## Forums Search for: Compression

## DCT in audio compression

inAfter reading, what seems like a lot of material, I'm still in doubt why DCT isnt used in audio-compression. Seeing as DCT assumes mirror...

After reading, what seems like a lot of material, I'm still in doubt why DCT isnt used in audio-compression. Seeing as DCT assumes mirror symmetry, my only idea for not validating DCT over MDCT is that with real-life signals you can rarely (if ever) expect a signal to have that property? Is that correct or is there a better explanation.

## Video Compression

inHello All, The task is to transmit the grayscale video over the ethernet in the real time. The input stream is 8bpp, 1024x768, 25fps. The...

Hello All, The task is to transmit the grayscale video over the ethernet in the real time. The input stream is 8bpp, 1024x768, 25fps. The compressed stream should be no more then ~30Mbps. The available computing power is ~300MIPS of the general purpose DSP. It is desired to preserve as much quality as possible. Do you know of a video compression algorithm which can fit into those ...

## Regarding PSNR for audio compression

Its known that PSNR (peak signal to noise ratio) is used to compare image quality after compression. Can it also be used for audio quality?

Its known that PSNR (peak signal to noise ratio) is used to compare image quality after compression. Can it also be used for audio quality?

## Wavelet data compression

inHello I am trying to do some data compression using the DWT techniques but i have encoutered some problems. Once i have set the threshold...

Hello I am trying to do some data compression using the DWT techniques but i have encoutered some problems. Once i have set the threshold values, all the DWT coefficients that were less than the chosen value were reduced to zero which was the purpose. But on the other hand i would like to reconstruct the signal using only the remained coefficients without using those coefficients replaced wit...

## Floating Point Data Compression?

inHi there, A quick question: Is there any way to compress the single point floating point data? Apparently most of the research and development...

Hi there, A quick question: Is there any way to compress the single point floating point data? Apparently most of the research and development work focuses on fixed point compression. James www.go-ci.com

## Compression artifacts

inCompression artifacts in compressed audio typically show up as ringing, pre-echo, drop-outs, warbling, metallic ringing, an underwater feeling,...

Compression artifacts in compressed audio typically show up as ringing, pre-echo, drop-outs, warbling, metallic ringing, an underwater feeling, hissing, or "graininess". How and when the artifacts above occured? Where can i get the appropriate speech samples to taste the effect? More,anyone can explain how the artifacts come into being in detail? Any coments would be appreciated. Rega...

## Voice Compression for digital storage and playback

inI am making a Digital Dictation Machine and I need a solution to digitize the voice, compress it and store it on a flash chip. It should then...

I am making a Digital Dictation Machine and I need a solution to digitize the voice, compress it and store it on a flash chip. It should then also be able to decompress it and play it back through a d/a. I need to control it using I2C. Questions: 1) Which are the latest voice compression algorithms out there?. i know of a-law u-law, but what about the ones used in cell phones and other ne...

## compression knee interpolation

inhowdy, i have a perhaps kind of silly question. i'm trying to program a compressor with a variable knee, expressed as dB above and below...

howdy, i have a perhaps kind of silly question. i'm trying to program a compressor with a variable knee, expressed as dB above and below the compression threshold. given the threshold, knee and ratio, i'd like to compute an interpolation function (preferably a polynomial for speed) that matches the values and first derivatives at the start and endpoints of the knee region. to be a li...

## references for image compression with neural networks

inWhere can i find the recent literature on image compression with neural networks?

Where can i find the recent literature on image compression with neural networks?

## motion sensor signal compression/prediction

Hi folks. I'm currently chewing on the following problem: I have a bunch of huge motion sensor signals to lossy compress. Since I need...

Hi folks. I'm currently chewing on the following problem: I have a bunch of huge motion sensor signals to lossy compress. Since I need random access to the samples block based compression schemes are out of question. The current approach works like this: I store every 8th sample, quantized from 32 bit down to 8 bits and use this as a rough approximation of the signal. Along with t...

## Linear prediction optimization?

Hey guys. So far, I've posted on a forum and a mailing list with no results, and only= just realized it's probably best to ask this question...

Hey guys. So far, I've posted on a forum and a mailing list with no results, and only= just realized it's probably best to ask this question on a DSP-specialized= group. (Sorry that my first post is a question > _

## ask for help on Hi Fidelity Audio Compression with ADPCM

inHi all, Currently, I am studying on how to get Hi Fidelity effects with ADPCM related compression methods. But it seems that the...

