Title:
DEVICE AND METHOD FOR TRANSMITTING AND RECEIVING DATA USING HDMI
Kind Code:
A1


Abstract:
A method for transmitting and receiving data of a sink device by using HDMI is disclosed. A method for transmitting and receiving data of a sink device by using HDMI according to the present invention comprises receiving at least one of video data or audio data from a source device through HDMI wherein the audio data include multi-stream audio data; transmitting a CEC message requesting multi-stream audio information to the source device; and receiving a response CEC message including multi-stream audio information from the source device.



Inventors:
Lee, Hyeonjae (Seoul, KR)
Kim, Dokyun (Seoul, KR)
Park, Jangwoong (Seoul, KR)
Yang, Hyunsik (Seoul, KR)
Application Number:
15/125519
Publication Date:
03/16/2017
Filing Date:
03/11/2015
Assignee:
LG ELECTRONICS INC. (Seoul, KR)
Primary Class:
International Classes:
H04N21/4363; H04N21/41; H04N21/434; H04N21/435; H04N21/439; H04N21/472; H04N21/81; H04N21/84
View Patent Images:



Primary Examiner:
SAINT CYR, JEAN D
Attorney, Agent or Firm:
BIRCH STEWART KOLASCH & BIRCH, LLP (8110 Gatehouse Road Suite 100 East FALLS CHURCH VA 22042-1248)
Claims:
1. In a method for transmitting and receiving data of a sink device by using HDMI, a method for transmitting and receiving data of a sink device, comprising: receiving at least one of video data or audio data from a source device through HDMI wherein the audio data include multi-stream audio data; transmitting a CEC message requesting multi-stream audio information to the source device; and receiving a response CEC message including multi-stream audio information from the source device.

2. The method of claim 1, wherein the multi-stream audio information includes at least one of channel information or attribute information of multi-stream audio.

3. The method of claim 2, further comprising providing a UI showing the multi-stream audio information; and in case a user input selecting one audio stream from the multi-stream audio, transmitting a CEC message requesting change of a multi-stream audio channel to the source device.

4. The method of claim 3, wherein a CEC message requesting change of the multi-stream audio channel includes channel information of at least one audio among the multi-stream audio.

5. The method of claim 1, wherein the multi-stream audio includes four audio channels.

6. In a sink device transmitting and receiving data by using HDMI, a sink device comprising: an HDMI receiver; and a controller controlling transmission and reception of data of the HDMI receiver, wherein the sink device receives at least one of video data or audio data through HDMI from a source device, wherein the audio data include multi-stream audio; transmits a CEC message requesting multi-stream audio information to the source device; and receives a response CEC message including multi-stream audio information from the source device.

7. The device of claim 6, wherein the multi-stream audio information includes at least one of channel information or attribute information of multi-stream audio.

8. The device of claim 7, providing a UI showing the multi-stream audio information; and in case a user input selecting one audio stream from the multi-stream audio, transmitting a CEC message requesting change of a multi-stream audio channel to the source device.

9. The device of claim 8, wherein a CEC message requesting change of the multi-stream audio channel includes channel information of at least one audio among the multi-stream audio.

10. The device of claim 6, wherein the multi-stream audio includes four audio channels.

11. In a method for transmitting and receiving data of a source device by using HDMI, a method for transmitting and receiving data of a source device, comprising: transmitting at least one of video data or audio data to a sink device through HDMI, wherein the audio data include multi-stream audio; receiving a CEC message requesting multi-stream audio information from the sink device; and transmitting a response CEC message including multi-stream audio information to the sink device.

12. The method of claim 11, wherein the multi-stream audio information includes at least one of channel information or attribute information of multi-stream audio.

13. The method of claim 12, further comprising receiving a CEC message requesting change of a multi-stream audio channel from the sink device; and controlling transmission of the multi-stream audio according to the received CEC message.

14. The method of claim 13, wherein the CEC message requesting change of a multi-stream audio channel includes channel information of at least one audio among the multi-stream audio.

