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Topic: Subband encoding

Related Topics

Filter bank

Range encoding

Psychoacoustic model

Entropy coding

Polyphase quadrature filter

Arithmetic coding

High frequency limit

Audio compression

Absolute threshold of hearing

MP3

Huffman coding

Auditory illusion

Image processing

SRGB color space

Ingrid Daubechies

	Subband encoding - Wikipedia, the free encyclopedia
		Subband encoding is an audio compression technique where the sound is split into frequency bands and then parts of the signal which the ear cannot detect are removed (e.g., a quiet sound masked by a loud one).
		The remaining signal is encoded using variable bit-rates with more bits per sample being used in the mid frequency range.
		Subband encoding is used, for example, in MPEG-1.
	en.wikipedia.org /wiki/Subband_encoding (121 words)

	[No title] (Site not responding. Last check: 2007-10-14)
		Similarly, subband signal generator 20 generates channel subband signals along paths 21 and 22 in response to an input signal received from path 2 and subband signal generator 30 generates channel subband signals along paths 31 and 32 in response to an input signal received from path 3.
		Similarly, subband signal generator 180 generates subband signals along paths 181 to 183 in response to the input signal received from path 2 and subband signal generator 190 generates subband signals along paths 191 to 193 in response to the input signal received from path 3.
		The composite subband signal is scaled by the ratio R of the measures for the largest channel subband signal in that particular frequency subband to the composite subband signal, or
	www.wipo.int /cgi-pct/guest/getbykey5?KEY=99/04498.990128&ELEMENT_SET=DECL (7391 words)

	[No title] (Site not responding. Last check: 2007-10-14)
		An encoding method according to claim 1, characterized in that, for each bitplane, the tree scanning is spatially oriented, all the temporal resolutions being successively scanned inside each spatial scale and resolution flags being introduced between any two spatial scales.
		An encoding method according to claim 1, characterized in that, for each bitplane, the tree scanning is temporally oriented, all the spatial resolutions being successively scanned inside each temporal scale and resolution flags being introduced between any two temporal scales.
		An encoding method according to claim 1, characterized in that, for each bitplane, an intermediate tree scanning is performed, all the temporal and spatial resolutions of the same scale being jointly scanned and resolution flags being introduced between any two spatial/temporal scales.
	www.wipo.int /cgi-pct/guest/getbykey5?KEY=01/84847.011108&ELEMENT_SET=DECL (3183 words)

	Audio data compression - Wikipedia, the free encyclopedia
		In contrast to the speed of compression, which is proportional to the number of operations required by the algorithm, here latency refers to the number of samples which must be analysed before a block of audio is processed.
		Speech encoding is an important category of audio data compression.
		Perhaps the earliest algorithms used in speech encoding (and audio data compression in general) were the A-law algorithm and the mu-law algorithm.
	en.wikipedia.org /wiki/Audio_data_compression (2102 words)

	Data Compression 1999: 2D Subband Encoding (Site not responding. Last check: 2007-10-14)
		The low-low subband could easily be encoded using a differential encoder since the difference on neighbour pixels is quite low [This is not done due to lack of time].
		The high-low band is encoded using a CFDM scheme separately on each row in the image [1 bit per pixel].
		The two remainding subbands were encoded with 8 bits per pixel [compression 4 bits/pixel].
	www.daimi.au.dk /~husted/dc/subband.html (174 words)

	Thesis (K. Lampert) - Chapter 7
		The temporal capabilities of the four sets of subband bit allocation scalars were not as useful as anticipated.
		The slowness by which the subbands are switched in and out, however, prevents the ear from being tricked into not noticing the missing subbands.
		The cost of this is audible quantization noise in the lower subbands (where bits were taken from) and in the upper subbands (where only a few bits could be added).
	www.music.miami.edu /programs/mue/research/klampert/chap7.html (1038 words)

