|
|
Broadcast & Professional Video Audio Equipment - HDV |
 |
|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||
|
Main Advantages of HDV On September 30, 2003, the HDV standard was agreed on by four companies: Canon Inc., Sharp Corporation, Sony Corporation, and the Victor Company of Japan, Limited. The concept of the HDV standard is to develop a home camcorder, which can record easily high quality HD movies. The HDV standard can be used with existing DV tape as the recording media. Thus, by using the mechanisms of a DV camcorder, mitigation of development costs and development efficiency is realized. Feature No. 1: Recording HD images on DV tapes The same videotapes used for DV recordings can also be used for HD recordings, and the recording time is also equivalent. Furthermore, the main recording mechanisms are also the same as for the DV standard. Feature No. 2: MPEG-2 is used as the compression format. The same MPEG-2 compression format that is used for digital broadcasts and DVDs is also used for HDV. Efficient compression is possible while maintaining the high quality of HD images. Therefore, using the same bit rate as for the DV standard, the recording and playing back of high resolution HD images has been realized. In order to use MPEG-2 to compress the large quantity of HD image data, which is much more than for the SD format, an extremely large signal processing circuit is required. However, due to the advancement of semiconductors and signal processing technology, it is now possible to use this format as a standard for personal devices. Feature No. 3: Powerful error correction capability With the MPEG-2 format, which uses interframe compression, the impact of missing data is much greater than for the DV standard where intraframe compression is used. For this reason, the amount of correction coding has increased with the HDV standard. Moreover, by turning the DV correction method that only operates within tracks into a correction method between multiple tracks, error correction capability has been drastically improved, and the tolerance for data loss in tracks caused by dropouts is greatly enhanced. Feature No. 4: Same sound quality as a CD MPEG-1 Audio Layer II is used for the audio compression format, allowing you to enjoy the same sound quality as from a CD. Feature No. 5: Two kinds of recording systems The HDV standard has two types of recording systems: the 720p (progressive) specification and the 1080i (interlace) specification. |
 |
||||||||||||||||||||||||||||||||||||||||||||||||||
With the HDV standard, the tape speed and track pitch is the same as for the DV format, and the main DV mechanisms, such as the data-reading drum and the cassette compartment housing the tape, can be adopted without any changes. Moreover, the ITI sector and subcode sector structures are also equivalent to the DV standard, and this has made it possible to record HD video and audio signals in the same running time as for the DV standard. ITI sector : The region where the tape is recorded including the tract structure and width Subcode sector : The region where the index flags and time codes are recorded on the tape
Powerful error correction capability With the MPEG-2 format, which uses interframe compression, the impact of missing data is much greater than for the DV format where intraframe compression is used. For this reason, the amount of correction coding has increased with the HDV standard. Moreover, by turning the DV correction method that only operates within tracks into a correction method between multiple tracks, error correction capability has been drastically improved, and the tolerance for missing data in tracks caused by dropouts is greatly enhanced. |
|||||||||||||||||||||||||||||||||||||||||||||||||||
