System and method for scaleable streamed audio transmission over a network

• US 5,835,495 A
• Filed: 10/11/1995
• Issued: 11/10/1998
• Est. Priority Date: 10/11/1995
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Ferriere, Philippe
• Primary Examiner(s): Jung, Min
• Application Number:
  US08/540,818
• Time in Patent Office: 1,126 Days
• Field of Search: 370/252, 370/465, 370/486, 370/521, 370/477, 375/222, 375/241, 375/242, 375/245, 379/68, 379/88, 379/89
• US Class Current: 370/465
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 69/24 Negotiation of communication capabilities
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04N 21/21 Server components or server architectures
• CPC Class Codes: H04N 21/23 Processing of content or additional data; Elementary server operations; Server middleware

Abstract

An audio data transmission system encodes audio files into individual audio data blocks which contain a variable number bits of digital audio data that were sampled at a selectable sample rate. The number of bits of digital data and the input sampling rate are scaleable to produce an encoded bit stream bit rate that is less than or equal to an effective operational bit rate of a recipient'"'"'s modem. The audio data transmission system uses computing units which are designed to select an appropriate combination of block size and input sampling rate to maximize the available bandwidth of the receiving modem. For example, if the modem connection speed for one modem is 14.4 kbps, a version of the audio data compressed at 13000 bits/s might be sent to the recipient; if the modem connection speed for another modem is 28.8 kbps, a version of the audio data compressed at 24255 bits/s might be sent to the receiver. The audio data blocks are then transmitted at the encoded bit stream bit rate to the intended recipient'"'"'s modem. The audio data blocks are decoded at the recipient to reconstruct the audio file and immediately play the audio file as it is received. The audio data transmission system can be implemented in online service systems, ITV systems, computer data network systems, and communication systems.

Claims

1. A method for encoding digital audio data to be transmitted to a modem operating at an effective bit rate, the method comprising the following steps:

sampling audio data at a first input sampling rate to produce audio samples;

encoding the audio samples into audio data blocks of a first block size selected from among a set of available block sizes, the block size representing a number of data bits contained within an individual audio data block, wherein the first block size and the first input sampling rate provide a first encoded bit stream bit rate that is less than or equal to the effective bit rate of the modem;

subsequently altering at least one of the first block size to a second block size or the first input sampling rate to a second input sampling rate; and

providing a second encoded bit stream bit rate as a result of the altering step by performing at least one of the following two steps;

(1) sampling the audio data at the second input sampling rate or (2) encoding the audio samples into audio data blocks having the second block size.

2. A method as recited in claim 1 further comprising the step of initially transmitting the audio data blocks at the first encoded bit stream bit rate and subsequently transmitting the audio data blocks at the second encoded bit stream bit rate.

3. A method for supplying digital audio files to a recipient, the recipient having a modem operating to receive digital data at an effective bit rate, the audio files being configured into individual audio data blocks wherein each audio data block contains a certain number of bits of digital audio data sampled at an input sampling rate, the method comprising the following steps:

storing multiple versions of an audio file, each version of the audio file being configured in audio data blocks of different block sizes and produced using different input sampling rates, wherein the block size represents a number of data bits contained within an individual audio data block;

choosing an appropriate version of the audio file that has a block size and an input sampling rate which produces a bit stream bit rate that is less than or equal to the effective bit rate of the recipient'"'"'s modem; and

transmitting the audio data blocks at the bit stream bit rate to the recipient'"'"'s modem.

4. A method as recite in claim 3 wherein the transmitting step comprises transmitting the audio data blocks over a distribution network.

5. A method as recited in claim 3 wherein the transmitting step comprises transmitting the audio data blocks over a communication network.

6. A method as recited in claim 3 further comprising the steps of receiving the audio data blocks at the recipient and reproducing audio sound from the audio data blocks as they are received.

