shithub: opus

--- a/COPYING

+++ b/COPYING

@@ -1,5 +1,5 @@

-Copyright 2005-2007 Christopher Montgomery, Jean-Marc Valin,

-                    Timothy Terriberry, CSIRO, and other contributors

+Copyright 2001-2009 Jean-Marc Valin, Timothy B. Terriberry,

+                    CSIRO, and other contributors

 Redistribution and use in source and binary forms, with or without

 modification, are permitted provided that the following conditions

--- a/README

+++ b/README

@@ -1,20 +1,88 @@

 CELT is a very low delay audio codec designed for high-quality communications.

-Its potential uses include video-conferencing and network music performance.

-The code is still in early stage, so it may be broken from time to time and

+Traditional full-bandwidth  codecs such as Vorbis and AAC can offer high

+quality but they require codec delays of hundreds of milliseconds, which

+makes them unsuitable  for real-time interactive applications like tele-

+conferencing. Speech targeted codecs, such as Speex or G.722, have lower

+20-40ms delays but their speech focus and limited sampling rates

+restricts their quality, especially for music.

+Additionally, the other mandatory components of a full network audio system—

+audio interfaces, routers, jitter buffers— each add their own delay. For lower

+speed networks the time it takes to serialize a  packet onto the network cable

+takes considerable time, and over the long distances the speed of light

+imposes a significant delay.

+In teleconferencing— it is important to keep delay low so that the participants

+can communicate fluidly without talking on top of each  other and so that their

+own voices don't return after a round trip as an annoying echo.

+For network music performance— research has show that the total one way delay

+must be kept under 25ms to avoid degrading the musicians performance.

+Since many of the sources of delay in a complete system are outside of the

+user's control (such as the  speed of light) it is often  only possible to

+reduce the total delay by reducing the codec delay.

+Low delay has traditionally been considered a challenging area in audio codec

+design, because as a codec is forced to work on the smaller chunks of audio

+required for low delay it has access to less redundancy and less perceptual

+information which it can use to reduce the size of the transmitted audio.

+CELT is designed to bridge the gap between "music" and "speech" codecs,

+permitting new very high quality teleconferencing applications, and to go

+further, permitting latencies much lower than speech codecs normally provide

+to enable applications such as remote musical collaboration even over long

+distances.

+In keeping with the Xiph.Org mission—  CELT is also designed to accomplish

+this without copyright or patent encumbrance. Only by keeping the formats

+that drive our Internet communication free and unencumbered can we maximize

+innovation, collaboration, and interoperability.  Fortunately, CELT is ahead

+of the adoption curve in its target application space, so there should be

+no reason for someone who needs what CELT provides to go with a proprietary

+codec.

+CELT has been tested on x86, x86_64, ARM, and the TI C55x DSPs, and should

+be portable to any platform with a working C compiler and on the order of

+100 MIPS of processing power.

+The code is still in early stage, so it may be broken from time to time, and

 the bit-stream is not frozen yet, so it is different from one version to

 another. Oh, and don't complain if it sets your house on fire.

+Complaints and accolades can be directed to the CELT mailing list:

+http://lists.xiph.org/mailman/listinfo/celt-dev/

 To compile:

 % ./configure

 % make

-To test the encoder:

+For platforms without fast floating point support (such as ARM) use the

+--enable-fixed argument to configure to build a fixed-point version of CELT.

+There are Ogg-based encode/decode tools in tools/. These are quite similar to

+the speexenc/speexdec tools. Use the --help option for details.

+There is also a basic tool for testing the encoder and decoder called

+"testcelt" located in libcelt/:

 % testcelt <rate> <channels> <frame size> <bytes per packet> input.sw output.sw

-where input.sw is a 16-bit (machine endian) audio file sampled at

-44.1 kHz or 48 kHz. The output file is already decompressed.

-the <rate> parameter is the number of bytes per packet to use.

+where input.sw is a 16-bit (machine endian) audio file sampled at 32000 Hz to

+96000 Hz. The output file is already decompressed.

-Alternatively, there are now Ogg-based tools in tools/. Use

-the --help option for details. These are quite similar to the

-speexenc/speexdec tools.

+For example, for a 44.1 kHz mono stream at ~64kbit/sec and with 256 sample

+frames:

+% testcelt 44100 1 256 46 intput.sw output.sw

+Since 44100/256*46*8 = 63393.74 bits/sec.

+All even frame sizes from 64 to 512 are currently supported, although

+power-of-two sizes are recommended  and most CELT development is done

+using a size of 256.  The delay imposed by CELT is  1.25x - 1.5x  the

+frame duration depending on the frame size and some details of CELT's

+internal operation.  For 256 sample frames the delay is 1.5x  or  384

+samples, so the total codec delay in the above example is 8.70ms

+(1000/(44100/384)).

