[0090] The third embodiment
[0091] According to an embodiment of the present invention, the alternative coding information of the currently transmitted audio service component is defined in the ASCTy field. The ASCTy field is transferred to the FIC of the transmission frame and the actual audio service component is transferred to the MSC.
[0092] That is, the value assigned to the ASCTy field can be used to confirm an alternative audio coding method for the audio service component transmitted through the MSC.
[0093] The ASCTy field indicates a value for identifying an audio service component coded using the MUSICAM audio coding method or another coding method.
[0094] Therefore, the broadcast receiver can decode audio service components compressed and transmitted using various encoding methods by parsing the ASCTy field.
[0095] FIG. 5 is a view showing the value of the ASCTy field according to an embodiment of the present invention.
[0096] FIG. 6 is a view showing the value of ASCTy according to another embodiment of the present invention.
[0097] FIG. 7 is a view showing the value of ASCTy according to another embodiment of the present invention.
[0098] According to an embodiment of the present invention, for example, by assigning a value such as 3, 4, or 5 to the ASCTy field instead of 0, 1, or 2, it can indicate that the audio service component is compressed using an alternative audio coding method instead of the MUSICAM method of.
[0099] The value of the ASCTy field is only exemplary and can be set to have other values.
[0100] 5 to 7 show various alternative audio coding methods and ASCTy fields allocated to the alternative audio coding methods.
[0101] Hereinafter, a method for encoding and transmitting audio services according to the present invention will be described with reference to FIGS. 5 to 7. According to the following embodiments of the present invention, the transmission method can be changed according to an alternative audio coding method.
[0102] As a first method, there is a method of transmitting service components compressed using multiple alternative audio coding methods through one sub-channel. Various alternative audio coding methods may include, for example, the AAC method, the SBR method, and the MPEG surround method. Alternatively, other audio coding methods can be used.
[0103] As shown in FIG. 5, for example, when the ASCTy field has a value of 3 (000011), it indicates that the service component foreground sound compressed using the AAC method, the SBR method, and the surround MPEG method is transmitted through one subchannel. The AAC method and the SBR method are collectively referred to as the High Efficiency Advanced Audio Coding (HE-AAC) method.
[0104] As shown in FIG. 5, when the ASCTy field has a value of 4 (000100), it indicates that the service component background sound compressed using the AAC method, the SBR method, and the MPEG surround method is transmitted through one subchannel.
[0105] As shown in FIG. 5, when the ASCTy field has a value of 5 (000101), it indicates that the service component multi-channel audio extension compressed using the AAC method, the SBR method, and the MPEG surround method is transmitted through one subchannel.
[0106] Here, the service component multi-channel audio extension may indicate additional information to have an upgraded audio effect. For example, the service component multi-channel audio extension may include information about implementing additional services (e.g., 5.1 channel audio services).
[0107]As a second scheme, there is a method of transmitting a service component compressed using a single alternative audio coding method through one subchannel. The alternative audio coding method may be the AAC method, the SBR method, or the MPEG surround method. Alternatively, other audio coding methods can be used. The solution indicates: when it is assumed that the audio service components are compressed using the AAC method and the SBR method respectively, the audio service components compressed using the AAC method and the audio service components compressed using the SBR method can be transmitted through the corresponding sub-channels.
[0108] As shown in FIG. 6, for example, when the ASCTy field has a value of 3 (000011), it indicates that the service component foreground sound compressed using the AAC method is transmitted through one sub-channel.
[0109] As shown in FIG. 6, when the ASCTy field has a value of 4 (000100), it indicates that the background sound of the service component compressed using the SBR method is transmitted through one subchannel.
[0110] As shown in FIG. 6, when the ASCTy field has a value of 5 (000101), it indicates that the service component multi-channel audio extension compressed using the surround MPEG method is transmitted through one sub-channel.
[0111] As a third scheme, there is a method of transmitting a part of a service component compressed using multiple alternative audio coding methods through one subchannel and transmitting another part through another subchannel. For example, the service component compressed using the AAC method and the SBR method may be transmitted through one subchannel, and the service component compressed using the surround MPEG method may be transmitted through another subchannel. The scheme indicates: when it is assumed that the audio service components are compressed using the AAC method, the SBR method and the MPEG surround method, the audio service components compressed using the AAC method and the SBR method can be transmitted through one sub-channel, and the audio service components compressed using the AAC method and the SBR method can be transmitted through another sub-channel Audio service components compressed using the surround MPEG method.
[0112] As shown in FIG. 7, for example, when the ASCTy field has a value of 3 (000011), it indicates that the foreground sound of the service component compressed using the AAC method and the SBR method is transmitted through one subchannel. The AAC method and the SBR method together are referred to as the High Efficiency Advanced Audio Coding (HE-AAC) method.
[0113] As shown in FIG. 7, when the ASCTy field has a value of 4 (000100), it indicates that the background sound of the service component compressed using the AAC method and the SBR method is transmitted through one subchannel.
[0114] As shown in FIG. 7, when the ASCTy field has a value of 5 (000101), it indicates that the service component multi-channel audio extension compressed using the surround MPEG method is transmitted through one sub-channel.
[0115] As shown in Figures 5 to 7, when the ASCTy field has a value of 63 (111111), it indicates that at least one service component is transmitted in the MPEG-2 transport stream. Here, the value 63 (111111) is only exemplary and another value may be used.
[0116] The at least one service component may include at least one of an audio service component, an A/V service component, and a data service component.
[0117] That is, the present invention is characterized in that the A/V service component and the data service component can also be defined in the ASCTy field and transmitted through the digital broadcast signal.
[0118] In the fourth embodiment, the process of decoding service components compressed using the above method will be described.