Transmission apparatus, transmission method, reception apparatus, and reception method

A transmission method of a transmission apparatus, the transmission method comprising:

• generating a watermark inclusion flag indicating whether a watermark is included in an audio stream of a broadcast signal;
• and
• transmitting the broadcast signal including the watermark inclusion flag, wherein
• the watermark inclusion flag is included in a layer of the audio stream,
• the audio stream includes the watermark when the watermark inclusion flag indicates that the watermark is included in the audio stream, and
• the audio stream does not include the watermark when the watermark inclusion flag indicates that the watermark is not included in the audio stream.

A reception apparatus comprising:

• circuitry configured to:
• receive a broadcast signal including a watermark inclusion flag indicating whether a watermark is included in an audio stream of the broadcast signal, the watermark inclusion flag being included in a layer of the audio stream;
• and
• process the watermark when the watermark inclusion flag indicates that the watermark is included in the audio stream.