similar to: Question regarding Speex

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,

> 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. Even then, it may be hard to hide data efficiently (so it's

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.

Hi everyone, I have got some questions about Speex, I am sorry if my questions are too newbie: 1. For the LP analysis, did Speex use the AR (Autoregressive) model or the ARMA model? 2. Am I right to say that Speex use a multistage VQ (since I believe Speex employs two or more VQ consecutively - based on the manual it says that Speex uses dynamically selectable codebooks (linear

And the main point of interest is the following: how much difference in SPEEX terms would it be if it were developed with ACELP in mind? (not that i would do an aSpeex codec implementing ACELP, just to know and point my efforts) -- John Villar Gerente de Proyectos Computadores Flor Hard Soft 2058 C.A. www.florhard.com -------------- next part -------------- A non-text attachment was

Hi, I have one doubt again, that is Vorbis use DCT/MDCT based algorithm and also use psychoacoustic model so this is lossy codec. And I dont think it ca regenerate a better matching waveform than speex. Then there comes FLAC which is the perfect answer to my question, I suppose. But my concern is this that FLAC use simple prediction algorithm and doesnt use any CELP based algo which could have

Hello Jean-Marc and all, I recently had a talk with somebody about CELP. He said, there is this federal standard 1016 (4.8kbps) with a reference implementation of the Department of Defense (only on Sun, unfortunately, if I got this right). This one is noticed in the manual already. He also said, since there is this implementation of the DoD, nobody would voluntarily re-implement CELP. If I read

Hi, I chose speex initially because i had some work in VQ on speex i.e. modifying split VQ to GMM based parametric VQ and I thought If I train the GMM based VQ codebooks with audio signal and then do audio coding with speex, I probably get a better(smaller) residual signal even with speex. But I couldnt get that. I was trying to get a lossless bitstream by MUXing the speex-bitstream and the

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

-----Original Message----- From: Jean-Marc Valin [mailto:jean-marc.valin@usherbrooke.ca] Sent: Tuesday, June 19, 2007 6:38 PM To: Michael Shatz Cc: speex-dev@xiph.org Subject: Re: [Speex-dev] Blackfin inline assembler and VisualDSP++ toolchain >> Yes, data footprint in the new version is quite manageable. Still I would >> wish better documentation for speex_alloc_scratch(). >

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++) {

Hi, Please brace yourselves for some possibly stupid questions. Why are there only 2 codebooks for floors and many more for residue values? What makes the encoding of floor values fundamentally different from encoding residue values? I have a basic understanding of VQ, and looking at the floor decode function, it all makes sense 1) Read the codebook index from the stream 2) Do a

Dear All, As i have understood it , the Huffman codebook uses a huffman code present in the bitstream ( lets us say it is decoding a floor 1 Y value using the specifed codebook number ) to walk through the huffman code book tree till it hits a leaf node which is nothing but the entry number. If we consider our floor 1 Y value example , this entry number is directly being used as the Y value.

hi, thanks for answers to my previous qns. have some more of them. hope it's ok to ask questions on the basics of CELP here. let me know if it's not. 1) synthesized filter stability after interpolation of LSFs I read from some resources that if LSF representation of LPCs is used for interpolation, stability of the synthesis filter is guaranteed. from another source, i read that the

Hi everyone! It's my first time posting to this list, and I've got a fairly technical question. I'm interested in doing phoneme extraction, and one of the first steps in the algorithm I'm planning to use is to get the LPC coefficients for an input frame. Since Speex is CELP-based, the coefficients must be generated in there somewhere. I've tried digging around in the source

Hello I'm working about audio and video codecs. I'm making a research about the state-of-the-art in coding technologies. My question is about the speex codec 1.0. I would like to know the name of the algorithms that it uses.(LPC,CELP..). It uses more or less the same algorithm for narrowband and wideband? Finally i would like to ask about future codec developement projects. Thanks

Hello, I recently measured the distances ndist[0][nb_subvect-1] which are used to make the decicion, which codebook entries are to be used in libspeex/cb_search.c (function split_cb_search_shape_sign). For that I took a couple of audio books (all german speech), downsampled the tracks to 8kHz and encoded them with "speexenc -n --bitrate 15000 ..." (I used svn revision 11825). Usually,

--- Jean-Marc Valin <jean-marc.valin@usherbrooke.ca> wrote: > > Sorry if this a repost but I want to create the > > smallest Speex library possible to be put in TI's > > TMS320 DSP. I'm only interested in one > configuration: > > 5.97 Kbps narrowband. What part of source code > can I > > remove? Currently, when I compiled the version >

Hi, Jean-Marc Valin wrote: > Well, you could change the order in the encoder as long as you reverse > it in the decoder as well. Ok, I see that in the split_cb_shape_sign_unquant function, that each coefficient is tied to it's position in the nb_subvect exc coefficients. Honestly, I have problems understanding what exactly the codebook search works like. If you have the time to to

Hi folks, My wife and I are taking a long weekend to celibrate our anniversary. I won't be around again until Wednesday to answer email or do anything else on Vorbis. Yeah, I know, I usually answer my email once a month anyway (so likely no one would notice me being gone), but just so folks know if anything really juicy comes up :-) I'll be merging my latest branch with mainline