MP3
???
????????
??????? ?
?????
?
????? ????? ??????
(lossy compression) ??
?????
???. ???? ????????? ??? ????? ????? ????? ?? ???? ????? ?????? ?????? ?
????
, ?? ????? ?????? ????? ???? ????? ???? ????????. ????? MP3 ?????? ?? ?
?????
???
??
??????
??????? ?????? ??.
??? ???? ?? ????????? ??? "MPEG-2 Audio Layer 3".
????? ????? ?????? (
?????
) ????? ???????? ????? ??? ????? ??. ????? ??? ??
???????
?????? ?????? ??? ????? ??????????? PCM ?? "
Pulse Code Modulation
", ????? ?? ??? 44,100 ?????? (??????) ?? 32
??????
(????? ??????? ? ??? ?????? ?? 16 ?????? ?? ???) ???? ??
?????
. ????? ?-1.4 ?????? ?????? ??????. ????????? ????? ?????? (??????
ZIP
) ???? ??????? ?????? ?? ??? ??????, ??? ?? ???? ??????. ?????, ???? ??????? ???????? ????? (128 ??? 320
????
-?????? ??????), ???? ????? MP3 ??? ??10%?20% ?????? ?????? ?? ?????. ??????, ??? ?????? 4 ????, ?????? ???? ?? ??????? ????? ??? ?? 40MB, ?? ???????? ?? ???? ??? ?????? MP3 ???? ????? ??? ?? ???? 4MB ????.
??? ?????? ?? ???? ?????, ????? ????????? ????? ???????? ??????? ?????? ?? ???? ?????? ??????? ?????? ???:
- ?? ???????
(The minimal audition threshold) ? ?????? ????? ?? ???? ?????? ??????? ??????? ??? ?????. ???????? ???? ??? ???? ??? ?? ???? ?
???
?????. ?? ?? ???? ???? ???? ?? ??? ????, ???? ??? ????? ???? ???? ???? ???? ???? ????. ??? ???? ????? ?? ?? ??????? ??? ?????? ?? ??? ????? ??????? ????? ?? ??? ???????? ?? ?????? ?????.
- ??????
(The masking effect) ? ????? ????? ????? ????? ???? ?????? ??????? ????? ??? ?????? ??????. ???? ???? ?
????? ??????
? ???? ????? ???? ?????? ???? ????? ?????? ?? ??? ??? ???? ?? ???, ????? ???? ???? ???? ????. ????? ???? ??? ???? ?? ???? ?? ?????? ???? ?????. ??? ?? ????
??????
??????? ??????? ?? ????? ???? ?????? ?? ??????, ?????? ??????? ?????? ?????-????????. ???????
???????????
???? ?????? ???? ???? ??? ??????, ????? ?? ???. ??? ???? ????? ???? ????? ??? ??? ?????? ???? ?????? ???? ?????? ????? ?? ????? ????????.
- ?????
??????
?????
(Joint Stereo coding) ? ??? ???? ?????? ????? ?????? ??? ?
???????
, ??????? ????? ?? ???. ??????? ??????? ?? ????? ???? ???? ?????? ??? ??? ???? ??? ??? ????? ???? ???? ???? ?????? ??.
???
???? ????? ?????? ?????? ??? ???? ?? ?????? ???? ???? ????? (?? ?? ??????? ?
????????
), ???? ????? ?? ????? ???? ????? ?????? ?? ?????? ???? ??????? ?? ???? ???? ?? ????? ???? ????? ?????. ???, ????? ????? ?? ??? ???????, ???? ????? ???? ?? ???? ??? ???? ?????? ???? ?????? ???? ?? ??????. ?????? ???? ???? ?????? ???? ????? ???? ??? ?????? ?????. ????? ??? ???? ????? ?? ????? ??? ????? ???? ????? ?? ??????? ???????? (???? ??? ???? ?
???? ???????????
).
- ??? ?????
(Huffman coding) ? ???? ????? ???? ?????? ????? ??????? ???????? ????? ????? ???? ????? ???? ?????? ????? ??????? ???????? ?????? ???? ?? ??????? ??????? ???? ?????. ??? ?? ????? ????? ?? ?? ????? ???????. ???? ???? ?????, ???? ???? ?????? ????? ???? ????? ?????, ??? ????? ?????? ????? ????? ??????-?????? ???? ??? ????? ???????? ?? ??? ?????. ????? ?????, ???? ?????? ?? ????? ?????? (???????? ????? ?????? ?? ????? ?????), ?? ????? ????? ??????? ?????? ??????? ???? ??? ????? ???? ?????? ????? ????.
- ???? ?????
