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100:. Where circuit costs are high and loss of voice quality is acceptable, it sometimes makes sense to compress the voice signal even further. An ADPCM algorithm is used to map a series of 8-bit ÎĽ-law (or a-law) PCM samples into a series of 4-bit ADPCM samples. In this way, the capacity of the line is doubled. The technique is detailed in the
142:(QMF) to get two subbands of the signal. When the ADPCM bitstream of each subband is obtained, the results are multiplexed, and the next step is storage or transmission of the data. The decoder has to perform the reverse process, that is, demultiplex and decode each subband of the bitstream and recombine them.
95:
PCM (Europe and most of the rest of the world). These are logarithmic compression systems where a 13- or 14-bit linear PCM sample number is mapped into an 8-bit value. This system is described by international standard
152:
Referring to the coding process, in some applications as voice coding, the subband that includes the voice is coded with more bits than the others. It is a way to reduce the file size.
458:
79:, a standard audio signal for a single phone call is encoded as 8000 analog samples per second, of 8 bits each, giving a 64 kbit/s digital signal known as
48:
Typically, the adaptation to signal statistics in ADPCM consists simply of an adaptive scale factor before quantizing the difference in the DPCM encoder.
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with two channels and ADPCM coding of each. Before the digitization process, it catches the analog signal and divides it in frequency bands with
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319:. ITU-T Recommendation G.722 (11/88), "7 kHz audio-coding within 64 kbit/s".
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Recommended
Practices for Enhancing Digital Audio Compatibility in Multimedia Systems
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276:(September 1973). "Adaptive quantization in differential PCM coding of speech".
415:"FFmpeg/adpcmenc.c at ee4aa388b2231e988eccdab652c55df080d6ad45 · FFmpeg/FFmpeg"
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to develop the legacy audio codecs ADPCM DVI, IMA ADPCM, and DVI4.
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supports ADPCM encoding on 64 simultaneous audio channels.
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communications. In the early 1990s, ADPCM was also used by
307:– legacy IMA ADPCM specification, Retrieved on 2009-07-06.
329:
Jerry D. Gibson; Toby Berger; Tom
Lookabaugh (1998).
357:"Differences Between PCM/ADPCM Wave Files Explained"
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134:operating at 48, 56 and 64 kbit/s, based on
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390:"FFmpeg General Documentation - Audio Codecs"
8:
27:Technique used to encode voices in telephony
31:Adaptive differential pulse-code modulation
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7:
332:Digital Compression for Multimedia
292:10.1002/j.1538-7305.1973.tb02007.x
175:audio codecs supporting ADPCM are
113:Interactive Multimedia Association
39:differential pulse-code modulation
25:
279:The Bell System Technical Journal
91:PCM (North America and Japan) or
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1632:
1623:
1622:
145:
1:
107:ADPCM techniques are used in
367:. 2011-09-24. Archived from
247:. McGraw-Hill Professional.
87:encoding on a DS0 is either
244:Principles of Digital Audio
119:Split-band or subband ADPCM
1690:
1514:Compressed data structures
836:RLE + BWT + MTF + Huffman
504:Asymmetric numeral systems
1618:
873:Discrete cosine transform
803:LZ77 + Huffman + context
140:quadrature mirror filters
130:standard wideband speech
1578:Smallest grammar problem
365:Microsoft Knowledge Base
241:Ken C. Pohlmann (2005).
51:ADPCM was developed for
1519:Compressed suffix array
1068:Nyquist–Shannon theorem
217:Audio data compression
1548:Kolmogorov complexity
1416:Video characteristics
793:LZ77 + Huffman + ANS
361:KB 89879 Revision 3.0
222:Pulse-code modulation
43:signal-to-noise ratio
1638:Compression software
1232:Compression artifact
1188:Psychoacoustic model
162:Windows Sound System
1628:Compression formats
1267:Texture compression
1262:Standard test image
1078:Silence compression
335:. Morgan Kaufmann.
212:Audio coding format
164:supported ADPCM in
1536:Information theory
1391:Display resolution
1217:Chroma subsampling
606:Byte pair encoding
551:Shannon–Fano–Elias
274:Flanagan, James L.
85:signal compression
37:) is a variant of
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1450:Deblocking filter
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342:978-1-55860-369-1
254:978-0-07-144156-8
61:James L. Flanagan
55:by P. Cummiskey,
16:(Redirected from
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1664:Data compression
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1455:Lapped transform
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1237:Image resolution
1222:Coding tree unit
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317:ITU-T G.722 page
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286:(7): 1105–1118.
270:Jayant, Nikil S.