15. The method of claim 11, wherein the multi-stream audio includes four audio channels.

16. In a source device transmitting and receiving data by using HDMI, a source device comprising: an HDMI transmitter transmitting and receiving data through HDMI; and a controller controlling data transmission and reception of the HDMI transmitter, wherein the source device transmits at least one of video data or audio data through HDMI to a sink device, wherein the audio data include multi-stream audio; receives a CEO message requesting multi-stream audio information from the sink device; and transmits a response CEC message including multi-stream audio information to the source device.

17. The device of claim 16, wherein the multi-stream audio information includes at least one of channel information or attribute information of multi-stream audio.

18. The device of claim 17, receiving a CEC message requesting change of a multi-stream audio channel from the sink device; and controlling transmission of the multi-stream audio according to the received CEC message.

19. The device of claim 18, wherein the CEO message requesting change of a multi-stream audio channel includes channel information of at least one audio among the multi-stream audio.

20. The device of claim 16, wherein the multi-stream audio includes four audio channels.

Description:

TECHNICAL FIELD

The present invention is related to a device and a method for transmitting and receiving data using HDMI (High Definition Multimedia Interface) and more specifically, a device and a method for transmitting and receiving data using HDMI, controlling a multi-stream audio output through a remote controller of an HDMI sink device in case multi-stream audio-enabled content is played.

BACKGROUND ART

HDMI is an interface/standard that develops a Digital Visual Interface (DVI) which is an interface standard of personal computers and displays for a use of AV electronic products. Since the HDMI transmits video/audio from a player to a display device without compressing it, there is very little latency between a source device and a sink device. And the HDMI has high format compatibility since the HDMI does not require separate decoder chip or software. In addition, the HDMI is available to make wirings between AV devices be simplified, which were complicated because video signals, audio signals and control signals are transmitted on only one cable, and the HDMI provides a High-bandwidth Digital Content Protection (HDCP) technique, thereby providing the copyright protection function.

INVENTION CONTENT

Technical Problem

HDMI can support multi-stream audio transmission when a source device transmits video/audio data. However, a CEC message/operation for a sink device to control selecting/changing the aforementioned multi-stream audio data by using a remote controller has not been proposed yet. Therefore, although multi-stream audio data can be transmitted from a source device to a sink device through HDMI, there is still an inconvenience/disadvantage that a remote controller of the sink device is incapable of controlling the multi-stream audio data.

Technical Solution

To solve the technical problem above, a method for transmitting and receiving data of a sink device by using HDMI according to the present invention comprises receiving at least one of video data or audio data from a source device through HDMI wherein the audio data include multi-stream audio data; transmitting a CEC message requesting multi-stream audio information to the source device; and receiving a response CEC message including multi-stream audio information from the source device.

Also, in a method for transmitting and receiving data of a sink device by using HDMI according to the present invention, the multi-stream audio information can include at least one of channel information or attribute information of multi-stream audio.

Also, a method for transmitting and receiving data of a sink device by using HDMI according to the present invention can further comprise providing a UI showing the multi-stream audio information; and in case a user input selecting one audio stream from the multi-stream audio, transmitting a CEC message requesting change of a multi-stream audio channel to the source device.

Also, in a method for transmitting and receiving data of a sink device by using HDMI according to the present invention, a CEC message requesting change of the multi-stream audio channel can include channel information of at least one audio among the multi-stream audio, and the multi-stream audio can include four audio channels.

A sink device transmitting and receiving data by using HDMI according to the present invention comprises an HDMI receiver; and a controller controlling transmission and reception of data of the HDMI receiver, wherein the sink device receives at least one of video data or audio data through HDMI from a source device, wherein the audio data include multi-stream audio; transmits a CEC message requesting multi-stream audio information to the source device; and receives a response CEC message including multi-stream audio information from the source device.

To solve the technical problem above, a method for transmitting and receiving data of a source device by using HDMI according to the present invention comprises transmitting at least one of video data or audio data to a sink device through HDMI, wherein the audio data include multi-stream audio; receiving a CEC message requesting multi-stream audio information from the sink device; and transmitting a response CEC message including multi-stream audio information to the sink device.

Also, in a method for transmitting and receiving data of a source device by using HDMI according to the present invention, the multi-stream audio information can include at least one of channel information or attribute information of multi-stream audio.

