Multimedia server

• US 6,477,541 B1
• Filed: 03/21/2000
• Issued: 11/05/2002
• Est. Priority Date: 03/23/1999
• Status: Expired due to Term

• Current Assignee: Gula Consulting Limited Liability Company (Intellectual Ventures LLC)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Korst, Johannes H. M., Coumans, Pascal F. A.
• Primary Examiner(s): Mizrahi, Diane D.
• Assistant Examiner(s): Veillard, Jacques
• Application Number:
  US09/531,943
• Time in Patent Office: 959 Days
• Field of Search: 707/104.1, 707/7, 709/231, 709/247, 711/100, 711/152, 711/157, 711/167
• US Class Current: 1/1
• CPC Class Codes: G11B 27/002 Programmed access in sequence to a plurality of record carriers or indexed parts, e.g. tracks, thereof, e.g. for editing; transfer of record carriers from magazine G11B15/68, G11B17/10; G11B17/22
• CPC Class Codes: H04N 21/2326 Scheduling disk or memory reading operations
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99936 Pattern matching access
• CPC Class Codes: Y10S 707/99942 Manipulating data structure, e.g. compression, compaction, compilation
• CPC Class Codes: Y10S 707/99945 Object-oriented database structure processing
• CPC Class Codes: Y10S 707/99948 Application of database or data structure, e.g. distributed, multimedia, or image

Abstract

A multimedia server retrieves blocks of data from a storage medium and supplies the blocks in the form of data streams to users. The streams include a group of high bit rate streams and a group of low bit rate streams. The system has a reader for in a sweep reading data blocks from the storage medium for a selected group of streams and for storing the data blocks in respective buffers. The system further has a scheduler for determining which of the streams is to be serviced, i.e. for which of the streams a block is to be read, in the next sweep of the reader. The scheduler according to the invention is operative to determine to service a low bit rate stream less often than a high bit rate stream.

Claims

1. A system for retrieving blocks of data from a storage medium and supplying the blocks in the form of a plurality of streams to users, wherein a stream of a first class of the streams may have an actual bit rate between a first minimum bit rate and a first maximum bit rate, wherein a stream of a second class of the streams may have an actual bit rate between a second minimum bit rate and a second maximum bit rate, and wherein the first maximum bit rate is substantially higher than the second maximum bit rate, the system comprising:

for each stream an associated buffer for storing the blocks of data;

a reader for sweep reading a data block from the storage medium for each stream of a selected group of the streams and for storing the read blocks in the respective buffers; and

a scheduler for repeatedly selecting the group of the streams for which a block is to be read in a next sweep of the reader, wherein the scheduler is operative to select a stream of the second class less often in the group for which a block is to be read than a stream of the first class.

2. A system as claimed in claim 1, wherein the scheduler is operative to select a particular stream of the second class in the group for which a block is to be read once every k sweeps, k being dependent on the first maximum consumption rate and the second maximum consumption rate.

3. A system as claimed in claim 1 with m streams of the second class, wherein the scheduler is operative to select the m streams in the group for which a block is to be read in one particular sweep.

4. A system as claimed in claim 2 with m streams of the second class, wherein the scheduler is operative to select a particular fraction m/k of the m streams in the group for which a block is to be read in one particular sweep, so as to evenly distribute selecting of the streams of the second class over the sweeps.

5. A method of retrieving blocks of data, such as audio and/or video, from a storage medium and supplying the blocks in the form of a plurality of streams to users, wherein a stream of a first class of the streams may have an actual bit rate between a first minimum bit rate and a first maximum bit rate, wherein a stream of a second class of the streams may have an actual bit rate between a second minimum bit rate and a second maximum bit rate, and wherein the first maximum bit rate is substantially higher than the second maximum bit rate, the method comprising the steps of:

for each stream storing the blocks of data in an associated buffer;

sweep reading a data block from the storage medium for each stream of a selected group of the streams and storing the read blocks in the respective buffers; and

repeatedly selecting the group of the streams for which a block is to be read in a next sweep, wherein a stream of the second class is selected less often in the group for which a block is to be read than a stream of the first class.