| US 7,589,791 B2 | ||
| Methods and systems for independently controlling the presentation speed of digital video frames and digital audio samples | ||
| James A. Baldwin, Emerald Hills, Calif. (US); James A. Lundblad, Mountain View, Calif. (US); and Louis F. Coffin, Mountain View, Calif. (US) | ||
| Assigned to Microsoft Corporation, Redmond, Wash. (US) | ||
| Filed on Jan. 16, 2009, as Appl. No. 12/355,671. | ||
| Application 12/355671 is a continuation of application No. 11/248550, filed on Oct. 12, 2005, granted, now 7,495,705. | ||
| Application 11/248550 is a continuation of application No. 09/652058, filed on Aug. 31, 2000, granted, now 6,975,363. | ||
| Prior Publication US 2009/0122192 A1, May 14, 2009 | ||
| Int. Cl. H04N 5/04 (2006.01) | ||
| U.S. Cl. 348—512 | 12 Claims |
| 1. A digital receiver that is configured to receive a digital video signal representing a plurality of digital video packets
and a digital audio signal representing a plurality of digital audio packets, the digital receiver being configured to implement
a method of independently timing the presentation of the video information of the digital video packets with respect to the
timing of the presentation of the audio information of the digital audio packets so that the video information and the audio
information may be accurately timed even if they are from different unrelated programs, the digital receiver comprising:
one or more storage media having machine-executable instructions for implementing the method, wherein the method comprises:
an act of receiving a digital video signal and a digital audio signal;
an act of extracting a plurality of digital video packets from the digital video signal;
an act of extracting a plurality of digital audio packets from the digital audio signal;
an act of adding a local audio time stamp to a digital audio packet at a substantially constant time period, packet to packet,
after the receiver receives the digital audio packet;
an act of comparing a program clock reference within the digital audio packet to the local audio time stamp;
an act of using an audio clock, based at least in part on the comparison of the program clock reference to the local audio
time stamp, to control the timing of the presentation of the audio information represented by the plurality of digital audio
packets, wherein the audio clock operates separately and independently of the video clock; and
an act of using a video clock to control the timing of the presentation of the video information represented by the plurality
of digital video packets.
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