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System and method for associating presented digital content within recorded digital stream and method for its playback from precise location

System and method for associating presented digital content within recorded digital stream and method for its playback from precise location description/claims

This application is a continuation of U.S. patent application Ser. No. 10/830,996, filed Apr. 22, 2004, which claims priority from U.S. provisional patent application Ser. No. 60/539,297, filed Jan. 26, 2004.

1. Field of the Invention

The present invention relates generally to television systems.

2. Description of the Related Art

A user of a personal video recorder (PVR) conveniently may record a video stream at the same time the user is viewing the stream live, i.e., as the stream is being received by the user's television system. If the user desires to leave the room but not miss any part of the program being recorded, the user may manipulate a remote control device to cause the system to “pause”, i.e., to freeze a frame on the TV display while continuing to record the program.

When the user wants to resume viewing the program, he again manipulates the remote control device to cause play to resume (e.g., by pressing a “play” button on the remote device). However, current solutions to providing for a smooth transition in the video from “pause” to resumed play have drawbacks, which can be better understood after the following brief discussion.

Digital multimedia streams may be sent to receivers in a format known as Moving Pictures Expert Group (MPEG) standards such as MPEG-1, MPEG-2 (also used for DVD format), MPEG-4 and other block based transform codecs. In MPEG formatting, the data is encoded using MPEG principles, sent to the receiver, and then decoded at the receiver.

As recognized herein, MPEG frames may have timestamps (sometimes referred to as presentation timestamps, or PTS for short) that can be used to identify the frames. As also understood herein, however, a PTS may not be unique, because MPEG streams can undergo time base discontinuities between frame segments, after which PTS numbers can repeat. Accordingly, while a PTS value identifies a frame within a segment, it does not necessarily uniquely identify the frame within the entire stream.

With the above in mind, one way to resume play is simply not to care about the possibility of discontinuity and either resume playing the live feed or resume playing using the recorded feed using, as a best guess of where the video was paused, the PTS of the last live frame that was displayed at the time of pause. For reasons set forth above this can result in undesired discontinuities that hinder viewing enjoyment.

A second way to resume play is to essentially never show the live feed, but rather to always display the video from the recorded stream as though it were the live feed. While this avoids discontinuities because the live feed is never used for display, it results in latency (delays) particularly if the user changes channels. With the above drawbacks in mind, the solutions herein have been provided.

The invention provides systems and methods for precisely associating and locating viewed digital content such as video frame with stored digital content using a pair of key information, namely, discontinuity counts and timestamps. The invention permits a user to precisely access any preferred video frame. Particular uses of the invention are in pausing and resuming play of a video stream, as well as bookmark operations for later access for viewing or editing. The digital data may be video or audio or other data whose presentation is based on timestamps.

In one aspect the invention precisely associates and locates viewed digital content such as video frames with stored digital content by using a pair of key information, namely, discontinuity count and timestamp (e.g., PTS) information. With the invention disclosed herein, a user may access digital content in precise locations, such as a specified video frame. In non-limiting examples the invention is useful for precise video pause/resume operations, bookmark applications including jumping to a certain video frame which is stored in a storage medium, and video stream editing applications. The invention is useful not only with video data but also audio data and other data, and it may be used to associate any presented digital content with stored data.

Accordingly, a television system includes a processor which associates at least one timestamp of at least one digital information element, such as a video frame, with at least one discontinuity count. A display presents digital data such as video streams from the processor, and a storage stores digital data such as video streams. The timestamp and discontinuity count are used by the processor for resuming play, using data in the storage, of a digital data stream such as a video stream that was paused or bookmarked during live play of the stream. The processor may be associated with a personal video recorder.

The preferred processor uses the timestamp and discontinuity count of a last-presented frame in a live digital stream to resume play using digital data in the storage. Digital frames in the storage are associated with respective timestamps and digital stream discontinuity counts.

In another aspect, a method for providing for smooth resumption of play of a digital stream includes sending the stream to a decoder for live display of the stream on a display. Also, the method includes sending the stream to a storage for storage of the stream, with frames of the stream that are sent to the storage being associated with respective timestamps and digital stream discontinuity counts. A “pause” command can be received, in which case the timestamp and discontinuity count of the paused frame are recorded. Upon receipt of a “resume play” command, using the timestamp and discontinuity count of the paused frame a frame is retrieved from the storage based on the frame having a discontinuity count matching the discontinuity count of the paused frame, and preferably based on the frame having the next sequential timestamp.

In still another aspect, a television system includes a TV display, a decoder driving the display, and means for sending a received digital stream having time base discontinuities through the decoder for presentation thereof on the display. Means are provided for pausing the display. Also, the system includes means for sending a recorded version of the received digital stream through the decoder for presentation thereof on the display upon resumption of play, with the means for sending a recorded version accounting for time base discontinuities in the stream.

• Provisional Patent
• Utility Patent

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