KR102091905B1 - AVB based SR Speaker System with Adjustable Presentation Time - Google Patents

Abstract

An AVB based SR speaker system having an adjustable PT is provided. The PT adjusting method according to an embodiment of the present invention receives TTs of audio data from audio receiving devices, adjusts PTs of the audio receiving devices using the received TTs, and delivers the adjusted PTs to the audio transmitting device. . As a result, the PT can be adjusted in the speaker system, so that even when speakers located far away from a large space such as a stadium or a concert are connected to a Daisy Chain structured network, audio can be streamed in real time without loss.

Description

AVB based SR speaker system with adjustable presentation time

The present invention relates to an SR speaker system, and more particularly, to a speaker system for streaming audio in real time without loss by connecting speakers located in a wide space such as a stadium or a concert hall with a network of a Daisy Chain structure.

Audio Video Bridging (AVB) technology uses real-time, low-cost local area network (LAN) cables to provide real-time AV content to address the complexity of wiring and cost issues associated with expensive cables in existing audio video (AV) systems. As a technology for transmitting losslessly to the castle, detailed standards have been established based on IEEE 802.1BA.

Looking at the operation of the devices in the AVB network, in order to transfer time-sensitive data in real time in a network environment sharing physical media such as Ethernet to transmit various types of data, all devices belonging to the same domain are identical. The same time must be synchronized to the grandmaster.

In addition, in order to prevent loss of real-time transmission data even in a situation where traffic is concentrated, resource reservation for a network path between a transmitting device and a receiving device must be preceded before transmitting data.

On the other hand, if the speakers located far away from a large space such as a stadium or a concert hall are connected by a Daisy Chain network, there is a problem in that the synchronization of AV content is lost and loss occurs.

The present invention has been devised to solve the above problems, and the object of the present invention is to provide real-time audio without loss even when speakers located in a wide space such as a stadium or a concert hall are connected to a network of a Daisy Chain structure. As a method for streaming, it is to provide a speaker system having an adjustable PT (Presentation Time).

According to an embodiment of the present invention for achieving the above object, the PT adjusting method comprises: receiving TTs (Transfer Times) of audio data from audio receiving devices; Adjusting the PT (Presentation Time) of the audio receivers using the received TTs; And transmitting the adjusted PT to the audio transmission device.

And, PT is expressed by the following equation, PT = CT (Current Time) + α, where α may be determined by the adjustment step.

Also, in the adjustment step, the maximum TT can be determined as α.

And, TT can be expressed by the following equation.

TT = RT (Receive Time) -PT-α

Also, the audio transmitting device and the audio receiving devices may be connected by a ring-type network.

And, in the receiving step, TTs may be received using a specific field of GET_CONTROL of the IEEE1722.1 protocol.

In addition, in the delivery step, PT can be recorded in SET_CONTROL of the IEEE1722.1 protocol, and transmitted to the audio transmission device.

Meanwhile, according to another embodiment of the present invention, an audio system includes: an audio transmission device; Audio receivers; And TT (Transfer Times) of the audio data received from the audio receivers to adjust the PT (Presentation Time) that the audio transmitter transmits with the audio data to the audio receivers, and the adjusted PT to the audio transmitter. It includes; a management system to deliver to.

As described above, according to the embodiments of the present invention, the PT can be adjusted in the speaker system, and even when the speakers located in a wide space such as a stadium or a concert hall are connected to a network of a Daisy Chain structure, there is no loss. You will be able to stream audio in real time.

1 is a block diagram of an SR speaker,
2 is a Daisy chain connection diagram of SR speakers,
3 is a maximum / minimum value of transmission time,
4 is a maximum / minimum average transmission time, and
It is a figure provided for description of a PT adjustment method.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

1. Outline

In an embodiment of the present invention, an audio video bridging (AVB) based SR speaker system having adjustable PT (Presentation Time) is presented. This is to enable streaming of audio in real time without loss, even when speakers located in a wide space such as a stadium or concert hall are connected to a network of a Daisy Chain structure, a kind of ring-type network structure.

To this end, in an embodiment of the present invention, the PT is adjusted so that the streaming service can be smoothed by analyzing the transmission time and PT through transmission measurement or experiment in a network environment.

