| //////////////////////////////////////////////////////////////////////////// |
| // **** WAVPACK **** // |
| // Hybrid Lossless Wavefile Compressor // |
| // Copyright (c) 1998 - 2004 Conifer Software. // |
| // All Rights Reserved. // |
| //////////////////////////////////////////////////////////////////////////// |
| |
| // words.c |
| |
| // This module provides entropy word encoding and decoding functions using |
| // a variation on the Rice method. This was introduced in version 3.93 |
| // because it allows splitting the data into a "lossy" stream and a |
| // "correction" stream in a very efficient manner and is therefore ideal |
| // for the "hybrid" mode. For 4.0, the efficiency of this method was |
| // significantly improved by moving away from the normal Rice restriction of |
| // using powers of two for the modulus divisions and now the method can be |
| // used for both hybrid and pure lossless encoding. |
| |
| // Samples are divided by median probabilities at 5/7 (71.43%), 10/49 (20.41%), |
| // and 20/343 (5.83%). Each zone has 3.5 times fewer samples than the |
| // previous. Using standard Rice coding on this data would result in 1.4 |
| // bits per sample average (not counting sign bit). However, there is a |
| // very simple encoding that is over 99% efficient with this data and |
| // results in about 1.22 bits per sample. |
| |
| #include "wavpack.h" |
| |
| #include <string.h> |
| |
| //////////////////////////////// local macros ///////////////////////////////// |
| |
| #define LIMIT_ONES 16 // maximum consecutive 1s sent for "div" data |
| |
| // these control the time constant "slow_level" which is used for hybrid mode |
| // that controls bitrate as a function of residual level (HYBRID_BITRATE). |
| #define SLS 8 |
| #define SLO ((1 << (SLS - 1))) |
| |
| // these control the time constant of the 3 median level breakpoints |
| #define DIV0 128 // 5/7 of samples |
| #define DIV1 64 // 10/49 of samples |
| #define DIV2 32 // 20/343 of samples |
| |
| // this macro retrieves the specified median breakpoint (without frac; min = 1) |
| #define GET_MED(med) (((c->median [med]) >> 4) + 1) |
| |
| // These macros update the specified median breakpoints. Note that the median |
| // is incremented when the sample is higher than the median, else decremented. |
| // They are designed so that the median will never drop below 1 and the value |
| // is essentially stationary if there are 2 increments for every 5 decrements. |
| |
| #define INC_MED0() (c->median [0] += ((c->median [0] + DIV0) / DIV0) * 5) |
| #define DEC_MED0() (c->median [0] -= ((c->median [0] + (DIV0-2)) / DIV0) * 2) |
| #define INC_MED1() (c->median [1] += ((c->median [1] + DIV1) / DIV1) * 5) |
| #define DEC_MED1() (c->median [1] -= ((c->median [1] + (DIV1-2)) / DIV1) * 2) |
| #define INC_MED2() (c->median [2] += ((c->median [2] + DIV2) / DIV2) * 5) |
| #define DEC_MED2() (c->median [2] -= ((c->median [2] + (DIV2-2)) / DIV2) * 2) |
| |
| #define count_bits(av) ( \ |
| (av) < (1 << 8) ? nbits_table [av] : \ |
| ( \ |
| (av) < (1L << 16) ? nbits_table [(av) >> 8] + 8 : \ |
| ((av) < (1L << 24) ? nbits_table [(av) >> 16] + 16 : nbits_table [(av) >> 24] + 24) \ |
| ) \ |
| ) |
| |
| ///////////////////////////// local table storage //////////////////////////// |
| |
| const char nbits_table [] = { |
| 0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, // 0 - 15 |
| 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, // 16 - 31 |
| 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, // 32 - 47 |
| 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, // 48 - 63 |
