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rockbox/apps/codecs/libwavpack/unpack.c
Dave Bryant 2446b22db9 Update libwavpack with latest changes from the tiny_encoder. This allows 
playback of floating-point audio files, fixes a obscure decoding bug, and
improves encoding speed somewhat.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@11944 a1c6a512-1295-4272-9138-f99709370657
2007-01-08 04:24:32 +00:00

764 lines
27 KiB
C
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////////////////////////////////////////////////////////////////////////////
// **** WAVPACK **** //
// Hybrid Lossless Wavefile Compressor //
// Copyright (c) 1998 - 2004 Conifer Software. //
// All Rights Reserved. //
// Distributed under the BSD Software License (see license.txt) //
////////////////////////////////////////////////////////////////////////////
// unpack.c
// This module actually handles the decompression of the audio data, except
// for the entropy decoding which is handled by the words.c module. For
// maximum efficiency, the conversion is isolated to tight loops that handle
// an entire buffer.
#include "wavpack.h"
#include <stdlib.h>
#include <string.h>
static void strcpy_loc (char *dst, char *src) { while ((*dst++ = *src++) != 0); }
#define LOSSY_MUTE
///////////////////////////// executable code ////////////////////////////////
// This function initializes everything required to unpack a WavPack block
// and must be called before unpack_samples() is called to obtain audio data.
// It is assumed that the WavpackHeader has been read into the wps->wphdr
// (in the current WavpackStream). This is where all the metadata blocks are
// scanned up to the one containing the audio bitstream.
int unpack_init (WavpackContext *wpc)
{
WavpackStream *wps = &wpc->stream;
WavpackMetadata wpmd;
if (wps->wphdr.block_samples && wps->wphdr.block_index != (uint32_t) -1)
wps->sample_index = wps->wphdr.block_index;
wps->mute_error = FALSE;
wps->crc = 0xffffffff;
CLEAR (wps->wvbits);
CLEAR (wps->decorr_passes);
CLEAR (wps->w);
while (read_metadata_buff (wpc, &wpmd)) {
if (!process_metadata (wpc, &wpmd)) {
strcpy_loc (wpc->error_message, "invalid metadata!");
return FALSE;
}
if (wpmd.id == ID_WV_BITSTREAM)
break;
}
if (wps->wphdr.block_samples && !bs_is_open (&wps->wvbits)) {
strcpy_loc (wpc->error_message, "invalid WavPack file!");
return FALSE;
}
if (wps->wphdr.block_samples) {
if ((wps->wphdr.flags & INT32_DATA) && wps->int32_sent_bits)
wpc->lossy_blocks = TRUE;
if ((wps->wphdr.flags & FLOAT_DATA) &&
wps->float_flags & (FLOAT_EXCEPTIONS | FLOAT_ZEROS_SENT | FLOAT_SHIFT_SENT | FLOAT_SHIFT_SAME))
wpc->lossy_blocks = TRUE;
}
return TRUE;
}
// This function initialzes the main bitstream for audio samples, which must
// be in the "wv" file.
int init_wv_bitstream (WavpackContext *wpc, WavpackMetadata *wpmd)
{
WavpackStream *wps = &wpc->stream;
if (wpmd->data)
bs_open_read (&wps->wvbits, wpmd->data, (unsigned char *) wpmd->data + wpmd->byte_length, NULL, 0);
else if (wpmd->byte_length)
bs_open_read (&wps->wvbits, wpc->read_buffer, wpc->read_buffer + sizeof (wpc->read_buffer),
wpc->infile, wpmd->byte_length + (wpmd->byte_length & 1));
return TRUE;
}
// Read decorrelation terms from specified metadata block into the
// decorr_passes array. The terms range from -3 to 8, plus 17 & 18;
// other values are reserved and generate errors for now. The delta
// ranges from 0 to 7 with all values valid. Note that the terms are
// stored in the opposite order in the decorr_passes array compared
// to packing.
