Performing DMA transfer of audio and video data received over a serial bus

• US 8,780,168 B2
• Filed: 12/16/2011
• Issued: 07/15/2014
• Est. Priority Date: 12/16/2011
• Status: Active Grant

• Current Assignee: Lifesize, Inc. (Enghouse Systems Limited)
• Original Assignee: Logitech Europe S A (Logitech International SA)
• Inventors: Corley, Robert A., McKinnon, Patrick R., Slivinski, Stefan F.
• Primary Examiner(s): ABAD, FARLEY J
• Application Number:
  US13/328,082
• Publication Number:
  US 20130155179A1
• Time in Patent Office: 942 Days
• Field of Search: 348/14.08, 710/308
• US Class Current: 348/14.08
• CPC Class Codes: G06F 13/36 for access to common bus or bus system
• CPC Class Codes: H04L 65/00 Network arrangements, protocols or services for supporting real-time applications in data packet communication real-time or near real-time messaging, e.g. instant messaging [IM] H04L51/04; selective video distribution H04N21/00
• CPC Class Codes: H04L 65/764 at the destination reformatting of additional data in video clients H04N21/4355
• CPC Class Codes: H04N 7/14 Systems for two-way working H04N7/12, H04N7/173 take precedence
• CPC Class Codes: H04N 7/155 involving storage of or access to video conference sessions tracking arrangements for later retrieval of a computer conference content or participants activities H04L12/1831

Abstract

DMA transfer of audio and video data. The audio and video data may be received over a serial bus. A DMA engine may provide audio and video data packets to data storage logic based on the audio and video data. The DMA engine may provide each of the audio data packets with a first, same destination address of a first memory and may provide each of the video data packets with a second, same destination address of the first memory. The data storage logic may maintain first and second pointers that indicate a next current memory location for audio data in a first buffer and video data in a second buffer in the first memory, respectively. The data storage logic may receive and store the audio and video data packets at respective locations in the first and second buffers based on current values of the first and second pointers.

Claims

1. A method for receiving and storing audio and video data into a first memory on a video presentation device, the method comprising:

receiving the audio data over a serial bus;

receiving the video data over the serial bus;

a direct memory access (DMA) engine providing audio data packets to data storage logic based on the audio data, wherein the DMA engine provides each of the audio data packets with a first destination address of a first memory, wherein the first destination address is the same address for all audio data packets;

the DMA engine providing video data packets to the data storage logic based on the video data, wherein the DMA engine provides each of the video data packets with a second destination address of the first memory, wherein the second destination address is the same address for all video data packets;

the data storage logic maintaining a first pointer that indicates a next current memory location for audio data in a first buffer in the first memory;

the data storage logic maintaining a second pointer that indicates a next current memory location for video data in a second buffer in the first memory;

the data storage logic receiving the audio data packets and storing the audio data packets at respective different locations in the first buffer in the first memory based on a current value of the first pointer;

the data storage logic receiving the video data packets and storing the video data packets at respective different locations in the second buffer in the first memory based on a current value of the second pointer.

2. The method of claim 1, wherein the DMA engine generating each of the audio data packets with the same first destination address and generating each of the video data packets with the same second destination address reduces a number of interrupts on the video presentation device.

3. The method of claim 1, wherein the first and second pointers indicate memory locations of the respective buffer in fixed size segments, wherein the method further comprises:

for each data packet, determining a length of the data stored in the respective buffer segment.

4. The method of claim 1, wherein the DMA engine is implemented using data receive logic.

5. The method of claim 4, wherein the data receive logic comprises a digital signal processor (DSP).

6. The method of claim 1, further comprising:

the data storage logic processing the audio and video data stored in the first and second buffers for presentation.

7. The method of claim 1, wherein the data storage logic is implemented at least in part by a programmable hardware element.

8. The method of claim 1, wherein the first and second buffers are circular buffers.

9. The method of claim 1, wherein the audio and video data is received over a universal serial bus (USB).

10. A method for receiving and storing video data into a first memory on a video presentation device, the method comprising:

receiving the video data over a serial bus;

a direct memory access (DMA) engine providing video data packets to storage logic based on the video data, wherein the DMA engine provides each of the video data packets with a first destination address of the first memory, wherein the first destination address is the same address for all video data packets, wherein the DMA engine providing each of the video data packets with the same first destination address reduces a number of interrupts on the video presentation device;

the data storage logic maintaining a first pointer that indicates a next current memory location in a circular buffer in the first memory;

the data storage logic receiving the video data packets and storing the video data packets at respective different locations in the circular buffer in the first memory based on a value of the first pointer.

11. A video presentation device, comprising:

a data input port coupled to receive audio and video data over a serial bus;

data receive logic coupled to the data input port, wherein the data receive logic is configured to receive the audio and video data via the data input port, and wherein the data receive logic is configured to implement a direct memory access (DMA) engine;

data storage logic coupled to the data receive logic; and

a first memory coupled to the data storage logic;

wherein the DMA engine is configured to;

provide audio data packets to the data storage logic based on the audio data, wherein the DMA engine provides each of the audio data packets with a first destination address of a first memory, wherein the first destination address is the same address for all audio data packets;

provide video data packets to the data storage logic based on the video data, wherein the DMA engine provides each of the video data packets with a second destination address of the first memory, wherein the second destination address is the same address for all video data packets;

wherein the data storage logic is configured to;

maintain a first pointer that indicates a next current memory location for audio data in a first buffer in the first memory;

maintain a second pointer that indicates a next current memory location for video data in a second buffer in the first memory;

receive the audio data packets and store the audio data packets at respective different locations in the first buffer in the first memory based on a current value of the first pointer;

receive the video data packets and store the video data packets at respective different locations in the second buffer in the first memory based on a current value of the second pointer.

12. The video presentation device of claim 11, wherein the DMA engine generating each of the audio data packets with the same first destination address and generating each of the video data packets with the same second destination address reduces a number of interrupts on the video presentation device.

13. The video presentation device of claim 11, wherein the first and second pointers indicate memory locations of the respective buffer in fixed size segments, wherein the data storage logic is further configured to:

for each data packet, determine a length of the data stored in the respective buffer segment.

14. The video presentation device of claim 11, wherein the data receive logic comprises a digital signal processor (DSP).

15. The video presentation device of claim 11, wherein the data storage logic is further configured to:

process the audio and video data stored in the first and second buffers for presentation.

16. The video presentation device of claim 15, further comprising:

a video output port coupled to the data storage logic, wherein the video output port is configured to provide video data to a display; and

an audio output port coupled to the data storage logic, wherein the audio output port is configured to provide audio to one or more audio output devices;

wherein the data storage logic is configured to provide the audio and video data for presentation via the video output and the audio output.

17. The video presentation device of claim 11, wherein the data storage logic is implemented at least in part by a programmable hardware element.

18. The video presentation device of claim 11, wherein the first and second buffers are circular buffers.

19. The video presentation device of claim 11, wherein the audio and video data is received over a universal serial bus (USB).

20. The video presentation device of claim 11, wherein the video presentation device comprises a videoconferencing device, wherein the videoconferencing device further comprises:

a video output port coupled to the data storage logic, wherein the video output port is configured to provide video data to a display;

an audio output port coupled to the data storage logic, wherein the audio output port is configured to provide audio to one or more audio output devices; and

a network port coupled to the data storage logic, wherein the network port is configured to provide videoconferencing data to one or more other videoconferencing devices during a videoconference.