search for: levinson

...r AVOptions: -lpc_coeff_precision <int> E...A... LPC coefficient precision (from 0 to 15) (default 15) -lpc_type <int> E...A... LPC algorithm (from -1 to 3) (default -1) none E...A... fixed E...A... levinson E...A... cholesky E...A... -lpc_passes <int> E...A... Number of passes to use for Cholesky factorization during LPC analysis (from 1 to INT_MAX) (default 2) -min_partition_order <int> E...A... (from -1 to 8) (default...

...39;s algo. have a few questions. 1) autocorrelation: in the function, _spx_autocorr (for floating point version), there is a line ac[0] += 10; correct me if i am wrong, i suppose the addition of 10 is used to condition the autocorrelation matrix. wonder how the value of 10 is arrived at? 2) levinson durbin (LD) algo in the function _spx_lpc, i referred to some LD algo online. am puzzled with the reflection coefficient's computation. from the code, i understand it to be r = [- Rxx(i) - sum(lpc*Rxx)] / [error + 0.003* Rxx(0)] first question is why is negative of Rxx(i) added? from the r...

...d say. One problem that i encountered is the high dynamic range of the results of the autocorrelation function. Think 96db squared. -> 192 dB ;) That is not very desirable when used as input for further processing. I have most precision issues pretty well under control until before I enter the Levinson Durbin algorithm. The Levinson Durbin routine is where things go bad. I am currently losing 2 dB of SNR when I apply the integerized version. The algorithm seems very sensitive to rounding and precision issues. Is there a way to alter the algorithm or to condition the input values and intermediate...

> 3) a more general question: > i have not been able to find any reason why > 10 lpcs are used. i suppose 10 lpcs are > enough for prediction and using more coeffs > would not have made too much difference. > and 10 is even, good for lpc->lsf. had read > somewhere "historically", during the analog > era, this number is used. or maybe 10 is analagous > to

Hey. The problems with Levinson -type algorithms and integrization are well known. Older codecs have usually solved the problem by using Schur decomposition for inversion of the autocorrelation matrix instead of Levinson. Another solution sometimes used is to use double precision - in this case you probably could code some ps...

Full_Name: Ronnen Levinson Version: 1.5.1 OS: Mac OS 10.1 Submission from: (NULL) (12.232.201.92) The value returned by strptime behaves badly after arithmetic operation and/or combination. > a=strptime("2002-06-01 12:15:01","%Y-%m-%d %H:%M:%S") > a [1] "2002-06-01 12:15:01" > a+0 [...

...fully run it from a command window. Hence, I have the following questions: (1) Is pipe() supported in R1.6.1 under WinXP? (2) Can anyone suggest how to get pipe("gawk...") to work again? Thanks, Ronnen. P.S. E-mailed cc:s of replies posted to the list would be appreciated. -- Ronnen Levinson, Ph.D. \/ RML27 at cornell.edu scientist || http://ronnen.com Lawrence Berkeley National Lab /\ fax 425.955.1992 ====================================== Take my word, the mockingbird'll sing the saddest kind o' song he knows things are wr...

...I would have expected the lower and upper prediction intervals to converge as x increases (and the noise decreases), but they seem to remain virtually equidistant. Can anyone explain (a) the behavior that I see, and (b) how to obtain curves that do bound the noise? Thanks, Ronnen. -- Ronnen Levinson, Ph.D. \/ RML27 at cornell.edu scientist || http://ronnen.com Lawrence Berkeley National Lab /\ fax 425.955.1992 ====================================== I took a speed reading course and read 'War and Peace' in twenty minutes. It involve...

...how acf and pacf works, so I tried to calculate ac and pac manually. For ac, I used the standard acf formula: acf(k) = sum(X(t)-Xbar)(X(t-k)-Xbar))/sum(X(t)-Xbar)^2. But for pac, I could not figure out how to calculate it by hand. I understand that in both R and EVIEWS, it is done using the Durbin-Levinson algorithm by the computer. However, I don't understand exactly how the algorithm works just by looking at the algorithm. Does anyone know if there is a short cut to calculate pac by hand (or in a spreadsheet), or is it too complex of a procedure that a computer is absolutely necessary? It seems...

Hi Jean-Marc, I did what you proposed. I changed the levinson durbin algorithm to: { int i, j; spx_word16_t r; spx_word16_t error = ac[0]; for (i = 0; i < p; i++) lpc[i] = 0; if (ac[0] == 0) { //for (i = 0; i < p; i++) // lpc[i] = 0; return 0; } for (i = 0; i < p; i++) { /* Sum up this...

...h i386 os mingw32 system i386, mingw32 status major 2 minor 6.1 year 2007 month 11 day 26 svn rev 43537 language R version.string R version 2.6.1 (2007-11-26) -- Ronnen Levinson, Ph.D. scientist, Lawrence Berkeley National Lab The Onion horoscope: Pisces February 19 - March 20 You will soon be unwillingly forced into a flurry of activity when you are chosen to host the 2014 Winter Olympiad.

