search for: codebook

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...

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 zero, a...

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

...ll, 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 them for further decode. And this is the dominant factor in decoder memory usage, am I right? There are two structures in this code to hold the codebooks, static_codebook and codebook. But in low mem code, the...

...audio streams realtime. After googling a little I had only two answers: 1 - decode,mix,encode 2 - lower quality, send streams at the same time and mix at the client. I didnt like either solutions. I?m not an audio expert, so I?m just saying something silly. I readed that speex uses a fixed "codebook". So I think that in a simplistic way this means that the encoded data are indexes in this codebook and some transformation information. Is it possible to create a "mixing codebook"? the idea is to generate all the mix combinations of each entry in the codebook., so two encoded frame...

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)...

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...

Hi, Am I correct in understanding that the codebooks are *not* adaptive during compression? I see that Packet #3 is written to the stream in the beginning of the encode process with no modification. If the codebooks are not adaptive, then why are codebooks included in the stream at all? Why not pass the mode type (A or B or C...) instead of all t...

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....

...ers: > > 1 - decode,mix,encode > > 2 - lower quality, send streams at the same time and mix at the client. > > > > I didnt like either solutions. > > > > I?m not an audio expert, so I?m just saying something silly. I readed > > that speex uses a fixed "codebook". So I think that in a simplistic way > > this means that the encoded data are indexes in this codebook and some > > transformation information. > > Is it possible to create a "mixing codebook"? the idea is to generate > > all the mix combinations of each entr...

Often it is useful to keep a "codebook" to document the contents of a dataset. (By "dataset" I mean a rectangular structure such as a dataframe.) The codebook has as many rows as the dataset has columns (variables, fields). The columns (fields) of the codebook may include: ? variable name ? type (chara...

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 th...

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 th...

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 and t...

The codebase sets up ogg_int32_t, etc, but then uses long directly in several structures. Unfortunately for me longs are 64 bits on my platform, not 32, and I end up getting hammered by unnecessary software math routine calls. Should I be able to just search/replace 'long' with 'ogg_int32_t' in the code or would that cause more problems than it fixes? -Dave --- >8 ---- List

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 Mapping [SK] +------Codebook [1] -------- What are the correspnding codewords? I have written b...

Hello, Vorbis uses codebooks, for example to do vectorquantization and huffman-encoding. My question is - are all these codebook dynamicly generated ("trained") or are there also static codebooks used ? If yes, what specific tasks are these 2 types used for, during encoding ? Thanks Stoffke <p>--- &...

I'm having trouble decoding the number of codebooks out of an ogg file, and was wondering if anyone here could lend a hand? I read in the sync pattern, and I think the codebook dimensions properly, but when I try and read in the number of codebook entries, I get a number larger than the number of bytes in the file, which I have to assume is wrong...

...a brick shit-house, asserts all over the place because I'm paranoid that I'll forget something subtle during any early-stage code production. Lots of XXX paranoia comments still to verify/clean up too. Edit rtvorb.h to enable debug code Soon to be added: link with libcurl to get .sdp or codebooks via http. Right now it just attemps fopen. (at some point, probably build in a 'standard' set of codebooks into the player, so normal folks don't have to have the decoder do anything special to retrieve codebooks. Codebook packets are checked by md5 sum) http://vorbis.on2.com/libv...

...ying to write a Vorbis decoder (just as a hobby) but I've got a problem with reading the setup header. According to the Vorbis documentation the first data that should be read after the initial 'vorbis' string is an eight bit integer which when incremented by one, contains the number of codebooks in the header. My problem is that whenever I read this number it seems to be wrong! For example, I created a very small Ogg Vorbis file and in this file the first byte of the setup header is 29 (hex). This means that 42 (dec) codebooks should follow. However this is not the case - in the entire fi...