Synthesis of vertical blanking signal

• US 7,668,099 B2
• Filed: 12/23/2003
• Issued: 02/23/2010
• Est. Priority Date: 06/13/2003
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Agnoli, Giovanni M., Dillon, Jeffrey C., Delwiche, James A., Abt, John O., Yanowitz, Andrew, Bowman, Samuel R.
• Primary Examiner(s): Ryman; Daniel J
• Assistant Examiner(s): ROBERTS, BRIAN S
• Application Number:
  US10/746,284
• Publication Number:
  US 20040252231A1
• Time in Patent Office: 2,254 Days
• Field of Search: None
• US Class Current: 370/235
• CPC Class Codes: H04N 21/4135 external recorder interface circuits between an apparatus for recording television signals and a television receiver H04N5/775
• CPC Class Codes: H04N 21/4143 embedded in a Personal Computer [PC]
• CPC Class Codes: H04N 21/4223 Cameras H04N23/00 takes precedence
• CPC Class Codes: H04N 21/4305 Synchronising client clock from received content stream, e.g. locking decoder clock with encoder clock, extraction of the PCR packets arrangements for synchronising receiver with transmitter by comparing receiver clock with transmitter clock H04L7/0012; arrangements for synchronising receiver with transmitter wherein the receiver takes measures against momentary loss of synchronisation H04L7/0083
• CPC Class Codes: H04N 21/43632 involving a wired protocol, e.g. IEEE 1394 high-speed IEEE 1394 serial bus H04L12/40052
• CPC Class Codes: H04N 5/765 Interface circuits between an apparatus for recording and another apparatus
• CPC Class Codes: H04N 7/088 the inserted signal being digital
• CPC Class Codes: H04N 7/56 Synchronising systems therefor

Abstract

A method of controlling transmission of data from a computer to a video client via an interface device, comprising: reading a register on the interface device to obtain a value indicating temporal proximity to an occurrence of a vertical blanking interval occurs, the value increased incrementally until a vertical blanking interval occurs, and then being reset; deriving a time value, the time value indicating the occurrence of a vertical blanking interval; sending an interrupt to a processor on the computer at the occurrence of the vertical blanking interval; and invoking code in response to an occurrence of the video blanking interval.

Claims

1. A method of controlling transmission of data from a computer to a video client via an interface device that buffers data frames sent between the computer and the video client and communicates to the computer and the video client using different protocols, the method implemented by the computer comprising:

reading a register on the interface device to obtain a value indicating temporal proximity to an occurrence of a vertical blanking interval;

deriving a time value, the time value indicating the occurrence of the vertical blanking interval;

sending an interrupt to a processor on the computer at the occurrence of the vertical blanking interval; and

invoking code in response to the occurrence of the vertical blanking interval.

2. The method of claim 1, wherein the time value is derived through extrapolation.

3. The method of claim 1, wherein invoking code comprises sending a command over a serial bus to obtain a time code value, the time code value describing video data.

4. The method of claim 1, wherein invoking code comprises sampling a time code value through a serial port.

5. The method of claim 1, wherein invoking code comprises recapturing video data using a time code value.

6. The method of claim 5, wherein recapturing is performed on the video data in batch mode based on the time code value.

7. The method of claim 1, wherein a time code value is used in a seek operation on a storage device to select stored video data.

8. The method of claim 1, wherein a time code value is used to uniquely identify a frame.

9. The method of claim 1, wherein a time code value is stored with an associated frame.

10. The method of claim 1, wherein invoking code comprises transmitting a data frame from the computer to the interface device in response to the sending of the interrupt.

11. The method of claim 1, wherein reading the register on the interface device comprises reading a register that rolls over at a multiple of an occurrence of the vertical blanking interval.

12. The method of claim 1, wherein invoking code comprises sampling a time code value multiple times per frame.

13. A computer readable apparatus having a storage medium with at least one computer program stored thereon, the at least one computer program comprising a plurality of computer executable instructions that when executed by a computer, control transmission of data from the computer to a video client via an interface device that buffers data frames sent between the computer and the video client and communicates to the computer and the video client using different protocols, by performing the acts of:

reading a register on the interface device to obtain a value indicating temporal proximity to an occurrence of a vertical blanking interval;

deriving a time value, the time value indicating the occurrence of the vertical blanking interval;

sending an interrupt to a processor on the computer at the occurrence of the vertical blanking interval; and

invoking code in response to the occurrence of the video blanking interval.

14. An apparatus that controls transmission of data from the apparatus to a video client via an interface device that buffers data frames sent between the apparatus and the video client and communicates to the apparatus and the video client using different protocols, the apparatus comprising:

means for reading a register on the interface device to obtain a value indicating temporal proximity to an occurrence of a vertical blanking interval;

means for deriving a time value, the time value indicating the occurrence of the vertical blanking interval;

means for sending an interrupt to a processor on the apparatus at the occurrence of the vertical blanking interval; and

means for invoking code in response to the occurrence of the video blanking interval.

15. An apparatus that controls transmission of data between the apparatus and a device, via an interface device that buffers data frames sent between the apparatus and the device, and communicates to the respective apparatus and device using different protocols, the apparatus comprising:

a network interface upon which the contents of a register on the interface device that are read are received to obtain a value indicating temporal proximity to an occurrence of a vertical blanking interval; and

a computer readable apparatus having a storage medium with at least one computer program stored thereon, the at least one computer program comprising a plurality of computer executable instructions that when executed by a processing apparatus;

derive a boundary associated with a transmitted frame such that other data within the transmitted frame that is synchronized to the occurrence of the vertical blanking interval can be accessed, said act of deriving using at least the value indicating temporal proximity to an occurrence of a vertical blanking interval read from the interface device; and

access said other data within the transmitted frame.

16. The apparatus of claim 15, wherein the other data within the transmitted frame are utilized for a sampling operation.

17. The apparatus of claim 15, wherein the other data within the transmitted frame is coincident with the vertical blanking interval but otherwise includes no information about the vertical blanking interval.

18. The apparatus of claim 15, wherein the other data within the transmitted frame comprises data that is valid for a period of time after the occurrence of the video blanking interval.

19. The apparatus of claim 18, wherein the other data within the transmitted frame comprises a time code, wherein the time code can be read by the apparatus and utilized by a plurality of various processing applications associated with the apparatus.