2. AVB based SR speaker transmission time measurement

PT (Presentation Time) refers to a time when video or audio signals are transmitted through a network and then played back through a display or speaker after decoding.

PT within the network is represented by a time expression determined by the terminals, and is calculated in a sequential relationship of playback in consideration of the network transmission state in a part that is reproduced in multiple parts in parts such as video and audio synchronization or audio transmission, and accurately PT control is required. PT is transmitted with stream data in the IEEE1722 frame.

In an embodiment of the present invention, an SR speaker based on a commercial AVB chip is proposed for transmission time measurement. 1 is a block diagram of an SR speaker. As shown in FIG. 1, the SR speaker has two Ethernet ports 101 and 102 intrinsically to implement a daisy chain network configuration.

The network is configured by arranging the audio talker 300, which is an audio transmission device, and the SR speakers 110, 120, 130, 140, which are audio reception devices (audio listeners) in a Daisy Chain manner as shown in FIG.

In addition, delay experiment devices (hubs) 210, 220, 230, and 240 are arranged between the SR speakers 110, 120, 130, and 140 to create a delay situation that may occur in a large outdoor space.

That is, the audio signal transmitted by the SR speakers (110,120,130,140) is delayed by the delay test devices (210,220,230,240).

The delay test devices 210, 220, 230, and 240 receive a distance, estimate a delay time proportional to the input distance, delay the received audio signal by the estimated delay time, and transmit it to the SR speakers 110, 120, 130, and 140.

1) The distance input to the delay test device-1 210 is a distance between the audio talker 300 and the SR speaker-1 110,

2) The distance input to the delay test device-2 220 is the distance between the SR speaker-1 110 and the SR speaker-2 120,

3) The distance input to the delay test device-3 (230) is the distance between the SR speaker-2 (120) and the SR speaker-3 (130),

4) The distance input to the delay test device-4 240 is a distance between the SR speaker-3 130 and the SR speaker-4 140.

The audio talker 300 transmits an audio signal, for example, 24bit / 48kHz PCM 4channel in IEEE 1722 frame form every 125 μs. At this time, the audio talker 300 designates PT 1 s later than the frame transmission time. This is to make it more sensitive to delays, and it is considered that the network transmission time is usually around 1 km.

The PC 400 functioning as a manager (management system) for network control is a terminal for controlling a connection between the audio talker 300 and the SR speakers 110, 120, 130, and 140 corresponding to the audio listeners.

The PC 400 can be used in a Windows environment, Riedel's IEEE1722.1. It can be implemented by using a base manager program, but does not exclude other implementations.

When the audio talker 300 transmits a data packet by displaying PT [= CT (Current Time) + α (1㎳)], the SR speaker (110,120,130,140) measures RT (Receive Time), which is the time the packet was received, and then TT (Transfer Time) can be calculated by

TT = RT-PT-α

SR packets (110, 120, 130, 140) observe all packets while 1000 incoming data comes in every 125 ,, and output and measure the maximum and minimum values, and perform these measurements for 500 times. The transmission time can be derived from the audio talker 300 at (110, 120, 130, 140).

In FIG. 3, Direct MIN / MAX is a transmission time measured by removing the delay test device-1 210 and directly connecting the audio talker 300 and the SR speaker-1 110. MIN is 1.29 ~ 1.30㎳, MAX is 1.39 ~ 1.40㎳, and noise is audible in the audio.

In FIG. 3, 2st MIN / MAX is a transmission time measured by the SR speaker-2 120 when the delay test device-1 210, the SR speaker-1 110, and the delay test device-2 220 are connected. to be. MIN is 1.37 ~ 1.40㎳, and MAX is 1.46 ~ 1.51㎳, which is a lot of noise in the audio.

In FIG. 3, 4st MIN / MAX is a delay test device-1 210, an SR speaker-1 110, a delay test device-2 220, an SR speaker-2 120, and a delay test device-3 230. ), When the SR speaker-3 130 and the delay test device-4 240 are connected, the transmission time measured by the SR speaker-4 140. MIN is 1.56 ~ 1.62㎳, MAX is 1.69 ~ 1.73㎳, and the audio is interrupted with noise.

FIG. 4 shows the result of obtaining the maximum / minimum average transmission time shown in FIG. 3, and as the delay test devices and SR speakers, which are delay elements, increase, the transmission time increases.