int read_decorr_terms (WavpackStream *wps, WavpackMetadata *wpmd)
{
int termcnt = wpmd->byte_length;
uchar *byteptr = wpmd->data;
struct decorr_pass *dpp;
if (termcnt > MAX_NTERMS)
return FALSE;
wps->num_terms = termcnt;
for (dpp = wps->decorr_passes + termcnt - 1; termcnt--; dpp--) {
dpp->term = (int)(*byteptr & 0x1f) - 5;
dpp->delta = (*byteptr++ >> 5) & 0x7;
if (!dpp->term || dpp->term < -3 || (dpp->term > MAX_TERM && dpp->term < 17) || dpp->term > 18)
return FALSE;
}
return TRUE;
}
// Read decorrelation weights from specified metadata block into the
// decorr_passes array. The weights range +/-1024, but are rounded and
// truncated to fit in signed chars for metadata storage. Weights are
// separate for the two channels and are specified from the "last" term
// (first during encode). Unspecified weights are set to zero.
int read_decorr_weights (WavpackStream *wps, WavpackMetadata *wpmd)
{
int termcnt = wpmd->byte_length, tcount;
signed char *byteptr = wpmd->data;
struct decorr_pass *dpp;
if (!(wps->wphdr.flags & MONO_DATA))
termcnt /= 2;
if (termcnt > wps->num_terms)
return FALSE;
for (tcount = wps->num_terms, dpp = wps->decorr_passes; tcount--; dpp++)
dpp->weight_A = dpp->weight_B = 0;
while (--dpp >= wps->decorr_passes && termcnt--) {
dpp->weight_A = restore_weight (*byteptr++);
if (!(wps->wphdr.flags & MONO_DATA))
dpp->weight_B = restore_weight (*byteptr++);
}
return TRUE;
}
// Read decorrelation samples from specified metadata block into the
// decorr_passes array. The samples are signed 32-bit values, but are
// converted to signed log2 values for storage in metadata. Values are
// stored for both channels and are specified from the "last" term
// (first during encode) with unspecified samples set to zero. The
// number of samples stored varies with the actual term value, so
// those must obviously come first in the metadata.
int read_decorr_samples (WavpackStream *wps, WavpackMetadata *wpmd)
{
uchar *byteptr = wpmd->data;
uchar *endptr = byteptr + wpmd->byte_length;
struct decorr_pass *dpp;
int tcount;
for (tcount = wps->num_terms, dpp = wps->decorr_passes; tcount--; dpp++) {
CLEAR (dpp->samples_A);
CLEAR (dpp->samples_B);
}
if (wps->wphdr.version == 0x402 && (wps->wphdr.flags & HYBRID_FLAG)) {
byteptr += 2;
if (!(wps->wphdr.flags & MONO_DATA))
byteptr += 2;
}
while (dpp-- > wps->decorr_passes && byteptr < endptr)
if (dpp->term > MAX_TERM) {
dpp->samples_A [0] = exp2s ((short)(byteptr [0] + (byteptr [1] << 8)));
dpp->samples_A [1] = exp2s ((short)(byteptr [2] + (byteptr [3] << 8)));
byteptr += 4;
if (!(wps->wphdr.flags & MONO_DATA)) {
dpp->samples_B [0] = exp2s ((short)(byteptr [0] + (byteptr [1] << 8)));
dpp->samples_B [1] = exp2s ((short)(byteptr [2] + (byteptr [3] << 8)));
byteptr += 4;
}
}
else if (dpp->term < 0) {
dpp->samples_A [0] = exp2s ((short)(byteptr [0] + (byteptr [1] << 8)));
dpp->samples_B [0] = exp2s ((short)(byteptr [2] + (byteptr [3] << 8)));
byteptr += 4;
}
else {
int m = 0, cnt = dpp->term;
while (cnt--) {
dpp->samples_A [m] = exp2s ((short)(byteptr [0] + (byteptr [1] << 8)));
byteptr += 2;
if (!(wps->wphdr.flags & MONO_DATA)) {
dpp->samples_B [m] = exp2s ((short)(byteptr [0] + (byteptr [1] << 8)));
byteptr += 2;
}
m++;
}
}
return byteptr == endptr;
}
// Read the int32 data from the specified metadata into the specified stream.
