Transmission device, transmission method, reception device, and reception method for a first stream having encoded image data of pictures on a low-level side and a second stream having encoded image data of pictures on a high-level side

A transmission method comprising:

• performing hierarchical encoding on image data of pictures constituting moving image data to generate a first stream having encoded image data of pictures on a low-level side and a second stream having encoded image data of pictures on a high-level side, the encoded image data having a network abstraction layer (NAL) unit structure;
• inserting a level specified value of the first stream together with a level specified value of a bit stream formed from a combination of the first stream and the second stream into a sequence parameter set (SPS) NAL unit of the first stream, the level specified value of the first stream being discrete from the level specified value of the bit stream formed from the combination of the first stream and the second stream;
• and
• multiplexing the first stream and the second stream generated at the image encoding to obtain a container in a predetermined format;
• inserting a first descriptor describing the level specified value of the first stream into the container at a first position other than in the SPS NAL unit and in correspondence with the first stream;
• inserting a second descriptor describing the level specified value of the bit stream formed from the combination of the first stream and the second stream into the container at a second position other than in the SPS NAL unit and in correspondence with the second stream;
• and
• transmitting the container in the predetermined format obtained at the multiplexing.

A reception device comprising:

• a receiver configured to receive a container in a predetermined format containing:
• a first stream having encoded image data of pictures on a low-level side and a second stream having encoded image data of pictures on a high-level side generated by performing hierarchical encoding on image data of pictures constituting moving image data, and
• a first descriptor describing a level specified value of the first stream positioned at a first position other than in a sequence parameter set (SPS) network abstraction layer (NAL) unit of the first stream and in correspondence with the first stream and a second descriptor describing a level specified value of a bit stream formed from a combination of the first stream and the second stream positioned at a second position other than in the SPS NAL unit and in correspondence with the second stream, wherein
• the encoded image data has a NAL unit structure, and
• the level specified value of the first stream is inserted together with the level specified value of the bit stream formed from the combination of the first stream and the second stream into the SPS NAL unit of the first stream, the level specified value of the first stream being discrete from the level specified value of the bit stream formed from the combination of the first stream and the second stream;
• and
• a processor configured to decode the first stream or both the first stream and the second stream contained in the received container depending on a decoding capability to obtain the image data of the pictures constituting moving image data.

A reception method comprising:

• receiving a container in a predetermined format containing
• a first stream having encoded image data of pictures on a low-level side and a second stream having encoded image data of pictures on a high-level side generated by performing hierarchical encoding on image data of pictures constituting moving image data, and
• a first descriptor describing a level specified value of the first stream positioned at a first position other than in a sequence parameter set (SPS) network abstraction layer (NAL) unit of the first stream and in correspondence with the first stream and a second descriptor describing a level specified value of a bit stream formed from a combination of the first stream and the second stream positioned at a second position other than in the SPS NAL unit and in correspondence with the second stream, wherein
• the encoded image data has a NAL unit structure, and
• the level specified value of the first stream is inserted together with the level specified value of the bit stream formed from the combination of the first stream and the second stream into the SPS NAL unit of the first stream, the level specified value of the first stream being discrete from the level specified value of the bit stream formed from the combination of the first stream and the second stream;
• and
• decoding the first stream or both the first stream and the second stream contained in the received container depending on a decoding capability to obtain the image data of the pictures constituting moving image data.