Because the playback device does the downmixing, producers do not have to create multiple audio signals for each playback device. The playback device's decoder downmixes the 5.1 channel signal to a mono signal allowing the television to use the received audio signal. For example, a 5.1 channel audio signal is delivered to a mono television. The decoder in the playback device delivers the audio signal specific to that particular device's ability. This multichannel scheme is known as 5.1 channel.īecause not everyone has the equipment needed to take advantage of Dolby Digital's 5.1 channel sound, developers included a downmixing feature that ensures compatibility with any playback device. The LFE channel is one-tenth of the bandwidth of the other channels and is sometimes erroneously called the subwoofer channel. A low frequency effect (LFE) channel is included that provides the sound needed for special effects and action sequences in movies. The European DVB standard does not use Dolby Digital for audio, but instead uses MPEG standard technology for both the audio and video signals.ĭolby Digital provides five full-bandwidth channels, front left, front right, center, surround left, and surround right, for true surround sound quality. It has been selected as the audio standard for digital television ( DTV).
Dolby Digital is used with digital versatile discs (DVDs), high definition television (HDTV), and digital cable and satellite transmissions. By reducing, eliminating, or masking the noise, the amount of data is reduced to one tenth of the data on a compact disk (CD).
Sometimes the coding noise is not in the same frequency of an audio signal and must be reduced or eliminated. When coding noise is close to the frequency of an audio signal, that audio signal masks the noise so that the human ear hears only the intended audio signal. Dolby Digital takes advantage of how the human ear processes sound. Dolby Digital, formerly known as AC-3, is a digital audio coding technique that reduces the amount of data needed to produce high quality sound.
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