similar to: How floor1 modifications may affect final (de)coded samples?

Hello, I have two questions concerning floor1 encoding/decoding. First I'll ask about the FLOOR1_fromdB_LOOKUP table: what is it's purpose? Is it to convert the amplitude differences between [floor1_Y] values to a dB scale? And, if I'm right with that, here comes the 2nd question: when render_line0 is used to encode floor1, then floor1_inverse2 must be used in decode (in order to

Hi everyone, after having an extensive look at the reference decoder as well as the specification documents, I'd like to point out what I think to be some minor omissions/flaws in the latter, and suggestions for correcting them. --- #1: in vorbis-spec-floor1.html, packet decode: Between 14) and 15) a crucial step is missing. Please insert: 14a) [cval] >>= [cbits] ---- #2: in

Hello, I was printing some Floor1 X values from a test audio file, and the values that I've obtained look mostly like the following: [23,33,46,65,79,93,111,130,158,186,220,260,312,372,464,556,750,1024] => For long blocks [8,16,33,70,128] => For short blocks Obviously they are not in Hz, so, could someone please tell me what is the unit used? In the specs it's said that the Floor1

Hi, We are two students doing project with Vorbis audio compression for our B.Sc studies. We have two questions: Our first question related to the floor1 inverse dB lookup table. As we understood the floor values encoded as offset integers (Y) from 1 to 256 and then used as index in the floor1_inverse_dB_table to get an encoded value. This value (denoted as X) is inverse of linear frequency so

Hello, I've read in a thread from this mailing list ( http://lists.xiph.org/pipermail/vorbis-dev/2009-September/020019.html) that the usage of FLOOR1_fromdB_LOOKUP table is to convert Floor1 values from a dB scale to a linear scale. In a dB scale, given a reference value, the other dB values are obtained from it, normally dB_value = 10log(p1/p0), where p0 is the reference value. Supposing p0

Hi, is there an error in the last part of the algorithm describing how to read a floor1 header? According to point 18 and 19, the vector [floor1_class_dimensions] must have at least [floor1_partitions] elements, but when reading/computing these two values on the beginning of the header, they are not related to eachother, and my attempts to apply this algorithm to real ogg-files gives me

Hello, There is a bug in the current version of vorbis/lib/floor1.c. The line that says:- qsort(sortpointer,n,sizeof(int),icomp); should be:- qsort(sortpointer,n,sizeof(int *),icomp); But somebody probably fixed that already. :) Also, I'd like to know how I can encode a file using the channel coupling modes. oggenc doesn't have an option for that yet. Greetings,

Hello, I'm trying to modify the residue vectors in Vorbis audio files at encoding time. For testing, I'm just adding +1 to each residue vector's element, so e.g., if I have an original residue vector of [0,1,2,3] I modify it during the encoding to be [1,2,3,4], and at the decoder's side I should receive the [1,2,3,4] vector. The problem is that, after adding the +1, I still

Hello, I've made some changes in the libvorbis-1.2.3 source code to introduce some functionality I need for a project I'm working on. For compilation, besides including some macro definitions I need to pass to the C preprocessor, and linking with the math library somewhere (and including the source files I've implemented, of course) I've made no big changes in the Makefile or

Hi According to vorbis I spec, there are several configurations. There are 2 formats of floor, 3 formats of residue and 3 look up types of VQ codebook, etc. I think to get all kinds of vorbis file with these configurations but what I have got from network only support some of the formats (Ex. floor1, residue 1 & 2, VQ lookup type0 & 1). I downloaded several freeware vorbis encoder

I've made 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 outdated,

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

Dear all, I am trying to make a series of waffle plot-like figures for my data to visualize the ratios of amino acid residues at each position. For each one of 37 positions, there may be one to four different amino acid residues. So the data consist of the positions, what residues are there, and the ratios of residues. The ratios of residues at a position add up to 100, or close to 100 (more on

Here is a test case: extern double floor(double); extern double floor_(double); double x = 1.5; double y, y_; void foo() { double y = floor(x); double y_ = floor_(x); } If I compile this for Mips16, it calls the proper helper function for floor_ but not for floor, because the signature for floor in callee info is wrong. Args[0] = void RetTy = void

Hello, You know, I always worry about the precision and the float constants... and there is a large lookup table in the floor1.c ... and I figure out a way to keep the code size and speed, but to improve the precision at this lookup table. (the difference is small, but audible) Here is the modifications in the floor1.c: tatic unsigned long FLOOR_fromdB_LOOKUP[256]={

Hi, as Conrad suggested, I've made a complete list of all points in the specification, which I beleive are errors, or where the explanation is unclear, contains unneccessary steps and so on. I hope someone has time to look through the points and if and when accepting or rejecting them be so very kind and inform me about it. I will also once again try to work through the residue

VorbisHi Any help is appreciate. I have two questions. First, I looked into the vorbis-?-specific and was confused by the floor1 algorithm. I think at last the aim is to derive the piecewise curve with the list X and Y,then when encodering ,why not use the selected point orderly to get the curve ? In other words, the specific use the list of [0,128,64,32,96,16,48,80] , why can not use

Hello. Earlier I asked if it would be possible to use one common large codebook for all audiofiles. Can you estimate how the following system would work? 1. The audio would be divided to 16 samples blocks. 2. For each block, the first sample would be stored without any encoding. 3. Linear interpolations between the stored samples are computed. 4. The residues (length of 16 samples) between the

Hi, In the course of some work which I describe below, I have found a very significant difference between the BARK function described in the Vorbis specification and its implementation in libvorbis. In the specificationhttp://xiph.org/vorbis/doc/Vorbis_I_spec.pdf bark(x) = 13.1arctan(.00074x) + 2.24arctan(.0000000185x**2 + .0001x) In the libvorbis code

Smack my curiosity, but I encoded some songs in Vorbis mode 2 and tried to be able to distinguish the difference between that and the uncompressed WAVs. (*smacks self*) but here's what I noted: It's actually kind of hard to tell the difference :) (and I consider myself to have a decent set of ears, though not anywhere near the best) I got my accuracy to about 90%, but I couldn't