Seminar 1: Wavelets and filterbanks

1
??????? 7
Dithering,noise shaping
2
??????

• ???? ???????? ??????????? (?.?. ??????????????
  ??????? ? ??????? ??????????? 24 ??? 32 ???? ?
  16-?????? CD ??????)
• ??????? ??????
• ?????????? (???????????) ??????? ??????? ????????
  ?????????? ?? ?????????? ??????? ???????
  ?????????? (truncation)

3
??????????

• ??? ?????????? ???????? ?????????!
• ??????????? ????????? ?????? ???????????
• ?????? ??????????? ?????????????? ? ????????
• ????????? ???????? ??????? ?? ????? ????????

??????? ??????????
?????????? ?? 8 ???
4
Dithering

• ??????? ?????????? ?????????? ???? ?????
  ???????????? dithering ????????????? ??????
  ??????????? ? ??????!
• ??? ????????????? ?????????
• ??? ?????? ? ??????????
• ?????????? ????? ??????? ????

5
Dithering

• ????????? ?????????
• ????????????? ???????? (TPDF, Gaussian)
• ???????? (?????? ???????? ?? ????????
  ????????????? ????????? ??? ?????? ? ??????
  ??????????? ?????????)
• ?????? (?????, ???????????????)

??????? ??????????
?????????? ?? 8 ???
Dithering
6
Dithering

• ????? ?? ????????? ?????????? ???? ??????????
• ?????????? ???????? ???? ????? ???????
  ??????????? ????????? ?????? ??????????? ????????
  ???????? ??? ??????? ????????????? ?????????
• ???????????? ?? (??????????????) ??? ??????????
• ??? ?????? ??????????? ??? ???? ?? ?????
  ?????????????? (??????????? ??????????? ?? ??
  ????? ???????)

7
Noise shaping

• ??????? ???????? ????? ?????? ???????????? ?????
  ??????? ?????? ????? ??????? ??????!
• ?????? ???? ??????????? ????? ???????
  ???????????? ? ????????? ? ?????????? (?
  ?????????? ????????????? ?? ????? ???????? ????)
• ????? ???????? ?????? ??????????? ?????????????
  (???????? ?? ??????? ??????????)

?????? H ????????? ??????
8
Noise shaping

• ??????????? ?? ????? ???????? ????

S1 S2
??????? ??????????
?????????? ?? 8 ???
Dithering
Noise shaping
9
???????? ?? ????????? ???????????

• ??????????? ??????????? ?? 1 ????

???????? 8-?????? ???????????
??????????? (?????????? ?? 1 ????)
?????????? ???? (dithering)
???????? ?????? (noise shaping)
10
???????????? ???????

• ???????????? ???????
• POW-R (several noise shaping options, most
  powerful pow-r3)
• Apogee UV22 and UV22-HR (specially generated
  dithering noise)
• Waves L1 and L2 IDR (several noise shaping
  options) from L1 and L2 Ultramaximizers)
• Sony Super Bit Mapping (noise shaping, adapts to
  spectrum to source signal)
• Many bit depth reductions in sound editors and
  hosts

11
??????????? ???????

• ?????????? ???????????? ?????? noise shaping
• ????? ????????????? ?????? noise shaping
• ???????? ????????????? ??????
• ?????? ??????? ??????? ? ?????? ?????? ?
  ?????????? ??????? ???? ???????????
• ? ?????????? ???????? ????????? ???? ????? ?? 8
  ??

12
??????????? ???????

• ?????????? ? ????????
• ?????????? ??????????? ?????????? ????
  ???????????
• ?? ????????? ??????????? ?????????? ????????
  ??-????
• ?????????? ??????????
• ??? ?????????? ?????????????
• ?????? ????? ???????, ????????????? ?????????????
  ??????? ?????? ??????????? ????????? ? ????????
  ????

13
??????????? ???????

• ??????? ? ???? ??????????? ????????
• ??????????? ??????? ???????? ???????? ?????????
  ?????? ???????????????? ??? ? ?????.

14
MBIT

• iZotope MBIT is an evolution of ExtraBit /
  MegaBitMax noise shaping algorithm
• Control of dithering amount, shaping
  aggressiveness, other options
• Graded number 1 at www.24-96.net/dither blind
  listening test

Result of truncation to 8 bits
Result of dithering
High-resolution audio
Competing noise shaping
MBIT