Displaying 20 results from an estimated 800 matches similar to: "Codebook decoding help"
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
2007 Dec 11
1
Doubts in codebook decoding
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).
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
2003 Aug 06
0
Re: [vorbis] question about codebook
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
2005 Dec 09
0
RE: nodebytes and leafwords
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
2005 Aug 08
3
Reg. getting codewords from codelengths
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
2005 Nov 28
1
nodebytes,leafwords
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
2005 Mar 30
1
Query on Codewords length
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
2005 Aug 17
1
Reg. vorbis_staticbook_unpack
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
2007 Dec 11
1
Query in codebook decoding
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.
2002 Jul 20
3
Vorbis 1.0 spec notes, part 1
I have undertaken a small project of writing a Vorbis decoder
completely from the spec, with the goal of catching any errors, both
typographically and algorithmically, in the spec. My "reference"
decoder is also being written in an extremely methodical style, with
practically no algorithmic optimization, such that it will be clear
that every step has been copied exactly from the spec.
2010 Mar 28
2
Status of s3tc patent in respect to open-source drivers and workarounds
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
2004 Jun 25
0
newbie questions about VQ
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.
2005 Jan 23
1
codebooks / codewords
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
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
2008 Jan 29
5
pivot table in R
Hello,
I'm struggling with an elementary problem with R. I have a simple data
frame such as this one giving the number of accidents subdivided by sex,
age and region.
sex age region no_of_accidents
F young north 10
F young south 12
F old north 5
F old south 7
M young north 24
M
2018 Mar 23
0
New package: codebook
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
2018 Mar 23
0
New package: codebook
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
2008 Mar 26
0
Mixing Codebook?
> ok, lets get to the point. :)
> I would need to mix some 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
2006 Feb 08
1
Speex Command line, Changing the LPC order and modifying the codebook
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.