--- a/libcelt/bands.h

+++ b/libcelt/bands.h

@@ -38,11 +38,6 @@

 #include "entdec.h"

 #include "rate.h"

-/** Applies a series of rotations so that pulses are spread like a two-sided

-exponential. The effect of this is to reduce the tonal noise created by the

-sparse spectrum resulting from the pulse codebook */

-void exp_rotation(celt_norm_t *X, int len, int dir, int stride, int iter);

 /** Compute the amplitude (sqrt energy) in each of the bands

  * @param m Mode data

  * @param X Spectrum

--- a/libcelt/celt.c

+++ b/libcelt/celt.c

@@ -656,10 +656,11 @@

-   /*fprintf (stderr, "remaining bits after encode = %d\n", nbCompressedBytes*8-ec_enc_tell(&st->enc, 0));*/

-   /*if (ec_enc_tell(&st->enc, 0) < nbCompressedBytes*8 - 7)

-      celt_warning_int ("many unused bits: ", nbCompressedBytes*8-ec_enc_tell(&st->enc, 0));*/

-   /*printf ("%d\n", ec_enc_tell(&st->enc, 0)-8*nbCompressedBytes);*/

+   /*fprintf (stderr, "remaining bits after encode = %d\n", nbCompressedBytes*8-ec_enc_tell(&enc, 0));*/

+   /*if (ec_enc_tell(&enc, 0) < nbCompressedBytes*8 - 7)

+      celt_warning_int ("many unused bits: ", nbCompressedBytes*8-ec_enc_tell(&enc, 0));*/

    /* Finishing the stream with a 0101... pattern so that the decoder can check is everything's right */

       int val = 0;

--- a/libcelt/celt.h

+++ b/libcelt/celt.h

@@ -159,7 +159,7 @@

  *                        (can change from one frame to another)

  @return Number of bytes written to "compressed". Should be the same as

  *       "nbCompressedBytes" unless the stream is VBR. If negative, an error

- *       has occured (see error codes). It is IMPORTANT that the length returned

+ *       has occurred (see error codes). It is IMPORTANT that the length returned

  *       be somehow transmitted to the decoder. Otherwise, no decoding is possible.

*/

 EXPORT int celt_encode_float(CELTEncoder *st, const float *pcm, float *optional_synthesis, unsigned char *compressed, int nbCompressedBytes);

@@ -176,7 +176,7 @@

  *                        (can change from one frame to another)

  @return Number of bytes written to "compressed". Should be the same as

  *       "nbCompressedBytes" unless the stream is VBR. If negative, an error

- *       has occured (see error codes). It is IMPORTANT that the length returned

+ *       has occurred (see error codes). It is IMPORTANT that the length returned

  *       be somehow transmitted to the decoder. Otherwise, no decoding is possible.

*/

 EXPORT int celt_encode(CELTEncoder *st, const celt_int16_t *pcm, celt_int16_t *optional_synthesis, unsigned char *compressed, int nbCompressedBytes);

--- a/libcelt/modes.c

+++ b/libcelt/modes.c

@@ -1,4 +1,4 @@

-/* (C) 2007-2008 Jean-Marc Valin, CSIRO

+/* (C) 2007-2009 Jean-Marc Valin, CSIRO

    (C) 2008 Gregory Maxwell */

/*

    Redistribution and use in source and binary forms, with or without

--- a/libcelt/quant_bands.c

+++ b/libcelt/quant_bands.c

@@ -112,7 +112,7 @@

    celt_word16_t prev = 0;

    celt_word16_t coef = m->ePredCoef;

    celt_word16_t beta;

-   /* The .7 is a heuristic */

+   /* The .8 is a heuristic */

    beta = MULT16_16_Q15(QCONST16(.8f,15),coef);

    bits = ec_enc_tell(enc, 0);

@@ -196,7 +196,7 @@

    unsigned bits;

    celt_word16_t prev = 0;

    celt_word16_t coef = m->ePredCoef;

-   /* The .7 is a heuristic */

+   /* The .8 is a heuristic */

    celt_word16_t beta = MULT16_16_Q15(QCONST16(.8f,15),coef);

    bits = ec_dec_tell(dec, 0);

--- a/libcelt/rate.c

+++ b/libcelt/rate.c

@@ -1,4 +1,4 @@

-/* (C) 2007-2008 Jean-Marc Valin, CSIRO

+/* (C) 2007-2009 Jean-Marc Valin, CSIRO

*/

/*

    Redistribution and use in source and binary forms, with or without