Displaying 20 results from an estimated 2000 matches similar to: "Floor codebooks vs. Residue codebooks"
2006 Feb 20
3
Huge VQ codebooks
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
2002 Oct 22
3
Spectral phase information in residue vectors
I found this sentence in the Ogg format specs:
http://www.xiph.org/ogg/vorbis/doc/vorbis-spec-res.html
"A residue vector may represent spectral lines, spectral magnitude, spectral phase or hybrids as mixed by channel coupling."
But where does the spectral phase information come from ?
AFAIK MDCT doesn't provide any phase information.
And in OGG-encoding, MDCT is taking place a few
2001 May 26
2
merging monty's branch
Hi folks,
I'm doing a merge of my current branch onto the mainline (for testing)
today. I believe it to be stable. Just a little more vorbisfile
testing. After the merge, I have a few more patches to apply, then
onto cascading/coupling.
New stuff:
Floor backend 1 and residue backend 1; both are present, but the
mainline modes won't use either yet. Naturally, both are enabled for
2005 Sep 13
1
Clarification on code books usage.
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.
2003 Jun 13
2
Trouble decoding number of codebooks
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 :)
Anyway this is how I read in the numbers :
2005 Oct 14
2
Steganographic extension to 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,
1995 Nov 14
1
Vorbis Codebooks
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
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1999 Nov 11
1
VQ codebook sanity check (please help)
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
2009 Aug 16
1
VQ and Huffman codebooks creation
Hello,
I'd like to know in detail how does the creation of VQ and Huffman codebooks
work in Vorbis. I've used the source code from *encoder_example* as guide,
but the only reference I've found is the function *_make_words *inside *
vorbis_book_init_encode*, which creates the Huffman tree if I'm not wrong.
So I have two doubts. The first is that, for creating the Huffman tree (and
2006 Sep 08
1
Question regarding Speex
Hi,
I have some questions regarding Speex. please reply as soon as
possible.
where are the two filter loops applied to the raw signal?
where is the residue (innovation) signal calculated?
where is the innovation mapped on a codebook entry (key)?
which bits of a transmitted frame are the two filters, which are codebook
keys?
Is the codebook from the beginning on static (so already known by
2002 Sep 24
5
Floor type 0 and residues type 0 and 1
Hi,
it seems to me as if all vorbis-files only contain floors of type
1 and residues of type 2. Is it possible to "force" the encoder to
somehow create a vorbis-file with the other floor and residue types?
Tor
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2003 Jun 30
2
Problem with decoding number of codebooks
Hello,
I'm trying 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
2004 Jan 02
1
A bitrate peeling attempt
Given all this talk of peeling lately, I thought I'd try out a method
I've been thinking about for a while now. It goes something like this:
* Peeling is achieved by dropping some of the residue.
* The encoder indicates how much of the residue to retain (e.g a number
of stages, 3 bits in the stream per packet, non-standard!).
* The decoder (peeler) copies the contents of packets except
2001 Apr 16
2
Dump utility?
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.
2004 Feb 19
1
read codebook function
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
2010 Mar 05
0
How are floor and residue used in OV Codec?
Hi All,
I have a doubt in Vorbis coding.
It is said, the encoder subtracts the floor from the MDCT of the data to
get the residue. But in the decoder, the 'dot product' of of the floor and
residue is done to get back the data. If subtraction is done at one end,
addition should be done at the other end. What exactly is 'dot product'?
Can you name the function in the decoder
2015 Feb 26
2
Vorbis I spec errata: single entry codebooks
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
2018 Mar 16
1
libvorbis 1.3.6 - critical security update
libvorbis 1.3.6 has been released. This release fixes several
vulnerabilities, including CVE-2018-5146, that could allow code
execution from a specially crafted Ogg Vorbis file.
* Fix CVE-2018-5146 - out-of-bounds write on codebook decoding.
* Fix CVE-2017-14632 - free() on unitialized data
* Fix CVE-2017-14633 - out-of-bounds read
* Fix bitrate metadata parsing.
* Fix out-of-bounds read in
2018 Mar 16
1
libvorbis 1.3.6 - critical security update
libvorbis 1.3.6 has been released. This release fixes several
vulnerabilities, including CVE-2018-5146, that could allow code
execution from a specially crafted Ogg Vorbis file.
* Fix CVE-2018-5146 - out-of-bounds write on codebook decoding.
* Fix CVE-2017-14632 - free() on unitialized data
* Fix CVE-2017-14633 - out-of-bounds read
* Fix bitrate metadata parsing.
* Fix out-of-bounds read in
2012 Feb 09
4
Getting codebook data into R
I've been trying to get some data from the National Survey for Family Growth
into R - however, the data is in a .dat file and the data I need doesn't
have any spaces or commas separating fields - rather you have to look into
the codebook and what number of digits along the line the data you need is.
The data I want are the following, where 1,12,int means that the data I'm
interested