similar to: huffman 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

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, 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).

Well, here you are. 24k; sorry if I'm not supposed to put this size things in your mailbox, didn't know where else to put it. And you all are subscribed to vorbis-dev, after all. I'm not that good at breaking patches apart, so it's one big patch. Sorry. Overview: configure.in make profiling easier & more useful decoder-example.c (#if 0'ed) dither output;

Hi, all I am studying the ogg-vorbis algorithm but I have less knowledge about the codebook structure of vorbis. After tracing the release source code, I found it doesn't use huffman tree to decode the huffman code instead of using a special mapping and pre-look. The memory requirement seems similar with huffman tree decoding. Could anyone tell me how the vorbis huffman decoding works

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

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

So, it turns out (and another implementation actually explicitly mentions it) that LSP->LPC computation using the FIR algorithm is very sensitive to noise (iterative algorithm) and really really requires doubles [we're not kidding]. This was complicating things for folks pursuing fixed point implementations, and also was a potential source for bugs if FP optimizations got out of hand. This

Hiya, Here is the sources to my "rehuff" program. ./rehuff in.ogg out.ogg does a lossless recoding of a vorbis stream. (It generates optimal huffman codes for the particular stream). This code is meant for developers only, until someone is kind enough to provide good build and configure support for it. I won't. And no installation help questions please. There is a little patch

There is bit space in Bitstream Header to put Huffman codes in. However, This space can take only 80 kinds of Huffman code set. And This space is divded into DC Huffman code set and AC Huffman set, and There are only 16 choices in each DC and AC Huffman code set. If we want to use this space, we find out best(or proper) performance 80 frequency counts(Huffman code sets) from tens thousands of

We've implemented a vorbis decoder based on Tremor and as part of the documentation we're also writing about psycho acoustic models and encoding. We're quite up to date with the decoding process and psycho acoustics in general but unfortunately not on the psycho acoustic encoding used in Vorbis. We have a few questions that would we would be very thankful to have answer to: Which

I want to analyse compressed data between VQ and Huffman coding steps. Where in source code can I access to data massive for this goal. -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.xiph.org/pipermail/vorbis/attachments/20090916/4529e42d/attachment-0001.htm

OK, into the nitty-gritty, albeit a high-level version. If it sounds like I'm glossing important details, you're right. This discusses only the basic DSP; precise coding, framing, sync, etc, will be in another mail. Vorbis is a hybrid transform domain general purpose audio encoder, like MPEG in some respects (it is rooted in much of the same basic theory). For the most part, the

Good day! I'm creating HDL IP CORE (for using in FPGA) for theora encoder (now only I-frames). I don't undestand one moment. Now i develop such stages: 1. From RBG(byer) to YCbCr converter 2. DCT processing (8x8 pixels blocks) 3. Quantizator of DCT coeff. 4. Zig-Zag of quantized DCT coeff. and now i have uresolved last stage of compression - how i must send 8x8 blocks to huffman

cb wrote: > Dear Segher, Hi, Why do you ask me? Why not try the vorbis-dev@xiph.org list? (Or the Tremor list). > I am a portable audio player firmware engineer. I try to add vorbis support to our ARM7 base board. Because the total SRAM of our board is only 48kB and only about 32KB can be used by decoder, I try to save all huffman table in flash ROM then don't need to extract the

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

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,

Hi all, The decoder is down 30% execution time, identical bit output. Didn't get the mdct yet; 1024 point mdct is a bit much to brute-force, and I'm not going to hand-unroll the whole thing either (the machine- unrolled version produced a 1.5M executable; understandably, it wasn't very fast. Still waiting for processors with 1.5M L1 code caches ;-) Slowest parts now are: -- mdct --

Hello all, I've been working a little inside the Theora decoder when I found that it seems that many videos had the very same huffman tables encoded into their bitstreams (at least the ones that I could take my time to dissecate). I found that the tables are listed as TH_VP31_HUFF_CODES in the file huffenc.c. I tried to investigate a little bit more to see who was setting the bitstream

Hi Segher, On Sun, Dec 2, 2018 at 3:48 PM Segher Boessenkool <segher at kernel.crashing.org> wrote: > > On Fri, Nov 30, 2018 at 10:06:02AM +0100, Boris Petkov wrote: > > On November 29, 2018 1:25:02 PM GMT+01:00, Segher Boessenkool <segher at kernel.crashing.org> wrote: > > >This will only be fixed from GCC 9 on, if the compiler adopts it. The > >