...fortunately is not. :( Does the following FFMPEG's FLAC encoder options affect the subset compliance of stream? -lpc_type <int> E...A... LPC algorithm (from -1 to 3) (default -1) none E...A... fixed E...A... levinson E...A... cholesky E...A... -lpc_passes <int> E...A... Number of passes to use for Cholesky factorization during LPC analysis (from 1 to INT_MAX) (default 2) -prediction_order_method <int> E...A... Search method for se...

Hello, I have read recent posts on this topic (Dr. Ronnen Levinson's Monday 02:39:55 pm), but before I install a 64 bit system, and purchase more RAM, I want to make sure I understand this interesting issue. I was attempting to plot a data frame containing Dow Jones stock information: > length(Date) [1] 19957 > length(Close) [1] 19957 > head(DowJo...

...uccessfully in both versions of R... plot(c(1,2),main=expression(a*"="*b*"="*c)) ...but I don't really understand why the first version works in 1.8.0 and not in 2.0.1. Yours truly, Ronnen. P.S. E-mailed CCs of posted replies appreciated. -- Ronnen Levinson, Ph.D. \/ [1]RML27 at cornell.edu scientist || [2]http://ronnen.com Lawrence Berkeley National Lab /\ fax 425.955.1992 ====================================== Men in colored shirts and seersucker suits, women in slacks and midriff dresses displa...

...to quantize the spectral envelope instead of simply quantizing the cepstrum (DCT(log(envelope))) or modified cepstrum (DCT(envelope.^alpha)). To me it seems like when the information is already in the frequency domain, there's no need to go back to LPC. Also, I think a DCT can be faster that a Levinson-Durbin recursion. This is why I'd like to know whether there's a special reason I'm not aware of for quantizing the LSP. Jean-Marc -- Jean-Marc Valin Universite de Sherbrooke - Genie Electrique valj01@gel.usherb.ca --- >8 ---- List archives: http://www.xiph.org/archives...

...UAL_ALLOC enabled ( similar to the c5x/c6x configuration). In file sb_celp.c, I noticed the scratch memory grow during recursive (UWB -> WB) calls to 'sb_encode'. 1. 'stack' was not tracked (with 'tmp_stack' as done at other palaces) after/before - auto-correlation/Levinson-Durbin scope (~line 597 - 621). 2. Similarly in the sub-frame encode loop (last major loop) after/before - LSP-interpolation/weighted-signal-frm-synthesized-speech calculations (~line 762 - 950). In <1>, the scope of the variable over after the braces, so I think that memory allocate...

Hi Jean-Marc I'm looking at the 1.0.5 source, and I'm not seeing an _spx_lpc(). There's an _spx_autocorr(), which is in lpc.c and is called near the start of the encoder function in nb_celp.c. The encoder seems to call the autocorr() function, then calls wld() to do something called Levinson-Durbin. Am I right in thinking that after the call to wld(), the st->lpc[] array contains the coefficients? Later on it computes "interpolated" LPCs -- are these what I want? Thanks again for the help -- it's appreciated! On 2/2/07, Jean-Marc Valin <jean-marc.valin@usherbr...

O.k., some more info: I just tested bandwidth widening to fix this. But I need to go to gamma values below 0.9 to become stable -- clearly too much widening, I think. I looked inside the Levinson-Durbin algorithm next. The lines #ifdef FIXED_POINT r = DIV32_16(rr+PSHR32(error,1),ADD16(error,8)); #else r = rr/(error+.003*ac[0]); #endif look interesting. While for floating point, .003*ac[0] is added to error, for fixed point, a constant value of 8 is added. When I alter this val...

Hi. Can anyone suggest a simple way to obtain in R a list of vector coordinates of the following form? The code below is Mathematica. In[5]:= Flatten[Table[{i,j,k},{i,3},{j,4},{k,5}], 2] Out[5]= {{1,1,1},{1,1,2},{1,1,3},{1,1,4},{1,1,5},{1,2,1},{1,2,2},{1,2,3},{1 ,2,4},{1,2, 5},{1,3,1},{1,3,2},{1,3,3},{1,3,4},{1,3,5},{1,4,1},{1,4,2},{1,4,3}, {1,4,

...Susan age=20 weight=130 Is there perhaps a clever solution involving expression()? Thanks, Ronnen. > version _ platform i386-pc-mingw32 arch i386 os mingw32 system i386, mingw32 status major 1 minor 5.1 year 2002 month 06 day 17 language R -- Ronnen Levinson, Ph.D. \/ RML27 at cornell.edu scientist || http://ronnen.com Lawrence Berkeley National Lab /\ fax 425.955.1992 ====================================== Should I marry W.? Not if she won't tell me the other letters in her name. -- Woody Alle...