Streaming information appliance with buffer read and write synchronization

• US 6,378,035 B1
• Filed: 04/06/1999
• Issued: 04/23/2002
• Est. Priority Date: 04/06/1999
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Lorton, Christopher W., Smirnov, Serge, Raja, Jayachandran, Parry, William G., Lee, Mingtzong
• Primary Examiner(s): Elmore, Reba I.
• Application Number:
  US09/287,075
• Time in Patent Office: 1,113 Days
• Field of Search: 711/110, 711/109, 711/117, 725/89
• US Class Current: 711/110
• CPC Class Codes: G11B 20/10 Digital recording or reproducing
• CPC Class Codes: G11B 20/10527 Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: G11B 2020/1062 Data buffering arrangements, e.g. recording or playback buffers
• CPC Class Codes: G11B 27/102 Programmed access in sequence to addressed parts of tracks of operating record carriers access by moving the head G11B3/08, G11B5/54, G11B7/085, G11B21/022; by moving the record carrier G11B15/005, G11B17/005, by driving of both record carrier and head G11B15/1816
• CPC Class Codes: H04N 21/4325 by playing back content from the storage medium reproduction of recorded television signals H04N5/76; reproduction of recorded television signals H04N9/79
• CPC Class Codes: H04N 21/4334 Recording operations recording of a television signal H04N5/76; arrangements for recording or accumulating broadcast information or broadcast-related information H04H60/27
• CPC Class Codes: H04N 21/4394 involving operations for analysing the audio stream, e.g. detecting features or characteristics in audio streams arrangements characterised by components specially adapted for monitoring, identification or recognition of audio in broadcast systems H04H60/58
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 21/44008 involving operations for analysing video streams, e.g. detecting features or characteristics in the video stream arrangements characterised by components specially adapted for monitoring, identification or recognition of video in broadcast systems H04H60/59
• CPC Class Codes: H04N 21/8453 by locking or enabling a set of features, e.g. optional functionalities in an executable program
• CPC Class Codes: H04N 21/8455 involving pointers to the content, e.g. pointers to the I-frames of the video stream

Abstract

An information appliance receives streaming information and includes a buffer, a writer module, a reader module and a synchronizer. The buffer has a plurality of storage locations, a logical head, a logical tail and a valid data area between the logical head and the logical tail. The logical head and the logical tail move sequentially through the plurality of storage locations in a first logical direction. The writer module has a write position at the logical head of the buffer. The writer module receives the streaming information and writes the streaming information to the buffer at the write position. The reader module is coupled to the buffer and has a first read position which is temporally movable with respect to the write position. The synchronizer is coupled to the writer module and the reader module and maintains the first read position within the valid data area.

Claims

1. An information appliance for receiving streaming information, the information appliance comprising:

a buffer having a plurality of storage locations, a logical head, a logical tail and a valid data area between the logical head and the logical tail, wherein the logical head and the logical tail move sequentially through the plurality of storage locations in a first logical direction;

a writer module having a write position at the logical head of the buffer, wherein the writer module receives the streaming information and writes the streaming information to the buffer at write position;

a first reader module which is coupled to the buffer and has a first read position which is temporally movable with respect to the write position; and

a synchronizer coupled to the writer module and the reader module which maintains the first read position within the valid data area.

2. The information appliance of claim 1 wherein the writer module and the reader module have independent rates of access to the buffer.

3. The information appliance of claim 1 wherein the buffer is a circular buffer in which the logical head and the logical tail move circularly through the plurality of storage locations in the first logical direction.

4. The information appliance of claim 1 and further comprising:

a second reader module which is coupled to the buffer and has a second read position which is temporally movable with respect to the write position and the first read position.

5. The information appliance of claim 1 wherein the buffer is a circular buffer in which the logical head and the logical tail move circularly through the plurality of storage locations in the first logical direction.

6. The information appliance of claim 1 wherein:

the writer module comprises means for writing a first block of the streaming information to a first sequence of successive ones of the storage locations; and

the synchronizer comprises means for temporarily blocking the means for writing the first block if the first read position is currently within the first sequence.

7. The information appliance of claim 6 wherein the synchronizer further comprises:

means for unblocking the means for writing the first block when the first read position advances past the first sequence relative to the first logical direction.

8. The information appliance of claim 7 wherein the synchronizer further comprises:

means for advancing the first read position in the first logical direction when the means for writing is blocked by the synchronizer.

9. The information appliance of claim 6 wherein the synchronizer further comprises:

means for advancing the logical tail of the buffer to an end of the first sequence of the successive ones of the storage locations prior to writing the first block of the streaming information; and

means for temporarily blocking the means for writing if the first read position is behind the logical tail relative to the first logical direction.

