similar to: Frequency Spectrum fft plot dillema

Jean-Marc Valin wrote: > There is definitely some use for a Neon fixed-point FFT. How much > exactly I'm not sure. Fixed-point is a bit more than just a fall-back Well, we use fixed-point mode by default in Firefox for both Firefox OS and Fennec (Firefox on Android). The reason is that, although there is some NEON-class hardware where float does finally appear to be a little bit

Thanks Timothy and Jean-Marc, I will start NEON optimizing fixed-point FFT. Is it int32 good enough? Benchmark data shows that FFT using int16 is much faster than FFT using int32. > -----Original Message----- > From: Timothy B. Terriberry [mailto:tterribe at xiph.org] > Sent: Friday, December 26, 2014 6:52 AM > To: Phil Wang; opus at xiph.org > Cc: Zhongwei Yao; Yang Zhang; Zhou

There is definitely some use for a Neon fixed-point FFT. How much exactly I'm not sure. Fixed-point is a bit more than just a fall-back for CPUs with no FPU. There are CPUs for which fixed-point is still faster. It depends on the exact model but also on what you run. For example, even on x86 I believe that SILK encoding is slightly faster in fixed-point, even though CELT is faster in float.

Hello! thank you for your efforts creating R! While preparing the next lessons I found that I had to multiply with 1/length(x) by hand if I want to get the inverse Fouriertransform. The help states it will do it by itself. Version R-0.60.1, Linux Seems to be pretty easy to correct either the fft or :-) the help(fft)! Cu Detlef Detlef Steuer Universitaet Dortmund ///////

Hi everyone, I have profiled Opus on AArch64. I just run opus_demo with some pcm files. Following is time proportion of FFT with different bitrate. Bitrate | Time cost by FFT/iFFT 24kb/s | 15% 48kb/s | 15% 96kb/s | 13% Any comment? I want some data close to real application, any suggestion? Thanks, Phil Wang -------------- next part -------------- An HTML attachment was scrubbed... URL:

> I am working on DSP module of Ne10. I see there are fixed-point and > floating-point FFT inside Opus. Is fixed-point FFT only a fall back for CPU > without VFP? On ARMv7-A and ARMv8-A, benchmark result shows that fixed-point > (int32) and floating-point (float32) FFT have similar performance. I guess > fixed-point version is not often used on these platforms. Is it worth the >

Hi, I am working on DSP module of Ne10. I see there are fixed-point and floating-point FFT inside Opus. Is fixed-point FFT only a fall back for CPU without VFP? On ARMv7-A and ARMv8-A, benchmark result shows that fixed-point (int32) and floating-point (float32) FFT have similar performance. I guess fixed-point version is not often used on these platforms. Is it worth the effort to NEON-optimize

I am in the process of dropping the TI DSP lib fft routines into the AEC. Currently, FFTWrap.c uses the USE_SMALLFT and USE_KISS_FFT to select between two packages of FFT routines. ] #ifdef USE_SMALLFT ... #elif defined(USE_KISS_FFT) ... #else #error No other FFT implemented #endif My guess is that every DSP and many other processors will have their own specific FFT and iFFT. What method

Dear Experts, I want to know if the KISS FFT in opus can be replaced with fast FFT. What are the implications & things to be taken care if this is done. Also, I saw in FFT code comments that in-line FFT not supported. Please let me know the reason for this. Thanks in advance. Regards, Mahantesh -------------- next part -------------- An HTML attachment was scrubbed... URL:

The book "Numerical Recipes in Fortran77" by Press, Teukolsky, Vetterling and Flannery describes a way to "pack" the even and odd coordinates of a real vector "R" into a complex vector "C" of half the length. Then using various FFT symmetries, they extract the FFT of "R" from the FFT of "C" which is half the length of "R",

Hi I have made a R function 'convolve2' for convolution of two real valued vectors based on Rs 'convolve' with option type="open" - see below. (exp.length and irf.length are variables set in another part of the program) I wish to implement the function convolve2 in C and use it in a function used from R with .Call - e.g. I need to call fft in C. All I can find in the

Hi Jerry, I'd say the best would be to simply replace the #ifdef USE_SMALLFT by #ifdef USE_TI_FFT #include "ti_fft_wrapper.h" #elif defined(USE_SMALLFT) and have everything in the include file. There's no real point in overriding individual functions since they all go together. Also, make sure you wrap the FFT in the same way as I did with the fixed-point kissfft. For example,

The characteristic function is the inverse Fourier transform of the distribution function. The characteristic function of a normaly distributed random variable is exp(-t^2/2). x=seq(-2,2,length=100) fft(pnorm(x),inverse=T)/length(x) exp(-x^2/2) Why aren't the inverse fft and the mentioned function the same? Thanks for help, Thomas

I am puzzled by a filtering problem using fft(). I don't blame R. I have a waveform y consisting of the sum of 2 sinewaves having freqs f1 and f2. I do s = fft() of y. Remove s's spike at freq=f2 Do inverse fft on s. The resulting waveform still has a lot of f2 in it! But the filtering should have removed it all. What is going on, and how to fix?? Thanks very much for any help. Bill

Hello, I'm new to R (using it since about two weeks), but absolutely a fan of it from the beginning on. :-) Best tool for working with data I found. :-) I tried using the fft() and other funcitons for analysing time series. What I would be glad to have, would be a convenient way to display the complex result of a fft in a way, that real and imaginary parts each use an axis for themselves,

Hi R-users: I want to know if there is an easy way to obtain a Fourier Transform form a vector or an array (just like fft does), but with a more density base. I mean, if I have a vector of 512 of length, I want the Fourier Transform to be 1024, or 2048, etc, in length (de u domain). Or should I modify the fft C code to do that? If I want to modify the precision of the fft function, which

Hello Timothy, Just FYI, Phil at ARM is still looking into why mdct is failing.. will keep you posted. In the mean time, do you want me to disable NE10 for mdct_forward and re-submit the patchset so we may make progress? Regards, Vish On 30 April 2015 at 09:33, Viswanath Puttagunta <viswanath.puttagunta at linaro.org> wrote: > > On 29 April 2015 at 17:22, Timothy B. Terriberry

I'm doing the time-series data analysis using FFT. After fft(), I used spectrum() to calculate the power spectrum, which is used to define the main frequency. Now I want to get the phase information according to this frequency. For example, input 12 time-point data,

Hi, I am a brand new user of R and I have a really stupid problem: I am having troubles applying fft on 2D matrices. I import a data file of 256*256 elements with read.table (it is actually a grey scale image, the corresponding data file being generated with Matlab), and I find that the fft can be applied on one single column of data, but not on one row. (Error message: Error in fft(z, inverse)

Hi Guys, I've just been looking into STATIC_MODES. My plan is to generate and store the modes as part of our sound banks when they are encoded. I have noticed that even with STATIC_MODES turned on, celt_mode_create still allocs and generates the fft and prob members (via pitch_state_alloc and quant_prob_alloc respectively). I also notice that in dump_modes.c, these two members are just