A digital receiver that is configured to process three-dimensional, 3D, video data comprising: a receiving unit (102, 122) configured to receive a first broadcast signal comprising first 3D service data and first signaling data for the first 3D service data through a first channel and to receive a second broadcast signal comprising second 3D service data related to the first 3D service data and second signaling data for the second 3D data service through a second channel, wherein the second 3D service data is 3D video data comprising right-eye image data and left-eye image data; a demultiplexer (106, 126) configured to demultiplex the first 3D service data, the second 3D service data and the signaling data from the first broadcast signal and the second broadcast signal; a controller configured to acquire information regarding a channel to receive the second broadcast signal based on the demultiplexed first signaling data; a decoder (110, 130) configured to decode the second 3D service data; a formatter configured to format the decoded second 3D service data; and a display unit configured to output the formatted second 3D service data to a display screen, wherein the first signaling data includes a first descriptor having a linked service type and the linked service type indicates that a type of the second 3D service data is a 3D picture-in-picture, PIP, service, wherein the first descriptor has connection information that identifies the second 3D service data linked with the first 3D service data, wherein the first signaling data further includes a second descriptor having display information for the 3D PIP service, wherein the display information comprises PIP position information indicating a distance from a depth plane at which a 3D PIP is to be located at the display screen, boundary position information indicating a distance from a depth plane at which a boundary of the 3D PIP is to be located at the display screen, boundary thickness information indicating a thickness of the boundary of the 3D PIP, and boundary style information indicating a style of the boundary of the 3D PIP, wherein the controller is further configured to parse the first signaling data to use the first signaling data to output the 3D PIP service, and wherein the second 3D service data is received through a different channel from the first 3D service data. a receiving unit (102, 122) configured to receive a first broadcast signal comprising first 3D service data and first signaling data for the first 3D service data through a first channel and to receive a second broadcast signal comprising second 3D service data related to the first 3D service data and second signaling data for the second 3D data service through a second channel, wherein the second 3D service data is 3D video data comprising right-eye image data and left-eye image data; a demultiplexer (106, 126) configured to demultiplex the first 3D service data, the second 3D service data and the signaling data from the first broadcast signal and the second broadcast signal; a controller configured to acquire information regarding a channel to receive the second broadcast signal based on the demultiplexed first signaling data; a decoder (110, 130) configured to decode the second 3D service data; a formatter configured to format the decoded second 3D service data; and a display unit configured to output the formatted second 3D service data to a display screen, wherein the first signaling data includes a first descriptor having a linked service type and the linked service type indicates that a type of the second 3D service data is a 3D picture-in-picture, PIP, service, wherein the first descriptor has connection information that identifies the second 3D service data linked with the first 3D service data, wherein the first signaling data further includes a second descriptor having display information for the 3D PIP service, wherein the display information comprises PIP position information indicating a distance from a depth plane at which a 3D PIP is to be located at the display screen, boundary position information indicating a distance from a depth plane at which a boundary of the 3D PIP is to be located at the display screen, boundary thickness information indicating a thickness of the boundary of the 3D PIP, and boundary style information indicating a style of the boundary of the 3D PIP, wherein the controller is further configured to parse the first signaling data to use the first signaling data to output the 3D PIP service, and wherein the second 3D service data is received through a different channel from the first 3D service data.