(Bytes reservoir) ? ????? ??????? ?????? ????? ???? ?????? ?????? ??? ????? ???? ????? ?? ?????. ???????, ????? ??????? ?????? ????? ?????? ???? ?????? ??????. ??? ?? ???? ?????? ????? ????? ??? "??????? ????? ?? ?? ?????? ????".
????? "MPEG-1 Audio Layer 2" ?? ?????? ?-MP2, ????? ?? ???? ???????
DAB
(??? ??? ?-
1987
??
1994
), ??? ?????
????? ?????????
???????
?????? ???????
(???? ????? ?-
EUREKA
, ????? ?? ?-EU-147). ?-
1991
????? ??? ????? ????????? ??????: Musicam ??-ASPEC, ???? ????? ?? Adaptive Spectral Perceptual Entropy Coding. ????? ???? Musicam ????? MP2 ???? ?????? ??? ???????? ??????. ????? ???????, ???
???????? ?????????
?
????? ??
???? ??????? ??????? ?-Musicam ??-ASPEC, ?????? ??? ??????? ????, ????? ?? ?-MP3, ???????? ????? ??? ????? ????? ?? ?????? ?? MP2 ?????? ?-192 ????
??? ??????
(Kb/s) ????? 128 ????
??? ??????
????. ????? ??? ??????????? ?????? ?-
1992
??????? ?"MPEG-1", ??? ?????? ?????? ??
MPEG
(??? ???? ??? ISO/IEC 11172-3) ??? ????? ?-
1993
.
?????
MP2
?????? ?
???????
?-
1993
. "????? ??????? ?? ????????" (?-IUMA) ????? ?????? ????? ??????? ???????. ?-IUMA ???? ???? ????? ?????? ?? MP2. ????
1995
, ?????????? ?? ????? ?-MP3 ????? ????? ?????. ????? ?? ?? ?????? ????? ??? ???? ??????? ?? ???? ?????? (????
Winamp
??
Nullsoft
) ??????? ?
????? ?????
??? ?????? ??
??????
.
????? ???? ?? ????? MP3 ?????? ???? ?????? ????? ????? ?? ?????? ???? ?????? ?????? ?????? ????? ????? ????????. ????? ??? ???? ?? ??????? ?????? ????? ?????? ????? ???? ????? ????? ?????? ??????? ??????? ?????.
????? ??????? ?? MP3, ?? ??
MPEG
, ??? ???????? ?-
AAC
?????? ???? 4-MPEG. ??? ????? ???? ???????? ????? ?????? ??????? ?????.
?-AAC ?? ???? ????? ?????????? ??? ????? ???? ?????????? ?????? ?? MP3 ? ??????? ?????? ??? ?? ????? ?????? (???? ????? ?????? ?????
DVD
) ??????? ??, ??? ?? ????? ?????????? ?? ??????
????? ????
??? ??????? ?? ?????? ?????? ?????? ?? ??? ?????? ????.
????? ?????? ????????? ?????? ??? ?
????
?-MP3 ???? ???? ????? ????? ??? ???????????. ?????? ??????? ??? ????? ??? 128Kb/s, ??? ????? ?????? ????? ???? ?? ?? ??? ????? ??? ?????? ????? ?????? ??? ????? ????? ????? ?????? ??.
???? ?????? ?????? (????? ????? ??? ????? ?-MP3) ????? ???? ????? ???? ?????????, ??? ?????? ??? ????? ?????? ??????. ?????? ??? ???? ????? ??? ?? ???????, ???????? ??????? ?????-???????? ?????, ??? ?????? ????? MP3 ?????. ????? ?????? ???????? ?????? (???? LAME) ?? ????? ????? ????? ???? ???? ??????? ??????.
???? ????????? ????? ??? ????? ???? ??????, ??? MPEG-4 AAC, AC3, ATRAC, MP3PRO, MPC,
Vorbis
, QDesign, AMR-WB+, RealAudio, Windows Media Audio
??? ??, ???? ???? ????????? ????? ???
????? ????
, ???:
FLAC
, Monkey's Audio, SHN, TTA, Wavpack
??? ????? ???, ??????????? ?????? ?????? ?????? ????? ???? ???? ??????? ?????? ????? ???? 128Kb/s ??? ???????? ?? ??????? ?????? ?????? ?????.
???? ????? ????? MP3 ?? ??? ???? ???? ?? ?????, ????: ?? ????????, ????, ??????, ???? ?????? ????.
????? ??????? ?? ?-
ID3
??-APEv2.
- FLAC
? ????? ??? ??? ????? ??????
- Mp3music
? ??? ??????? ????? ???????
??????? ???????: