similar to: Monty on holiday

Hello, Jean-Marc Valin schrieb: >>I am planning on creating a steganographic extension for speex/CELP. >>Since speex/CELP is lossy, there should be quite many bits that one >>can use for hiding data. > > Quite the opposite. Speex uses very few bits, so every bit you corrupt > is likely to be heard. You would need to use "fractions of bits" at a > time.

During the interesting interview that binaryfreedom has made with Monty and Jack, Monty mentions cascading, a feature that will be added, quote: "Cascading is the ability to make multiple passes through the frequency spectrum, iteratively filling in more detail, like a progressive jpeg". What are the advantages of something like this - does this generally improves quality or is it used

Hi I have gone through the document available in the net regarding the Vorbis encoder /Decoder. Based on that i have prepared a understanding document on the encoder/decoder block. I would like to know whether my understanding of the coder is OK. If there are any other additional block /information pl. provide me with the same. Thanks and regards S.Padmashri <HR NOSHADE> <UL>

(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

Hi, Can someone please tell me how should I go about changing the frame size which is hardcoded to 160 for NB and WB and 320 for UWB. For NB speech(8KHz) the framesize of 160 is 20ms frame but for WB and UWB its 10ms. What are the parameters being affected by simply changing the framesize and sub-frame size in "modes.c" How to change the buffer size and how its affected. can we have a

Hi, can someone help me understand and experiment with Speex in a better way than my knowledge. I want to change the LPC filter order of the Speex algorithm. I think I need to change the LPC order( or lpcSize) in modes.c file. but to make it work I need to modify the codebook also, can someone tell me how to go about changing the codebook entries to support the changed order of prediction.

Hi folks, I'm doing a merge of my current branch onto the mainline (for testing) today. I believe it to be stable. Just a little more vorbisfile testing. After the merge, I have a few more patches to apply, then onto cascading/coupling. New stuff: Floor backend 1 and residue backend 1; both are present, but the mainline modes won't use either yet. Naturally, both are enabled for

Okay, Not exactly the answer I was looking for. This sounds like a big change. I don't mind re-writing the LSP quantizer but re-training code books and breaking compatibility is not what I want to do. I am working on an optimization for an ARM cortex-A8. It is desirable to process things in 4 element blocks. Is there a simpler approach you could recommend? Vasant Shridhar

Hi folks, some notes about goings on. After opportunity to think aloud, I have the pieces of the VQ system more or less in place. I need to finish the codebook generation core (this is not libvorbis code, but an external utility). I then need to write the encode/ decode/packing code that makes use of the codebook. This future code is already specced. Tony: I haven't worked on the xmms

Hi folks, some notes about goings on. After opportunity to think aloud, I have the pieces of the VQ system more or less in place. I need to finish the codebook generation core (this is not libvorbis code, but an external utility). I then need to write the encode/ decode/packing code that makes use of the codebook. This future code is already specced. Tony: I haven't worked on the xmms

I would like to make lpcSize a multiple of 4. In the current library for narrow band mode lpcSize is currently set to 10. I would like to increase this 12 for optimization reasons. Is it a simple matter of just changing lpcSize in the structures in mode.c or are there other implications to doing this? I did try and change the value but I seem to be getting some runtime errors indicating a

I've not so much bandwidth to add channel coding but i've few bytes to spare for error detection. With a polynomial CRC-8 i've already more than 99.6 % to detect a burst error in a frame. So let's suppose the critical fields of Speex are: Wideband bit Mode ID LSP OL pitch OL pitch gain OL Exc gain So my plans are to calculate a CRC on these fields for each frame i send, then if i

Hi Jean-Marc, I thought at quality 3 (wideband) - wb_submode1 that the 4-8k band was not using a codebook table. From the code I can see that some sort of "lsp" encoding is performed. What exactly does this encode? (I assume lsp means line-spectral pairs) The reason I am asking is I'm comparing the "effective" spectral bandwidth of Speex against the

Hello kind developers, I am planning on creating a steganographic extension for speex/CELP. Since speex/CELP is lossy, there should be quite many bits that one can use for hiding data. I'm familiar with the principles of CELP (two filter loops, one for pitch, the other for formants, let the raw speech frame run through those filter loops, take residue signal, map it on a codebook entry,

Hi, Jean-Marc Valin wrote: > Not sure I understand your question. Change the order of what within what? In cb_search, we iterate nb_subvect times over a codebook, finding nb_subvect codebook entries to quantize the excitation signal. After finding these nb_subvect codebook entries, they're written into the stream: /*save indices*/ for (i=0;i<nb_subvect;i++) {

I've made a block diagram of the encoder because I tried to find out, how it works http://stoffke.freeshell.65535.net/ogg/block.html Although there are specifiation docs, that give very detailed information about single aspects of the encoding (or decoding) , I'm missing documenations that give a more general overview, about how the encoder works. (Vorbis Illuminated seems a bit

Hi, Jean-Marc Valin wrote: >> 1. What is the point in multiplying a codebook index with some number >> ant adding a loop variable to it as done in the exc unquant function. >> for (j=0;j<subvect_size;j++) >> exc[subvect_size*i+j]+=s*0.03125*shape_cb[ind[i]*subvect_size+j]; > > That's just how you represent a 2D array in C: the codebook has

Hello, just to make sure I haven't gotten anything wrong: In cb_search.c (function split_cb_search_shape_sign) after all that searching nb_subvect CB entries are being written into the stream. These are all taken from the same codebook. If I wanted to, I could just change their order, couldn't I? Because important is only the linear combination of them all together, which I keep

hi, basically I am anyway using GMM based parametric VQ for LSF quantization so that is not a problem. Can you plz. tell me how to retrain the pitch codebook and innovation codebook. what are the tools to train the pitch and innovation codebook? Regarding the pitch prediction for high-band, I understand your reason of not using it for high-band. There is one paper, "A 14 kb/s wideband

Dear Speex developers, I think I found a typo in libspeex/preprocess.c (that still in the SVN version too). Please correct me if I would be wrong. Patch is attached. (Yours :parenthetically &dezzy) -------------- next part -------------- A non-text attachment was scrubbed... Name: noise_var.patch Type: text/x-patch Size: 518 bytes Desc: not available Url :