| 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // 64 - 79 |
| 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // 80 - 95 |
| 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // 96 - 111 |
| 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // 112 - 127 |
| 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 128 - 143 |
| 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 144 - 159 |
| 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 160 - 175 |
| 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 176 - 191 |
| 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 192 - 207 |
| 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 208 - 223 |
| 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 224 - 239 |
| 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 // 240 - 255 |
| }; |
| |
| static const uchar log2_table [] = { |
| 0x00, 0x01, 0x03, 0x04, 0x06, 0x07, 0x09, 0x0a, 0x0b, 0x0d, 0x0e, 0x10, 0x11, 0x12, 0x14, 0x15, |
| 0x16, 0x18, 0x19, 0x1a, 0x1c, 0x1d, 0x1e, 0x20, 0x21, 0x22, 0x24, 0x25, 0x26, 0x28, 0x29, 0x2a, |
| 0x2c, 0x2d, 0x2e, 0x2f, 0x31, 0x32, 0x33, 0x34, 0x36, 0x37, 0x38, 0x39, 0x3b, 0x3c, 0x3d, 0x3e, |
| 0x3f, 0x41, 0x42, 0x43, 0x44, 0x45, 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4d, 0x4e, 0x4f, 0x50, 0x51, |
| 0x52, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x5c, 0x5d, 0x5e, 0x5f, 0x60, 0x61, 0x62, 0x63, |
| 0x64, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x74, 0x75, |
| 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, |
| 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, |
| 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, |
| 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, 0xb0, 0xb1, 0xb2, 0xb2, |
| 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, 0xc0, 0xc0, |
| 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb, 0xcb, 0xcc, 0xcd, 0xce, |
| 0xcf, 0xd0, 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd8, 0xd9, 0xda, 0xdb, |
| 0xdc, 0xdc, 0xdd, 0xde, 0xdf, 0xe0, 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe4, 0xe5, 0xe6, 0xe7, 0xe7, |
| 0xe8, 0xe9, 0xea, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xee, 0xef, 0xf0, 0xf1, 0xf1, 0xf2, 0xf3, 0xf4, |
| 0xf4, 0xf5, 0xf6, 0xf7, 0xf7, 0xf8, 0xf9, 0xf9, 0xfa, 0xfb, 0xfc, 0xfc, 0xfd, 0xfe, 0xff, 0xff |
| }; |
| |
| static const uchar exp2_table [] = { |
| 0x00, 0x01, 0x01, 0x02, 0x03, 0x03, 0x04, 0x05, 0x06, 0x06, 0x07, 0x08, 0x08, 0x09, 0x0a, 0x0b, |
| 0x0b, 0x0c, 0x0d, 0x0e, 0x0e, 0x0f, 0x10, 0x10, 0x11, 0x12, 0x13, 0x13, 0x14, 0x15, 0x16, 0x16, |
| 0x17, 0x18, 0x19, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1d, 0x1e, 0x1f, 0x20, 0x20, 0x21, 0x22, 0x23, |
| 0x24, 0x24, 0x25, 0x26, 0x27, 0x28, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2c, 0x2d, 0x2e, 0x2f, 0x30, |
| 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3a, 0x3b, 0x3c, 0x3d, |
| 0x3e, 0x3f, 0x40, 0x41, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x48, 0x49, 0x4a, 0x4b, |
| 0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, |
| 0x5b, 0x5c, 0x5d, 0x5e, 0x5e, 0x5f, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, |
| 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, |
| 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x87, 0x88, 0x89, 0x8a, |
| 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, |
| 0x9c, 0x9d, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, |
| 0xaf, 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xbc, 0xbd, 0xbe, 0xbf, 0xc0, |
| 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc8, 0xc9, 0xca, 0xcb, 0xcd, 0xce, 0xcf, 0xd0, 0xd2, 0xd3, 0xd4, |