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813:LZSS + Huffman
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136:subband coding
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89:ÎĽ-law (mu-law)
83:. The default
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823:LZ77 + Range
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371:on 2013-12-31
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181:adpcm_ima_wav
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109:voice over IP
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53:speech coding
49:
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40:
36:
32:
19:
1674:Audio codecs
1594:Hutter Prize
1558:Quantization
1463:Compensation
1257:Quantization
1126:
980:Compensation
937:
546:Shannon–Fano
486:Entropy type
425:. Retrieved
423:. 2017-02-15
418:
409:
398:. Retrieved
384:
373:. Retrieved
369:the original
360:
351:
331:
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197:
193:adpcm_yamaha
192:
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177:adpcm_ima_qt
176:
170:
159:
151:
144:
122:
106:
74:
71:In telephony
50:
47:
34:
30:
29:
1553:Prefix code
1406:Frame types
1227:Color space
1053:Convolution
783:LZ77 + ANS
694:Incremental
667:Other types
586:Levenshtein
1658:Categories
1610:Mark Adler
1568:Redundancy
1485:Daubechies
1468:Estimation
1401:Frame rate
1323:Daubechies
1283:Chain code
1242:Macroblock
1048:Companding
985:Estimation
905:Daubechies
611:Lempel–Ziv
571:Exp-Golomb
499:Arithmetic
427:2018-02-05
400:2013-12-30
375:2013-12-30
229:References
104:standard.
1587:Community
1411:Interlace
797:Zstandard
576:Fibonacci
566:Universal
524:Canonical
189:adpcm_swf
77:telephony
67:in 1973.
65:Bell Labs
1573:Symmetry
1541:Timeline
1524:FM-index
1369:Bit rate
1362:Concepts
1210:Concepts
1073:Sampling
1026:Bit rate
1019:Concepts
721:Sequitur
556:Tunstall
529:Modified
519:Adaptive
477:Lossless
206:See also
200:GameCube
185:adpcm_ms
168:files.
156:Software
1531:Entropy
1480:Wavelet
1459:Motion
1318:Wavelet
1298:Fractal
1293:Deflate
1276:Methods
1063:Latency
976:Motion
900:Wavelet
817:LHA/LZH
767:Deflate
716:Re-Pair
711:Grammar
541:Shannon
514:Huffman
470:methods
1642:codecs
1603:People
1506:Theory
1473:Vector
990:Vector
807:Brotli
757:Hybrid
656:Snappy
509:Golomb
420:GitHub
394:FFmpeg
339:
251:
173:FFmpeg
126:is an
1433:parts
1431:Codec
1396:Frame
1354:Video
1338:SPIHT
1247:Pixel
1202:Image
1156:ACELP
1127:ADPCM
1117:ÎĽ-law
1112:A-law
1105:parts
1103:Codec
1011:Audio
950:ACELP
938:ADPCM
915:SPIHT
856:Lossy
840:bzip2
831:LZHAM
787:LZFSE
689:Delta
581:Gamma
561:Unary
536:Range
224:(PCM)
132:codec
128:ITU-T
124:G.722
102:G.726
98:G.711
93:A-law
35:ADPCM
18:ADPCM
1445:DPCM
1252:PSNR
1183:MDCT
1176:WLPC
1161:CELP
1122:DPCM
970:WLPC
955:CELP
933:DPCM
883:MDCT
827:LZMA
728:LDCT
706:DPCM
651:LZWL
641:LZSS
636:LZRW
626:LZJB
396:.org
337:ISBN
249:ISBN
191:and
171:The
160:The
59:and
1490:DWT
1440:DCT
1384:VBR
1379:CBR
1374:ABR
1333:EZW
1328:DWT
1313:RLE
1303:KLT
1288:DCT
1171:LSP
1166:LAR
1151:LPC
1144:FFT
1041:VBR
1036:CBR
1031:ABR
965:LSP
960:LAR
945:LPC
910:DWT
895:FFT
890:DST
878:DCT
777:LZS
772:LZX
748:RLE
743:PPM
738:PAQ
733:MTF
701:DMC
679:CTW
674:BWT
646:LZW
631:LZO
621:LZ4
616:842
288:doi
166:WAV
81:DS0
75:In
63:at
1660::
1308:LP
1139:FT
1132:DM
684:CM
417:.
392:.
363:.
359:.
284:52
282:.
272:;
195:.
187:,
183:,
179:,
45:.
1644:)
1640:(
460:e
453:t
446:v
430:.
403:.
378:.
345:.
294:.
290::
257:.
33:(
20:)
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