To provide a method and device for processing digital signals, which allows a receiver to generate an identification signal FR for a 2-frame period in order to identify a front frame and a rear frame which are missing when a signal with the SDL format of an NTSC signal is transmitted through an IEEE 1394 bus.

The device detects positions of tracks of a main area of video auxiliary data and audio auxiliary data in the data sent through the IEEE 1394 bus to generate a 1st identification signal FR1. Further, the device generates a 2nd identification signal FR2 for the front frame and the rear frame with the SDL format from a DFF(DIF Frame Flag) in the data sent through the IEEE 1394 bus. When the device cannot obtain the priority identification signal by placing priority on the 1st identification signal FR1 or the 2nd identification signal FR2, the device uses the other identification signal as an identification result.