FIG. 13 is a flowchart of an operation of data generation device 110 according to the present embodiment. Data generation device 110 generates HDR video data having reproduction compatibility with the first device that does not support reproduction of HDR video and supports reproduction of SDR video.

First, video signal generator 111 generates a video signal by converting a luminance value of a source image into a code value using the second OETF (S101). Next, encoder 112 generates a video elementary stream by encoding the video signal. At this time, encoder 112 stores, into the VUI in the video data (the video elementary stream), the first transfer function information for identifying the first OETF to be referred to by the first device supporting only the SDR when the first device reproduces the video data. Furthermore, the second transfer function information for identifying the second OETF to be referred to by the second device supporting the HDR when the second device decodes the video data is stored into the SEI in the video data (S102).

The VUI and the SEI belong to the video coding layer. The first OETF is, for example, the OETF defined in BT. 709 or BT. 2020, and the second OETF is, for example, a BBC hybrid gamma OETF.

Furthermore, encoder 112 may store, into the SEI, dynamic range increase information indicating a difference between the luminance dynamic range of the video data and luminance dynamic range SDR. Moreover, encoder 112 may store, into the SEI, maximum average picture level information indicating the highest average luminance value among the average luminance values of all the pictures included in the video sequence.