compression

compression

Reviews Compression can be applied to data files, images, audio or video. Lossless compression is used for software, text files or any application where all the original bits must be retained when a file is decompressed.

20 December 2006, 16:46

audio compression

Reviews Audio compression works by setting a limit for how loud sound can get while raising low parts of a song to a certain extent, depending on the level of compression. Basically, the lowest and highest volume levels of a song come closer together.

20 December 2006, 14:15

lossless compression

Reviews A method of data compression that retains all of the original file's data -- for example, the Graphics Interchange File (GIF) format used for images. Also see lossy compression.

21 December 2006, 13:41

lossy compression

Reviews A method of file compression in which some data in the original file is lost when the compressed file is restored. With graphics, video, and audio files, a certain degree of lost data won't be noticeable, so many of those file formats use lossy...

21 December 2006, 13:43

vertical compression

Reviews Feature found on 4:3 TVs designed to take advantage of the extra resolution in anamorphic DVDs and other wide-screen content. Pioneered by Sony, this feature squeezes the TV raster so that the electron beam scans in a smaller area.

3 January 2007, 10:59

MP3 (MPEG-1, Layer 3)

Reviews A compression technology, part of the MPEG specification, that produces small, high-quality audio files by eliminating sound signals that the human ear cannot register. MP3 refers to the file format as well as the compression standard.

21 December 2006, 14:46

AAC (Advanced Audio Coding)

Reviews An audio compression scheme defined as part of the MPEG-2 standard (also known as MPEG-2 AAC or MPEG-2 NBC, or Not Backwards Compatible). It offers better sound and a roughly 30 per cent superior compression ratio compared to the MPEG-1 MP3 format.

3 January 2007, 16:08

MPEG-4

Reviews Advanced compression scheme finalised October 1998, designed to enable transmission and reception of high-quality audio and video over the Internet and next-generation mobile telephones -- potentially enables mobile video phones, video email and...

21 December 2006, 14:55

How does an MP3 player work?

Reviews The sound depends on two factors: the quality of this compression algorithm and the bit rate at which the song is encoded, measured in Kbps. Each second of true CD-quality sound takes up more than 1.3MB of disk space, which is why file compression...

9 May 2005, 15:33

JVC Everio GZ-HD7 review

Reviews The first, 1,920x1,080 pixels, dubbed 'FHD' for 'Full HD', uses variable bit rate compression for a theoretically better picture. Perhaps it's because of the demanding MPEG-2-TS (transport stream) compression and encoding the HD7 uses to write...

Editor's rating   6.3

Tags: jvc, hard disk, pixels, camcorder

18 June 2007, 11:00

Hitachi DZ-GX3200E review

Reviews It records video in MPEG-2 compression to allow 18 to 60 minutes of footage per side, depending on the quality level you choose. At low compression, video was sharp with some motion artefacts and edge crawl, along with some blooming.

Editor's rating   6.6

Tags: hitachi, mini, scenes, compression

24 July 2006, 11:35

How do digital cameras differ from film?

Reviews Small and fast for capture, but has file compression that may introduce artefacts that degrade image quality. Large files that can slow down your shooting and fill up your media, but have no compression artefacts.

12 May 2005, 18:50

Hitachi DZ-GX20E review

Reviews The camcorder records using MPEG-2 compression and can hold 18 to 60 minutes per side, depending upon the quality level you select. At the lowest compression level, video was reasonably sharp, with moderate motion artefacts, some edge crawl and...

Editor's rating   6.9

Tags: hitachi, conditions, ram, camcorders

1 September 2005, 19:13

Hitachi DZ-GX3300E review

Reviews It records video in MPEG-2 compression to allow 18 to 60 minutes of footage per side, depending on what quality level you choose. Image qualityAt low compression, video was sharp with some motion artefacts and edge crawl, along with some blooming.

Editor's rating   6.6

Tags: hitachi, scenes, microphone, jack

13 July 2006, 12:16

Canon PowerShot A700 review

Reviews Continuous-shooting mode clocked 2fps regardless of resolution or compression, with seemingly no limit to the number of shots. Information, such as drive, meter and flash modes; image size and compression; exposure compensation and shots remaining...

Editor's rating   7.6

Tags: canon, colours, scene, accessories

25 May 2006, 11:34