3. PT adjustment method

5 is a view provided for explaining a method for adjusting PT through the IEEE1722.1 protocol. As shown in FIG. 5, PT adjustment is performed by the PC 400.

For PT adjustment, the PC 400 functioning as a manager collects TT measurements from SR speakers 110, 120, 130, and 140. TT measurements can be collected through GET_CONTROL by defining and recording a new field in GET_CONTROL.

Next, the PC 400 compares the collected TT measurement values to calculate an appropriate PT. When PT adjustment is required, the PC 400 issues a PT adjustment command to the audio talker 300. The PT adjustment command may transmit an appropriate PT to SET_CONTROL and transmit it to the audio talker 300.

The audio talker 300 that has received the command can prevent loss of audio due to transmission delay by adjusting PT, specifically, “α” in the above formula in units of ㎲. In an environment in which transmission delay as shown in FIGS. 3 and 4 occurs, it is preferable to adjust “α” to 1.73 ms or more, but it is not necessarily limited to such adjustment.

4. Modification

So far, a technique for enabling the PT of an audio talker to be adjusted by confirming a transmission delay occurring in real-time streaming in an AVB-based audio system in the IEEE1772.1 manager has been described in detail with reference to preferred embodiments.

In the above embodiment, an AVB-based audio system is assumed, which is only exemplary. It goes without saying that the technical idea of the present invention can also be applied to other standard / structured audio systems.

On the other hand, the technical idea of the present invention can be applied to a computer-readable recording medium containing a computer program that performs functions of the apparatus and method according to the present embodiment. Further, the technical idea according to various embodiments of the present invention may be implemented in the form of computer-readable codes recorded on a computer-readable recording medium. The computer-readable recording medium can be any data storage device that can be read by a computer and stores data. Of course, the computer-readable recording medium may be a ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical disk, hard disk drive, or the like. In addition, computer-readable codes or programs stored in a computer-readable recording medium may be transmitted through a network connected between computers.

In addition, although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific embodiments described above, and the technical field to which the present invention belongs without departing from the gist of the present invention claimed in the claims. In addition, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical idea or prospect of the present invention.

110,120,130,140: SR speaker
210,220,230,240: delay test device
300: audio talker
400: PC

Claims (8)

Receiving TTs (Transfer Times) of audio data from audio receivers;
Adjusting PT (Presentation Time) of the audio receivers using the received TTs;
And transmitting the adjusted PT to the audio transmission device.
PT is expressed by the following equation,
PT = CT (Current Time) + α
α is PT adjustment method characterized in that it is determined by the adjustment step.
delete The method according to claim 1,
The adjustment step,
PT adjustment method characterized in that the maximum TT is determined by α.
The method according to claim 1,
TT = RT (Receive Time) -PT-α
TT is PT adjustment method, characterized in that represented by the above formula.
The method according to claim 1,
The audio transmitter and the audio receiver,
PT adjustment method characterized in that the connection to the ring network.
Receiving TTs (Transfer Times) of audio data from audio receivers;
Adjusting the PT (Presentation Time) of the audio receivers using the received TTs;
And transmitting the adjusted PT to the audio transmission device.
The audio transmitter and the audio receiver,
It is connected by a ring network,
The receiving phase,
A PT adjustment method characterized by receiving TTs using a specific field of GET_CONTROL of the IEEE1722.1 protocol.
Receiving TTs (Transfer Times) of audio data from audio receivers;
Adjusting the PT (Presentation Time) of the audio receivers using the received TTs;
And transmitting the adjusted PT to the audio transmission device.
The audio transmitter and the audio receiver,
It is connected by a ring network,
The delivery phase,
A PT adjustment method characterized in that PT is recorded in SET_CONTROL of the IEEE1722.1 protocol and transmitted to an audio transmission device.
An audio transmission device;
Audio receivers; And
Adjust the PT (Presentation Time) that the audio transmission device transmits along with the audio data to the audio reception devices by using TT (Transfer Time) of the audio data received from the audio reception devices, and the adjusted PT to the audio transmission device. The delivery management system; includes,
PT is expressed by the following equation,
PT = CT (Current Time) + α
α is an audio system characterized by being determined by a management system.

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