10. The information appliance of claim 9 wherein:

reader module comprises means for reading a second block of the streaming information from a second sequence of successive ones of the storage locations while advancing the first read position through the second sequence; and

the synchronizer further comprises means for unblocking the means for writing the first block after the means for reading advances the first read position if the first read position is ahead of the logical tail relative to the first logical direction.

11. The information appliance of claim 1 wherein:

the reader module comprises means for reading a first block of the streaming information from a first sequence of successive ones of the storage locations; and

the synchronizer comprises means for temporarily blocking the means for reading the first block if an end of the first sequence is ahead of the logical head relative to the first logical direction and therefore outside the valid data area.

12. The information appliance of claim 11 wherein:

the writer module comprises means for writing a second block of the streaming information to a second sequence of successive ones of the storage locations; and

the synchronizer further comprises;

means for advancing the logical head of the buffer to an end of the second sequence after the means for writing writes the second block; and

means for unblocking the means for reading the first block after the step of the synchronizer advances the logical head if the end of the first sequence is behind the logical head relative to the first logical direction.

13. The information appliance of claim 1 wherein:

the reader module comprises means for reading a block of the streaming information from a first sequence of successive ones of the storage locations; and

the synchronizer comprises means for failing the means for reading the block if a beginning of the first sequence is behind the logical tail relative to the first logical direction and therefore outside the valid data area.

14. A computer readable medium including instructions readable by an information appliance having a buffer with a fixed number of storage locations which, when implemented, cause the information appliance to handle streaming information by performing steps comprising:

defining a logical head and tail in the buffer and a valid data area between the logical head and tail which comprises a portion of the storage locations;

writing streaming information to the logical head of the buffer with a writer module;

moving the logical head and tail through the storage locations in a first logical direction while writing the streaming information;

reading the streaming information from a first read position within the valid data area with a first reader module, wherein the first read position is temporally movable with respect to the logical head and tail; and

synchronizing the steps of writing the streaming information and reading the streaming information.

15. The computer readable medium of claim 14 wherein:

the step of writing comprises writing a first block of the streaming information to a first sequence of successive ones of the storage locations; and

the step of synchronizing comprises temporarily blocking the step of writing the first block of the streaming information if the first reader module is currently reading from one of the storage locations within the sequence.

16. The computer readable medium of claim 15 wherein the step of synchronizing further comprises:

unblocking the step of writing a block of the streaming information when the first read position advances past the first sequence relative to the first logical direction.

17. The computer readable medium of claim 16 wherein the step of synchronizing further comprises:

increasing a rate at which the reader module accesses the buffer until the first read position advances past the first sequence relative to the first logical direction.

18. The computer readable medium of claim 15 wherein the step of synchronizing further comprises:

advancing the logical tail of the buffer to an end of the first sequence of the successive ones of the storage locations prior to performing the step of writing the first block of the streaming information; and

temporarily blocking the step of writing a block if the first read position is behind the logical tail relative to the first logical direction.

19. The computer readable medium of claim 18 wherein:

the step of reading comprises reading a second block of the streaming information from a second sequence of successive ones of the storage locations while advancing the first read position through the second sequence; and

the step of synchronizing further comprises unblocking the step of writing the first block of the streaming information after advancing the read position if the first read position is ahead of the logical tail relative to the first logical direction.

20. The computer readable medium of claim 14 wherein:

the step of reading comprises reading a first block of the streaming information from a first sequence of successive ones of the storage locations; and

the step of synchronizing comprises temporarily blocking the step of reading the first block of the streaming information if an end of the first sequence is ahead of the logical head relative to the first logical direction and therefore outside the valid data area.

21. The computer readable medium of claim 20 wherein:

the step of writing comprises writing a second block of the streaming information to a second sequence of successive ones of the storage locations; and

the step of synchronizing further comprises;

advancing the logical head of the buffer to an end of the second sequence after writing the second block; and

unblocking the step of reading a first block of the streaming information after the step of advancing if the end of the first sequence is behind the logical head relative to the first logical direction.

22. The computer readable medium of claim 14 wherein:

the step of reading comprises reading a block of the streaming information from a first sequence of successive ones of the storage locations; and

the step of synchronizing comprises failing the step of reading the block of the streaming information if a beginning of the first sequence is behind the logical tail relative to the first logical direction and therefore outside the valid data area.

23. The computer readable medium of claim 14 wherein the step of moving the logical head and tail comprises moving the logical head and tail circularly through the storage locations in the first logical direction.

24. The computer readable medium of claim 14 and further comprising:

reading the streaming information from a second read position within the valid data area with a second reader module, wherein the second read position is temporally movable with respect to the logical head and tail and with respect to the first read position.