Digital sound on modern home theater equipment.
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The modern consumer AV equipment industry has more than a dozen digital audio coding algorithms in use, both stereo and multichannel.
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Some allow you to firmly “pack” the stream, but at the expense of quality, others – to convey it in all its glory. Can all the abbreviations be understood? Let’s try.
Digital sound: formats, abbreviations, varieties
Digital sound: formats, abbreviations, varieties
In order to somehow structure the data, we decided to link digital audio formats to media formats such as audio CD, DVD-Video, etc. Since the topic is too broad, this time we will consider only those audio formats that are used in consumer equipment. We will leave the sound formats for computer games for one of the following articles.
Audio CD
Digital Sound: Audio CD
Digital Sound: Audio CD
Description
Regular music CD. It is based on a single coding algorithm: LPCM, linear pulse code modulation – linear pulse code modulation. The Audio CD format assumes two-channel (stereo) audio encoding with a sampling frequency of 44.1 kHz and 16 bits with a bit rate of 1.4 Mbps.
Digital output methods
Via Optical TosLink, Electrical Coaxial, HDMI in any version.
DVD-Video
Digital sound: DVD-Video
Digital sound: DVD-Video
Description
Unlike a music CD, the DVD-Video format involves a more developed audio component, which includes not only stereo, but also multi-channel sound. However, even stereo sound is encoded in higher quality DVD-Video than audio CD. LPCM can also be used for encoding, but with a sampling rate of 48 kHz and a resolution of up to 24 bits.
Dolby Digital
Founded by Ray Dolby Laboratories, Dolby has established Dolby Digital, perhaps the most famous of the modern multichannel audio formats. It is based on a compression algorithm that allows a full-range multi-channel audio signal with up to six channels (5.1) to be “packed” into a stream with a bit rate of up to 448 kbps. The sampling frequency is 48 kHz. For the sake of fairness, it is worth mentioning that the Dolby Digital format itself allows you to encode thicker streams for better sound (for example, on Blu-ray, Dolby Digital’s standard bit rate is 640 kbps) , but for DVD-Video it was such a limitation. Later, the Dolby Digital Surround EX format was introduced, whose main difference from the basic Dolby Digital is the number of channels increased to 7 (6.1).
DTS
California-based Digital Theater System’s alternative multi-channel audio coding algorithm … Thanks to a more efficient “compression” mechanism and higher bit rate, DTS soundtracks are traditionally considered to have better sound quality than those of Dolby Digital. That is why music DVD videos (concerts, video clips) are preferable to buying with a DTS track. Initially, DTS had a bit rate of 768 kbps or 1536 kbps, the number of channels was up to six (5.1), and the sample rate was 48 kHz. Later, more progressive varieties of DTS appeared: DTS ES with a large number (up to 8) of channels and DTS 96/24, in which each audio channel had 96 kHz / 24-bit parameters. Before the advent of the latest high definition digital audio formats, DTS 96/24 was a very attractive format for storing multichannel music recordings.
MP2
Sampling frequency 48 kHz, number of channels up to 8 (7.1), bit rate – 912 kbps. But it makes no sense to talk about the MP2 format for a long time, since in our latitudes it is very difficult to find DVD with such an audio track.
Digital output methods
All the above formats can be transmitted via Optical TosLink, Electrical Coaxial and HDMI of any version.
Blu-ray Disc (BD) and HD DVD
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Digital sound: Blu-ray Disc
Description
Blu-ray and HD DVD specifications cover a wide range of audio formats. Most of those described above are included in it, however, they differ, as a rule, in slightly higher bit rates: the “blue” means allow this, and the sound quality requirements since the advent of DVD have increased. However, in addition to high definition video, Blu-ray and HD DVD also offer a completely new soundtrack, also in high definition.
Dolby Digital Plus
The evolutionary development of Dolby Digital. The number of channels has been increased to fourteen (13.1), although in fact only six (5.1) or eight (7.1) are used so far, the bit rate has been increased to 6 Mbps (maximum; in practice – up to 3 Mbps for HD DVD and 1.7 Mbps / s for Blu-ray).
