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Discussion Groups > Compression


Comp.dsp is a worldwide Usenet news group that is used to discuss various aspects of digital signal processing.

We found 497 threads matching "compression"

You are looking at page 1 of 13.

The most relevant threads are listed first

Amplitude Compression

bogfrog - 2008-08-04 22:54:00
I am working on audio, samples are 16 bits, values ranging from -1 to +1 for each sample. I want to implement what a paper I am reading calls "amplitude compression." These are the 3 specifications given for the amplitude compression I want to implement: (1) Compression ratio of 8.94:1 for |A| ...Amplitude Compression

Custom compression methods

Hi. Just out of curiosity, has anyone designed and built their own method for music compression. I realise that the ogg format is open-source and relatively unencumbered by licencing issues. But I'm curious if anyone has written their own compression method "because they can". Cheers, Ross...Custom compression methods

aggressive compression

HyeeWang - 2009-05-04 02:57:00
What is "aggressive" compression technology? How to identify a aggressive compression algo, especially in speech coding domain, which is my interst. Anyway, i am talking the concept of "aggressive " used here. Any comments would be appreciated! HyeeWang ...aggressive  compression

Re: Audio Compression

Jerry Avins - 2007-03-26 08:52:00
Udhay wrote: > Thanks for your reply. > > I want to know about the data compression of audio. > > i need some links regarding this. > > which algorithm is good example for audio compression? MP3 is widely used for music and general sounds. Other methods are more efficient for...Re: Audio Compression

Newbie Question

nija - 2007-05-25 06:44:00
Hi all, I am new to the field of DSP/Video Compression. I wanted to learn MPEG 4 Video Compression standard in particular as it is required in my current project which is about Live Video streaming using RTSP/RTP protocol on the internet using MPEG 4 codec. I have read some articles/ISO st...Newbie Question

Anybody using compression option for blackfin loader?

Andre - 2008-11-06 06:08:00
Hi VDSP-Experts, I am trying to use the "compression" feature of the loader on the BF533 with VDSP5.0 update 4. I have ticked "enable compression" in project options and selected a zlib init file in load/options. The only thing I modified from the default one (ADSP-BF533_zlib_init_SDRAM.dx...Anybody using compression option for blackfin loader?

Wavelets compression for circular data?

Ksen - 2006-08-16 09:35:00
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 disc...Wavelets compression for  circular data?

Image compression DSP

amerdsp - 2006-04-20 20:20:00
Greetings, I am looking for a low power image compression for a mobile application. It is meant to compress image data from an image sensor so it can be transmitted over GPRS. Does anyone have any recommendations? Currently I am still looking for a microcontroller, probably a PIC to do th...Image compression DSP

Low complexity compression algorithm

I. R. Khan - 2004-01-26 21:16:00
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...Low complexity compression algorithm

Voice Compression for digital storage and playback

Kunal - 2004-06-18 16:17:00
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 algo...Voice Compression for digital storage and playback

Re: how do I do DCT on a 100x100 image?

SteveSmith - 2008-05-28 16:37:00
Is this simply for data compression, or are you trying to extract key parameters from the original data set? If for data compression, is a lossy algorithm OK, or do you need it to be lossless? ...Re: how do I do DCT on a 100x100 image?

DWT and Data Compression

Umutesi Faith - 2006-03-29 13:54:00
Hello About the DWT: The DWT provides data compression by setting a threshold value and all coefficients that are less than the choosen value will be reduced to zero or eliminated and the signal can be reconstructed from the thresholded coefficients. Therefore, I would like to ask about the lo...DWT and Data Compression

"Lena" or similar compression tests

2008-03-17 13:43:00
Does anyone have source data for any standard image compression images such as "Lena" in integer/unsigned char format? If not - is there an easy way I can obtain this by opening an image in Matlab? Cheers Gary ...

DCT in audio compression

eblade - 2008-09-20 09:28:00
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 cor...DCT in audio compression

Regarding PSNR for audio compression

vasindagi - 2008-07-05 10:33:00
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? ...Regarding PSNR for audio compression

AAC compression chips? Other compression chips?

Michal - 2003-11-25 22:29:00
Dear All, I'm looking for inexpensive hardware solution (chips) to encode groups of 6 channel 44/48k signals into streams of preferably AAC. Or WMA or MP3 or AC-3 if it is simpler. The idea is that signal is input as regular 48k/24bit pcm, than the user can select compression DR (eg 64kb...AAC compression chips? Other compression chips?

Floating Point Data Compression?

DigitalSignal - 2008-11-06 17:19:00
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 ...Floating Point Data Compression?

Compression artifacts

HyeeWang - 2009-05-04 04:08:00
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 c...Compression artifacts

SNR penalty due to Linear Interpolation

cpshah99 - 2009-03-18 14:25:00
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/com...SNR penalty due to Linear Interpolation

Standard audio compression (LA-2A, not MP3) algorithm

Pat Farrell - 2005-10-14 00:19:00
This may be a FAQ, but I don't see one, and you guys seem pretty smart. Is there a standard algorithm for doing audio compression in a DSP context? I mean the type of compression that recording studios and radio stations used to use a Universal LA2A or Universal Audio 1176LN. While these are t...Standard audio compression (LA-2A, not MP3) algorithm

references for image compression with neural networks

cyril prasanna raj.p - 2004-05-04 01:52:00
Where can i find the recent literature on image compression with neural networks? ...references for image compression with neural networks

