Time warping for video viewing

• US 5,438,423 A
• Filed: 05/11/1994
• Issued: 08/01/1995
• Est. Priority Date: 06/25/1993
• Status: Expired due to Term

• Current Assignee: Tektronix Incorporated (Fortive Corp.)
• Original Assignee: Tektronix Incorporated (Fortive Corp.)
• Inventors: Lynch, Eugene F., Cherry, Guy W., Schwartz, Mayer D.
• Primary Examiner(s): Chin, Tommy P.
• Assistant Examiner(s): Truong, Khoi
• Application Number:
  US08/240,942
• Time in Patent Office: 447 Days
• Field of Search: 358/335, 358/337, 358/338, 358/339, 358/310, 360/31, 360/33.1, 360/36.2, 360/5, 360/13, 360/14.1, 360/14.2, 360/14.3
• US Class Current: 386/295
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• CPC Class Codes: G11B 27/032 on tapes G11B27/036, G11B27/038 take precedence
• CPC Class Codes: H04N 21/4147 PVR [Personal Video Recorder] H04N5/76 takes precedence ; arrangements for broadcast with accumulation-type receivers H04H20/40
• CPC Class Codes: H04N 21/4333 Processing operations in response to a pause request
• CPC Class Codes: H04N 21/4334 Recording operations recording of a television signal H04N5/76; arrangements for recording or accumulating broadcast information or broadcast-related information H04H60/27
• CPC Class Codes: H04N 21/47217 for controlling playback functions for recorded or on-demand content, e.g. using progress bars, mode or play-point indicators or bookmarks specific graphical features in visual interfaces H04N21/4312
• CPC Class Codes: H04N 21/8455 involving pointers to the content, e.g. pointers to the I-frames of the video stream
• CPC Class Codes: H04N 5/44 Receiver circuitry for the reception of television signals according to analogue transmission standards H04N5/14 takes precedence
• CPC Class Codes: H04N 5/4448 for frame-grabbing

Abstract

Time warping for video viewing is achieved by providing a random access dynamic buffer for a video signal from a selected video channel. The video signal is continuously written into the dynamic buffer in a recirculating fashion, and may be read out on a random access basis so that the viewer may control the realtime video viewing in the same manner as controlling a video cassette recorder up to the duration of the video signal stored in the dynamic buffer. In addition the viewer may view the video at various speeds and skip to any point in the stored information. Portions of the video signal in the dynamic buffer may be stored in a static buffer or transferred permanently to a video cassette recorder for subsequent manipulation by the viewer. To expand the capacity of the dynamic buffer a compression circuit may be provided for compressing the video signal before being written into the dynamic buffer. Likewise a decompression circuit for the compressed video signal from the dynamic buffer reconstructs a full bandwidth video signal for display.

Claims

1. A system of time warping for video viewing in a video receiver having a tuner for selecting a video channel and providing a time linear input video signal and a display device for displaying a video signal comprising:

a recirculating dynamic buffer coupled to the tuner for continuously receiving the time linear input video signal provided by the tuner so that a segment of the time linear input video signal having a predetermined duration is temporarily stored in the recirculating dynamic buffer;

control means responsive to a PAUSE command for marking the segment of the time linear video signal stored in the recirculating dynamic buffer with an access point; and

means for randomly accessing the segment of the time linear video signal stored in the recirculating dynamic buffer to provide an output video signal for display by the display device so that the segment of the time linear video signal can be accessed for subsequent display from the access point simultaneously with continued buffering of the time linear input video signal.

3. The system of claim 1 further comprising a static buffer coupled to the recirculating dynamic buffer for storing selected segments of the video signal from the recirculating dynamic buffer for subsequent review, the selected segments being determined by the marking means.

4. The system of claim 3 further comprising means for permanently storing the video signal from the recirculating dynamic buffer or the static buffer.

2. The system of claim further comprising:

means for compressing the video signal prior to inputting to the recirculating dynamic buffer; and

means for decompressing the compressed video signal from the recirculating dynamic buffer prior to inputting to the display circuitry.