// This data is used for integer data that has more than 24 bits of magnitude
// or, in some cases, used to eliminate redundant bits from any audio stream.
int read_int32_info (WavpackStream *wps, WavpackMetadata *wpmd)
{
int bytecnt = wpmd->byte_length;
char *byteptr = wpmd->data;
if (bytecnt != 4)
return FALSE;
wps->int32_sent_bits = *byteptr++;
wps->int32_zeros = *byteptr++;
wps->int32_ones = *byteptr++;
wps->int32_dups = *byteptr;
return TRUE;
}
// Read multichannel information from metadata. The first byte is the total
// number of channels and the following bytes represent the channel_mask
// as described for Microsoft WAVEFORMATEX.
int read_channel_info (WavpackContext *wpc, WavpackMetadata *wpmd)
{
int bytecnt = wpmd->byte_length, shift = 0;
char *byteptr = wpmd->data;
uint32_t mask = 0;
if (!bytecnt || bytecnt > 5)
return FALSE;
wpc->config.num_channels = *byteptr++;
while (--bytecnt) {
mask |= (uint32_t) *byteptr++ << shift;
shift += 8;
}
wpc->config.channel_mask = mask;
return TRUE;
}
// Read configuration information from metadata.
int read_config_info (WavpackContext *wpc, WavpackMetadata *wpmd)
{
int bytecnt = wpmd->byte_length;
uchar *byteptr = wpmd->data;
if (bytecnt >= 3) {
wpc->config.flags &= 0xff;
wpc->config.flags |= (int32_t) *byteptr++ << 8;
wpc->config.flags |= (int32_t) *byteptr++ << 16;
wpc->config.flags |= (int32_t) *byteptr << 24;
}
return TRUE;
}
// This monster actually unpacks the WavPack bitstream(s) into the specified
// buffer as 32-bit integers or floats (depending on orignal data). Lossy
// samples will be clipped to their original limits (i.e. 8-bit samples are
// clipped to -128/+127) but are still returned in int32_ts. It is up to the
// caller to potentially reformat this for the final output including any
// multichannel distribution, block alignment or endian compensation. The
// function unpack_init() must have been called and the entire WavPack block
// must still be visible (although wps->blockbuff will not be accessed again).
// For maximum clarity, the function is broken up into segments that handle
// various modes. This makes for a few extra infrequent flag checks, but
// makes the code easier to follow because the nesting does not become so
// deep. For maximum efficiency, the conversion is isolated to tight loops
// that handle an entire buffer. The function returns the total number of
// samples unpacked, which can be less than the number requested if an error
// occurs or the end of the block is reached.
#if defined(CPU_COLDFIRE) && !defined(SIMULATOR)
extern void decorr_stereo_pass_cont_mcf5249 (struct decorr_pass *dpp, int32_t *buffer, int32_t sample_count);
#elif defined(CPU_ARM) && !defined(SIMULATOR)
extern void decorr_stereo_pass_cont_arm (struct decorr_pass *dpp, int32_t *buffer, int32_t sample_count);
extern void decorr_stereo_pass_cont_arml (struct decorr_pass *dpp, int32_t *buffer, int32_t sample_count);
#else
static void decorr_stereo_pass_cont (struct decorr_pass *dpp, int32_t *buffer, int32_t sample_count);
#endif