| 0xd6, 0xd7, 0xd8, 0xd9, 0xdb, 0xdc, 0xdd, 0xde, 0xe0, 0xe1, 0xe2, 0xe4, 0xe5, 0xe6, 0xe8, 0xe9, |
| 0xea, 0xec, 0xed, 0xee, 0xf0, 0xf1, 0xf2, 0xf4, 0xf5, 0xf6, 0xf8, 0xf9, 0xfa, 0xfc, 0xfd, 0xff |
| }; |
| |
| static const char ones_count_table [] = { |
| 0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,5, |
| 0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,6, |
| 0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,5, |
| 0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,7, |
| 0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,5, |
| 0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,6, |
| 0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,5, |
| 0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,4,0,1,0,2,0,1,0,3,0,1,0,2,0,1,0,8 |
| }; |
| |
| ///////////////////////////// executable code //////////////////////////////// |
| |
| void init_words (WavpackStream *wps) |
| { |
| CLEAR (wps->w); |
| } |
| |
| static int mylog2 (unsigned long avalue); |
| |
| // Read the median log2 values from the specifed metadata structure, convert |
| // them back to 32-bit unsigned values and store them. If length is not |
| // exactly correct then we flag and return an error. |
| |
| int read_entropy_vars (WavpackStream *wps, WavpackMetadata *wpmd) |
| { |
| uchar *byteptr = wpmd->data; |
| |
| if (wpmd->byte_length != ((wps->wphdr.flags & MONO_FLAG) ? 6 : 12)) |
| return FALSE; |
| |
| wps->w.c [0].median [0] = exp2s (byteptr [0] + (byteptr [1] << 8)); |
| wps->w.c [0].median [1] = exp2s (byteptr [2] + (byteptr [3] << 8)); |
| wps->w.c [0].median [2] = exp2s (byteptr [4] + (byteptr [5] << 8)); |
| |
| if (!(wps->wphdr.flags & MONO_FLAG)) { |
| wps->w.c [1].median [0] = exp2s (byteptr [6] + (byteptr [7] << 8)); |
| wps->w.c [1].median [1] = exp2s (byteptr [8] + (byteptr [9] << 8)); |
| wps->w.c [1].median [2] = exp2s (byteptr [10] + (byteptr [11] << 8)); |
| } |
| |
| return TRUE; |
| } |
| |
| // Allocates the correct space in the metadata structure and writes the |
| // current median values to it. Values are converted from 32-bit unsigned |
| // to our internal 16-bit mylog2 values, and read_entropy_vars () is called |
| // to read the values back because we must compensate for the loss through |
| // the log function. |
| |
| void write_entropy_vars (WavpackStream *wps, WavpackMetadata *wpmd) |
| { |
| uchar *byteptr; |
| int temp; |
| |
| byteptr = wpmd->data = wpmd->temp_data; |
| wpmd->id = ID_ENTROPY_VARS; |
| |
| *byteptr++ = temp = mylog2 (wps->w.c [0].median [0]); |
| *byteptr++ = temp >> 8; |
| *byteptr++ = temp = mylog2 (wps->w.c [0].median [1]); |
| *byteptr++ = temp >> 8; |
| *byteptr++ = temp = mylog2 (wps->w.c [0].median [2]); |
| *byteptr++ = temp >> 8; |
| |
| if (!(wps->wphdr.flags & MONO_FLAG)) { |
| *byteptr++ = temp = mylog2 (wps->w.c [1].median [0]); |
| *byteptr++ = temp >> 8; |
| *byteptr++ = temp = mylog2 (wps->w.c [1].median [1]); |
| *byteptr++ = temp >> 8; |
| *byteptr++ = temp = mylog2 (wps->w.c [1].median [2]); |
| *byteptr++ = temp >> 8; |
| } |
| |
| wpmd->byte_length = byteptr - (uchar *) wpmd->data; |
| read_entropy_vars (wps, wpmd); |
| } |
| |
| // Read the hybrid related values from the specifed metadata structure, convert |
| // them back to their internal formats and store them. The extended profile |
| // stuff is not implemented yet, so return an error if we get more data than |
| // we know what to do with. |
| |
| int read_hybrid_profile (WavpackStream *wps, WavpackMetadata *wpmd) |
| { |
| uchar *byteptr = wpmd->data; |
| uchar *endptr = byteptr + wpmd->byte_length; |
| |