WSQ image library for Texas Instruments family microprocessors released

2008-12-05 00:07:00
Cognaxon has released "WSQ image library" for Texas Instruments family microprocessors (embedded systems). Importance of WSQ format: Electronic fingerprints submitted to the FBI either through Integrated Automated Fingerprint Identification System (IAFIS), or Electronic Fingerprint Image Prin...WSQ image library for Texas Instruments family microprocessors  released

ask for help on Hi Fidelity Audio Compression with ADPCM

Jessecw - 2006-12-08 01:14:00
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 m...ask for help on Hi Fidelity Audio Compression with ADPCM

ask for help on Hi Fidelity Audio Compression with ADPCM

jessecw - 2006-12-08 14:14:00
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. ...ask for help on Hi Fidelity Audio Compression with ADPCM

In what "dimension" does JPEG compression loss occur for color images

Richard Owlett - 2006-02-02 15:21:00
I understand that JPEG is a "lossy" compression method. For color images is loss in: 1. resolution 2. color depth a. would that include contrast 3. resolution AND color depth I intuitively suspect #3. If so is it possible trade off resolution for color depth and vice versa? ...In what

Video Compression

Vladimir Vassilevsky - 2006-11-04 18:35:00
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 mu...Video Compression

Wavelets for circular data?

Ksen - 2006-08-16 13:03:00
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...Wavelets for circular data?

video compression java code

nandoscherp - 2007-11-12 19:50:00
Hi there! Does anyone have a source code of any video compression algorithm in java? Thanks! ...video compression java code

MPEG video compression

jerome - 2005-05-24 10:12:00
Hi guys, I'd like to know if some of you have already implemented MPEG (2 or 4) video compression on DSP. What free source codes have you used ? Could you give me some links to good free source codes ? I've searched on the net but haven't found anything really good. Thanks for your help. ...MPEG video compression

dynamic compression/noisegating/sound schemes

Thomas Pototschnig - 2004-08-07 19:26:00
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 ...dynamic compression/noisegating/sound schemes

Re: Sampling rate conversion

cpshah99 - 2009-02-10 16:16:00
Hi thanks a lot for ur reply. I have done something using linear interpolation but then I should get some kind of compression of the signal, but I am not getting that. Now, my o/p sampling rate is 47968 Hz. so what i did was generate the signal at 96 KHz and do linear interpolation. but ...Re: Sampling rate conversion

MPEG2 MP@LL and MPEG1?

Davy - 2005-09-04 10:32:00
Hi all, I heard that MPEG2 and MPEG1 use same compression methods. MPEG2's MP@LL and MPEG1 are all 4:2:0, 352*288*30. But MPEG2's MP@LL is 4Mbit/s and MPEG1 is 1.5Mbit/s. Why they have different bit rates? And if I want to do 352*288*30 video compression. Shall I choose MPEG2 or MPEG1?? ...MPEG2 MP@LL and MPEG1?

Re: data file similarity metric/software

Andor - 2005-03-22 05:21:00
Matt, after having read your first two paragraphs, I was going to suggest what you wrote in the third. Why don't you try a string alignment algorithm? That also gives you quantitative measures for metrics and quality / relevance of the alignment. Another approach could be via the Kolmogorov...Re: data file similarity metric/software

DSP algorithm for Image compression

SHIBASIS - 2003-07-22 15:02:00
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 ima...DSP algorithm for Image compression

Wavelet data compression

Umutesi Faith - 2006-09-12 04:30:00
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 recon...Wavelet data compression

Probably NAIVE question on (lossy?) voice compression

Richard Owlett - 2004-04-19 16:14:00
I'm interested in settling in my own mind what makes speech intelligible. In past wanderings of the WEB I have gathered the impression that there are a wide variety of compression.decompression algorithms available depending on your optimization target. Unfortunately, I don't have a good re...Probably NAIVE question on (lossy?) voice compression

G.728 re-entry algorithm

P.Krishna - 2006-07-12 10:16:00
Hi, We have G.728 speech compression algorithm for ADSP218x DSP, as per my understanging it works for only one channel. To make multiple channels work we need to use G.728 re-entry algorithm for ADSP218x DSP, where can I get this algorithm? earlier we bought G.728 speech compression algorithm from ...G.728 re-entry algorithm

switched ADPCM

Jessecw - 2006-12-14 05:45:00
Hi All, I am preparing to develop an real time audio compression codec for high quality audio signals. Due to the heavy calculation burden, I will not adopt MP3 as my compression algorithm. I get from google search engine that there is an algorithm called switched ADPCM that can code high q...switched ADPCM

Re: Aliasing in MDCT

Chris Felton - 2009-01-15 11:48:00
> But where exactly does the time-domain aliasing occur in the > reconstructed signal, and why? In most applications, such as audio compression, the aliasing is directly from the transform. You can go to the frequency domain and back without any aliasing, using the DFT, DCT, etc. If you ...Re: Aliasing in MDCT

Re: Internet Stream Audio [Was Re: Bit-resolution decrease for internet]

Ben Pope - 2003-12-15 03:04:00
Radium wrote: > Transistor can only be "on" or "off". However, regions on a magnetic > disc do not need to be, So along with your CoDec (which is clearly impossible because compression has been around for a long time, is well understood and has been proven that you cannot compress a signal ...Re: Internet Stream Audio [Was Re: Bit-resolution decrease for internet]
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