Access point pictures designated as randomly accessible positions are I pictures or P pictures. Information indicating the decoding sequence (I1, P1, B1, B2, B3, B4, P2, . . . ) of pictures functioning as access points and attribute information (picture_type) indicating whether a picture functions as an access point or is necessary for decoding of the access point following a given access point are recorded on the video information recording medium. Random access is possible even if the GOP interval is lengthened.

A media file system, apparatus, computer program product and method for storing a media file in a media file system. An exemplary method includes obtaining a predetermined number of frames and determining a set of portions for storing the media file, each portion having an identifier that is indicative of a multiple of the predetermined number of frames. Further, for each portion of the set of portions, associating with the portion the segment of the media file containing the frame indicated by the identifier of the portion, and associating each of the remaining segments of the media file with a portion of the set of portions. Moreover, storing the media file in the media file system as the set of determined portions, each portion comprising its associated segments of the media file.

A playback method of reading out and playing streams from a recording medium is provided, in which are recorded a stream file including a first luminance video expressed by luminance of a first dynamic range, and a second luminance video expressed by luminance of a second dynamic range that is broader than the first dynamic range, and a playlist file for controlling playback of the stream file. The playback method includes, in a case of playing the first luminance video, reading out the first audio streams listed in the first combination information of the playlist file, and playing at the same time with the first luminance video, and in a case of playing the second luminance video, reading out the second audio streams listed in the second combination information of the playlist file, and playing at the same time with the second luminance video.

A playback device plays video streams recorded in a recording medium, in which are one or more video streams including at least one of an HDR stream whose dynamic range of luminance of video corresponds to a high dynamic range (HDR), and an SDR stream whose dynamic range of luminance of video corresponds to a standard dynamic range (SDR) narrower than HDR, and identification information indicating whether the HDR stream is included in the one or more video streams. A playback method of the playback device includes: reading the identification information from the recording medium; acquiring playback capability information indicating whether the playback device can play the HDR stream, and display capability information indicating whether a connected display device can display the HDR video; and deciding on a video stream from the one or more video streams, according to the identification information, the playback capability information, and the display capability information.

A file generating method according to one aspect of the present disclosure is a file generating method for generating an MP4 file, the file generating method including: step S11 of acquiring an original file made in a file format different from MP4; step S12 of acquiring a difference file including data that is not included in the original file; step S13 of acquiring a procedure file indicating a procedure for generating the MP4 file; and step S14 of generating the MP4 file by combining the data included in the difference file and data included in the original file in accordance with the procedure indicated in the procedure file.

A recording medium is provided in which are recorded a stream file including a first luminance video expressed by luminance of a first dynamic range, a second luminance video expressed by luminance of a second dynamic range that is broader than the first dynamic range, and a playlist file for controlling playback of the stream file. The first and second combination information, representing combinations of elementary streams that can be played at the same time, is described in the playlist file. Elementary streams that can be played at the same time with the first luminance video are listed in the first combination information. Elementary streams that can be played at the same time with the second luminance video are listed in the second combination information. The number of elementary streams of a predetermined type listed in the first combination information and the second combination information are equal.

A method in an encoder, the method comprising: receiving a video; encoding a segment of the video at different bit rates to generate multiple representations of the segment at different bit rates; generating a quality metric for each representation of the video segment; and storing the lowest bit rate representation of the video segment for which the respective quality metric meets a predefined minimum quality threshold.

A file generating method according to one aspect of the present disclosure is a file generating method for generating an MP4 file, the file generating method including: step S11 of acquiring an original file made in a file format different from MP4; step S12 of acquiring a difference file including data that is not included in the original file; step S13 of acquiring a procedure file indicating a procedure for generating the MP4 file; and step S14 of generating the MP4 file by combining the data included in the difference file and data included in the original file in accordance with the procedure indicated in the procedure file.

A recording medium includes a video stream of a standard-luminance range and a video stream of high-luminance range, which are used selectively in accordance with a playback environment. The recording medium also includes a subtitle stream of the standard-luminance range and a subtitle stream of the high-luminance range, which are used selectively in accordance with the playback environment. A playlist file includes a management region where playback control information relating to a main stream is stored, and includes an extended region. The management region stores first playback control information specifying playing of the video stream of the high-luminance range and the subtitle stream of the high-luminance range in combination. The extended region stores second playback control information specifying playing of the video stream of the standard-luminance range and the subtitle stream of the standard-luminance range in combination.

In the case where an input image is an image of a non-YUV420 format and an encoding unit is the smallest CU block, an adaptive-sub-sampling luma reference pixel acquisition unit sub-samples reference pixels existing neighboring a luma block corresponding to a chroma prediction target block based on a luma intra prediction mode, and acquires a pixel value of each of the sub-sampled reference pixels. In the case where the input image is an image of a non-YUV420 format and the encoding unit is the smallest CU block, an adaptive-sub-sampling chroma reference pixel acquisition unit sub-samples reference pixels existing neighboring the chroma prediction target block based on the luma intra prediction mode, and acquires a pixel value of each of the sub-sampled reference pixels.