PCM audio is a way to digitize analog audio information, which means that a sound is converted to a binary code that computer devices such as DVD players will understand as audio. This format was first used for audio CDs, but was later adopted by the DVD standard due to its ability to replicate audio recordings accurately in a digital format. In fact, at the highest quality setting for PCM audio, the recordings contain sound information that cannot even be heard by humans. Also, professional digital recording studios and applications will record to PCM audio files.
Many different audio formats can be used for audio tracks on DVD video discs. Among them is audio encoded in the pulse code modulation (PCM) format. While this format is not used as often as Dolby Digital or MPEG audio compression, you may still find that some DVDs offer a PCM audio track, especially music albums released on as DVD Audio (DVD-A).
What is PCM Audio?
The main advantage of using PCM audio on a DVD is that the audio is uncompressed, meaning that no audio information is lost. Also, PCM audio on a DVD can be set at 48 kilohertz, which provides audio quality that is slightly better than that of a standard audio CD. The enhanced quality is why PCM audio tracks are typically found on DVD-A albums and also on live music concerts released on DVD video discs.
The main disadvantage of PCM audio tracks on a DVD is that the file size is large due to the fact that the audio is not compressed. Audio encoded in Dolby Digital, DTS or MPEG is compressed, which means that the file size is much smaller and more information is available for high-quality video and other extras on the disc. Also, PCM audio can only be recorded in stereo, while Dolby Digital and DTS audio tracks can be encoded for multichannel surround sound.
PCM Audio for Movies on DVD
Full-length movies and television shows on DVD typically do not offer a PCM audio track, because including uncompressed audio will take away the disc space required to provide the best quality video. Also, the space required for using PCM audio tracks would make it difficult to include multiple audio tracks for foreign languages or audio commentaries on a DVD. Plus, the surround sound audio used in most modern big-budget movies could not be included as a PCM audio track on a DVD.
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