## ITUT G729 preprocessing question

Started by in comp.dsp12 years ago 17 replies

About ITUT G729, I have two questions. 1. In the processing section of G729 spec, it says to apply a high pass filter with a cut-off...

About ITUT G729, I have two questions. 1. In the processing section of G729 spec, it says to apply a high pass filter with a cut-off frequency of 140 Hz. As we know, the range of pitch is between 55 and 400 Hz. Then, how to search the pitch with frequency below 140Hz with such a preprocessing algo? It is as fetching the moon from sea. 2. G729 preprocessing section uses a second ord...

## Cochlea uses "Parallel Hz"

Started by in comp.dsp17 years ago 6 replies

Nerves can fire up to 1 KHz max. At pitches above 1 KHz our cochlea makes-up for this by firing different lines of neurons at succesive cycles....

Nerves can fire up to 1 KHz max. At pitches above 1 KHz our cochlea makes-up for this by firing different lines of neurons at succesive cycles. http://www.cns.nyu.edu/~msl/courses/0022/lecturenotes/pitch/pitch.html "Volley Principle: The volley principle reconciles the fact that the cochlear microphonic mimics the sound pressure waves with the implausibility of the temporal code. Weve...

## Slow Motion Recording

Started by in comp.dsp14 years ago 10 replies

How do you slow down a digital audio recording and keep the same pitch? For example if the audio sample was recorded at 44.1k you could, by...

How do you slow down a digital audio recording and keep the same pitch? For example if the audio sample was recorded at 44.1k you could, by S/W intervention, tell it to play at 22.05k. That will slow it down by half speed. However, it will also lower the pitch by half also. The approach I would take to slow down by 2 is: 1) Find a way to double the frequency of the audio sample. I would try...

## ITUT G729 preprocessing question

Started by in comp.dsp12 years ago

About ITUT G729, I have two questions. 1. In the processing section of G729 spec, it says to apply a high pass filter with a cut-off frequency...

About ITUT G729, I have two questions. 1. In the processing section of G729 spec, it says to apply a high pass filter with a cut-off frequency of 140 Hz. As we know, the range of pitch is between 55 and 400 Hz. Then, how to search the pitch with frequency below 140Hz with such a preprocessing algo? It is as fetching the moon from sea. 2. G729 preprocessing section uses a second order pol...

## Prior art for speech/pitch processing patents (\$50k prize)

Started by in comp.dsp12 years ago 8 replies

My dad forwarded me this yesterday. Maybe one of us can win some...

My dad forwarded me this yesterday. Maybe one of us can win some easy money! https://www.myninesigma.com/sites/public/_layouts/RFPs/NineSigma_RFP_65415.pdf The '055 Patent relates generally to a speech processing system, and more particularly to accounting for periodicity when the pitch period is shorter than the adaptive and fixed codebook vectors. The '485 Patent relates generally to ...

## Request for comments : Non-causal pitch modulation via instantaneous frequency

Started by in comp.dsp8 years ago 3 replies

Hi all ! My goal is to implement non-causal harmonic pitch-shifting on a fully-known real audio signal. * denotes multiplication, ÷...

Hi all ! My goal is to implement non-causal harmonic pitch-shifting on a fully-known real audio signal. * denotes multiplication, ÷ denotes division, exp() denotes exponentiation. (a J b) denotes the complex number of real part a and of imaginary part b. If a is omited it defaults to 0, and b to 1, so that J on itw own denotes (0J1). (m Z p) denotes the complex number of magnitude...

## pitch synthesis and lpc codebooks and excitation signal

Started by in comp.dsp12 years ago 2 replies

I am trying to use gsm network to send secure data encoded as voice. For this purpose during my initial research I used 8 bits as lpc codebook...

I am trying to use gsm network to send secure data encoded as voice. For this purpose during my initial research I used 8 bits as lpc codebook index and 4 bits as pitch index. I used these 12 bits to produce 160 samples of voice like data. I am new to dsp so using my limited knowledge I generated random sequences, passed it thru lpc and used these coefficients to generate codebook. I used impul...

## Timestretching with Granular Synthesis: Keeping the pitch constant?

Started by in comp.dsp13 years ago 4 replies

I have made a program that timestretches WAV sound files using granular synthesis. It has three variable input values: % stretch factor, grain...

I have made a program that timestretches WAV sound files using granular synthesis. It has three variable input values: % stretch factor, grain length (in samples) and grains per second. All seems to be working fine except for one problem I'm having with the pitch of the stretched sound. If, for example, I stretch a sound to 200% with a grain length of 1000 samples and 41 grains per seco...