| if (wps->wphdr.flags & HYBRID_BITRATE) { |
| wps->w.c [0].slow_level = exp2s (byteptr [0] + (byteptr [1] << 8)); |
| byteptr += 2; |
| |
| if (!(wps->wphdr.flags & MONO_FLAG)) { |
| wps->w.c [1].slow_level = exp2s (byteptr [0] + (byteptr [1] << 8)); |
| byteptr += 2; |
| } |
| } |
| |
| wps->w.bitrate_acc [0] = (long)(byteptr [0] + (byteptr [1] << 8)) << 16; |
| byteptr += 2; |
| |
| if (!(wps->wphdr.flags & MONO_FLAG)) { |
| wps->w.bitrate_acc [1] = (long)(byteptr [0] + (byteptr [1] << 8)) << 16; |
| byteptr += 2; |
| } |
| |
| if (byteptr < endptr) { |
| wps->w.bitrate_delta [0] = exp2s ((short)(byteptr [0] + (byteptr [1] << 8))); |
| byteptr += 2; |
| |
| if (!(wps->wphdr.flags & MONO_FLAG)) { |
| wps->w.bitrate_delta [1] = exp2s ((short)(byteptr [0] + (byteptr [1] << 8))); |
| byteptr += 2; |
| } |
| |
| if (byteptr < endptr) |
| return FALSE; |
| } |
| else |
| wps->w.bitrate_delta [0] = wps->w.bitrate_delta [1] = 0; |
| |
| return TRUE; |
| } |
| |
| // This function is called during both encoding and decoding of hybrid data to |
| // update the "error_limit" variable which determines the maximum sample error |
| // allowed in the main bitstream. In the HYBRID_BITRATE mode (which is the only |
| // currently implemented) this is calculated from the slow_level values and the |
| // bitrate accumulators. Note that the bitrate accumulators can be changing. |
| |
| void update_error_limit (struct words_data *w, ulong flags) |
| { |
| int bitrate_0 = (w->bitrate_acc [0] += w->bitrate_delta [0]) >> 16; |
| |
| if (flags & MONO_FLAG) { |
| if (flags & HYBRID_BITRATE) { |
| int slow_log_0 = (w->c [0].slow_level + SLO) >> SLS; |
| |
| if (slow_log_0 - bitrate_0 > -0x100) |
| w->c [0].error_limit = exp2s (slow_log_0 - bitrate_0 + 0x100); |
| else |
| w->c [0].error_limit = 0; |
| } |
| else |
| w->c [0].error_limit = exp2s (bitrate_0); |
| } |
| else { |
| int bitrate_1 = (w->bitrate_acc [1] += w->bitrate_delta [1]) >> 16; |
| |
| if (flags & HYBRID_BITRATE) { |
| int slow_log_0 = (w->c [0].slow_level + SLO) >> SLS; |
| int slow_log_1 = (w->c [1].slow_level + SLO) >> SLS; |
| |
| if (flags & HYBRID_BALANCE) { |
| int balance = (slow_log_1 - slow_log_0 + bitrate_1 + 1) >> 1; |
| |
| if (balance > bitrate_0) { |
| bitrate_1 = bitrate_0 * 2; |
| bitrate_0 = 0; |
| } |
| else if (-balance > bitrate_0) { |
| bitrate_0 = bitrate_0 * 2; |
| bitrate_1 = 0; |
| } |
| else { |
| bitrate_1 = bitrate_0 + balance; |
| bitrate_0 = bitrate_0 - balance; |
| } |
| } |
| |
| if (slow_log_0 - bitrate_0 > -0x100) |
| w->c [0].error_limit = exp2s (slow_log_0 - bitrate_0 + 0x100); |
| else |
| w->c [0].error_limit = 0; |
| |
| if (slow_log_1 - bitrate_1 > -0x100) |
| w->c [1].error_limit = exp2s (slow_log_1 - bitrate_1 + 0x100); |
| else |
| w->c [1].error_limit = 0; |
| } |
| else { |
| w->c [0].error_limit = exp2s (bitrate_0); |
| w->c [1].error_limit = exp2s (bitrate_1); |
| } |
| } |
| } |
| |
| static ulong read_code (Bitstream *bs, ulong maxcode); |
| |
| // Read the next word from the bitstream "wvbits" and return the value. This |
| // function can be used for hybrid or lossless streams, but since an |
| // optimized version is available for lossless this function would normally |
| // be used for hybrid only. If a hybrid lossless stream is being read then |
| // the "correction" offset is written at the specified pointer. A return value |
| // of WORD_EOF indicates that the end of the bitstream was reached (all 1s) or |
| // some other error occurred. |
| |
| long get_words (long *buffer, int nsamples, ulong flags, |
| struct words_data *w, Bitstream *bs) |
| { |
| register struct entropy_data *c = w->c; |
