search for: quantisation

The following creates a point process version of a sinewave (maybe there's a better way): p<-amp*cos(2*pi*freq*(1:n)/n ) + 0.5 as.numeric(runif(1:n)<p) I get something like this: 1 o oo oo o o ooooo o 0 ooo o o o o o ooo ooo In case it's not obvious, this is a noisy version of 1 ooooooo ooooooo 0 ooooooo

...rbank the maximum aplitude in each band decides about the nessesary bits, then the psychoacoustic model decides how much of the signal can be truncated without hearable noise. What do you think about quantising the remaining bits nonlinear with a logarithmic scale? This would share 25%. Nonlinear quantisation is used for instance in a-law or for the longplay-mode of DAT-recorders. The disadvantages of nonlinear quantisation will not apply here, because the 576 frequency bands are too narrow. The harmonics of the square waves are outside these bands and will be filtered out by the filterbank on the play...

..., gain);*/ - } - for (i=C*pBands[m->nbPBands];i<C*pBands[m->nbPBands+1];i++) - P[i] = 0; -} - static void intensity_band(celt_norm_t * restrict X, int len) { int j; @@ -352,13 +335,15 @@ void stereo_decision(const CELTMode *m, celt_norm_t * restrict X, int *stereo_mo /* Quantisation of the residual */ -void quant_bands(const CELTMode *m, celt_norm_t * restrict X, celt_norm_t *P, celt_mask_t *W, const celt_ener_t *bandE, const int *stereo_mode, int *pulses, int shortBlocks, int fold, int total_bits, ec_enc *enc) +void quant_bands(const CELTMode *m, celt_norm_t * restrict X, cel...

Hi guys, Here's two patches I'm planning to apply to simplify the pitch quantisation. Can you test them and let me know how it works? Thanks, Jean-Marc -------------- next part -------------- A non-text attachment was scrubbed... Name: 0001-Moved-the-application-of-the-pitch-gain-to-un-quant.patch Type: text/x-patch Size: 8182 bytes Desc: not available Url : http://lists.xiph.or...

Hi everyone, first of all, I searched through the archives for any posts resembling this, I didn't read all posts about the patents so if this has been suggested before I apologise. I read in an article on C|Net (I think, it was linked from Slashdot anyway) that Thompson are threatening to sue you if Ogg Vorbis becomes a success. Which is evil, and I'm also mad at them because they never

...d (returned) * @param bank Square root of the energy for each band */ -void compute_pitch_gain(const CELTMode *m, const celt_norm_t *X, const celt_norm_t *P, celt_pgain_t *gains); +int compute_pitch_gain(const CELTMode *m, const celt_norm_t *X, const celt_norm_t *P, celt_pgain_t *gains); /** Quantisation/encoding of the residual spectrum * @param m Mode data diff --git a/libcelt/celt.c b/libcelt/celt.c index 61aa1fb..bd6cfbc 100644 --- a/libcelt/celt.c +++ b/libcelt/celt.c @@ -44,7 +44,6 @@ #include "bands.h" #include "modes.h" #include "entcode.h" -#include &quo...

I have been using libvorbis for the past few weeks and have been asked to summarise what I have discovered about the codec. There is an early draft of the document at http://www.geocities.com/gatewaystation/vorbis/vorbis.htm - Please forgive the dodgy formatting (it was formerly a MS word document that got converted with their 'save as html' feature). I still have some additions to

Hello, I am working on Cirrus ARM-EDB 9302 and using speex-1.1.7. I have tried encoding a wav file of 7sec long and it took 6 sec to encode it for default settings of encoder with both files on the RAM.Next I tried encodeing for 1 minute wav file and it took 2.2min for default settings. Why is it that as size of input file increases,encoding time also increases drastically?( I decoded

Hi, I've been reading through the Theora format spec and API reference trying to find an answer to this but haven't come across anything certain. I'm wondering whether it would be theoretically possible to change the encoded bit rate (or target video qiality) during a live stream without a standard theora decoder having any problems. I had assumed that this must be possible, given

> Yes, I have enabled the the current ARM4 assembly bits. I have tried > to optimize these functions(filter_mem16(),iir_mem16() and > fir_mem16()) in C code, but the effect is very small, and I am going > to do assembly optimization for these functions. Do you have another C > code about these functions for assembly optimisations? Can you give me > some information and

Ha ha! I'm don't know what change I made that cleared up the errors, but I can figure that out later. Of course, I immediately tested my new oggenc. Using the same input file and default options, I get these results: [MSVC] File length: 4m 21.0s Elapsed time: 0m 54.0s Rate: 4.8333 Average bitrate: 129.6 kb/s File size: 4,229,428 [BCB]

Hello, I wanted to find out more about square polar mapping, cause that whole stuff is a bit tricky - to me - and not so easy to understand. Searching the web did't get me any results, so I wonder what the background of square polar mapping is. Is it derived from some mathematical publications or just the result of a brilliant intuition of a Vorbis programmer ? ;) Thanks. Stoffke

On Mon, 7 Aug 2023, Chris Rapier wrote: > > The broader issue of hiding all potential keystroke timing is not yet fixed. > > Could some level of obfuscation come from enabling Nagle for interactive > sessions that has an associated TTY? Though that would be of limited > usefulness in low RTT environments. I don't like the idea of having a steady > drip of packets as that

Hi?Jean-Marc? Thanks for your suggestions very much! > > I am porting speex on ARM7TDMI, I have done some optimization, the > > result is that the encoder and decoder need about 60 MCPS for 5.96kbps > > bitrate and complexity 0. Can someone give me informtion about Speex > > optimization on ARM7? > > That's quite good. A few suggestions here: > 1) Don't

Hi, I've read the Vorbis stereo documentation on square polar mapping and currently reading the source code to understand it. But there are some things which I don't quite understand and hope I can get some guidance on. I understand the decoding/decoupling part as it is the same as the one described in the stereo docs: From mapping0.c: /* channel coupling */

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

I sent a little mail some time ago asking if there was going to be an ogg pic-format, and you replied that PNG, MNG and JNG is good enough (sorry for this late answer btw).. But, consider this: The ogg video-format (tarkin ? where do you get these names from anyway ? :) ) needs a way to compress its frames. Are you going to use MNG for that ? :) .. If you had an ogg pic format, that format could

...to 8 ratio. The voice encoding steps of the Nellymoser encoder can be described in 4 steps: 1.Transformation: the original 256 audio samples are transformed in the frequency domain. 2.Masking: the masking is applied on the frequency domain to reduce the number of the significant coefficients. 3.Quantisation: a number of the most significant frequency coefficients are quantized. 4.Compression: the coefficients are Huffman (or similar) encoded to reduce redundancies and to take advantage of low entropy. The binary data represented as stream or vectors (refer to MPEG-1 encoding) usually contain many cons...

...to 8 ratio. The voice encoding steps of the Nellymoser encoder can be described in 4 steps: 1.Transformation: the original 256 audio samples are transformed in the frequency domain. 2.Masking: the masking is applied on the frequency domain to reduce the number of the significant coefficients. 3.Quantisation: a number of the most significant frequency coefficients are quantized. 4.Compression: the coefficients are Huffman (or similar) encoded to reduce redundancies and to take advantage of low entropy. The binary data represented as stream or vectors (refer to MPEG-1 encoding) usually contain many cons...

Tracing Fans, I know it''s been a long time in coming but the CPU Performance Counter (CPC) provider is almost here! The code is currently in for review and a proposed architecture document is attached here for review. Any and all feedback/questions on the proposed implementation is welcome. Thanks. Jon. -------------- next part -------------- An embedded and charset-unspecified text