Also, a method for transmitting and receiving data of a source device by using HDMI according to the present invention can further comprise receiving a CEC message requesting change of a multi-stream audio channel from the sink device; and controlling transmission of the multi-stream audio according to the received CEC message.

Also, in a method for transmitting and receiving data of a source device by using HDMI according to the present invention, the CEC message requesting change of a multi-stream audio channel can include channel information of at least one audio among the multi-stream audio, and the multi-stream audio can include four audio channels.

In a source device transmitting and receiving data by using HDMI according to the present invention, a source device transmitting and receiving data by using HDMI comprises an HDMI transmitter transmitting and receiving data through HDMI; and a controller controlling data transmission and reception of the HDMI transmitter, wherein the source device transmits at least one of video data or audio data through HDMI to a sink device, wherein the audio data include multi-stream audio; receives a CEO message requesting multi-stream audio information from the sink device; and transmits a response CEC message including multi-stream audio information to the source device.

Advantageous Effect

According to the present invention, the user can control multi-stream audio transmitted from a source device by using a remote controller that transmits commands to a sink device.

Also, according to the present invention, by newly defining CEO messages for controlling multi-audio streams, the user can control multi-audio stream outputs of a source device by entering commands to a sink device through a remote controller.

Also, according to the present invention, by requesting/receiving multi-audio stream information in the form of a CEO message, a sink device may show information about multi-stream audio that can be provided or that is currently provided through a UI.

Also, if an output audio is determined among multi-stream audio, a source device may stop other audio stream outputs, thereby improving efficiency of utilizing HDMI bandwidth.

DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an HDMI system according to one embodiment of the present invention and data transmission and reception channels included in the HDMI system.

FIG. 2 illustrates devices of an HDMI system according to one embodiment of the present invention and physical addresses assigned to the devices.

FIG. 3 illustrates devices of another HDMI system according to one embodiment of the present invention and logical addresses assigned to the devices.

FIG. 4 illustrates a header/data block as an HDMI CEC data format according to an embodiment of the present invention.

FIG. 5 illustrates an HDMI CEC sequence according to an embodiment of the present invention.

FIGS. 6 to 11 illustrate embodiments of various scenarios for controlling a source device by using the HDMI CEC protocol.

FIG. 12 illustrates HDMI CEC communication devices according to one embodiment of the present invention.

FIG. 13 is a flow diagram illustrating a method for controlling multi-stream audio by using the HDMI CEC protocol according to one embodiment of the present invention.

FIG. 14 illustrates a TV UI according to an embodiment of the present invention.

FIG. 15 illustrates a CEC message format according to an embodiment of the present invention.

BEST MODE FOR INVENTION

In what follows, preferred embodiments of the present invention will be described in detail with reference to appended drawings. Detailed descriptions given below with reference to appended drawings are not limited only to those embodiments that can be realized according to the embodiments of the present invention, but they are intended to describe preferred embodiments of the present invention. The following descriptions include specific details to provide thorough understanding of the present invention. However, it should be clearly understood by those skilled in the art that the present invention can be implemented without employing the specific details.

Most terms used in this document are used widely in the corresponding technical field, but part of the terms have been chosen arbitrarily by the applicant, of which the meaning will be described in detail in the following description depending on the needs. Therefore, the present invention should be understood by the intended meaning of used terms rather than their apparent names or immediate implication.

FIG. 1 illustrates an HDMI system and data transmission and reception channels included in the HDMI system according to one embodiment of the present invention.

Devices that transmit and receive video/audio/control data using HDMI can be called collectively an HDMI system, and the HDMI system can comprise a source device 1010, a sink device 1020, and a cable. In the HDMI system, a device that transmits video/audio data through HDMI corresponds to the source device 1010, a device that receives video/audio data through HDMI corresponds to the sink device 1020, and an HDMI cable supporting data transmission and reception connects the two devices.

Though illustrated briefly in FIG. 1, a source device 1010 can include an HDMI transmitter transmitting and receiving data through HDMI; and a controller controlling the HDMI transmitter and data communication through HDMI of the source device. Also, the sink device 1020 can include an HDMI receiver transmitting and receiving data through HDMI; and a controller controlling the HDMI receiver and data communication through HDMI of the sink device.

