Synchronized transmission of audio and video data from a computer to a client via an interface

• US 7,353,284 B2
• Filed: 12/23/2003
• Issued: 04/01/2008
• Est. Priority Date: 06/13/2003
• Status: Expired due to Fees

• 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): Nguyen; Quang N.
• Application Number:
  US10/746,283
• Publication Number:
  US 20040255339A1
• Time in Patent Office: 1,561 Days
• Field of Search: 709/231, 709/232, 709/249, 709/233, 709/218, 709/224, 709/235, 370/389, 370/477, 370/516, 370/517, 370/465, 725/25
• US Class Current: 709/233
• CPC Class Codes: G06F 3/14 Digital output to display device ; Cooperation and interconnection of the display device with other functional units
• CPC Class Codes: G09G 2350/00 Solving problems of bandwidth in display systems
• CPC Class Codes: G09G 2370/025 LAN communication management
• CPC Class Codes: G09G 2370/10 Use of a protocol of communication by packets in interfaces along the display data pipeline
• CPC Class Codes: H04L 47/30 in combination with information about buffer occupancy at either end or at transit nodes
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 21/4113 PC
• 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 21/64707 for transferring content from a first network to a second network, e.g. between IP and wireless

Abstract

A method for controlling data transmission between a computer and a video client via an interface, the method comprising: the computer polling the interface a first time to determine the size of the buffer on the interface; receiving a first buffer size value from the interface; sending a plurality of frames of video and audio data to the buffer on the interface such that a delay period exists between the sending of each frame; the computer polling the interface a second time to determine buffer size after the frames are sent to the interface; receiving a second buffer size value from the interface; and modifying the amount of time between the transmission of frames.

Claims

1. In a system having a computer, a video client, and an interface coupled between the computer and video client that facilitates data transmission between the computer and the video client, the interface having a buffer for storing data frames received from the computer to be sent to the video client, the buffer having a fill amount that varies with the amount of data it stores, the interface having an optimal buffer fill amount, a method of performing data transmission flow control, the method comprising:

the computer polling the interface a first time to determine the fill amount of the buffer on the interface;

receiving a first buffer fill amount value from the interface;

sending a plurality of frames of video and audio data in an isochronous manner to the buffer on the interface such that a delay period exists between the sending of each frame, wherein each frame of said plurality of frames comprises at least one header, a video portion, and an audio portion;

the computer polling the interface a second time to determine the buffer fill amount after the plurality of frames are sent to the buffer on the interface;

receiving a second buffer fill amount value from the interface; and

if the second buffer fill amount value is smaller than the optimal fill amount, and smaller than the first buffer fill amount value, then decreasing the delay period between transmission of frames from the computer to the buffer on the interface,

if the second buffer fill amount value is larger than the optimal fill amount, and larger than the first buffer fill amount value, then increasing the delay period between transmission of frames from the computer to the buffer on the interface.

2. The method of claim 1, wherein the size of at least one frame of said plurality of frames varies to accommodate various video formats.

3. The method of claim 1, wherein each frame of said plurality of frames comprises a NTSC format frame.

4. The method of claim 1, wherein each frame of said plurality of frames comprises a PAL format frame.

5. The method of claim 1, wherein the video portion and the audio portion of each frame of said plurality of frames are of a predetermined size.

6. The method of claim 5, wherein any empty portions of the video portion and the audio portion of each frame in said plurality of frames are filled with zeros.

7. A computer readable storage medium containing instructions which, when executed by a computer, performs data transmission flow control by performing the acts of:

polling for a first time an interface in communication with the computer, the interface having a buffer for storing data frames received from the computer, the frames to be sent to the video client, the buffer having a fill amount that varies with the amount of data contained in the buffer, the buffer having an optimal fill amount;

receiving a first buffer fill amount value from the interface;

sending a plurality of frames of video and audio data in an isochronous manner to the buffer on the interface such that a delay period exists between the sending of each frame, wherein each frame of said plurality comprises at least one header, a video portion, and an audio portion;

polling the interface a second time to determine the buffer fill amount after the plurality of frames are sent to the buffer on the interface;

receiving a second buffer fill amount value from the interface; and

if the second buffer fill amount value is smaller than the optimal fill amount, and smaller than the first buffer fill amount value, then decreasing the delay period between transmission of frames from the computer to the buffer on the interface,

if the second buffer fill amount value is larger than the optimal fill amount, and larger than the first buffer fill amount value, then increasing the delay period between transmission of frames from the computer to the buffer on the interface.

8. The computer readable storage medium of claim 7, wherein the video portion and the audio portion of each frame of said plurality of frames are of a predetermined size.

9. The computer readable storage medium of claim 7, wherein said interface is in data communication with said computer via a standardized bus utilizing a serialized protocol.

10. The computer readable storage medium of claim 9, wherein the size of each frame of said plurality of frames varies to accommodate various video formats.

11. In a system having a computer, a video client, and an interface coupled between the computer and video client that facilitates data transmission between the computer and the video client, the interface connected to the computer via a standardized bus, the interface having a buffer for storing data frames received from the computer to be sent to the video client, the buffer having a fill amount that varies with the amount of data it stores, the interface having an optimal buffer fill amount, an apparatus for performing data transmission flow control, the apparatus comprising:

apparatus adapted to poll the interface a first time to determine the fill amount of the buffer on the interface;

apparatus adapted to receive a first buffer fill amount value from the interface;

apparatus adapted to send a plurality of frames of video and audio data in an isochronous manner to the buffer on the interface such that a delay period exists between the sending of each frame, wherein each frame of said plurality of frames comprises at least one header, a video portion, and an audio portion;

apparatus adapted to poll the interface a second time to determine the buffer fill amount after the plurality of frames are sent to the buffer on the interface;

apparatus adapted to receive a second buffer fill amount value from the interface; and

apparatus adapted to if the second buffer fill amount value is smaller than the optimal fill amount, and smaller than the first buffer fill amount value, decrease the delay period between transmission of frames from the computer to the buffer on the interface,

apparatus adapted to, if the second buffer fill amount value is larger than the optimal fill amount, and larger than the first buffer fill amount value, increase the delay period between transmission of frames from the computer to the buffer on the interface.

