A playback device is provided that reads out and plays content from a recording medium, in which are recorded a video stream that is encoded video information, map information, and bitrate information of the video stream. The map information includes playback start time information, start position information, and size information. The playback device includes a readout unit that reads out the map information and the bitrate information, a determining unit that determines the stipulated data size indicated by the size information included in the map information, an acquisition unit that acquires the picture from the video stream based on the result of the determination, and a video playback unit that decodes and plays the acquired picture.

Recorded in a recording medium is a video stream, map information, and bitrate information of the video stream. The map information includes size information indicating data size of a section where a picture is recorded in the video stream, based on a predetermined stipulated data size. The stipulated data size differs in accordance with the bitrate information.

Various illustrative aspects are directed to a data storage device, method, and one or more processing devices that are configured to: maintain respective measures of write commands associated with respective ones of shingled magnetic recording (SMR) zones defined in a data storage device, wherein data associated with the write commands is stored in a write cache associated with the data storage device; select one of the SMR zones based on the respective measures; perform a pre-heat operation of a laser diode included in a head associated with the selected one of the SMR zones; and perform a continuous write operation in the selected one of the SMR zones following the pre-heat operation, wherein the continuous write operation writes at least a portion of data stored in the write cache associated with the selected one of the SMR zones.

A waveform data structure includes a plurality of types of frames having different data sizes. Each of the plurality of types of frames includes an auxiliary information area and a data area. The auxiliary information area includes an area for storing common effective-bit length data for a section of waveform samples, and an area for storing an identifier for identifying one of the plurality of types of frames. The data area is an area for storing extracted waveform samples which are extracted from the waveform samples based on the common effective-bit length. The number of the extracted waveform samples is determined based on the common effective-bit length.