7. A method for supplying digital audio files to a recipient, the recipient having a modem operating to receive digital data at an effective bit rate. the method comprising the following steps:

storing an audio file in uncompressed format;

configuring the audio file into individual audio data blocks in real-time wherein each audio data block contains a selected number of bits of digital audio data sampled at a selected input sampling rate, the selected number of bits and the selected input sampling rate determining a bit stream bit rate that is less than or equal to the effective bit rate of the recipient'"'"'s modem; and

transmitting the audio data blocks at the bit stream bit rate to the recipient'"'"'s modem.

8. A method as recited in claim 7 wherein the transmitting step comprises transmitting the audio data blocks over a distribution network.

9. A method as recited in claim 7 wherein the transmitting step comprises transmitting the audio data blocks over a communication network.

10. A method as recited in claim 7 further comprising the steps of receiving the audio data blocks at the recipient and reproducing audio sound from the audio data blocks as they are received.

11. A method for transmitting multiple digital audio files concurrently to a recipient, the recipient having a modem operating to receive digital data at an effective bit rate, the method comprising the following steps:

performing for each digital audio file the following steps;

configuring the audio file into individual audio data blocks, each audio data block containing a certain number bits of digital audio data sampled at an input sampling rate;

selecting a block size for the audio data blocks from among a set of available block sizes and an input sampling rate from among a set of available input sampling rates that determine a bit stream bit rate, the block size representing the number of bits of digital audio data in an individual audio data block;

said selecting step selecting the block size and the input sampling rate for each audio file which ensure that a total bit stream bit rate made up of combined bit stream bit rates of all digital audio files is less than or equal to the effective bit rate of the recipient'"'"'s modem; and

transmitting the audio data blocks for each audio file at the bit stream bit rate to the recipient'"'"'s modem.

12. A method as recited in claim 11 further comprising the following additional steps:

receiving the audio data blocks at the recipient; and

reproducing and mixing audio sound from the audio data blocks as they are received.

13. An audio file distribution system comprising:

a client computing unit having a modem operating to receive digital data at an effective bit rate;

an audio file database to store multiple versions of an audio file, each version of the audio file being configured in audio data blocks of different block sizes and produced using different input sampling rates, wherein block size represents a number of data bits contained within an individual audio data block; and

an audio server to select an appropriate version of the audio file that has a block size and an input sampling rate which produces a bit stream bit rate that is less than or equal to the effective bit rate of the client'"'"'s modem, the audio server retrieving the appropriate version from the audio file database and supplying the audio file to the client computing unit.

14. An audio file distribution system as recited in claim 13 wherein the client computing unit decodes the audio data blocks and reproduces audio sound therefrom as the audio data blocks are received from the audio server.

15. An audio file distribution system comprising:

a client computing unit having a modem operating to receive digital data at an effective bit rate;

an audio file database to store an audio file in uncompressed format; and

an audio server to encode the audio file into individual audio data blocks in real-time wherein each audio data block contains a selected number of bits of digital audio data sampled at a selected input sampling rate, the selected number of bits and the selected input sampling rate determining a bit stream bit rate that is less than or equal to the effective bit rate of the client'"'"'s modem.

16. An audio file distribution system as recited in claim 15 wherein the client computing unit decodes the audio data blocks and reproduces audio sound therefrom as the audio data blocks are received from the audio server.

17. An audio file distribution system comprising:

a client computing unit having a modem operating to receive digital data at an effective bit rate;

an audio file database to store an audio file; and

an audio server to supply the audio file as individual audio data blocks which contain a certain number of bits of digital audio data that have been sampled at a selected sampling rate, the audio server having a size/rate lookup table listing various combinations of the number of bits and the sampling rates indexed with associated encoded bit stream bit rates, the audio server being configured to select the number of bits and the sampling rate using the size/rate lookup table so that the associated encoded bit stream bit rate is less than or equal to the effective bit rate of the client'"'"'s modem.

18. An audio file distribution system as recited in claim 17 wherein the client computing unit decodes the audio data blocks and reproduces audio sound therefrom as the audio data blocks are received from the audio server.

