In the present day, the SHVC encoding technology (scalable expansion of HEVC) is known that enables expansion to super-resolution videos such as 4K resolution videos at a low bitrate using HDTV video transmission. Herein, HDTV stands for High-definition television, SHVC stands for Scalable High-efficiency Video Coding, and HEVC stands for High-efficiency Video Coding.
In the SHVC encoding technology, in addition to performing inter-screen prediction and in-screen prediction used in HEVC, inter-layer prediction meant for predicting 4K images from among HDTV images is also performed; and the subjective image quality is improved by holding down the volume of data assigned to such image areas which have movement-induced distortion and by assigning a greater volume of data to such in-focus image areas which have less movement. Moreover, temporal-spatial image processing is performed so that the difficult-to-compress noise components are removed in advance from the 4K images. That enables achieving control on the decline in the feel of resolution at a low bit rate. For that reason, even in the case in which the additional bit rate is set to 10 Mbps, it becomes possible to maintain the feel of resolution of the 4K images. In order to distribute videos of 4K resolution, it is necessary to have the bit rate of, for example, about 30 Mbps. However, as a result of implementing the HEVC encoding technology, the additional transmission bandwidth that is required can be reduced to about 10 Mbps that is one-third of 30 Mbps.
In a narrow-bandwidth video transmission system in which SHVC is used, reference images are shared in advance between the transmission side and the reception side. The transmission side transmits encoding data representing only the difference with the reference images. The reception side decodes the received encoding data using the reference images shared in advance. Since the encoding data represents only the difference with the reference images, it becomes possible to reduce the volume of data and to perform video streaming having excellent bandwidth usage efficiency.