As shown in FIG. 1, the HDMI cables and the connectors may perform pairing of four channels that provides a Transition Minimized Differential Signaling (TMDS) data channel and a TMDS clock channel. The TMDS data channels may be used for forwarding video data, audio data and auxiliary data. These channels can be used to deliver video data, audio data, and auxiliary data.

Additionally, the HDMI system provides a VESA (Video Electronics Standards Association) DDC (Display Data Channel). The DDC is used for configuration of one source device and one sink device and exchange of status information between them. A CEC protocol can provide a high-level control function among various audio-visual products in a user environment and may be used optionally. Also, an optional HEAC (HDMI Ethernet and Audio Return Channel) may provide Ethernet-compatible data networking among an ARC (Audio Return Channel) and connected devices in the opposite direction from a TMDS.

Video data, audio data and supplementary data may be transmitted and received through three TDMS data channels. Commonly, a TMDS clock runs a video pixel rate, and is transmitted through a TMDS clock channel. The TMDS clock may be used as a reference frequency for data recovery in three TMDS data channels in an HDMI receiver. In a source device, the data of 8 bits per TMDS data channel may be transformed into a sequence of 10 bits of which transition is minimized, which is DC balanced, and transmitted in serial manner with a rate of 10 bits per TMDS clock period.

In order to transmit audio data and supplementary data through the TMDS channel, the HDMI uses a packet structure. In order to attain high reliability for audio data and control data, data may be transmitted in word of 10 bits which is generated by using a BCH error correction code and an error reduction coding.

The source device can figure out configuration information and available functions of the sink device by reading out E-EDID (Enhanced Extended Display Identification Data) of the sink device in the DDC (Display Data Channel).

A utility line can be used for an optional extension function such as HEAC.

CEC (Consumer Electronics Control) specifies interoperability between devices within the HDMI system and can include various features that reinforce functionality of the devices. By using the HDMI-CEC protocol, the user can control a source device connected to a sink device through HDMI as well as the sink device itself by using a control device of the sink device (for example, remote controller). In what follows, the HDMI-CEC protocol will be described in more detail.

Table 1 and 2 below illustrate the structure/features that the HDMI-CEC protocol provides.

Table 1 illustrates an end-user structure/features that the HDMI-CEC protocol provides.

TABLE 1
One Touch PlayVideo play is started by one click of a
button, and device is switched to an active
source state.
System StandbyAll of the connected devices are switched
to a waiting mode.
One Touch RecordControl the function of recording a program
played in TV
Timer ProgrammingSet up the timer of a different device from
one device
Deck ControlControl a play device from a different device
Tuner ControlControl the tuner of a different device
Device Menu ControlMake menus of a device controlled by using
a TV remote controller
Remote Control Transmit the command received from the
Pass Throughremote controller to a different device
System Audio ControlTransmit a command that controls audio play

Table 2 illustrates a structure/features that the HDMI-CEC protocol supports.

TABLE 2
Device OSD Name Transmit a configured device name to a TV set
Transfer
Device Power StatusCheck the current power status of a device
OSD DisplayTransmit text from a device to display the
text on the screen of a TV set
Routing ControlControl routing of an HDMI network when a
CEC switch is used
System InformationSet by a device to use the same OSD and menu
language as the TV.
Vendor Specific Commands defined by a vendor
Commands
Audio Rate ControlMove an audio source slightly forward or
backward
Audio Return Channel Used to control Audio Return Channel (ARC)
Control
Capability Discovery Used to control HDMI Ethernet Channel
and Control(HEC)

Devices of the HDMI system have physical addresses to perform addressing specific physical devices and to control switching by using the HDMI-CEC protocol. A physical address is determined by a physical address recovery operation, and the sink device can generate and utilize a unique physical address comprising 4 numbers, each of which consisting of 4 bits (n.n.n.n). In addition, CEC-enabled devices can have logical addresses according to their respective features.

In what follows, related to the HDMI CEC protocol, terms such as initiator and follower can be used in addition to the terms of source device and sink device. An initiator is a device that has transmitted or transmits a CEC message and depending on situations, indicates a device waiting for a response from a follower while the follower is a device that has received a CEO message and indicates a device that has to respond to the received message.