19. An audio file distribution system comprising:

a client computing unit having a modem operating to receive digital data at an effective bit rate;

an audio file database to store a plurality of audio files; and

an audio server to retrieve multiple audio files from the audio file database and encode the audio files as individual audio data blocks which contain a certain number bits of digital audio data that have been sampled at a selected sampling rate wherein the number of bits of digital data and the sampling rate are selected to provide an encoded bit stream bit rate that is less than or equal to the effective bit rate of the client'"'"'s modem; and

the client computing unit is configured to decode the audio data blocks into audio frames, mix the audio frames, and reproduce sound from the audio frames.

20. A communication system comprising:

first and second communication units, each communication unit being equipped with a modem operating to receive and transmit data at an effective bit rate;

a network interconnecting the first and second communication units;

said first communication unit being configured to supply the effective bit rate of the modem for the first communication unit to the second communication unit;

said second communication unit being configured to determine a smallest effective bit rate from between the effective bit rates for the modems of the first and second communication units and to send the smallest effective bit rate back to the first communication unit;

said first and second communication units being configured to generate digital audio samples representative of an audio signal at a selected input sampling rate, the first and second communication units being equipped with an audio coder/decoder having multiple quantizers that encode the digital audio samples into various sized audio data blocks which contain various quantities of bits of the audio samples, said first and second communication units using an appropriate input sampling rate and selecting an appropriate quantizer to encode the audio samples into audio data blocks that yield an encoded bit stream bit rate less than or equal to the smallest effective bit rate of the modems; and

said first and second communication units exchanging the audio data blocks over the network.

21. A communication system as recited in claim 20 wherein the network is a wireless communication network.

22. A communication system as recited in claim 20 wherein the network is a wire-based data network.

23. A communication system as recited in claim 20 wherein the audio coder/decoder comprises a predictive audio coder/decoder.

24. A communication system as recited in claim 20 wherein the first and second communication units are configured to reproduce the audio signal from the audio data blocks as the audio data blocks are received.

25. An audio file serving system for serving an audio file to a recipient having a modem that receives digital data at an effective bit rate, comprising:

an audio file database to store multiple versions of an audio file, each version of the audio file being configured in audio data blocks having different block sizes and produced using different input sampling rates, wherein block size represents a number of data bits contained within an individual audio data block; and

an audio server to select an appropriate version of the audio file that has a block size and an input sampling rate that produces a bit stream bit rate that is less than or equal to the effective bit rate of the recipient'"'"'s modem, the audio server retrieving the appropriate version from the audio file database and supplying the audio file to the recipient.

26. An audio file serving system for serving an audio file to a recipient having a modem that receives digital data at an effective bit rate, comprising:

an audio file database to store an audio file in uncompressed format; and

an audio server to encode the audio file into individual audio data blocks in real-time wherein each audio data block contains a selected number of bits of digital audio data sampled at a selected input sampling rate, the selected number of bits and the selected input sampling rate determining a bit stream bit rate that is less than or equal to the effective bit rate of the recipient'"'"'s modem.

27. An audio file serving system for serving an audio file to a recipient having a modem that receives digital data at an effective bit rate, comprising:

an audio file database to store an audio file; and

an audio server to supply the audio file as individual audio data blocks which contain a certain number of bits of digital audio data that have been sampled at a selected sampling rate, the audio server having a size/rate lookup table listing various combinations of the number of bits and the sampling rates that yield associated encoded bit stream bit rates, the audio server being configured to select the number of bits and the sampling rate using the size/rate lookup table so that the associated encoded bit stream bit rate is less than or equal to the effective bit rate of the recipient'"'"'s modem.

28. A method for supplying digital audio files to a recipient, the recipient having a modem to receive digital data at an effective bit rate, the audio files being configured into individual audio data blocks wherein each audio data block has a block size, which represents a number bits of digital audio data, and an input sampling rate, which represents the sample rate at which the digital audio data is sampled, the method comprising the following steps:

storing various combinations of block sizes and sampling rates in a table;

selecting a block size and a sampling rate from the table that yield an encoded bit stream bit rate is less than or equal to the effective bit rate of the recipient'"'"'s modem; and

supplying the audio file at the encoded bit stream bit rate.