System and method for timestamps for media stream data

• US 8,179,789 B2
• Filed: 06/30/2006
• Issued: 05/15/2012
• Est. Priority Date: 07/01/2005
• Status: Expired due to Fees

• Current Assignee: Winnov, L.P.
• Original Assignee: Winnov, L.P.
• Inventors: Graham, Harry L.
• Primary Examiner(s): Yao, Kwang B
• Assistant Examiner(s): Skripnikov, Alex
• Application Number:
  US11/479,355
• Publication Number:
  US 20070005794A1
• Time in Patent Office: 2,146 Days
• Field of Search: None
• US Class Current: 370/229
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/80 Responding to QoS

Abstract

Within a computer system, a system and method of providing timestamps for media stream input data is provided. A first clock count register is responsive to a first timebase, and a second clock count register is responsive to a second timebase. The first and second time bases can be correlated. When a frame of media stream input data is captured, the value of the first clock count register can be preserved. This value is a timestamp expressed in terms of the first timebase. The timestamp value in terms of the second timebase is computed and associated with the captured frame of media stream input data.

Claims

1. In a computer system having a media stream input, a system for providing timestamps within media stream input data comprising:

a media sample time register;

a first clock circuit comprising a first clock count register;

wherein the first clock circuit is at least responsive to and disposed with a first timebase;

a second clock circuit comprising a second clock count register;

wherein the second clock circuit is at least responsive to and disposed with a second timebase;

means for capturing a frame of media stream input data;

wherein the system is adapted to load the media sample time register from the first clock count register responsive to a capture of a frame of media stream input data;

wherein the system is adapted to read a media sample time value from the media sample time register;

wherein the system is adapted to correlate the first timebase with the second timebase by

performing a first measurement of the first clock count register and the second clock count register at a first specified time,

performing a second measurement of the first clock count register and the second clock count register at a second specified time, and,

determining a parameter set that defines a relationship between the second timebase and the first timebase, at least responsive to the first measurement and the second measurement;

wherein the system is adapted to compute a timestamp value in terms of the second timebase, responsive to the media sample time value, responsive to the capture of the frame of media stream input data, and responsive to the correlation of the first timebase with the second timebase; and

wherein the system is adapted to associate the timestamp value that is in terms of the second timebase with the captured frame of media stream input data.

2. The system of claim 1

wherein the system is adapted to store the timestamp value that is in terms of the second timebase with the captured frame of media stream input data.

3. The system of claim 2, further comprising:

a PCI system clock; and

,

wherein the first timebase is responsive to the PCI system clock.

4. The system of claim 2, further comprising:

an audio sample clock; and

,

wherein the first timebase is responsive to the audio sample clock.

5. In a computer system having a media stream input node, a method of providing timestamps for media stream input data comprising the steps of:

providing a media sample time register;

providing a first clock circuit comprising a first clock count register at least responsive to and disposed with a first timebase;

providing a second clock circuit comprising a second clock count register at least responsive to and disposed with a second timebase;

capturing a frame of media stream input data;

loading the media sample time register from the first clock count register responsive to the capture of the frame of media stream input data;

reading a media sample time value from the media sample time register;

correlating the first timebase with the second timebase;

wherein correlating the first timebase with the second timebase comprises the steps of;

performing a first measurement of the first clock count register and the second clock count register at a first specified time;

performing a second measurement of the first clock count register and the second clock count register at a second specified time; and

,

determining a parameter set that defines a relationship between the second timebase and the first timebase, at least responsive to the first measurement and the second measurement;

computing a timestamp value in terms of the second timebase, responsive to the media sample time value, responsive to the capture of the frame of media stream input data, and responsive to the correlation of the first timebase with the second timebase; and

associating the timestamp value that is in terms of the second timebase with the captured frame of media stream input data.

6. The method of claim 5, further comprising the steps of:

providing a PCI system clock; and

disposing the first timebase as responsive to the PCI system clock.

7. The method of claim 5, further comprising the steps of:

providing an audio sample clock; and

disposing the first timebase as responsive to the audio sample clock.