Reception device, reception method, transmission device, and transmission method

A reception method comprising:

• receiving a video stream having video data and a subtitle stream having subtitle data;
• performing decode processing to the video stream to acquire the video data;
• performing decode processing to the subtitle stream to acquire bitmap data of subtitles;
• performing subtitle processing of correcting at least one of a size of the subtitles and a display position of the subtitles, to the bitmap data of the subtitles;
• and
• superimposing the bitmap data of the subtitles to which the processing has been performed, on the video data,
• wherein the subtitle processing is configured to perform a scale-down correction to the size of the subtitles when a correction factor is less than a first threshold value, and to perform a scale-up correction to the size of the subtitles when the correction factor is greater than a second threshold value, and the correction factor is proportional to a viewing distance, and inversely proportional to a height dimension of a monitor and a value dependent on a resolution of a video.

A transmission device comprising:

• a transmitter configured to transmit a container, the container including a video stream having video data and a subtitle stream having subtitle data;
• and
• processing circuitry configured to insert at least one of a piece of information indicating an allowable range of size correction of subtitles and a piece of information indicating an allowable range of display position correction of the subtitles, into a layer of the subtitle stream, the at least one of the piece of information being included in subtitle processing,
• wherein the subtitle processing is configured to perform a scale-down correction to the size of the subtitles when a correction factor is less than a first threshold value, and to perform a scale-up correction to the size of the subtitles when the correction factor is greater than a second threshold value, the correction factor is proportional to a viewing distance, and inversely proportional to a height dimension of a monitor and a value dependent on a resolution of a video.

A transmission method comprising:

• transmitting a container by a transmitter, the container including a video stream having video data and a subtitle stream having subtitle data;
• and
• inserting at least one of a piece of information indicating an allowable range of size correction of the subtitles and a piece of information indicating an allowable range of display position correction of the subtitles, into a layer of the subtitle stream, the at least one of the piece of information being included in subtitle processing,
• wherein the subtitle processing is configured to perform a scale-down correction to the size of the subtitles when a correction factor is less than a first threshold value, and to perform a scale-up correction to the size of the subtitles when the correction factor is greater than a second threshold value, and the correction factor is proportional to a viewing distance, and inversely proportional to a height dimension of a monitor and a value dependent on a resolution of a video.