Audio-on-demand communication system

• US 5,793,980 A
• Filed: 11/30/1994
• Issued: 08/11/1998
• Est. Priority Date: 11/30/1994
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: RealNetworks, Inc.
• Inventors: Glaser, Robert D., O'Brien, Mark, Goldberg, Randy Glen, Boutell, Thomas B.
• Primary Examiner(s): Rienhart, Mark H.
• Application Number:
  US08/347,582
• Time in Patent Office: 1,350 Days
• Field of Search: 395/200.13, 395/200.09, 395/200.14, 395/200.17, 395/806, 395/807, 395/849, 395/850, 395/200.61, 395/200.49, 395/200.67, 395/200.66, 370/231, 370/476, 370/486, 370/496, 370/528, 364/514 A, 364/514 C, 375/257, 375/369, 375/370, 345/302
• US Class Current: 709/231
• CPC Class Codes: H04H 20/28 Arrangements for simultaneous broadcast of plural pieces of information
• CPC Class Codes: H04H 20/30 by a single channel
• CPC Class Codes: H04H 20/40 Arrangements for broadcast specially adapted for accumulation-type receivers
• CPC Class Codes: H04H 20/46 specially adapted for broadcast systems covered by groups H04H20/53-H04H20/95
• CPC Class Codes: H04H 20/82 using signals not modulated onto a carrier
• CPC Class Codes: H04H 20/83 not sharing the network with any other service
• CPC Class Codes: H04H 60/27 Arrangements for recording or accumulating broadcast information or broadcast-related information
• CPC Class Codes: H04H 60/51 of receiving stations
• CPC Class Codes: H04H 60/73 using meta-information

Abstract

An audio-on-demand communication system provides real-time playback of audio data transferred via telephone lines or other communication links. One or more audio servers include memory banks which store compressed audio data. At the request of a user at a subscriber PC, an audio server transmits the compressed audio data over the communication link to the subscriber PC. The subscriber PC receives and decompresses the transmitted audio data in less than real-time using only the processing power of the CPU within the subscriber PC., According to one aspect of the present invention, high quality audio data compressed according to lossless compression techniques is transmitted together with normal quality audio data. According to another aspect of the present invention, metadata, or extra data, such as text, captions, still images, etc., is transmitted with audio data and is simultaneously displayed with corresponding audio data. The audio-on-demand system also provides a table of contents indicating significant divisions in the audio clip to be played and allows the user immediate access to audio data at the listed divisions. According to a further aspect of the present invention, servers and subscriber PCs are dynamically allocated based upon geographic location to provide the highest possible quality in the communication link.

Claims

1. A data stream, stored in a computer readable medium, comprising:

a plurality of stop markers, each of said stop markers marking a termination point in said data stream such that a first computer transmitting said data stream halts said transmission at said termination point until a second computer indicates to said first computer that said second computer has received data of said data stream;

a plurality of acknowledge markers different from said stop markers and interleaved between said stop markers, the interval between each acknowledge marker and the next stop marker being related to the time it takes to transmit data from said first computer to said second computer, said second computer responsive to said acknowledge markers to indicate to said first computer that said second computer has received data of said data stream.

6. The data stream as defined in claim 1, wherein said intervals between each acknowledge marker and the next stop marker are equal.

2. A method of controlling the transmission of an audio data stream including a plurality of stop markers, and a plurality of acknowledge markers interleaved between said stop markers, said method comprising the steps of:

sending said acknowledge markers from a first location to a second location;

receiving said acknowledge markers at said second location;

generating an acknowledge signal and sending said acknowledge signal to said first location upon receiving said acknowledge marker; and

continuing sending data past said stop marker if said acknowledge marker is received at said first location.

3. A method as defined in claim 2, wherein said audio data stream includes a plurality of data blocks, and wherein said acknowledge and stop markers are included at the ends of said data blocks.

4. A method of regulating the flow of compressed audio data between an audio server and a subscriber PC in an audio-on-demand system, said method comprising the steps of:

storing compressed audio data as audio data blocks within an audio data memory bank;

including an acknowledge marker in a plurality of said blocks;

including a stop marker in a plurality of said blocks wherein each of said stop markers is preceded by one of said acknowledge markers and wherein said stop markers have corresponding acknowledge markers;

transmitting said blocks from said audio server to said subscriber PC until said audio server detects one of said stop markers;

receiving said blocks at said subscriber PC;

transmitting an acknowledge signal from said subscriber PC to said audio server whenever said subscriber PC receives one of said acknowledge markers; and

continuing transmission of said blocks from said audio server to said subscriber PC despite the reading of a stop marker whenever said audio server receives an acknowledge signal corresponding to the stop marker.

5. The method of claim 4, wherein the acknowledge and stop markers are identical and located at the same place in the audio data blocks.