static void decorr_mono_pass (struct decorr_pass *dpp, int32_t *buffer, int32_t sample_count);
static void decorr_stereo_pass (struct decorr_pass *dpp, int32_t *buffer, int32_t sample_count);
static void fixup_samples (WavpackStream *wps, int32_t *buffer, uint32_t sample_count);
int32_t unpack_samples (WavpackContext *wpc, int32_t *buffer, uint32_t sample_count)
{
WavpackStream *wps = &wpc->stream;
uint32_t flags = wps->wphdr.flags, crc = wps->crc, i;
int32_t mute_limit = (1L << ((flags & MAG_MASK) >> MAG_LSB)) + 2;
struct decorr_pass *dpp;
int32_t *bptr, *eptr;
int tcount;
if (wps->sample_index + sample_count > wps->wphdr.block_index + wps->wphdr.block_samples)
sample_count = wps->wphdr.block_index + wps->wphdr.block_samples - wps->sample_index;
if (wps->mute_error) {
memset (buffer, 0, sample_count * (flags & MONO_FLAG ? 4 : 8));
wps->sample_index += sample_count;
return sample_count;
}
if (flags & HYBRID_FLAG)
mute_limit *= 2;
///////////////////// handle version 4 mono data /////////////////////////
if (flags & MONO_DATA) {
eptr = buffer + sample_count;
i = get_words (buffer, sample_count, flags, &wps->w, &wps->wvbits);
for (tcount = wps->num_terms, dpp = wps->decorr_passes; tcount--; dpp++)
decorr_mono_pass (dpp, buffer, sample_count);
for (bptr = buffer; bptr < eptr; ++bptr) {
if (labs (bptr [0]) > mute_limit) {
i = bptr - buffer;
break;
}
crc = crc * 3 + bptr [0];
}
}
//////////////////// handle version 4 stereo data ////////////////////////
else {
eptr = buffer + (sample_count * 2);
i = get_words (buffer, sample_count, flags, &wps->w, &wps->wvbits);
if (sample_count < 16)
for (tcount = wps->num_terms, dpp = wps->decorr_passes; tcount--; dpp++)
decorr_stereo_pass (dpp, buffer, sample_count);
else
for (tcount = wps->num_terms, dpp = wps->decorr_passes; tcount--; dpp++) {
decorr_stereo_pass (dpp, buffer, 8);
#if defined(CPU_COLDFIRE) && !defined(SIMULATOR)
decorr_stereo_pass_cont_mcf5249 (dpp, buffer + 16, sample_count - 8);
#elif defined(CPU_ARM) && !defined(SIMULATOR)
if (((flags & MAG_MASK) >> MAG_LSB) > 15)
decorr_stereo_pass_cont_arml (dpp, buffer + 16, sample_count - 8);
else
decorr_stereo_pass_cont_arm (dpp, buffer + 16, sample_count - 8);
#else
decorr_stereo_pass_cont (dpp, buffer + 16, sample_count - 8);
#endif
}
if (flags & JOINT_STEREO)
for (bptr = buffer; bptr < eptr; bptr += 2) {
bptr [0] += (bptr [1] -= (bptr [0] >> 1));
if (labs (bptr [0]) > mute_limit || labs (bptr [1]) > mute_limit) {
i = (bptr - buffer) / 2;
break;
}
crc = (crc * 3 + bptr [0]) * 3 + bptr [1];
}
else
for (bptr = buffer; bptr < eptr; bptr += 2) {
if (labs (bptr [0]) > mute_limit || labs (bptr [1]) > mute_limit) {
i = (bptr - buffer) / 2;
break;
}
crc = (crc * 3 + bptr [0]) * 3 + bptr [1];
}
}
if (i != sample_count) {
memset (buffer, 0, sample_count * (flags & MONO_FLAG ? 4 : 8));
wps->mute_error = TRUE;
i = sample_count;
}
fixup_samples (wps, buffer, i);
if (flags & FALSE_STEREO) {
int32_t *dptr = buffer + i * 2;
int32_t *sptr = buffer + i;
int32_t c = i;
while (c--) {
*--dptr = *--sptr;
*--dptr = *sptr;
}
}
wps->sample_index += i;
