Synchronization of independent output streams

• US 9,913,033 B2
• Filed: 05/30/2014
• Issued: 03/06/2018
• Est. Priority Date: 05/30/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Wyatt, Douglas S., Guetta, Anthony J.
• Primary Examiner(s): MONIKANG, GEORGE C
• Application Number:
  US14/292,690
• Publication Number:
  US 20150350803A1
• Time in Patent Office: 1,376 Days
• Field of Search: 381 61- 62
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
• CPC Class Codes: H04R 2499/15 Transducers incorporated in visual displaying devices, e.g. televisions, computer displays, laptops
• CPC Class Codes: H04R 3/12 for distributing signals to two or more loudspeakers specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04R 5/04 Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments combinations of amplifiers H03F3/68; stereophonic systems H04S

Abstract

A system determines to use at least two independent renderers to render at least two output streams that are to be synchronized. The independent renderers are provided with a shared synchronization object when instructed to render the respective output stream. A time when all of the independent renderers can render a respective first buffer of the respective output stream is determined from the shared synchronization object. Rendering of the output streams utilizing the independent renderers is begun at the determined time. In this way, rendering of the output streams may be synchronized.

Claims

1. A system for synchronizing independent output streams, comprising:

at least one non-transitory storage medium storing instructions; and

at least one processing unit that executes the instructions stored in the at least one non-transitory storage medium to;

determine to render at least two output streams that are to be synchronized using at least first and second independent renderers;

provide the first and second independent renderers a shared synchronization object when instructing the first and second independent renderers to render a respective one of the at least two output streams;

determine, from the shared synchronization object, a render time when all of the first and second independent renderers can render based on a latest of a first time and a second time; and

begin rendering the at least two output streams at the render time utilizing the first and second independent renderers;

wherein

the shared synchronization object includes the first time and the second time;

the first time is added to the shared synchronization object by the first independent renderer;

the second time is added to the shared synchronization object by the second independent renderer;

the first time indicates when the first independent renderer can first render a first respective buffer; and

the second time indicates when the second independent renderer can first render a second respective buffer.

2. The system of claim 1, wherein the at least two output streams are transmitted as first and second audio channels of a stereo audio channel to the first and second independent renderers.

3. The system of claim 2, wherein the shared synchronization object identifies the first and second independent renderers, a status time for each of the first and second independent renderers, a number frames requested for rendering for each of the first and second independent renderers, and a status for each of the first and second independent renderers.

4. The system of claim 2, wherein the shared synchronization object comprises an array.

5. The system of claim 2, wherein a time delay is inserted into a beginning of the first respective buffer.

6. The system of claim 2, further comprising a codec that executes both of the first and second independent renderers.

7. The system of claim 6, wherein the codec is coupled to the at least one processing unit by a stereo audio connection.

8. The system of claim 7, wherein the codec is coupled to a speaker by a first audio connection and an actuator by a second audio connection.

9. The system of claim 8, wherein the first audio connection and the second audio connection are both mono audio connections.

10. The system of claim 2, wherein the at least one processing unit determines the time when all of the first and second independent renderers can render by utilizing the shared synchronization object to ascertain that all of the first and second independent renderers have checked in.

11. The system of claim 2, further comprising a first codec that receives the output of the first of the first and second independent renderers and a second codec that receives the output of the second of the first and second independent renderers.

12. The system of claim 2, wherein the at least two output streams are rendered in multiple loops and a starting point for each loop is determined from the shared synchronization object.

13. The system of claim 2, wherein a waveform for at least one of the at least two output streams is retrieved from the at least one non-transitory storage medium for rendering.

14. The system of claim 2, wherein a waveform for at least one of the at least two output streams is synthesized for rendering.

15. The system of claim 2, wherein the at least two output streams have different numbers of frames requested for rendering.

16. The system of claim 2, wherein the at least two output streams have different sampling rates.

17. The system of claim 2, wherein the at least two output streams have different durations.

18. The system of claim 2, wherein synchronization of the at least two output streams enables the system to stay within a power utilization constraint.

19. A method for synchronizing independent output streams, the method comprising:

determining to render at least two output streams that are to be synchronized using at least first and second independent renderers;

providing the first and second independent renderers a shared synchronization object when instructing the first and second independent renderers to render a respective one of the at least two output streams;

determining, from the shared synchronization object, a render time when all of the first and second independent renderers can render based on a latest of a first time and a second time; and

beginning rendering the at least two output streams at the render time utilizing the first and second independent renderers;

wherein

the shared synchronization object includes the first time and the second time;

the first time is added to the shared synchronization object by the first independent renderer;

the second time is added to the shared synchronization object by the second independent renderer;

the first time indicates when the first independent renderer can first render a first respective buffer; and

the second time indicates when the second independent renderer can first render a second respective buffer.

20. A computer program product, tangibly embodied in at least one non-transitory storage medium, comprising:

a first set of instructions, stored in at least one non-transitory storage medium, executable by at least one processing unit to determine to render at least two output streams that are to be synchronized using at least first and second independent renderers;

a second set of instructions, stored in the at least one non-transitory storage medium, executable by the at least one processing unit to provide the first and second independent renderers a shared synchronization object when instructing the first and second independent renderers to render a respective one of the at least two output streams;

a third set of instructions, stored in the at least one non-transitory storage medium, executable by the at least one processing unit to determine, from the shared synchronization object, a render time when all of the first and second independent renderers can render based on a latest of a first time and the second time; and

a fourth set of instructions, stored in the at least one non-transitory storage medium, executable by the at least one processing unit to begin rendering the at least two output streams at the render time utilizing the first and second independent renderers;

wherein

the shared synchronization object includes the first time and the second time;

the first time is added to the shared synchronization object by the first independent renderer;

the second time is added to the shared synchronization object by the second independent renderer;

the first time indicates when the first independent renderer can first render a first respective buffer; and

the second time indicates when the second independent renderer can first render a second respective buffer.