Systems, methods and computer-readable media for configuring receiver latency

• US 8,966,109 B2
• Filed: 03/21/2012
• Issued: 02/24/2015
• Est. Priority Date: 04/21/2006
• Status: Active Grant

• Current Assignee: Audinate Holdings Pty Limited
• Original Assignee: Audinate Pty Ltd (Audinate Group Ltd.)
• Inventors: White, Andrew, Williams, Aidan
• Primary Examiner(s): NGUYEN, PHUOC H
• Application Number:
  US13/426,179
• Publication Number:
  US 20120195313A1
• Time in Patent Office: 1,070 Days
• Field of Search: 709/203, 709/219, 709/223, 709/224, 709/232
• US Class Current: 709/232
• CPC Class Codes: H04J 3/0632 Synchronisation of packets and cells, e.g. transmission of voice via a packet network, circuit emulation service [CES] queuing arrangements in packet switching elements H04L49/90; synchronising systems for the synchronous transmission of a pulse code modulated video signal with one or more other pulse code modulated signals H04N7/56
• CPC Class Codes: H04J 3/0667 Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays arrangements for monitoring round trip delays in packet switching networks H04L43/0864
• CPC Class Codes: H04L 43/0858 One way delays
• CPC Class Codes: H04L 67/10 in which an application is distributed across nodes in the network software deployment G06F8/60; multiprogramming arrangements G06F9/46
• CPC Class Codes: H04N 21/233 Processing of audio elementary streams monitoring, identification or recognition of audio in broadcast systems H04H60/58
• CPC Class Codes: H04N 21/23406 involving management of server-side video buffer
• CPC Class Codes: H04N 21/2368 Multiplexing of audio and video streams
• CPC Class Codes: H04N 21/2402 Monitoring of the downstream path of the transmission network, e.g. bandwidth available traffic monitoring in data switching networks H04L43/00; monitoring data switching networks utilization H04L43/0876
• CPC Class Codes: H04N 21/242 Synchronization processes, e.g. processing of PCR [Program Clock References] arrangements for synchronising broadcast or distribution via plural systems in broadcast distribution systems H04H20/18
• 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 21/4341 Demultiplexing of audio and video streams
• CPC Class Codes: H04N 21/64322 IP
• CPC Class Codes: H04N 21/845 Structuring of content, e.g. decomposing content into time segments

Abstract

The present disclosure is related to transmitting and receiving media channels, such as audio and video channels. These channels may be transmitted as packets from one or more transmitting devices to one or more receiving devices for playout. Certain embodiments of the present disclosure include systems, methods, and computer-readable media for determining latency of a data network for synchronized playout of received signals. Additionally, certain embodiments of the present disclosure include a systems, methods, and computer-readable media for synchronizing playout among devices connected to a data network.

Claims

1. A processor-implemented method of synchronizing rendering of a media channel among a group of receiving devices, wherein each receiving device in the group performs a method comprising:

receiving a signal from a transmitting device via a media channel, wherein the signal includes a timestamp;

determining a transmission latency from the transmitting device to the receiving device based on the timestamp;

obtaining a latency of the transmitting device, wherein the latency of the transmitting device corresponds to an amount of time between when media data is sampled and when the media data receives a timestamp;

determining a minimum end-to-end latency based on the latency of the transmitting device, the transmission latency, and a latency of the receiving device, wherein the latency of the receiving device corresponds to an amount of time between when media data is written to a receiver buffer and when the media data is rendered;

determining a maximum end-to-end latency based on the latency of the transmitting device, the latency of the receiving device, and a receiver buffer capacity;

transmitting a multicast message to other receiving devices in the group, wherein the multicast message includes the minimum end-to-end latency;

setting a current latency value of the receiving device to the greater of the minimum end-to-end latency of the receiving device or a minimum end-to-end latency of another receiving device in the group; and

rendering the media channel at the receiving device according to the current latency value, such that the rendering of the media channel by the receiving device is synchronized with the rendering of the media channel by other receiving devices in the group.

2. The method of claim 1 wherein the media channel is an audio channel.

3. The method of claim 1 wherein the media channel is a video channel.

4. The method of claim 1 wherein the media channel transmits compressed audio.

5. The method of claim 1 wherein the multicast message further comprises a group identification number, the maximum end-to-end latency, and the current latency.