FIG. 2 illustrates devices of an HDMI system according to one embodiment of the present invention and physical addresses assigned to the devices.

A physical address may refer to the address system for indicating positions of devices used on the CEC bus. As described in detail above, a physical address can comprise four number, each of which consists of 4 bits (n.n.n.n), and a source device can check the physical address through EDID (Extended Display Identification Data) of a sink device.

As shown in FIG. 2, a device operating as a CEC root device such as the sink device or repeater can have a physical address as 0.0.0.0. A sink device can generate physical addresses for individual source devices by assigning port numbers to the unique physical addresses of connected source devices and set the generated address values to the EDID of the corresponding ports. In other words, if a new device is connected, the sink device can assign an address to the source device through CEA (Consumer Electronics Association) extension of the E-EDID (Enhanced EDID).

FIG. 3 illustrates devices of another HDMI system according to one embodiment of the present invention and logical addresses assigned to the devices.

As described with reference to FIG. 2, in case a new physical address is found as a device is connected to the HDMI system, and the connected device supports the CEC, the sink device can assign a logical address to the connected device. The assigned logical address can be used as a source address and a destination address when a CEC message is transmitted.

Table 3 illustrates an embodiment of a logical address assigned according to the features of a device.

TABLE 3
Logical
addressDevice
0TV
1Recording device 1 (Recording Device 1)
2Recording device 2 (Recording Device 1)
3Tuner 1
4Playback device 1 (Playback Device 1)
5Audio system
6Tuner 2
7Tuner 3
8Playback device 2
9Recording device 3
10Tuner 4
11Playback device 3
12Back-up 1 (For device types of “playback devices o
“recording device of “tunerding de “processor devn case
all of the specified logical addresses are assigned)
13Back-up 2 (For device types of “playback device”,
“recording device”, “tuner”, and “processor”, in case
all of the specified logical addresses are assigned)
14Specific Use
15Unregistered (Initiator Address)
Broadcast (Destination Address)

In case one CEC line is used as shown in FIG. 3(a) and a primary CEC line and a secondary CEC line are used as shown in FIG. 3(b), a physical address 0.0.0.0 is assigned to the main TV and a logical address 0 is assigned thereto. And for other connected devices, logical addresses can be assigned according to the types of the connected devices as shown in FIG. 3. The sink device can inform other devices about the assigned logical addresses through broadcasting.

FIG. 4 illustrates a header/data block as an HDMI CEC data format according to an embodiment of the present invention.

The HDMI CEC performs control operations by transmitting and receiving a CEC message through a CEC line. The data by which the CEC messages are transmitted can be transmitted and received in the form of a frame format.

A CEC frame can include a start bit, header block, and at least one optional data block. As an embodiment, size of one block can be 10 bit, and size of the maximum message can be 16*10 bit (excluding the start bit). Table 4 provides a brief description of the blocks included in the CEC frame.

TABLE 4
NameDescription
StartSpecial start ‘biti
Header BlockSource and Destination addresses;
Logical Address
Data Block 1(opcode block)Opcode (optional)
Data Block 2(operand blocks)Operand(s) specific to opcode
(optional, depending on opcode)

All of the header blocks and data blocks have 10 bit-length and can have a basic structure which is the same as shown in FIG. 4. As shown in FIG. 4, the information bits field can be data, opcode, or address. Control bits such as EOM and ACK can always be defined within a block and used in the same way. In the case of the header block, the information bits can include a logical address ( 4 bits) of an initiator and a logical address ( 4 bits) of a target device. The data block follows subsequent to the header block, and data such as operands can be transmitted after the opcode is transmitted.

The EOM (End of Message) bit indicates whether the corresponding block is the last one or a succeeding data block exists. As an example, in case there is a succeeding data block, the EOM bit can be set to 0 while a message is completed in the corresponding data block, the EOM can be set to 1.

The ACK (Acknowledge) bit can be used for a follower to check reception of data or a header block. As an example, reception of data or a header block can be checked by the initiator's sending the ACK bit by setting it to 1 and the follower's setting it to 0.

An opcode (operation code) is part of machine commands and describes an operation that has to be performed. In other words, an opcode is used as a name to identify a CEC message and can have a unique identifier/value. In addition to opcodes, commands can have the corresponding data values in the form of operands.