| int csamples; |
| |
| if (!(flags & MONO_FLAG)) |
| nsamples *= 2; |
| |
| for (csamples = 0; csamples < nsamples; ++csamples) { |
| ulong ones_count, low, mid, high; |
| |
| if (!(flags & MONO_FLAG)) |
| c = w->c + (csamples & 1); |
| |
| if (!(w->c [0].median [0] & ~1) && !w->holding_zero && !w->holding_one && !(w->c [1].median [0] & ~1)) { |
| ulong mask; |
| int cbits; |
| |
| if (w->zeros_acc) { |
| if (--w->zeros_acc) { |
| c->slow_level -= (c->slow_level + SLO) >> SLS; |
| *buffer++ = 0; |
| continue; |
| } |
| } |
| else { |
| for (cbits = 0; cbits < 33 && getbit (bs); ++cbits); |
| |
| if (cbits == 33) |
| break; |
| |
| if (cbits < 2) |
| w->zeros_acc = cbits; |
| else { |
| for (mask = 1, w->zeros_acc = 0; --cbits; mask <<= 1) |
| if (getbit (bs)) |
| w->zeros_acc |= mask; |
| |
| w->zeros_acc |= mask; |
| } |
| |
| if (w->zeros_acc) { |
| c->slow_level -= (c->slow_level + SLO) >> SLS; |
| CLEAR (w->c [0].median); |
| CLEAR (w->c [1].median); |
| *buffer++ = 0; |
| continue; |
| } |
| } |
| } |
| |
| if (w->holding_zero) |
| ones_count = w->holding_zero = 0; |
| else { |
| int next8; |
| |
| if (bs->bc < 8) { |
| if (++(bs->ptr) == bs->end) |
| bs->wrap (bs); |
| |
| next8 = (bs->sr |= *(bs->ptr) << bs->bc) & 0xff; |
| bs->bc += 8; |
| } |
| else |
| next8 = bs->sr & 0xff; |
| |
| if (next8 == 0xff) { |
| bs->bc -= 8; |
| bs->sr >>= 8; |
| |
| for (ones_count = 8; ones_count < (LIMIT_ONES + 1) && getbit (bs); ++ones_count); |
| |
| if (ones_count == (LIMIT_ONES + 1)) |
| break; |
| |
| if (ones_count == LIMIT_ONES) { |
| ulong mask; |
| int cbits; |
| |
| for (cbits = 0; cbits < 33 && getbit (bs); ++cbits); |
| |
| if (cbits == 33) |
| break; |
| |
| if (cbits < 2) |
| ones_count = cbits; |
| else { |
| for (mask = 1, ones_count = 0; --cbits; mask <<= 1) |
| if (getbit (bs)) |
| ones_count |= mask; |
| |
| ones_count |= mask; |
| } |
| |
| ones_count += LIMIT_ONES; |
| } |
| } |
| else { |
| bs->bc -= (ones_count = ones_count_table [next8]) + 1; |
| bs->sr >>= ones_count + 1; |
| } |
| |
| if (w->holding_one) { |
| w->holding_one = ones_count & 1; |
| ones_count = (ones_count >> 1) + 1; |
| } |
| else { |
| w->holding_one = ones_count & 1; |
| ones_count >>= 1; |
| } |
| |
| w->holding_zero = ~w->holding_one & 1; |
| } |
| |
| if ((flags & HYBRID_FLAG) && ((flags & MONO_FLAG) || !(csamples & 1))) |
| update_error_limit (w, flags); |
| |
| if (ones_count == 0) { |
| low = 0; |
| high = GET_MED (0) - 1; |
| DEC_MED0 (); |
| } |
| else { |
| low = GET_MED (0); |
| INC_MED0 (); |
| |
| if (ones_count == 1) { |
| high = low + GET_MED (1) - 1; |
| DEC_MED1 (); |
| } |
| else { |
| low += GET_MED (1); |
| INC_MED1 (); |
| |
| if (ones_count == 2) { |
| high = low + GET_MED (2) - 1; |
| DEC_MED2 (); |
| } |
| else { |
| low += (ones_count - 2) * GET_MED (2); |
| high = low + GET_MED (2) - 1; |
| INC_MED2 (); |
| } |
| } |
| } |
| |
| mid = (high + low + 1) >> 1; |
| |
| if (!c->error_limit) |
| mid = read_code (bs, high - low) + low; |
| else while (high - low > c->error_limit) { |
| if (getbit (bs)) |
| mid = (high + (low = mid) + 1) >> 1; |
| else |
| mid = ((high = mid - 1) + low + 1) >> 1; |
| } |
| |
| *buffer++ = getbit (bs) ? ~mid : mid; |
| |
| if (flags & HYBRID_BITRATE) |
| c->slow_level = c->slow_level - ((c->slow_level + SLO) >> SLS) + mylog2 (mid); |
| } |
| |
| return (flags & MONO_FLAG) ? csamples : (csamples / 2); |
| } |
| |
| // Read a single unsigned value from the specified bitstream with a value |
| // from 0 to maxcode. If there are exactly a power of two number of possible |