Hi all, Currently, I am studying on how to get Hi Fidelity effects with ADPCM related compression methods. But it seems that the traditional IMA ADPCM and MS ADPCM will not get the satisfied results. Any one can give me some suggestions? 16 bit PCM to 5 bit PCM will be accepted by me. Thanks in advance. Jessecw

## ask for help on Hi Fidelity Audio Compression with ADPCM

inHi all, Currently, I am studying on how to get Hi Fidelity effects with ADPCM related compression methods. But it seems that the...

Hi all, Currently, I am studying on how to get Hi Fidelity effects with ADPCM related compression methods. But it seems that the traditional IMA ADPCM and MS ADPCM will not get the satisfied results. Any one can give me some suggestions? 16 bit PCM to 5 bit PCM will be accepted by me. Thanks in advance. Jesse

## Wavelets compression for circular data?

Is anyone aware of doing wavelet based compression of arrays of angular data (or phase data)? Instead of normal grau=yscale images, you have...

Is anyone aware of doing wavelet based compression of arrays of angular data (or phase data)? Instead of normal grau=yscale images, you have values from 0-360 degree (which you can quantize between 0-255), but if you have two neighboring pixzels with values of 255 an d0, dont treat it like a discontinuity.. hence this is tricky! Also, would the SAR imagery community (or any other community)...

## dynamic compression/noisegating/sound schemes

inhi NG I want to develop an small extern device with a small DSP for improving audio with dynamic compression, noise gating and sound...

hi NG I want to develop an small extern device with a small DSP for improving audio with dynamic compression, noise gating and sound schemes. But before I can start with the hardware and software of the DSP I want to test different algorithms on the PC. Unfortunately I didn't find anything which can help me for this project in the internet. Now my question: Does anyone know good sour...

## SNR penalty due to Linear Interpolation

inHi All As we know that due to relative motion between TX and RX, the transmitted signal undergoes expansion/compression. And due to this symbol...

Hi All As we know that due to relative motion between TX and RX, the transmitted signal undergoes expansion/compression. And due to this symbol and phase synchronization is lost. I have simulated this perticular thing, where I am using matlab's resample function to introduce this expansion/compression. Now, at receiver I have used adaptive linear interpolation to correct this expansion/c...

## Low complexity compression algorithm

inHi all, I posted this to comp.comression but perhaps some one here can also help me. I am working on a project related to 3D modelling, and...

Hi all, I posted this to comp.comression but perhaps some one here can also help me. I am working on a project related to 3D modelling, and need some simple algorithm to transmit 3D meshes to cell phones. As 3D meshes have quite large data and cell phone's CPU is not as powerful as that of a PC, the compression algorithm should be of very low computational complexity. I am asked to make ...

## Formula to calculate the rate for a compression algorithm

inHi all, In the case I don't know the sampling frequency. Specifically, I only given a discrete function: f[n]= blah blah..... with length...

Hi all, In the case I don't know the sampling frequency. Specifically, I only given a discrete function: f[n]= blah blah..... with length N. I use wavelet based compression method: Decompose the signal into N wavelet coefficients, quantize and then encode these coefficients with M bits for each coefficient. Now to report the algorithm, I need to submit it's RATE. In the case, wh...

## basic questions on jpeg compression

inFolks, I have few basic questions on related to compression used in JPEG. 1. Is the DCT applied over Y, CB and CR separately? 2. Is there...

Folks, I have few basic questions on related to compression used in JPEG. 1. Is the DCT applied over Y, CB and CR separately? 2. Is there a specific reason why DCT is chosen over DFT? 3. Can quantization step be roughly seen as a filter since it basically tones down high frequency components? As an observation on point 3 above, we know that filter aims to achieve high attenuation i...

## DSP algorithm for Image compression

inDear All, I am a new member in this group, I am developing a image compression algorithm on a texas dsp tms320c6701.The algorithms needs to be...

Dear All, I am a new member in this group, I am developing a image compression algorithm on a texas dsp tms320c6701.The algorithms needs to be run within 0.1 sec.The DSP has a processing speed of 160Mhz. What kind of algorithm will I choose.I am looking for a algorithm that can compress the image about 80%.How can I analyze, how much time my dsp algorihm is taking. I am using the texas instr...