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Glossary & Acronyms: L-M
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LaserDisc: is an analog video format based on a large disc. Later versions of LaserDiscs support audio encoded as Dolby Digital or DTS surround sound. The DVD format is superior to that of LaserDisc, due to its digital, higher resolution MPEG-2 video encoding and higher data capacity (meaning you can watch a movie all the way through without having to manually "flip" the LaserDisc as with some movies). The LaserDisc format has been phased out due to the popularity of the DVD format. A few DVD players offer LaserDisc compatibility. For examples of DVD-LaserDisc combination players, click here.
layer switch: see RSDL layer switch.
letterbox widescreen: refers to a DVD-Video that is encoded in the 4:3 (full frame) aspect ratio format. DVD-Video can accommodate video encoding in either 4:3 aspect ratio or 16:9 aspect ratio. Because most movies are theatrically shown in 1.85:1 or 2.35:1 aspect ratios, a letterbox (i.e., the black horizontal bars at the top and bottom of the TV screen) presentation is used to preserve the theatrical aspect ratio within a 4:3 aspect ratio screen. Read more about letterbox widescreen on our Anamorphic Widescreen page.
LFE: see low frequency effects.
lossless: is used in the context of describing audio encoding schemes (e.g., PCM, MLP) where no detail or nuance of the original analog master or source material/signal are lost during the analog-to-digital and digital-to-analog conversion process. See Pulse Code Modulation (PCM) or Meridian Lossless Packing (MLP).
lossy: is used in the context of describing audio encoding schemes where some detail or nuance of the original analog master or source material/signal are lost during the analog-to-digital and digital-to-analog conversion process. Lossy audio encoding algorithms are used when the data for lossless encoding schemes would far exceed the capacity of the recording/transmission medium. Examples of lossy audio encoding schemes are the Dolby Digital or DTS. To minimize loss of audio performance, lossy audio encoding schemes uses perceptual encoding, where psycho-acoustics is used to encode the information that most humans are most likely to hear.
low frequency effects (LFE): this refers to the deep bass effects that represent the ".1" of the "5.1" channel surround sound. It makes explosions more explosive, and give the foot stomps of the dinosaurs in "Jurassic Park" and "Godzilla" a more terrifying effect. To fully realize the impact of low frequency effects, subwoofers are usually recommended. However, if you have main speakers that can reproduce frequencies down to about 20-30 Hz, you may find that adequate for your needs, particularly if your receiver can divert the LFE signal to the main speakers.
luminance: refers to the brightness information of the overall video signal. Also see chrominance, component video, and S-video.
MBytes: see Megabytes.
Mbps: short for Megabits per second (a million bits per second). A unit of how much digital information is transferred over time. DVD-Video signal runs about 3-7 Mbps, with a maximum of 10 Mbps.
Megabytes: approximately one million bytes.
Motion Picture Association of America (MPAA): assigns ratings (e.g., G, PG, PG-13, R, etc.) to movies.
Also see MPAA rating.
MPAA: see Motion Picture Association of America.
MPAA rating: Motion Picture Association of America assigns the following ratings to movies:
G = General audience
PG = Parental guidance suggested
PG-13 = Parents strongly cautioned
R = Restricted
NC-17 = No one 17 and under admitted
X = No one 17 and under admitted
Motion Pictures Experts Group (MPEG): A professional association of motion picture engineers who develops standards for compressing audio and video signal, including the MPEG-1 and MPEG-2 video compression algorithms.
MP3: A compressed audio format that is popular for downloading across the internet and for use with memory-based audio players. Files may be recorded on CD-R or CD-RW media for playback in compatible DVD players, audio CD players, and CD-ROM drives. Files are usually named as "*.mp3". Sound quality varies as a function of the recording/encoding bit rate. In our opinion, anything recorded with less than 128 kbps data rate will sound degraded. For a high fidelity home audio system, we would recommend MP3s encoded at no less than 256 kbps data rate. Anything less would mean too much compression was used at the cost of sound fidelity. See Windows Media Audio (WMA).
MPEG: See Motion Pictures Experts Group.
MPEG-1: A video compression algorithm that is part of the Video CD standard. The algorithm is developed by the Motion Pictures Experts Group (MPEG). MPEG-1 effectively compresses the video picture to about 1/140 of its original size. Also see MPEG-2.
MPEG-2: A video compression algorithm that is part of the DVD-Video, Digital Broadcast Satellite, and Digital TV (including HDTV) standard. The algorithm is developed by the Motion Pictures Experts Group (MPEG). MPEG-2 effectively compresses the video picture to about 1/40 of its original size. The picture quality from a MPEG-2 encoded source is superior to that of MPEG-1.
multi-channel: usually refers to the use of more than two channels, for either movie surround sound (5-channel or 6-channel) or music surround sound (5-channel or 6-channel DVD-Audio and Super Audio CD). Stereo is equivalent to two-channel. Mono is the same as one-channel.
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