search for: quantized

Hi all, I'd like to quantize a variable to map it into a limited set of integers for use with a colormap. "image" and filled.contour" do this mapping inside somewhere, but I'd like to choose the colors for plotting a set of polygons. Is there a pre-existing function that does something like this well? i.e., is capable of using 'breaks'?

Hi. I have been talking with Psytel MPEG-4 AAC developer (www.psytel.com) about various compression formats, and to make it short he said that one of the main drawbacks of Vorbis is its vector quantization - it introduces more error then other quantization methods (like non-uniform scalar quantization, if I got it right), probably used in AAC and other similar codecs. I know vector quantization

I have some data measured with a coarsely-quantized clock. Let's say the real data are q<- sort(rexp(100,.5)) The quantized form is floor(q), so a simple quantile plot of one against the other can be calculated using: plot(q,type="l"); points(floor(q),col="red") which of course shows the characteristic sta...

...tive to quantization error. I don't know how much space the LPC coefficients occupy in the resulting FLAC file - if its not much, it probably doesn't matter. But if its a significant amount of data, it might be better to convert the LPC coefficients to LSF/LSP coefficients, and store those quantized. This should provide the same quality at a lower bit count, if I'm right. Here is a link that describes LSF/LPC coefficients: http://en.wikipedia.org/wiki/Line_spectral_pairs ? Cu... Stefan -- Stefan Westerfeld, Hamburg/Germany, http://space.twc.de/~stefan -------------- next part ---------...

...doc/html/format.html | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/doc/html/format.html b/doc/html/format.html index 8598941..2ce82c2 100644 --- a/doc/html/format.html +++ b/doc/html/format.html @@ -1578,7 +1578,7 @@ &lt;5&gt; </td> <td> - Quantized linear predictor coefficient shift needed in bits (NOTE: this number is signed two's-complement). + Quantized linear predictor coefficient shift needed in bits (NOTE: this number is signed two's-complement and must be non-negative). </td> </tr> <tr> -- 2.4.9...

I am, as this question will make very obvious, not exactly a guru when it comes to audio under Linux. I'd like to record some prompts using a nice microphone and my Ensoniq sound card, and then convert them to gsm/wav for use with asterisk. What Linux command would I use to a) do the recordings, and then b) convert them to the appropriate formats? I know there are

(Disclaimer: this is not an LPC vs. LSP question) After looking at the Vorbis code I was wondering why you were using LSP 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

Comments? ---------------------------------------- "Mark Taylor" <mt@sulaco.org> wrote: [...] > This is related to one minor objection I have to vector quantization > based codecs like Vorbis and the MPEG4 VQ codec: they do not compute > the quantization noise during the encoding process. The choice of > codebooks (use a big codebook: low quantization noise, use a

Hello! I just noticed how the LPC prediction is quantized by browsing the source code of the java port jFlac: : int sum = 0; for (int j = 0; j < order; j++) sum += qlpCoeff[j] * data[startAt+i-j-1]; data[startAt + i] = residual[i] + (sum >> lpQuantization); : I checked the C version (libFLAC) and it matches. However, it was a surprise be...

...a much better approximation to the sphere. In OVQ, the resolution parameter K is replaced by two (int) parameters A and B. Quantization then proceeds very simply: all components greater than B are subjected to PVQ (after subtracting B) with resolution A, and all components less than B are scalar-quantized. Thus, setting B=0 gives PVQ, and setting A=0 gives scalar quantization. In L dimensions, for large L, the best approximation to a sphere should happen at a ratio of A/B = sqrt(L). I believe that OVQ is asymptotically better than PVQ, but a fair comparison is tricky because for B>0, they requ...

Here's the problem: > 2) Encoding with rate control as in single pass "Bitrate > control" will not > lead to better quality than fixed quant (with the right value > of the fixed > quant). Ratecontrol doens't know anything about "quality". It > will try to > reach more-or-less CBR. > > But somehow this is not a fair comparison, because

Hi I am a student and working on Speech Coding and Speex. I just want to know where to get the document describing subvector quantization of innovation. Is there any document which can help me know how C code works or any paper exactly explainin the idea? regards Faisal __________________________________ Do you Yahoo!? Friends. Fun. Try the all-new Yahoo! Messenger.

...positive shifts are encoded and the decoder only accepts positive shifts. The ffmpeg FLAC encoder and decoder show the same behaviour. Now, the documentation in the source code is fixed, the documentation on the website (which I was looking at) isn't yet. The website format.html states: "Quantized linear predictor coefficient shift needed in bits (NOTE: this number is signed two's-complement)." The source code format.html says "Quantized linear predictor coefficient shift needed in bits (NOTE: this number is signed two's-complement; but, due to implementation details, must...

Tristan Matthews wrote: > Refs http://sourceforge.net/p/flac/bugs/424/ > - Quantized linear predictor coefficient shift needed in bits (NOTE: this number is signed two's-complement). > + Quantized linear predictor coefficient shift needed in bits (NOTE: this number is signed two's-complement and must be non-negative). Maybe it's better to explain why? At least...

Hi, I am kind of new to DTrace , I have written a script to time function calls in our application library , Wanted to know how to interpret the output from quantize of the elapsed time in each function call , here is a sample Here is the entry and return function for the library that is being traced pid$1:libswduar::entry { duarEntry[probefunc] = timestamp;

Hello everybody, my name is Francesco, I am an italian student graduating in physics. I'm studing the Theora video codec and making some comparative tests. Unfortunately i'm not able to find some informations that could be useful. If someone could make clear some concepts, (or tell me where i can find these informations), i'll be very happy. ( I've yet read the Theora Format

Hi, I'm studying at ETH Zurich and want to use a pyramid vector quantization for my semester thesis. Unfortunately, I have some troubles with generating the codebooks for high dimensions. For vectors with dimension bigger than 12 it takes such a long computation time to generate. I thought maybe you could help me out with a efficient way to do this? Is there some code available? Thanks for

Hello Srikant - A quantization distributes the results of your aggregation into ranges ordered by a power-of-two. Presumably what you''d do in your script is capture the inclusive elapsed time of each function call in your library, then use this quantization to see how tightly-banded the times are. Perhaps there''s some blocking I/O in some of your calls, for example, in which

I have a probe: pid111::myfunc:entry { self->arg = arg0; } pid111::myfunc:return /self->arg/ { @[self->arg] = quantize(); } works great, but i''d like arg0 to be printed in hex. I''ve tried numerous approaches to do this but i''ve hit a wall every time. I''ve tried: 1) self->arg = sprintf(arg0); no, cuz dtrace has no sprintf 2) self->arg

Hello! I'm an Italian student in computer engineering (University "Federico II" of Naples) and I have to write my graduation thesis in the field of signal processing. My teacher (Prof. Giovanni Poggi http://www.diet.unina.it/giovanni.poggi/) has published a research about multiple description vector quantizers by means of the self organizing maps, applying his idea to the images and