| // codes then this will read a fixed number of bits; otherwise it reads the |
| // minimum number of bits and then determines whether another bit is needed |
| // to define the code. |
| |
| static ulong read_code (Bitstream *bs, ulong maxcode) |
| { |
| int bitcount = count_bits (maxcode); |
| ulong extras = (1L << bitcount) - maxcode - 1, code; |
| |
| if (!bitcount) |
| return 0; |
| |
| getbits (&code, bitcount - 1, bs); |
| code &= (1L << (bitcount - 1)) - 1; |
| |
| if (code >= extras) { |
| code = (code << 1) - extras; |
| |
| if (getbit (bs)) |
| ++code; |
| } |
| |
| return code; |
| } |
| |
| void send_words (long *buffer, int nsamples, ulong flags, |
| struct words_data *w, Bitstream *bs) |
| { |
| register struct entropy_data *c = w->c; |
| |
| if (!(flags & MONO_FLAG)) |
| nsamples *= 2; |
| |
| while (nsamples--) { |
| long value = *buffer++; |
| int sign = (value < 0) ? 1 : 0; |
| ulong ones_count, low, high; |
| |
| if (!(flags & MONO_FLAG)) |
| c = w->c + (~nsamples & 1); |
| |
| if (!(w->c [0].median [0] & ~1) && !w->holding_zero && !(w->c [1].median [0] & ~1)) { |
| if (w->zeros_acc) { |
| if (value) |
| flush_word (w, bs); |
| else { |
| w->zeros_acc++; |
| continue; |
| } |
| } |
| else if (value) { |
| putbit_0 (bs); |
| } |
| else { |
| CLEAR (w->c [0].median); |
| CLEAR (w->c [1].median); |
| w->zeros_acc = 1; |
| continue; |
| } |
| } |
| |
| if (sign) |
| value = ~value; |
| |
| if ((unsigned long) value < GET_MED (0)) { |
| ones_count = low = 0; |
| high = GET_MED (0) - 1; |
| DEC_MED0 (); |
| } |
| else { |
| low = GET_MED (0); |
| INC_MED0 (); |
| |
| if (value - low < GET_MED (1)) { |
| ones_count = 1; |
| high = low + GET_MED (1) - 1; |
| DEC_MED1 (); |
| } |
| else { |
| low += GET_MED (1); |
| INC_MED1 (); |
| |
| if (value - low < GET_MED (2)) { |
| ones_count = 2; |
| high = low + GET_MED (2) - 1; |
| DEC_MED2 (); |
| } |
| else { |
| ones_count = 2 + (value - low) / GET_MED (2); |
| low += (ones_count - 2) * GET_MED (2); |
| high = low + GET_MED (2) - 1; |
| INC_MED2 (); |
| } |
| } |
| } |
| |
| if (w->holding_zero) { |
| if (ones_count) |
| w->holding_one++; |
| |
| flush_word (w, bs); |
| |
| if (ones_count) { |
| w->holding_zero = 1; |
| ones_count--; |
| } |
| else |
| w->holding_zero = 0; |
| } |
| else |
| w->holding_zero = 1; |
| |
| w->holding_one = ones_count * 2; |
| |
| if (high != low) { |
| ulong maxcode = high - low, code = value - low; |
| int bitcount = count_bits (maxcode); |
| ulong extras = (1L << bitcount) - maxcode - 1; |
| |
| if (code < extras) { |
| w->pend_data |= code << w->pend_count; |
| w->pend_count += bitcount - 1; |
| } |
| else { |
| w->pend_data |= ((code + extras) >> 1) << w->pend_count; |
| w->pend_count += bitcount - 1; |
| w->pend_data |= ((code + extras) & 1) << w->pend_count++; |
| } |
| } |
| |
| w->pend_data |= ((long) sign << w->pend_count++); |
| |
| if (!w->holding_zero) |
| flush_word (w, bs); |
| } |
| } |
| |
| // Used by send_word() and send_word_lossless() to actually send most the |
| // accumulated data onto the bitstream. This is also called directly from |
| // clients when all words have been sent. |
| |
| void flush_word (struct words_data *w, Bitstream *bs) |
| { |
| int cbits; |
| |
| if (w->zeros_acc) { |
| cbits = count_bits (w->zeros_acc); |
| |
| while (cbits--) { |
| putbit_1 (bs); |
| } |
| |
| putbit_0 (bs); |
| |
| while (w->zeros_acc > 1) { |
| putbit (w->zeros_acc & 1, bs); |
| w->zeros_acc >>= 1; |
| } |
| |
| w->zeros_acc = 0; |
| } |
| |
| if (w->holding_one) { |
| if (w->holding_one >= LIMIT_ONES) { |
| putbits ((1L << LIMIT_ONES) - 1, LIMIT_ONES + 1, bs); |
| w->holding_one -= LIMIT_ONES; |
