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We've implemented a vorbis decoder based on Tremor and as part of the documentation we're also writing about psycho acoustic models and encoding. We're quite up to date with the decoding process and psycho acoustics in general but unfortunately not on the psycho acoustic encoding used in Vorbis. We have a few questions that would we would be very thankful to have answer to: Which

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

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, 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

[ I'm not in the list because I didn't find a digested version; please move the lists to sourceforge.net, and we would have the digested version. I read the replies from the archive. ] Hello. Would it be possible to allow Vorbis use the same codebook for multiple files? I could keep a 650 MB codebook on CD-R and use that for all my audiofiles. If that is possible, how much the

Hello folks, The codebook infrastructure for Vorbis is now well underway. This is it! The last piece needed for *real* bitstreams. To that end, I have a decent VQ codebook generator running. I was originally using some farily typical merge/split algorithms and then decided that the right way to do this was to model a VQ codebook as an m-dimensional set of bubbles (like a foam). I know there

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.

Hello all, Please try this "patch". It changes the way the noise floor is used for quantization in a not-so-subtle way. At the very end of _vp_compute_mask, add the lines: for(i=0;i<n;i++) flr[i]=.01f*sqrt(flr[i]); The .01 is there to ensure the current codebooks will work. We will really need different, newly-trained codebooks with this change; then the

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

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

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

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'm trying to understand the residuevqtrain program, and I have some questions for Monty, Erik, or anyone that understands how it's supposed to work. I captured TRAIN_RES data from an encoding of a single track (about 4:43), producing two files, residue_0.vqd (3727 lines, = 3727 points?) and residue_1.vqd (huge). I then did a run with the parameters from the usage message

I've tried to understand the codebook matter (but haven't yet had time to read the source). I want to understand how ibg is the flexibility resulting from packing the codebook in the header of every bitstream. Can we, for example, change the volume of the whole sound by scaling the vectors in the codebook? (My guess is that this wouldn't be enough, as we have to scale the floor of

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>

Is there any dump utility that exists for vorbis streams? What I am intersted in is something that will do a break down like: How many bits are used for encoding _each_ codebooks, how many bits are used for the residue, how much is used for the lpc coefficints. A selective dump of the codebooks themselves would be nice too of course. I'm wondering if anyone has such a little dump utility.

Hi all, I'm porting the Tremor code to an ARM platform. Unfortunately, we didn't use the low mem branch code for CPU performance consideration, and now I find the memory use in it is huge for the embedded system. After looking into the code, I found the header parse, especially, the codebook unpack part takes a lot of memory. Tremor decodes the codebooks to a cache to store

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

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