## Reference implementation of pitch detection

Started by in comp.dsp18 years ago 21 replies

Could someone point me to a reference/example implementation of pitch detection?

Could someone point me to a reference/example implementation of pitch detection?

## Downshifted pitches and sample-rates to decrease bandwidth-usage of audio files.

Started by in comp.dsp14 years ago 6 replies

Hi: Decreasing the pitch of the audio in an audio linear-PCM [wave] file means the sample-rate of the wave file can be decreased without...

Hi: Decreasing the pitch of the audio in an audio linear-PCM [wave] file means the sample-rate of the wave file can be decreased without causing aliasing. If the bit-resolution and # of channels [1 in mono, 2 in stereo] of the file are kept constant, then decreasing the sample-rate will decrease the file size. Adobe Audition allows the alteration of pitch without changing speed. ht...

## Re: OT Re: trying to generate a wave file of 440 Hz...

Started by in comp.dsp11 years ago

When I was a lad, C256 was known as "physicist's pitch". Jerry

When I was a lad, C256 was known as "physicist's pitch". Jerry

## Detectiong CW

Started by in comp.dsp16 years ago 6 replies

What's the slickest way of turning an I/Q data stream, tuned to baseband, into audible Morse Code with user-selectable pitch using strictly...

What's the slickest way of turning an I/Q data stream, tuned to baseband, into audible Morse Code with user-selectable pitch using strictly digital signal processing?

## changer voice

Started by in comp.dsp16 years ago 1 reply

How to change voice (disguise) without formant, pitch analysis,etc, using only simple common DSP method as Hilbert transform and...

How to change voice (disguise) without formant, pitch analysis,etc, using only simple common DSP method as Hilbert transform and forth. Unfortunetly I have some mips only. Maybe this problem hasn't decision in these circumstances ?

## Speed Change

Started by in comp.dsp17 years ago 5 replies

Can you recommend a package that manipulates audio speed without pitch change and is provided with source code (c or c++)? Thanks, Ury...

Can you recommend a package that manipulates audio speed without pitch change and is provided with source code (c or c++)? Thanks, Ury Jamshy.

## how does one change the timbre of a sound

Started by in comp.dsp16 years ago 6 replies

I was wondering how one changes the timbre of a sound without changing the pitch. Igor

I was wondering how one changes the timbre of a sound without changing the pitch. Igor

## Time Domain Harmonic Scaling

Started by in comp.dsp18 years ago 1 reply

Hi, i'm looking for pointers to a more detailed explanation of this approach to time/pitch scaling, after reading stephan sprenger's short...

Hi, i'm looking for pointers to a more detailed explanation of this approach to time/pitch scaling, after reading stephan sprenger's short description @ dspdimension and googling without satisfactory results ... thanks, sammy

## Cepstrum problems

Started by in comp.dsp13 years ago 5 replies

Hello, I'm getting a lot of noise on my cepstum plots, and I wondered if I'm creating them correctly. Even when I play a simple sinusoidal...

Hello, I'm getting a lot of noise on my cepstum plots, and I wondered if I'm creating them correctly. Even when I play a simple sinusoidal sound, I'm getting spikes at certain places, but unstable at other note pitches. I can't currently see how anyone could track pitch if it's right. I tried all combinations of step and FFT point sizes, plus different windowing functions. Also, from th...

## Anti-Doppler

Started by in comp.dsp7 years ago 9 replies

The 'Doppler' thread got me wondering: How would you undo doppler effects to a signal without generating too many inaccuracies. The pitch shift...

The 'Doppler' thread got me wondering: How would you undo doppler effects to a signal without generating too many inaccuracies. The pitch shift is gradual, so there's no way to simply precompute some multirate formula. I'm sure this kind of thing must be common in some sectors. Any ideas on how it's normally implemented?

## whammy

Started by in comp.dsp17 years ago 3 replies

hello I need to code the "whammy" effect (like http://www.digitech.com/products/whammy.htm ) but I didn't find any references to it on...

hello I need to code the "whammy" effect (like http://www.digitech.com/products/whammy.htm ) but I didn't find any references to it on comp.dsp or other sites I checked Is there another name for this effect? Pitch Space maybe? thanks

## voice changer

Started by in comp.dsp15 years ago 6 replies

is it possible to change someone's voice to sound like a particular person's voice? e.g make my voice sound like George Bush(accent, pitch, length...

is it possible to change someone's voice to sound like a particular person's voice? e.g make my voice sound like George Bush(accent, pitch, length of words and all). i'm thinking of doing this as a university project but i am completely new to this field of dsp. are there algorithms for doing this? please advice me.