| cbits = count_bits (w->holding_one); |
| |
| while (cbits--) { |
| putbit_1 (bs); |
| } |
| |
| putbit_0 (bs); |
| |
| while (w->holding_one > 1) { |
| putbit (w->holding_one & 1, bs); |
| w->holding_one >>= 1; |
| } |
| |
| w->holding_zero = 0; |
| } |
| else |
| putbits ((1L << w->holding_one) - 1, w->holding_one, bs); |
| |
| w->holding_one = 0; |
| } |
| |
| if (w->holding_zero) { |
| putbit_0 (bs); |
| w->holding_zero = 0; |
| } |
| |
| if (w->pend_count) { |
| |
| while (w->pend_count > 24) { |
| putbit (w->pend_data & 1, bs); |
| w->pend_data >>= 1; |
| w->pend_count--; |
| } |
| |
| putbits (w->pend_data, w->pend_count, bs); |
| w->pend_data = w->pend_count = 0; |
| } |
| } |
| |
| // The concept of a base 2 logarithm is used in many parts of WavPack. It is |
| // a way of sufficiently accurately representing 32-bit signed and unsigned |
| // values storing only 16 bits (actually fewer). It is also used in the hybrid |
| // mode for quickly comparing the relative magnitude of large values (i.e. |
| // division) and providing smooth exponentials using only addition. |
| |
| // These are not strict logarithms in that they become linear around zero and |
| // can therefore represent both zero and negative values. They have 8 bits |
| // of precision and in "roundtrip" conversions the total error never exceeds 1 |
| // part in 225 except for the cases of +/-115 and +/-195 (which error by 1). |
| |
| |
| // This function returns the log2 for the specified 32-bit unsigned value. |
| // The maximum value allowed is about 0xff800000 and returns 8447. |
| |
| static int mylog2 (unsigned long avalue) |
| { |
| int dbits; |
| |
| if ((avalue += avalue >> 9) < (1 << 8)) { |
| dbits = nbits_table [avalue]; |
| return (dbits << 8) + log2_table [(avalue << (9 - dbits)) & 0xff]; |
| } |
| else { |
| if (avalue < (1L << 16)) |
| dbits = nbits_table [avalue >> 8] + 8; |
| else if (avalue < (1L << 24)) |
| dbits = nbits_table [avalue >> 16] + 16; |
| else |
| dbits = nbits_table [avalue >> 24] + 24; |
| |
| return (dbits << 8) + log2_table [(avalue >> (dbits - 9)) & 0xff]; |
| } |
| } |
| |
| // This function returns the log2 for the specified 32-bit signed value. |
| // All input values are valid and the return values are in the range of |
| // +/- 8192. |
| |
| int log2s (long value) |
| { |
| return (value < 0) ? -mylog2 (-value) : mylog2 (value); |
| } |
| |
| // This function returns the original integer represented by the supplied |
| // logarithm (at least within the provided accuracy). The log is signed, |
| // but since a full 32-bit value is returned this can be used for unsigned |
| // conversions as well (i.e. the input range is -8192 to +8447). |
| |
| long exp2s (int log) |
| { |
| ulong value; |
| |
| if (log < 0) |
| return -exp2s (-log); |
| |
| value = exp2_table [log & 0xff] | 0x100; |
| |
| if ((log >>= 8) <= 9) |
| return value >> (9 - log); |
| else |
| return value << (log - 9); |
| } |
| |
| // These two functions convert internal weights (which are normally +/-1024) |
| // to and from an 8-bit signed character version for storage in metadata. The |
| // weights are clipped here in the case that they are outside that range. |
| |
| signed char store_weight (int weight) |
| { |
| if (weight > 1024) |
| weight = 1024; |
| else if (weight < -1024) |
| weight = -1024; |
| |
| if (weight > 0) |
| weight -= (weight + 64) >> 7; |
| |
| return (weight + 4) >> 3; |
| } |
| |
| int restore_weight (signed char weight) |
| { |
| int result; |
| |
| if ((result = (int) weight << 3) > 0) |
| result += (result + 64) >> 7; |
| |
| return result; |
| } |