FIG. 5 illustrates an HDMI CEC sequence according to an embodiment of the present invention.

First, the source device and the sink device can check HDMI cable connection S5010. As shown in FIG. 5, if it is checked that 5V is applied to pin 18 of the source device, and 5V is applied to pin 19 (HPD) of the sink device, it can be determined that an HDMI cable has been connected between the source device and the sink device.

And the source device and the sink device can transmit/receive information of connected devices S5020. As shown in FIG. 5, by transmitting an EDID (Enhanced Display Identification Data) request to the sink device through a DDC (Display Data Channel) and receiving EDID information and EDID extension information from the sink device, the source device can read the EDID of the sink device.

Next, the source device and the sink device can exchange keys required for encrypting data transmission for the purpose of security S5030. This step is optional, and the source device and the sink device can exchange HDCP keys through the DDC.

And data transmission status can be controlled through the sequence based on the HDMI CEC protocol according to the command that the user has entered S5040. FIG. 5 is an embodiment in which deck control is performed by using the HDMI CEC protocol.

First, requesting and receiving deck status information, the sink device can check the deck status of the source device. And if the user inputs ‘play’ through an input device such as a remote controller, a play command (argument: “Forward”) can be transmitted to the source device. The source device can recognize the received CEC command and transmit video data and audio data to the sink device. Now, if the user additionally inputs ‘Next Chapter’, the sink device can transmit a deck control command (argument: “Skip Forward”) to the source device, and the source device can recognize this CEC command and transmit video data and audio data of the next chapter to the sink device.

FIGS. 6 to 11 illustrate embodiments of various scenarios for controlling a source device by using the HDMI CEC protocol.

In FIG. 6, FIG. 6(a) illustrates a scenario in which deck control is performed through the sink device, and FIG. 6(b) illustrates a scenario in which a new service is selected through the sink device.

In FIG. 7, FIG. 7(a) illustrates a scenario in which TV initiate system audio control, and FIG. 7(b) illustrates a scenario in which an amplifier initiates system audio control.

In FIG. 8, FIG. 8(a) illustrates a scenario in which a vendor-specific scenario is transmitted to the source device, and FIG. 8(b) illustrates a scenario in which the timer of the source device is programmed.

In FIG. 9, FIG. 9(a) illustrates a message exchange scenario for obtaining a TV menu language, and FIG. 9(b) illustrates a scenario in which the user changes a menu language setting.

In FIG. 10, FIG. 10(a) illustrates a scenario in which one-touch display is performed, and FIG. 10(b) illustrates a broadcast system standby scenario.

In FIG. 11, FIG. 11(a) illustrates a routing control scenario, and FIG. 11(b) illustrates a one-touch record scenario.

FIG. 12 illustrates HDMI CEC communication devices according to one embodiment of the present invention.

As described above, in view of CEO communication, the HDMI system can be described as comprising an initiator 12020 that transmits a CEC message and a follower 12010 that receives a CEC message and responds to the received CEC message. In other words, an initiator 12020 can refer to a device which initiates a CEC command and delivers the CEO command to a follower, thereby controlling the follower while a follower 12010 can refer to a device that responds to the CEC command, performs a request, and informs the initiator of the performance result. Both devices comprise the same sub-modules by default, and thus descriptions about the same modules will not be repeated. A module refers to a logical or physical unit within a device performing a specific operation; one module may correspond to one or more components, or one or more modules may correspond to one component.

The bus interface module 12030 represents a physical device that enables transmission of a command between devices; a message such as request, action, or response; or data.

The micom module 12040 represents a physical device that generates a signal for data transmission; or manages priorities, retransmission for reliable transmission, and the like. The mode protocol 12050 refers to the protocol used for efficient resource management required for high speed/low speed data transmission. The high mode module 12060 represents a logical device responsible for processing high speed data transmission in a bus interface architecture. The low mode module 12070 represents a logical device responsible for processing low speed data transmission in the bus interface architecture.

The buffer module 12080 represents a physical device temporarily storing transmitted messages or data to improve reliability thereof.

The bus protocol layer module 12090 is a logical device processing data transmitted through a bus-based transmission method and delivering necessary information to an upper layer and can include a module determination component module 12100.

