similar to: VQ codebook sanity check (please help)

Hi, I am trying to implement ogg vorbis real time decoder on SHARC ADSP 21364 processor. I am writing my own version of the decoder using the documentation vorbis_I_spec.pdf from xiph.org. However I am facing certain hurdles in floor curve decoding during audio packet decode. In the spec it says that [cval] = read from packet using codebook number [so and so] in *scalar context*.(page no 43).

Hi, I am a bit confused on how code-words are derived from the codeword lengths. I will appreciate if someone can point me in the correct direction. I will take the example of an actual codebook that i found in a valid vorbis encoded file as shown below. [SK] +------Codebook [0] -------- [SK] Codebook Dimensions = 1 [SK] Codebook Entries = 8 [SK] Unordered [SK] 1, 6, 3, 7, 2, 5, 4, 7, [SK] NO

The following has been committed to the Vorbis I spec as of r19445: Errata 20150226: Single entry codebooks A ?single-entry codebook? is a codebook with one active codeword entry. A single-entry codebook may be either a fully populated codebook with only one declared entry, or a sparse codebook with only one entry marked used. The Vorbis I spec provides no means to specify a codeword length of

Hi, Does anybody know how codebooks are generated in OggVorbis encoder? We are porting oggorbis encoder on embedded platform for which VQ codebook memory is hugeeee to imagine. How can we reduce that? Can we do VQ with less codebooks and if yes how? If any help available? Parul Embedded Engineer Einfochips Ltd

Hi, I've been using the Vorbis codec for a while and recently I got the source code and had a look at the spec (great job on the doc BTW). I don't have any former experience with audio compression, but I do know what a DCT does and I totally grok Huffman coding (so I guess I'm not that much of a newbie, am I?). Anyway I just had some questions about how VQ works on the encoding side.

Dear Sir or Maddam, we're in the progress of developing a multimedia framework for Java. We started with programming a Vorbis (ogg) codec and demultiplexer and have still some problems with this. The problem occured when trying to read the setup header of a vorbis file. After a certain time we have to decode the codebook_lengths but this does not work. We followed the instructions in the

Hi, All help is appreciated. I am looking at the function "vorbis_staticbook_unpack" in codebook.c I guess this function just reads the codebooks in some structure (static_codebook) and does not actually map the codewords to the codevalues. Does anyone know what functions can I use in this function to actually view this mapping? I just want to display something like below: I can

hello, does anybody know whether the codewords have a special meaning? whether they have a different influence like the quantization matriy in jpeg? e.g. do lower or the first entries have a greater influence than the last or higher codewords? thanks gerald

Hi, We are porting the Ogg Vorbis fixed point decoder to a 24 bit fixed point precision processor. We are trying to reduce the number of cycles for MIPS optimization. In this process we observed that most of the songs do not have "maximum codeword length" greater than 24 bits. We are planning to reduce most of the double word operations (in our case 32 bit data is stored as double

Hello Monty, Sorry for the wrong subject title last time. A little more clarification needed. When reading bit-by-bit, there is no MSb/LSb, just 'first bit' and 'last bit'. The Huffman tree is traversed from 'first bit' to last bit'. This is a conceptual layer above the bitpacker; all you need to know is what order the bits come out, which happens to be LSb-first.

Hi, From the vorbis decoder specification, it is clear that the decoder needs to have all the codebooks before decoding can actually begin. I will appreciate if someone can clear the following questions: 1. I guess the codebooks are derived from the actual input data. Probably the encoder may be making two passes through the input. The first pass finds out the frequency of different symbols

Áô©~ªº ¦Ñ¤H wrote: > Dear Segher > > Thanks for your information. Besides, the mechanism of the huffman > decoding seems can not work in a 24-bit processor if the code length > exceeds 24, though I have checked several vorbis file from network and > they are all below 24 bit True; but you can special case the >24 bit codebook to use a more "traditional" decoding

hi kuhlen, what you said is correct. i am talking about how you are going to arrange these codewords into an array, i.e. in the function _make_decode_table. there he uses node bytes and leaf words for memory management. i got a 24 bit platform. so if i assume that max. codeword length that could be possible as 24 bits can i allocate a memory of (2 * used entries - 2), to arrange the whole tree in

hello all, we are developing and porting vorbis1decoder on a 24 bit platform. in the process we came across somedoubts about node bytes and leaf words. from the specification we got that we are arranging the huffman codeword tree into an array. the nodebytes are the number of bytes that are required to represent a node and leafwords are the no. of bytes required to represent the leaf i.e the

Hi radeonhd, nouveau, mesa3d developers, Firstly, thank you all very much for all the important work you do. I've been working as a part-time developer on the "Spring RTS" project (open-source game engine) which runs on linux (and other os). Some time ago I tried the engine on the open-source ATI radeonhd driver, which I understand to be partly based on mesa 3d, and all textures

The VQ codebook generation utilities are more or less ready to go. Minor things are left to do, but those will have to be handled as I to them :-) The next thing to do is complete the interface to get compression modes and codebooks to the library for encoding (minor stuff), and then arrange how exactly the MDCT residue is filtered through the codebooks. VQ codebook util instructions:

Dear R users, codebook (v. 0.5.8) was just released on CRAN. https://CRAN.R-project.org/package=codebook It uses the metadata/attributes that some other packages add (item labels, value labels, labelled missings) to automatically generate a codebook that is both human- and machine-readable. It combines metadata about the variables with data summaries. Many people will import this kind of

Dear R users, codebook (v. 0.5.8) was just released on CRAN. https://CRAN.R-project.org/package=codebook It uses the metadata/attributes that some other packages add (item labels, value labels, labelled missings) to automatically generate a codebook that is both human- and machine-readable. It combines metadata about the variables with data summaries. Many people will import this kind of

Anexed is my function for reading codebooks and the Vq Table. My problem is: I read a codeBook number of 41, so i called this function above 41 times. The firtst time, the sync patterns (BCV) is alligned correctly, so it reads correctly. the sencond time it is executed, the patter is not there anymore and there are only 8 BCV in my file. function fReadBits1 is the same as the ogg's read bit

please add the following diffs to the vorbis/vq dir. - include files changed so things actually compile in new scheme - _ogg_...alloc cleanups caught a half-dozen typos or so - minor Makefile touchup. (stuff is still not tested, but this will compile at least) Would someone with cvs write access commit them for me please? Erik diffs: ------------------------ diff -bBu2r vorbis/vq/Makefile