A transport stream processing apparatus (100, 500, 900), comprising: a demodulation module (102, 1302), configured for demodulating an input signal to generate a first transport stream; a transport stream storage module (110, 910), configured for storing a second transport stream; a multiplexer, having an output port, a first input port configured for receiving the first transport stream, and a second input port configured for receiving the second transport stream, wherein the multiplexer selectively couples the first input port or the second input port to the output port; and a conditional access system interface, coupled to the output port of the multiplexer and configured for coupling a conditional access module, wherein the conditional access system interface transmits a transport stream outputted from the output port of the multiplexer to the conditional access module for signal processing when the conditional access module is coupled to the conditional access system interface; characterized in that: in a first case where the conditional access module complying with a first conditional access specification is coupled to the conditional access system interface, the multiplexer is controlled to couple the first input port to the output port, and the first transport stream is transmitted from the demodulation module (102, 1302) to the conditional access module via the multiplexer and the conditional access system interface for descrambling; and in a second case where the conditional access module complying with a second conditional access specification different from the first conditional access specification is coupled to the conditional access system interface, the multiplexer is controlled to couple the second input port to the output port, and the second transport stream is transmitted from the transport stream storage module (110, 910) to the conditional access module via the multiplexer and the conditional access system interface for descrambling. a demodulation module (102, 1302), configured for demodulating an input signal to generate a first transport stream; a transport stream storage module (110, 910), configured for storing a second transport stream; a multiplexer, having an output port, a first input port configured for receiving the first transport stream, and a second input port configured for receiving the second transport stream, wherein the multiplexer selectively couples the first input port or the second input port to the output port; and a conditional access system interface, coupled to the output port of the multiplexer and configured for coupling a conditional access module, wherein the conditional access system interface transmits a transport stream outputted from the output port of the multiplexer to the conditional access module for signal processing when the conditional access module is coupled to the conditional access system interface; in a first case where the conditional access module complying with a first conditional access specification is coupled to the conditional access system interface, the multiplexer is controlled to couple the first input port to the output port, and the first transport stream is transmitted from the demodulation module (102, 1302) to the conditional access module via the multiplexer and the conditional access system interface for descrambling; and in a second case where the conditional access module complying with a second conditional access specification different from the first conditional access specification is coupled to the conditional access system interface, the multiplexer is controlled to couple the second input port to the output port, and the second transport stream is transmitted from the transport stream storage module (110, 910) to the conditional access module via the multiplexer and the conditional access system interface for descrambling.