Panasonic SC-PT 250 Glossary, Decoder, DivX, Dolby Digital, DTS Digital Theater Systems, I/P/B

Glossary

Decoder

A decoder restores the coded audio signals on DVDs to normal. This is called decoding.

DivX

DivX is a popular media technology created by DivX, Inc. DivX media fi les contain highly compressed video with high visual quality that maintains a relatively small fi le size.

Dolby Digital

This is a method of coding digital signals developed by Dolby Laboratories. Apart from stereo (2-channel) audio, these signals can also be multi-channel audio. A large amount of audio information can be recorded on one disc using this method.

DTS (Digital Theater Systems)

This surround system is used in many movie theaters around the world. There is good separation between the channels, so realistic sound effects are possible.

Dynamic range

Dynamic range is the difference between the lowest level of sound that can be heard above the noise of the equipment and the highest level of sound before distortion occurs.

Film and video

DVD-Videos are recorded using either fi lm or video. This unit can determine which type has been used, then uses the most suitable method of progressive output.

Film: Recorded at 25 frames per second (PAL discs) or 24 frames per second (NTSC discs). (NTSC discs recorded at 30 frames per second as well). Generally appropriate for motion picture fi lms.

Video: Recorded at 25 frames/50 fi elds per second (PAL discs) or 30 frames/60 fi elds per second (NTSC discs). Generally appropriate for TV drama programs or animation.

Frame still and field still

Frames are the still pictures that go together to make a moving picture.

There are about 30 frames shown each second.

		One frame is made up of two fi elds. A regular television
ENGLISH		shows these fi elds one after the other to create frames.
		A still is shown when you pause a moving picture. A frame
		still is made up of two alternating fi elds, so the picture may
		appear blurred, but overall quality is high.
		A fi eld still is not blurred, but it has only half the information
		of a frame still so picture quality is lower.
		I/P/B
REFERENCE
		MPEG 2, the video compression standard adopted for use
		with DVD-Video, codes frames using these 3 picture types.
		I: Intra coded picture
		This picture has the best quality and is the best to use
		when adjusting the picture.
		P: Predictive coded picture
		This picture is calculated based on past I or P-pictures.
		B: Bidirectionally-predictive coded picture
		This picture is calculated by comparing past and
		future I and P-pictures so it has the lowest volume of
		information.
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JPEG (Joint Photographic Experts Group)

This is a system used for compressing/decoding color still pictures. If you select JPEG as the storage system on digital cameras, etc., the data will be compressed to 1/10–1/100 of its original size. The benefi t of JPEG is less deterioration in picture quality considering the degree of compression.

Linear PCM (Pulse Code Modulation)

These are uncompressed digital signals, similar to those found on CDs.

MP3 (MPEG Audio Layer 3)

An audio compression method that compresses audio to approximately one tenth of its size without any considerable loss of audio quality.

MPEG4

A compression system for use on mobile devices or a network, that allows highly effi cient recording at a low bit rate.

Playback control (PBC)

If a Video CD has playback control, you can select scenes and information with menus.

Progressive/Interlaced

The PAL video signal standard has 576 interlaced (i) scan lines, whereas progressive scanning, called 576p, uses twice the number of scan lines. For the NTSC standard, these are called 480i and 480p respectively.

Using progressive output, you can enjoy the high-resolution video recorded on media such as DVD-Video. Your television must be compatible to enjoy progressive video.

Sampling frequency

Sampling is the process of converting the heights of sound wave (analog signal) samples taken at set periods into digits (digital encoding).

Sampling frequency is the number of samples taken per second, so larger numbers mean more faithful reproduction of the original sound.

WMA (Windows MediaTM Audio)

WMA is a compression format developed by Microsoft Corporation. It achieves the same sound quality as MP3 with a fi le size that is smaller than that of MP3.

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