12. The apparatus of claim 11, wherein each frame of said plurality of frames comprises a NTSC format frame.

13. The apparatus of claim 11, wherein the size of at least several frames of said plurality of frames varies to accommodate various video formats.

14. The apparatus of claim 13, wherein said interface receives signals from said video client and converts said signals into a second plurality of frames, and sends one frame from said second plurality of frames to said computer at each vertical blanking interval.

15. A device adapted for performing data transmission flow control, comprising:

apparatus adapted to determine a first fill amount of a buffer on an interface coupled between a computer and a video client, wherein the buffer on the interface facilitates data transmission between the computer and the video client;

apparatus adapted to send a plurality of frames of video and audio data in an isochronous manner to the buffer on the interface such that a delay period exists between the sending of each frame, wherein each frame of said plurality of frames comprises at least one header, a video portion, and an audio portion;

apparatus adapted to determine a second fill amount of the buffer on the interface after the frames are sent to the buffer on the interface; and

apparatus adapted to, if the second buffer fill amount value is smaller than an optimal fill amount of the buffer on the interface, and smaller than the first buffer fill amount value, decrease the delay period between the sending of said frames to the buffer on the interface, and if the second buffer fill amount value is larger than the optimal fill amount, and larger than the first buffer fill amount value, increase the delay period between the sending of said frames to the buffer on the interface.

16. The device of claim 15, wherein the size of at least one frame of said plurality of frames varies to accommodate various video formats.

17. The device of claim 15, wherein each frame of said plurality of frames comprises an NTSC format frame.

18. The device of claim 15, wherein each frame of said plurality of frames comprises a PAL format frame.

19. The device of claim 15, wherein the video portion and the audio portion of each frame of said plurality of frames are of a predetermined size.

20. The device of claim 19, wherein any empty portions of the video portion and the audio portion of each frame in said plurality of frames are filled with zeros.

21. The device of claim 15, wherein the interface is in data communication with the computer via a bus utilizing a serialized protocol.

22. A device adapted for performing data transmission flow control, comprising:

a computer readable storage medium containing instructions which, when executed by a computer, performs the acts of;

determining a first fill amount of a buffer on an interface between a computer and a video client, wherein the buffer on the interface facilitates data transmission between the computer and the video client;

sending a plurality of frames of video and audio data in an isochronous manner to the buffer on the interface such that a delay period exists between the sending of each frame, wherein each frame of said plurality of frames comprises at least one header, a video portion, and an audio portion;

determining a second fill amount of the buffer on the interface after the frames are sent to the buffer on the interface; and

if the second buffer fill amount value is smaller than an optimal fill amount of the buffer on the interface, and smaller than the first buffer fill amount value, decreasing the delay period between the sending of said frames to the buffer on the interface, and if the second buffer fill amount value is larger than the optimal fill amount, and larger than the first buffer fill amount value, increasing the delay period between the sending of said frames to the buffer on the interface.

23. The device of claim 22, wherein the size of at least one frame of said plurality of frames varies to accommodate various video formats.

24. The device of claim 22, wherein each frame of said plurality of frames comprises an NTSC format frame.

25. The device of claim 22, wherein each frame of said plurality of frames comprises a PAL format frame.

26. The device of claim 22, wherein the video portion and the audio portion of each frame of said plurality of frames are of a predetermined size.

27. The device of claim 22, wherein any empty portions of the video portion and the audio portion of each frame in said plurality of frames are filled with zeros.

28. The device of claim 22, wherein the interface is in data communication with the computer via a bus utilizing a serialized bus protocol.

29. A method of performing data transmission flow control, comprising:

determining a first fill amount of a buffer on an interface between a computer and video client, wherein the buffer on the interface facilitates data transmission between the computer and the video client;

sending a plurality of frames of video and audio data in an isochronous manner to the buffer on the interface such that a delay period exists between the sending of each frame, wherein each frame of said plurality of frames comprises at least one header, a video portion, and an audio portion;

determining a second fill amount of the buffer on the interface after the frames are sent to the buffer on the interface; and

if the second buffer fill amount value is smaller than an optimal fill amount of the buffer on the interface, and smaller than the first buffer fill amount value, decreasing the delay period between the sending of said frames to the buffer on the interface, and if the second buffer fill amount value is larger than the optimal fill amount, and larger than the first buffer fill amount value, increasing the delay period between the sending of said frames to the buffer on the interface.

30. The method of claim 29, wherein the size of at least one frame of said plurality of frames varies to accommodate various video formats.

31. The method of claim 29, wherein each frame of said plurality of frames comprises an NTSC format frame.

32. The method of claim 29, wherein each frame of said plurality of frames comprises a PAL format frame.

33. The method of claim 29, wherein the video portion and the audio portion of each frame of said plurality of frames are of a predetermined size.

34. The method of claim 29, wherein any empty portions of the video portion and the audio portion of each frame in said plurality of frames are filled with zeros.

35. The method of claim 29, wherein the interface is in data communication with the computer via a bus utilizing a serialized bus protocol.