	Predictive audio encoding (Site not responding. Last check: 2007-10-14)
		Subband filtering, commonly used in all forms of audio data compression, divides the incoming audio into a specific number of equal width frequency bands.
		The four reduced subband outputs, when multiplexed produce a 16-bit apt-X encoded sample, now representative of the 64 bits at the input, a reduction of 4:1.
		The reason is that the data errors only affect the differential signal and because the errors that appear in one subband have no influence on the operation of the other subbands.
	beradio.com /codecs/radio_predictive_audio_encoding (874 words)

	Thesis (K. Lampert) - Chapter 5
		The subbands with the most noise are given the highest priority and are first in line to receive more bits.
		Once the maximum number of bits allowable have been allocated to a subband (now controllable by the first VLBR control) that subband is tagged as full and the remaining bits are given to the other subbands.
		The settings for the advanced subband controls are saved in a file called coolmpeg.ini so that they may be restored each time the dialog box is opened.
	www.music.miami.edu /programs/mue/research/klampert/chap5.html (1969 words)

	Sub-Band Coding
		Using 8-bit mu-law encoding would cut our one channel of CD audio down to about 350k bps, which is better but still pretty high, and is often audibly poorer quality than the original (this scheme doesn't really model masking effects).
		The masking threshold is compared to the maximum signal level for the subband, producing a signal-to-masker ratio (SMR) which is the input to the quantizer.
		The number of bits used to describe bit allocations varies with subband: 4 bits for the low subbands, 3 bits for the middle subbands, and 2 bits for the high subbands (this follows critical bandwidths).
	www.otolith.com /otolith/olt/sbc.html (1840 words)

	ANSDIT - The letter "S" (Site not responding. Last check: 2007-10-14)
		Such data may be further encoded for speech compression or security.
		The term "speech coding" is often used for the combined operation of encoding, compression, and, possibly, encryption.
		The generation of a replica of the original speech from encoded data by the use of a functional unit.
	www.ncits.org /tc_home/k5htm/s3.htm (3706 words)

	EZW Encoding
		When an image is wavelet transformed the energy in the subbands decreases as the scale decreases (low scale means high resolution), so the wavelet coefficients will, on average, be smaller in the higher subbands than in the lower subbands.
		A coefficient in a low subband can be thought of as having four descendants in the next higher subband (see figure 1).
		It is in the encoding of the positions where the efficient encoders are separated from the inefficient ones.
	perso.wanadoo.fr /polyvalens/clemens/ezw/ezw.html (3191 words)

	Digital transmission system using subband coding of a digital signal (EP0400755B1)
		The digital signal is subband coded into M subbands with sampling rate reduction.
		The signal processing unit 9 is adapted to supply output signals on each of the M outputs, an output signal being a combination of at least a number of input signals applied to its 2M inputs.
		Encoding system and encoding method for encoding a digital signal having at least a first and a second digital component
	www.delphion.com /details?&pn=EP00400755B1 (453 words)

	Part II: Subband Coding for Image Compression
		For M subbands and an average b bits per pixel,Bits allocated to the kth subband is given by
		Huffman Encoding is very useful reduces the number of bits per pixel by almost half because of the skewed pdf.
		Since the DPCM error is encoded for the low pass component the image variance to be used in the formula is the error variance and thus ratio of bits of low pass and high pass reduces.
	www.cfar.umd.edu /~namrata/reports/dsp_proj1.html (1931 words)

	Subband Encoding (APGV04 supplement)
		In this paper, we propose a simple approach to HDR encoding that parallels the evolution of color television from its grayscale beginnings.
		We present specifics of the method and the results of encoding a series of synthetic and natural HDR images, using various published global and local tone-mapping operators to generate the foreground images.
		Errors are visible in only a very small percentage of the pixels after decoding, and the technique requires only a modest amount of additional space for the subband data, independent of image size.
	www.anyhere.com /gward/papers/apgv04 (277 words)

	Subband encoding: Facts and details from Encyclopedia Topic (Site not responding. Last check: 2007-10-14)
		Subband encoding is an audio compression audio compression quick summary:
		Subband encoding is used, EHandler: no quick summary.
		Mpeg-1 is the designation for a group of audio and video coding standards agreed upon by mpeg (moving pictures experts group)....
	www.absoluteastronomy.com /encyclopedia/s/su/subband_encoding.htm (477 words)