The upper layer module 12110 represents a logical/physical device actually processing commands.

In what follows, described will be a method for transmitting and receiving multi-stream audio and controlling the multi-stream audio in the HDMI system in which a source device and a sink device transmitting audio/video data by using HDMI are connected to each other.

Multi-Stream Audio (MSA) refers to a collection of audio streams related to at least one video stream. MSA is a data communication method defined for the HDMI system to support multi-view video streaming or multi-video streams. In particular, the HDMI 2.0 system is capable of transmitting up to four stereo audio streams simultaneously.

In an embodiment, content played in a source device such as an STB (Set-Top Box) can support multi-stream audio: for example, 1) English, 2) Korean, 3) English commentary, and 4) Korean commentary. In this case, although multi-stream audio is being received, a sink device or a remote controller in the current HDMI system that controls the sink device is unable to select/change the multi-stream audio. Therefore, the present invention proposes a method for selecting/changing multi-stream audio by using a remote controller of the sink device by newly defining/adding CEC commands in case multi-stream audio-enabled content is played.

FIG. 13 is a flow diagram illustrating a method for controlling multi-stream audio by using the HDMI CEC protocol according to one embodiment of the present invention.

In the embodiment of FIG. 13, it is assumed that TV is the sink device, and a set-top box (STB) is the source device. According to the HDMI CEC protocol, TV can be an initiator while the set-top box can be a follower. As shown in FIG. 13, information request/response/command between the initiator and the follower is transmitted and received in the form of a CEC message through the CEO channel. FIG. 13 mainly illustrates communication between the sink device and the source device, and corresponding CEO messages will be described in more detail later.

TV can request information about multi-stream audio (MSA) of content to be played or being played in the set-top box S13010 <Request MSA info>. TV may perform this step automatically when content is played or when the user enters a multi-audio related function by using a TV remote controller.

The STB can transmit multi-stream audio information in response to the request for multi-stream audio information received from the TV S13020. In other words, TV can receive a multi-stream audio information response from the STB S13020. Multi-stream audio information is related to multi-stream audio of the content played in the STB and can include the number and attributes (or descriptions) of supported multi-stream audio, such as 1) Korean, 2) English, 3) Korean commentary, and 4) English commentary.

TV can provide information about received multi-stream audio; and output at least one of the received audio streams or provide a UI (User Interface) by which output audio can be changed S13030. TV can parse information about multi-stream audio received from the STB, inform the user about the parsed information by displaying the information or outputting the information as a sound output, and receive an input selecting at least one audio from among the multi-stream audio S13040. These steps (S13030 and S13040 ) may be performed optionally.

Receiving an audio selection/change input from a remote controller, TV can transmit a multi-stream audio change command to the set-top box S13050. The multi-stream audio change command, as a CEC command, can include a multi-stream audio ID (MSA chID). An audio ID may be identified as a channel number or channel ID of the corresponding audio.

According to the received multi-stream audio change command, the set-top box can change an audio output into the audio having an ID included in the received command S13060. At this time, the set-top box may stop other multi-stream audio outputs other than the audio having an ID included in the received CEC message. For example, if a CEC message commanding to output only one audio stream, the ID of which is 1, is received as shown in FIG. 13 while four audio streams, the audio channel IDs of which are 1, 2, 3, and 4 respectively are transmitted together or about to be transmitted, only the audio stream with an ID of 1 may be transmitted while transmitted of the remaining audio streams of which the IDs range from 2 to 4 may be stopped. In this case, bandwidth required for outputting other multi-stream audio may be redirected to be used for outputting video, thereby improving utilization efficiency of HDMI bandwidth.

FIG. 14 illustrates a TV UI according to an embodiment of the present invention. As described in FIG. 13, if TV receives multi-audio stream information from the set-top box, TV can provide multi-audio stream information and a UI by which the user can select audio.

As shown in FIG. 13, TV can provide such a UI in the lower part of the screen. The UI shown in FIG. 13 can display attributes of the multi-stream audio respectively as “1. English, 2. Korean, 3. English commentary, and 4. Korean commentary”. And the user can select one of the four audio streams as output audio by using a left-right movement button or a selection button or by entering a number key by using an input device such as a remote controller. TV can receive an audio selection/change input of the user according to the displayed UI.

