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HDV is a format for recording of high-definition video on DV cassette tape. The format was originally developed by JVC and supported by Sony, Canon, and Sharp. The four companies formed the (HDV consortium ) in September 2003. Conceived as an affordable high definition format for digital camcorders, HDV quickly caught on with many amateur and professional videographers due to its low cost, portability, and image quality acceptable for many professional productions. HDV and HDV logo are trademarks of JVC and Sony. ==Video and audio coding== HDV video and audio are encoded in digital form, using lossy interframe compression. Video is encoded with the H.262/MPEG-2 Part 2 compression scheme, using 8-bit chroma and luma samples with 4:2:0 chroma subsampling. Stereo audio is encoded with the MPEG-1 Layer 2 compression scheme. The compressed audio and video are multiplexed into an MPEG-2 transport stream, which is typically recorded onto magnetic tape, but can also be stored in a computer file. The data rate for both the audio and video is constant and is roughly the same as DV data rate. The relatively low video data rate can cause ''bit rate starvation'' in scenes that have lots of fine detail, rapid movement or other complex activity like flashing lights, and may result in visible artifacts, such as blockiness and blurring. In contrast to the video, HDV audio bitrate is relatively generous. At the coded bitrate of 384 kbit/s, MPEG-1 Layer 2 audio is regarded as ''perceptually lossless''. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「HDV」の詳細全文を読む スポンサード リンク
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