	AAC beaten at low bitrates, why? - Hydrogenaudio Forums
		I think what he's saying is that subband coding in itself is not patented, but the specific way it's done in Musepack now is.
		Because the FFT in subband coders like MPC is done in psychoacoustics calculations which is a separate process.
		With subband codecs transform coefficients are not used in actual encoding/quantization.
	www.hydrogenaudio.org /forums/index.php?showtopic=2824&st=50& (1426 words)

	[No title]
		Subband encoding is the frequency domain equivalent of multiresolution in signal space.
		Subband Encoding Subband encoding is the process whereby an analysis filter bank decomposes a signal into separate frequency bands, implementing multirate signal processing.
		This action reduces sampling frequency of subbands by a factor of M [3].
	www.eng.auburn.edu /pmc2004/P-HPM1-8.doc (2402 words)

	AAC beaten at low bitrates, why? - Hydrogenaudio Forums
		I imagine that there is a fairly strong positive correlation between a 'challenging sample' for a particular codec, and the bitrate of the encoded file produced by that codec - assuming that you are using a quality based encode (--alt-preset standard, Vorbis -q 6, to name the two which I'm most interested in).
		Then, you would practically have generic music, but you have cut out all the easily encoded bits, and just have the more taxing stuff, which could then be used to better distinguish between encoders.
		So as I just batch encoded at a certain quality level and then deleted the originals, I later found out shit, I can't trust it to encode at a set quality level.
	www.hydrogenaudio.org /forums/index.php?showtopic=2824&st=25 (3750 words)

	AAC beaten at low bitrates, why? - Hydrogenaudio Forums
		Oh, and theoretically subband encoders are not as efficient in encoding some signals as transform coders (frequency based vs time based), but I don't believe that is actually what is causing the bitrate increase here, because certainly the jump would not be that high...
		Since Musepack performs spectral analysis and subband encoding, a Fourier transform is somewhat of a necessity.
		Maybe frames with strong transients could be encoded as well as mpc does, and more tonally simple ones could be encoded efficiently as with aac or vorbis...
	www.hydrogenaudio.org /forums/index.php?showtopic=2824&st=25& (3428 words)

	mpc better quality than aac, why actually? - Hydrogenaudio Forums
		Also note that for the given encoding speed of MPC, it's performance on difficult samples is also typically much better than that of Vorbis.
		There are of course other issues like the lack of widespread hardware support, but none of that is related to the technical attributes and/or limitations of the format itself, but rather are related to "standardization" and marketing of the technology.
		For instance, the very first song I encoded to MPC was Another Rainy Night by Queensrÿche from their 1990 Empire release, using the --radio profile.
	www.hydrogenaudio.org /forums/index.php?showtopic=5306&st=25 (3541 words)

	[No title] (Site not responding. Last check: 2007-10-14)
		A pyramid structure of an image is frequently used in computer vision and image coding since the scheme can inherently achieve a successive approximation or multiresolution.
		For the critically sampled subband pyramid coder, we are making a choice among memoryless encoding, run-length encoding or Shapiro's zero-tree encoding of the subband coefficients.
		For the over-complete pyramid structure, we may use memoryless encoding of the error images or we can apply a transform coding, e.g.
	www.stanford.edu /class/ee368b/Proposals/sehan.txt (202 words)

	(WO 99/04498) METHOD AND APPARATUS FOR ENCODING AND DECODING MULTIPLE AUDIO CHANNELS AT LOW BIT RATES (Site not responding. Last check: 2007-10-14)
		The spatial-characteristics signals may be generated in either or both of two forms.
		In a first form, the signal represents measures of signal levels for subband signals from the input channels.
		Temporal smoothing and spectral smoothing may be applied to gain factors derived from the spatial-characteristics signals in a decoder.
	wipo.int /cgi-pct/guest/getbykey5?KEY=99/04498.990128&ELEMENT_SET=DECL (267 words)