Although the embodiment of FIG. 14 adopts a GUI (Graphical User Interface) as a UI for providing/selecting multi-stream audio information, the UI for providing/selecting information may be implemented by a voice UI.

FIG. 15 illustrates a CEC message format according to an embodiment of the present invention.

FIG. 15 illustrates an embodiment in which CEC messages of FIG. 13 are defined; the CEC messages defined in the present invention are defined only to describe the corresponding operations and are not necessarily defined according to the same syntax.

As described above, an operator represents a CEC command, opcode represents a name by which a CEC message is identified, and operand represents data values corresponding to a CEO command/message. In particular, an operand can correspond to the data specific to a particular opcode.

First, opcodes of the operator of FIG. 15(a) defined according to the present invention will be described.

<Request MSA Info>: opcode representing a CEC message/command requesting multi-stream audio information of current content <Report MSA Info>: opcode representing a CEC message/command reporting multi-stream audio information of current content. This opcode can be transmitted together with the operand [MSA Info].

<Change MSA ch>: opcode representing a CEO message/command changing a multi-stream audio channel. This opcode can be transmitted together with the operand [MSA ch].

Next, operands of FIG. 15(b) defined according to the present invention will be described.

[MSA Info]: operand representing multi-stream audio information. This operand can be transmitted together with the opcode <Report MSA Info> and as a multi-stream audio parameter, can represent such information as language, commentary, or audio channel.

[MSA ch]: operand representing an audio channel selected for multi-stream audio. This operand can be transmitted together with the opcode <Change MSA ch> and can represent at least one of the provided multi-stream audio as a channel. A channel number/ID can correspond to at least one of the entire channel numbers provided by the [MSA Info] operand.

In the embodiment of FIG. 15, the operand [MSA Info] has been defined by assuming a multi-stream audio environment comprising a maximum of four audio streams. This is so because the current HDMI system limits the size of a CEC operand up to 14 bytes in order to prevent channel monopoly. Therefore, in case the present invention is performed on multi-stream audio (MSA) comprising four or more audio streams under the aforementioned limitation, the opcode <Request MSA Info> can be performed many times to obtain the operand [MSA Info]. According to embodiments, the ISO639.2 code serial number may be applied to the operand [Ch name] to save data bits. In this case, the length of the operand [Ch name] can be reduced from 3 bytes to 1 byte.

FIGS. 13 to 15 illustrate embodiments of multi-audio streams. However, in addition to audio, the embodiments as shown in FIGS. 13 to 15 can be applied to multi-subtitles in which multiple subtitles are provided.

For example, TV can request multi-subtitle information from a set-top box, and in response to the request, TV can receive multi-subtitle information from the set-top box. Multi-subtitle information can include a plurality of subtitles that are transmitted/supported by current content and attribute information of the plurality of subtitles. TV can provide multi-subtitle information in the form of a UI and if receiving an input selecting/changing a particular subtitle from a remote controller, transmit a subtitle change command to the set-top box.

In this embodiment, opcode/operands of FIG. 15 can be modified to be suited for multi-subtitles, respectively. Individual opcodes/operands can still be used by replacing audio information of FIG. 15 such as <Request MST Info>, <Report MST Info>, <Change MST ch>, [MST Info], and [MST ch] with subtitle information.

It will be understood by those skilled in the art to which the present invention belongs that the present invention can be modified or changed in various ways without departing from the technical principles or scope of the present invention. Therefore, it is intended that the present invention includes modifications and changes of the present invention provided within the technical scope defined by appended claims and their equivalents.

In this document, the device and the method according to the present invention have been described fully, and descriptions for the device and method can be applied to each other in a complementary manner.

MODE FOR INVENTION

Various embodiments are described in Best mode for invention.

INDUSTRIAL APPLICABILITY

The present invention is used in a series of HDMI fields.

It is apparent to an ordinary skilled person in the art that various modifications and changes may be made without departing from the spirit and scope of the present invention. Accordingly, the present invention is intended to include the modifications and changes of the present invention within the attached claims and the equivalent scope.