5. A method of time warping for video viewing a video signal from a selected video channel comprising the steps of:

continuously writing the video signal into a dynamic buffer, the buffer storing a segment of the video signal;

simultaneously reading the video signal on a random access basis from the dynamic buffer for display until a PAUSE command is asserted; and

upon assertion of the PAUSE command, interrupting the reading of the video signal from the dynamic buffer without interrupting writing of the video signal to the dynamic buffer and marking the segment of the video signal in the dynamic buffer with an access point so that the video signal can be accessed for subsequent reading from the access point onward.

6. The method as recited in claim 5 wherein the reading step comprises the step of controlling a speed and direction in which the video signal is read from the dynamic buffer.

7. A method of time warping for video viewing a time linear video signal from a selected video channel as it is being received comprising the steps of:

continuously writing the time linear video signal into a dynamic recirculating buffer, the buffer storing a segment of the video signal having a predetermined duration;

simultaneously displaying the video signal from the dynamic recirculating buffer on a display device until a PAUSE command is asserted;

upon assertion of the PAUSE command, interrupting the displaying of the video signal and marking the dynamic recirculating buffer at a point of the stored segment of the video signal where the interruption occurs; and

subsequently restarting from the marked point the displaying of the video signal from the dynamic recirculating buffer so that the video signal is displayed in time sequence.

8. Apparatus for time warping a time linear input video signal comprising:

a dynamic buffer connected to continuously receive the time linear input video signal and temporarily store a time segment of the time linear input video signal;

reading means for reading the time segment of the time linear input video signal to provide an output video signal;

command means for asserting a PAUSE command and for subsequently asserting a CONTINUE command;

control means responsive to the PAUSE command for marking the time segment of the time linear input video signal stored in the dynamic buffer with an access point without interrupting writing of the time linear input video signal to the dynamic buffer, the reading means being responsive to the CONTINUE command for reading the time segment of the time linear input video signal stored in the dynamic buffer from the access point onward to provide a time linear output video signal without interrupting writing of the time linear input video signal to the dynamic buffer.

9. Apparatus according to claim 8, wherein the dynamic buffer has a plurality of storage locations defined by respective addresses, and the apparatus comprises an address counter for generating write addresses in recirculating fashion for writing the time linear input video signal to the dynamic buffer, and a pause register, and wherein the control means is responsive to the PAUSE command to store a current address for the dynamic buffer in the pause register.

10. Apparatus according to claim 8, wherein the dynamic buffer has a plurality of storage locations defined by respective addresses, the command means is operative to assert a MARK command and subsequently assert a REPLAY command, and the apparatus comprises an address counter for generating write addresses in recirculating fashion for writing the time linear input video signal to the dynamic buffer, and a mark register, and wherein the control means is responsive to the MARK command to store a current address for the dynamic buffer in the mark register while continuing to read the video signal from the dynamic buffer and is responsive to the REPLAY command to read the time segment of the time linear input video signal stored in the dynamic buffer from the stored address onward to provide a time linear output video signal without interrupting writing of the time linear input video signal to the dynamic buffer.

11. Apparatus according to claim 8, comprising a display device coupled to display the video signal read by the reading means from the dynamic buffer.

12. Apparatus according to claim 8, comprising a tuner for selecting the time linear input video signal from among a plurality of available signals.

13. A method of time warping a video signal from a selected video channel comprising the steps of:

continuously writing the video signal into a dynamic buffer, the buffer storing a segment of the video signal;

simultaneously reading the video signal from the dynamic buffer until a PAUSE command is asserted;

upon assertion of the PAUSE command,

interrupting the reading of the video signal from the dynamic buffer while continuing to write the video signal to the dynamic buffer, and

marking the video signal in the dynamic buffer with an access point so that the video signal can be accessed by the randomly accessing means for subsequent reading from the access point; and

upon subsequent assertion of a CONTINUE command, resuming reading of the video signal from the dynamic buffer from the marked access point so that the video signal is read from the dynamic buffer in time sequence.

14. A method according to claim 13, further comprising asserting a MARK command and, in response to the MARK command, marking the video signal in the dynamic buffer with an access point while continuing to write the video signal to and read the video signal from the dynamic-buffer, and subsequently asserting a REPLAY command and, in response to the REPLAY command, reading the video'"'"'signal from the dynamic buffer from the access point that was marked in response to the MARK command.

15. A method according to claim 13, further comprising the step of displaying the video signal read from the dynamic buffer.