6. The method of claim 1 further comprising updating the current latency value if another receiving device in the group transmits a multicast message indicating that the other receiving device has a minimum end-to-end latency greater than the current latency value.

7. The method of claim 1 further comprising determining a latency offset for the receiving device based on the latency of the transmitting device, the latency of the receiving device, and the current latency value, and setting a buffer position in the receiving device based on the latency offset.

8. A non-transitory computer-readable medium storing a program configured to cause a computer to perform the steps comprising:

receiving a signal from a transmitting device via a media channel, wherein the signal includes a timestamp;

determining a transmission latency from the transmitting device to the receiving device based on the timestamp;

obtaining a latency of the transmitting device, wherein the latency of the transmitting device corresponds to an amount of time between when media data is sampled and when the media data receives a timestamp;

determining a minimum end-to-end latency based on the latency of the transmitting device, the transmission latency, and a latency of the receiving device, wherein the latency of the receiving device corresponds to an amount of time between when media data is written to a receiver buffer and when the media data is rendered;

determining a maximum end-to-end latency based on the latency of the transmitting device, the latency of the receiving device, and a receiver buffer capacity;

transmitting a multicast message to other receiving devices in the group, wherein the multicast message includes the minimum end-to-end latency;

setting a current latency value of the receiving device to the greater of the minimum end-to-end latency of the receiving device or a minimum end-to-end latency of another receiving device in the group; and

rendering the media channel at the receiving device according to the current latency value, such that the rendering of the media channel by the receiving device is synchronized with the rendering of the media channel by other receiving devices in the group.

9. The computer-readable medium of claim 8 wherein the media channel is an audio channel.

10. The computer-readable medium of claim 8 wherein the media channel is a video channel.

11. The computer-readable medium of claim 8 wherein the media channel transmits compressed audio.

12. The computer-readable medium of claim 8 wherein the multicast message further comprises a group identification number, the maximum end-to-end latency, and the current latency.

13. The computer-readable medium of claim 8 further comprising updating the current latency value if another receiving device in the group transmits a multicast message indicating that the other receiving device has a minimum end-to-end latency greater than the current latency value.

14. The computer-readable medium of claim 8 further comprising determining a latency offset for the receiving device based on the latency of the transmitting device, the latency of the receiving device, and the current latency value, and setting a buffer position in the receiving device based on the latency offset.

15. A system for synchronizing rendering of a media channel among a group of receiving devices, wherein each receiving device in the group comprises:

a processor; and

a memory configured to cause the processor to perform steps comprising;

receiving a signal from a transmitting device via a media channel, wherein the signal includes a timestamp;

determining a transmission latency from the transmitting device to the receiving device based on the timestamp;

obtaining a latency of the transmitting device, wherein the latency of the transmitting device corresponds to an amount of time between when media data is sampled and when the media data receives a timestamp;

determining a minimum end-to-end latency based on the latency of the transmitting device, the transmission latency, and a latency of the receiving device, wherein the latency of the receiving device corresponds to an amount of time between when media data is written to a receiver buffer and when the media data is rendered;

determining a maximum end-to-end latency based on the latency of the transmitting device, the latency of the receiving device, and a receiver buffer capacity;

transmitting a multicast message to other receiving devices in the group, wherein the multicast message includes the minimum end-to-end latency;

setting a current latency value of the receiving device to the greater of the minimum end-to-end latency of the receiving device or a minimum end-to-end latency of another receiving device in the group; and

rendering the media channel at the receiving device according to the current latency value, such that the rendering of the media channel by the receiving device is synchronized with the rendering of the media channel by other receiving devices in the group.

16. The system of claim 15 wherein the media channel is an audio channel.

17. The system of claim 15 wherein the media channel is a video channel.

18. The system of claim 15 wherein the multicast message further comprises a group identification number, the maximum end-to-end latency, and the current latency.

19. The system of claim 15 further comprising updating the current latency value if another receiving device in the group transmits a multicast message indicating that the other receiving device has a minimum end-to-end latency greater than the current latency value.

20. The system of claim 15 further comprising determining a latency offset for the receiving device based on the latency of the transmitting device, the latency of the receiving device, and the current latency value, and setting a buffer position in the receiving device based on the latency offset.