	[No title]
		C.-M. Huang, Q. Bi, G.S. Stiles, and R.W. Harris 413 On 2-D Recursive LMS Algorithms Using ARMA Prediction for ADPCM Encoding of Images..................................
		Anamorphic lenses have been developed that permit this to project "wide-screen" pictures with an aspect ratio of 16:9, in addition to normal lenses that yield a standard television picture of 4:3 aspect ratio.
		Although transform and subband representations appear to be different, in fact, they are equivalent.
	spib.rice.edu /news/imdsp-e-letter/1992.03 (4553 words)

	gcompet.html
		The block encoding method which is used in Digimarc's scheme is susceptible to overencoding by using the Digimarc process a second time on the same image.
		The spread-spectrum subbands are periodic over time/space, failing to utilize more of the available space to embed a watermark message.
		Additionally, when relying on frequency masking to boost the encoding level, as proposed by BBN (US Patent#5,319,735), this same masking acts as a weakness which can be exploited in randomization attacks.
	www.bluespike.com /giovanni/gcompet.html (3438 words)

	Curriculum Vitae
		Al-Asmari, "Low-Complexity Subband Encoding for HDTV Images", IEEE Journal on Selected Areas in Commun., Vol.
		Al-Asmari, "Low Complexity Subband Encoding for HDTV Images," IEEE Proceeding on the Data Compression Conference, Snowbird, Utah, March 23-26, 1992, U.S.A. Awad Kh.
		Al-Asmari, "Compressing the Composite Digital Television Signal by Encoding the Sub-Bands", IEEE Region 10 Inter.
	www.ballasmer.8m.com /cve.htm (2030 words)

	fxguide - visual effects news - Art of HDR
		"Although RGBE is a big improvement over the standard RGB encoding, both in terms of precision and in terms of dynamic range, it has some important shortcomings," says Ward "Firstly, the dynamic range is much more than anyone else could ever utilize as a color representation.
		The full TIFF format was built on the original PIXAR Log Encoding TIFF, which was a log 11bits per channel file format, developed in house at Pixar by Loren Carpenter to maximize the use of their film recorder.
		This new encoding was based on visual perception and designed so that the quantization steps matched human contrast and color detection thresholds much more closely.
	www.fxguide.com /article268.html&mode=nested (5251 words)

	[music-dsp] fixed point lame mp3 encoding (Site not responding. Last check: 2007-10-14)
		In lame mp3 encoding, the = results of subband analysis exceed int, before, i calc subband systhesis = using exponent+mantissa, but it runs slowly!
		But the precision is = not enough, and the SNR of final mp3 encoding with this method isn't as = good as old.
		= But the=20 precision is not enough, and the SNR of final mp3 encoding with this = method=20 isn't as good as old.
	shoko.calarts.edu /pipermail/music-dsp/2001-October/012472.html (270 words)

	No match for subband coding (Site not responding. Last check: 2007-10-14)
		Sorry, the term subband coding is not in the dictionary.
		Please send in a definition so I can add it to the dictionary.
		Nearby terms: STX « su « SUB « subband encoding » subclass » subject » subject index
	ftp.sunet.se /foldoc/foldoc.cgi?subband+coding (59 words)

	Noise reduction: Encyclopedia topic (Site not responding. Last check: 2007-10-14)
		The first really useful audio noise reduction technique was developed by Ray Dolby (Ray Dolby: thumbright200pxdolby (left) is inducted into the nihfray dolby (born january 18, 1933)...
		It was a encode/decode system in which the volume of certain frequencies were increased during recording (encoding), then decreased proportionately during playback (decoding).
		In particular, when recording quiet parts of an audio signal, the high frequency part of the signal would have its volume increased.
	www.absoluteastronomy.com /reference/noise_reduction (976 words)

	Speech recognition with amplitude and frequency modulations -- Zeng et al. 102 (7): 2293 -- Proceedings of the National ...
		Before the subband summation, both the AM and the AM+FM processed
		subbands were subjected to the same bandpass filter as the corresponding
		encoding of the slowly varying changes in intensity and frequency
	www.pnas.org /cgi/content/full/102/7/2293 (4079 words)

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