control logic for copying audio data from the non-volatile memory unit into the volatile memory unit while said fast start logic is playing the audio data stored in the non-volatile memory buffer, and for playing, without interruption, the audio data stored in the volatile memory unit when the fast start logic finishes playing the audio data stored in the non-volatile memory buffer.

6. The audio player of claim 1, further including:

play control logic for playing, without interruption, audio data stored in the first memory unit when the fast start logic finishes playing the audio data stored in the non-volatile memory buffer.

7. A multimedia player, comprising:

a first memory unit;

a non-volatile memory buffer;

fast-start logic for copying a predefined portion of multimedia data from said first memory unit into said non-volatile memory buffer upon the occurrence of a first predefined condition, and for playing the multimedia data stored in said non-volatile memory buffer upon the occurrence of a second predefined condition;

wherein the first memory unit has a longer data access time than a data access time associated with the non-volatile memory buffer;

whereby the fast-start logic enables the multimedia player to resume playing multimedia data within a time period corresponding to the data access time associated with the non-volatile memory buffer upon the occurrence of the second predefined condition.

8. The multimedia player of claim 7, wherein said multimedia data comprises compressed audio data.

9. The multimedia player of claim 7, wherein said multimedia data comprises audio-visual data.

10. The multimedia player of claim 7, wherein said first predefined condition comprises a command to turn off the multimedia player, and wherein said second predefined condition comprises a command to resume playing multimedia data.

11. The multimedia player of claim 7, further comprising:

play control logic, wherein said first memory unit comprises a non-volatile memory unit and a volatile memory unit, said play control logic for copying multimedia data from the non-volatile memory unit into the volatile memory unit while said fast start logic is playing the multimedia data stored in the non-volatile memory buffer.

12. A method of reducing data-retrieval latency in an audio player, comprising:

detecting a first predefined condition;

copying a predefined portion of audio data from a first memory unit into a non-volatile memory buffer upon detection of the first predefined condition;

the first memory unit having a longer data access time than a data access time associated with the non-volatile memory buffer;

detecting a second predefined condition; and

playing the audio data stored in said non-volatile memory buffer upon detection of the second predefined condition;

whereby the audio player begins playing audio data within a time period corresponding to the data access time associated with the non-volatile memory buffer upon the occurrence of the second predefined condition.

13. The method of claim 12, wherein said first predefined condition comprises a command to turn off the audio player, and wherein said second predefined condition comprises a command to resume playing audio data.

14. The method of claim 12, wherein said first predefined condition comprises an absence of user-input to the audio player for a predetermined time interval when said audio player is not playing audio data.

15. The method of claim 12, wherein the predefined portion of audio data that is copied into the non-volatile memory buffer upon detection of said first predefined condition comprises a sequence of the next data to be played by the audio player, said sequence having a predetermined length.

16. A data storage and transmission unit, comprising:

a non-volatile memory unit;

a volatile memory unit;

a non-volatile memory buffer;

the non-volatile memory unit having a longer data access time than a data access time associated with the non-volatile memory buffer;

an output port for transmitting data from the volatile memory unit to an output device;

control logic for copying data from the non-volatile memory unit into the volatile memory unit, wherein the time required to transmit the copied data is greater than the time required to copy the data from the non-volatile memory unit into the volatile memory unit; and

fast-start logic for copying a predefined amount of data from the volatile memory unit into the non-volatile memory buffer under predefined conditions before the data storage and transmission unit is commanded to turn off, and for transmitting the predefined amount of data when the data storage and transmission unit is commanded to resume transmitting data.

17. The data storage and transmission unit of claim 16, wherein the non-volatile memory buffer has a data access time that is less than a data access time of the non-volatile memory unit.

18. A method of transmitting an audio signal with a compressed audio data player, comprising:

playing compressed audio data stored in a memory unit, including transmitting compressed audio data from a memory unit to a data converter, converting the compressed audio data into a decompressed audio signal, and transmitting the decompressed audio signal to an output port;

detecting a first predefined condition;

copying a predefined portion of compressed audio data from the memory unit into a non-volatile memory buffer upon detection of the first predefined condition;

detecting a second predefined condition; and

playing the compressed audio data stored in said non-volatile memory buffer upon detection of the second predefined condition, and then without interruption, playing compressed audio data stored in the memory unit.

19. The method of claim 18, wherein the step of playing the compressed audio data stored in the non-volatile memory buffer further comprises:

copying the predefined portion of compressed audio data from the non-volatile memory buffer into the memory unit;

transmitting the predefined portion of compressed audio data from the memory unit to the data converter;

converting the predefined portion of compressed audio data into a predefined decompressed audio signal;

transmitting the predefined decompressed audio signal to the output port.

20. A method of operating an audio player, comprising:

playing audio data stored in a first memory unit;

copying a predefined amount of audio data from the first memory unit into a non-volatile memory buffer under predefined conditions before the audio player is powered down; and

after the audio player has powered down and upon receiving a resume play command, playing the audio data stored in the non-volatile memory buffer, and then without interruption, playing audio data stored in the first memory unit.

21. An audio player, comprising:

a first memory unit;

a non-volatile memory buffer;

fast-start logic for copying a predefined amount of audio data from the first memory unit into the non-volatile memory buffer under predefined conditions before the audio player is powered down, and for playing the audio data stored in the non-volatile memory buffer when the audio player is commanded to resume playing after being powered down; and

play control logic for playing, without interruption, audio data stored in the first memory unit when the fast start logic finishes playing the audio data stored in the non-volatile memory buffer.