Multimedia presentation latency minimization

• US 7,424,730 B2
• Filed: 09/10/2003
• Issued: 09/09/2008
• Est. Priority Date: 12/04/1998
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Chou, Philip A.
• Primary Examiner(s): Vu; Ngoc K
• Application Number:
  US10/658,898
• Publication Number:
  US 20040049793A1
• Time in Patent Office: 1,826 Days
• Field of Search: 725/87, 725 89- 90, 725 93- 94, 725/98, 725/118, 725/119, 370230-232, 370235-236, 370/468, 709/219, 709/247, 348/394.1, 348/395.1, 348/409.1, 348/410.1, 348/425, 348/438.1, 348/384.1, 348/425.1, 375/240.1, 375/240.11, 375/240.19, 375/240.08
• US Class Current: 725/87
• CPC Class Codes: H04N 19/33 in the spatial domain
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/234327 by decomposing into layers, e.g. base layer and one or more enhancement layers
• CPC Class Codes: H04N 21/23439 for generating different versions
• CPC Class Codes: H04N 21/2401 Monitoring of the client buffer
• CPC Class Codes: H04N 21/4384 involving operations to reduce the access time, e.g. fast-tuning for reducing channel switching latency
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer
• CPC Class Codes: H04N 21/6125 involving transmission via Internet transmission by internet of broadcast information H04H60/82
• CPC Class Codes: H04N 21/6377 directed to server one-way streaming services wherein the source is controlled by the destination H04L65/613
• CPC Class Codes: H04N 21/658 Transmission by the client directed to the server
• CPC Class Codes: H04N 7/17336 Handling of requests in head-ends

Abstract

Systems and methods for presenting time-varying multimedia content are described. In one aspect, a lower quality data stream for an initial portion of the multimedia content is received. The lower quality data stream is received at a rate faster than a real-time playback rate for the multimedia content. The lower quality data stream was encoded at a bit rate below a transmission rate. A higher quality data stream of a subsequent portion of the multimedia content is received. The higher quality data stream was encoded at a bit rate that equals the transmission rate. The initial portion and the subsequent portion of the multimedia content are presented at the real-time playback rate. Receiving the initial portion faster than the real-time playback rate provides for a reduction of latency due to buffering by a desired amount.

Claims

1. A method of minimizing latency for streaming time-varying multimedia content, the method comprising:

constructing an encoded bit stream for the multimedia content, the encoded bit stream having;

an initial portion encoded at a bit rate less than a transmission rate and represented with a low resolution encoding; and

a subsequent portion encoded at a bit rate equal to the transmission rate and represented with an encoding having a higher resolution than the low resolution encoding; and

transmitting the encoded bit stream to a client buffer so that the client buffer receives the initial portion faster than the initial portion is removed from the client buffer during real-time playback of the multimedia content;

wherein transmitting the initial portion faster than a realtime playback rate reduces the latency due to buffering to near zero.

2. The method of minimizing latency as claimed in claim 1, wherein constructing an encoded bit stream is performed by an encoder having a buffer that starts out non-empty.

3. The method of minimizing latency as claimed in claim 1, wherein constructing an encoded bit stream comprises reducing a number of enhancement layers in an embedded bit stream to produce the initial portion of the multimedia content.

4. The method of minimizing latency as claimed in claim 1, wherein constructing an encoded bit stream comprises splicing together one or more low resolution encodings for the initial portion of the multimedia content with a higher resolution encoding for the subsequent portion of the multimedia content.

5. A computer system for receiving and playing back multimedia data, the computer system comprising:

a buffer;

a processor;

a memory operatively coupled to the processor; and

an application executed in the processor from the memory which enables the system to;

receive multimedia data over a network wherein the multimedia data is received as an encoded bit stream having an initial portion and a subsequent portion so that the buffer receives the initial portion faster than the initial portion is removed from the buffer during real-time playback of the multimedia data;

present in real-time the initial portion of the encoded bit stream;

present in real-time the subsequent portion of the encoded bit stream;

continuing to receive the initial portion of the encoded bit stream until the buffer of the computer system contains enough multimedia data to prevent underflow or overflow while presenting the subsequent portion of the encoded bit stream; and

stopping reception of the initial portion of the encoded bit stream and beginning reception of the subsequent portion when the buffer of the computer system contains enough multimedia data to prevent underflow or overflow while presenting the subsequent portion of the encoded bit stream.

6. A computer readable medium having instructions stored thereon for causing a computer to perform a method of minimizing latency for streaming time-varying multimedia content, the method comprising:

constructing an encoded bit stream for the multimedia content, the encoded bit stream having;

an initial portion encoded at a bit rate less than a transmission rate and represented with a low resolution encoding; and

subsequent portion encoded at a bit rate equal to the transmission rate and represented with an encoding having a higher resolution than the low resolution encoding; and

transmitting the encoded bit stream to a client buffer so that the client buffer receives the initial portion faster than the initial portion is removed from the client buffer during real-time playback of the multimedia content to permit beginning playback of the initial portion without significant buffering.

7. The computer readable medium of claim 6, wherein constructing an encoded bit stream is performed by an encoder having a buffer that starts out non-empty.

8. The computer readable medium of claim 6, wherein constructing an encoded bit stream comprises reducing a number of enhancement layers in an embedded bit stream to produce the initial portion of the multimedia content.

9. The computer readable medium of claim 6, wherein constructing an encoded bit stream comprises splicing together one or more low resolution encodings for the initial portion of the multimedia content with a normal resolution encoding for the subsequent portion of the multimedia content.

10. A computer readable medium having instructions stored thereon for causing a computer to perform a method of delivering time-varying multimedia data, the method comprising:

delivering multimedia data over a network to a client buffer by;

delivering an initial portion of an encoded bit stream, wherein the initial portion is encoded at a bit rate less than a transmission rate; and

delivering a subsequent portion of the encoded bit stream, wherein the subsequent portion is encoded at a bit rate equal to the transmission rate, so that the client buffer receives the initial portion faster than the initial portion is removed from the client buffer during real-time playback of the multimedia data;

stopping the delivering of the initial portion of the encoded bit stream and starting the delivering of the subsequent portion when the buffer of the client contains enough multimedia data to prevent underflow or overflow while presenting the, subsequent portion of the encoded bit stream.

11. The computer readable medium of claim 10, wherein the method further comprises constructing the encoded bit stream having the initial portion represented with a low resolution encoding and the subsequent portion represented with an encoding having a higher resolution than the low resolution encoding.