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| Digital Video Compression Standards |
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Digital video can be viewed as a series of images in sequence. When uncompressed, massive storage space and a very high transfer bandwidth are required. Therefore, A compression standard is needed to effectively reduce the amount video data without lowering the overall video quality, and this is where multiple video compression standards that are being developed come into play. For example, ITU standardized H.261, H.263, and H.264 as well as the MPEG standards MPEG-1, MPEG-2, MPEG-4, and MPEG07. We will be discussing the three main compression standards commonly used by DVR devices on the market.
The most common compression standards used by DVR devices include M-JPEG, MPEG4 and H.264. These three compression standards are commonly seen on various digital surveillance products on the market, and the respective compression standard impacts the recording quality and storage capacity (video compression ratio) for the DVR. The following is an introduction of the definitions and features of the three compression standards:
M-JPEG
M-JPEG (Motion-JPEG) is a video compression technique stemming from the JPEG, image compression standard, as sequential images become motion video. The compression algorithm is applied to each individual image, but not to relation among images. The advantage of using M-JPEG is the convenience of individual image capture with clear result. On the other hand, as the images are individually compressed and does not take advantage of inter-frame compression, thus the result is massive redundant information and low compression ratio. The compressed file takes up larger storage space and M-JPEG does not support synchronous audio transmission.
MPEG4
After the ISO Moving Picture Experts Group (MPEG) standardized MPEG1 and MPEG2, they introduced the MPEG4 compression standard incorporating next-generation object-oriented compression technology for even more efficient video compression. The algorithm tracks the motion of objects in between frames for higher compression ratio and video quality, with resolutions ranging from 320*240 to 1280*1024. The greatest advantage of MPEG4 is the ability to retain video quality while significantly conserving storage space.
H.264
H.264, also known as MPEG4 Part10 AVC (Advanced Video Coding), is a joint standard between the ITU and MPEG with the goal of reducing by half or more the bandwidth required by the older compression format (including M-JPEG, MPEG2, MPEG4…) while retaining good video quality. Along with the rise requirements in high-quality video and resolution, the much higher compression ratio offered by H.264 will be even more advantageous, providing MPEG2 quality only at a half or third of the bandwidth and also achieving four times the resolution of MPEG part2 at the same bandwidth. |
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About ACARD Technology Corp.
ACARD Technology is a Taiwanese-based company specializing in storage IC design. The company develops SCSI, IDE and SATA chips as well as RAID storage devices. ACARD products are used by PC, Macintosh, Linux and Unix workstation users all around the world. ACARD Technology has years of development and design experience for SCSI, IDE and SATA hardware so it knows what the market needs and understand customers' requirements. Since 1999 ACARD Technology has been actively investing in the development of key technologies aimed at the fast-developing network storage market as well as the management and protection of critical data on storage devices. ACARD products are now available from the company's distributors around the world.For more information, please visit our website at www.acard.com or call +886(2)8512 2290 and e-mail to sales@acard.com
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