Compressed audio encoding formats.
MP3 (or rather, MPEG 1 Audio Level 3): no comment, compatible everywhere and by everyone, the lack of this “eternal” format is one: only two channels, which limits its use in cinema systems at home modern.
Multi-channel MP3 (5.1) MPEG 2 Audio Level 3.
WMA: Windows Media Audio, formally a better and more modern competitor to Microsoft’s mp3. It is not used much, although it is widely compatible with hardware.
OGG Vorbis is a best modern mp3 competitor from the open source community. Deprived of any license restrictions, it is used more and more frequently.
AAC: Advanced Audio Coding is Apple’s main audio format built into all of its iPads, iPhones, iTunes, etc. The main advantage is that it is technically more advanced than mp3, allowing sample rates of up to 96 kHz and theoretically a completely insane number of channels in one file, up to 48. It is also used in digital satellite radio. Just as mp3 is a compressed format, the quality of 96Kbps AAC is comparable to the quality of 128Kbps of mp3 (we are talking about two channels in both cases).
Dolby Digital (AC-3) is probably the most popular standard for digital audio in cinematography, due to the fact that it appeared on the market as early as 1995, it exists in two versions: DD2.0 (for high-quality stereo sound) and DD5 .1 – five full channels and one defective for a subwoofer. Players are compatible with all of them for obvious reasons, the bitrate is 640Kbps in all cases.
Dolby Digital Plus or E-AC-3 is an attempt to improve on the usual Dolby Digital, but the previous generation decoders and receivers do not support tracks in the Dolby Digital Plus format, the reasons for this are radical changes: the number of channels increased to 7.1, the bit rate – to 1, 7 Mbps This will not go through S / PDIF (when transmitting via such a cable, you will have to use downmix on DD5.1 or on DTS with quality loss), but HDMI normally copes with Dolby Digital Plus as of version 1.3, you can find such tracks on Blu-Ray discs …
Dolby TrueHD – We practically have 8 tracks almost uncompressed at 96 KHz / 24 bits or 6 at 192 KHz / 24 bits, the total bit rate reaches 18 Mbit / sec, which requires decoding in the player and transmission to the receiver in the analog path, or using HDMI 1.3 or higher. For Blu-Ray, this audio coding system is optional.
DTS is a lossy digital audio coding system for cinemas, which later appeared on DVD, it is analogous to Dolby Digital 5.1, but somewhat more flexible, allowing in addition to 2.0 and 5.1 to use other schemes, such as 4.0 and 4.1, there is also a choice between two fixed bit rates of 1500 Kbps and 750 Kbps. In the first case, DTS clearly outperforms Dolby Digital in sound quality; in the second, the difference between systems is controversial.
DTS-HD is a further evolution of DTS, the number of channels has been brought to 7.1 in 96KHz / 24bit mode, the bit rate can be selected between 6Mbps and 3Mbps, it is an optional audio format for Blu-Ray. The situation with the sound transmission to the receiver is almost the same as with DolbyTrueHD.
Lossless or uncompressed compressed audio encoding formats.
LPCM is simply uncompressed audio. It is usually stereo. It should not be confused with a WAV file, it is a container and there may be something other than PCM WAV inside.
APE is a specific lossless audio compression format. Loved by audiophiles.
Flac is its competitor and analog, the differences between them are beyond the scope of this review.
Lossless audio
Lossless apple
Subtitle formats.
SRT: text format, can be attached as a separate file with the same extension. Compared to the first versions of this format, the design possibilities have been significantly increased. It can also exist within MKV.
SUB / IDX is a graphic subtitle format extracted from DVD. It can fit MKV or MP4.
s2k, ssa, ass: some more advanced text formats, ass can be placed inside MKV.
smi is a textual format based on SGML, the direct ancestor of HTML.
PGS is a graphical subtitle format, the main one for Blu-Ray, but it can also exist in ts and MKV containers.