wps->crc = crc;
return i;
}
static void decorr_stereo_pass (struct decorr_pass *dpp, int32_t *buffer, int32_t sample_count)
{
int32_t delta = dpp->delta, weight_A = dpp->weight_A, weight_B = dpp->weight_B;
int32_t *bptr, *eptr = buffer + (sample_count * 2), sam_A, sam_B;
int m, k;
switch (dpp->term) {
case 17:
for (bptr = buffer; bptr < eptr; bptr += 2) {
sam_A = 2 * dpp->samples_A [0] - dpp->samples_A [1];
dpp->samples_A [1] = dpp->samples_A [0];
dpp->samples_A [0] = apply_weight (weight_A, sam_A) + bptr [0];
update_weight (weight_A, delta, sam_A, bptr [0]);
bptr [0] = dpp->samples_A [0];
sam_A = 2 * dpp->samples_B [0] - dpp->samples_B [1];
dpp->samples_B [1] = dpp->samples_B [0];
dpp->samples_B [0] = apply_weight (weight_B, sam_A) + bptr [1];
update_weight (weight_B, delta, sam_A, bptr [1]);
bptr [1] = dpp->samples_B [0];
}
break;
case 18:
for (bptr = buffer; bptr < eptr; bptr += 2) {
sam_A = (3 * dpp->samples_A [0] - dpp->samples_A [1]) >> 1;
dpp->samples_A [1] = dpp->samples_A [0];
dpp->samples_A [0] = apply_weight (weight_A, sam_A) + bptr [0];
update_weight (weight_A, delta, sam_A, bptr [0]);
bptr [0] = dpp->samples_A [0];
sam_A = (3 * dpp->samples_B [0] - dpp->samples_B [1]) >> 1;
dpp->samples_B [1] = dpp->samples_B [0];
dpp->samples_B [0] = apply_weight (weight_B, sam_A) + bptr [1];
update_weight (weight_B, delta, sam_A, bptr [1]);
bptr [1] = dpp->samples_B [0];
}
break;
default:
for (m = 0, k = dpp->term & (MAX_TERM - 1), bptr = buffer; bptr < eptr; bptr += 2) {
sam_A = dpp->samples_A [m];
dpp->samples_A [k] = apply_weight (weight_A, sam_A) + bptr [0];
update_weight (weight_A, delta, sam_A, bptr [0]);
bptr [0] = dpp->samples_A [k];
sam_A = dpp->samples_B [m];
dpp->samples_B [k] = apply_weight (weight_B, sam_A) + bptr [1];
update_weight (weight_B, delta, sam_A, bptr [1]);
bptr [1] = dpp->samples_B [k];
m = (m + 1) & (MAX_TERM - 1);
k = (k + 1) & (MAX_TERM - 1);
}
if (m) {
int32_t temp_samples [MAX_TERM];
memcpy (temp_samples, dpp->samples_A, sizeof (dpp->samples_A));
for (k = 0; k < MAX_TERM; k++, m++)
dpp->samples_A [k] = temp_samples [m & (MAX_TERM - 1)];
memcpy (temp_samples, dpp->samples_B, sizeof (dpp->samples_B));
for (k = 0; k < MAX_TERM; k++, m++)
dpp->samples_B [k] = temp_samples [m & (MAX_TERM - 1)];
}
break;
case -1:
for (bptr = buffer; bptr < eptr; bptr += 2) {
sam_A = bptr [0] + apply_weight (weight_A, dpp->samples_A [0]);
update_weight_clip (weight_A, delta, dpp->samples_A [0], bptr [0]);
bptr [0] = sam_A;
dpp->samples_A [0] = bptr [1] + apply_weight (weight_B, sam_A);
update_weight_clip (weight_B, delta, sam_A, bptr [1]);
bptr [1] = dpp->samples_A [0];
}
break;
case -2:
for (bptr = buffer; bptr < eptr; bptr += 2) {
sam_B = bptr [1] + apply_weight (weight_B, dpp->samples_B [0]);
update_weight_clip (weight_B, delta, dpp->samples_B [0], bptr [1]);
bptr [1] = sam_B;
dpp->samples_B [0] = bptr [0] + apply_weight (weight_A, sam_B);
update_weight_clip (weight_A, delta, sam_B, bptr [0]);
bptr [0] = dpp->samples_B [0];
}
break;
case -3:
for (bptr = buffer; bptr < eptr; bptr += 2) {
sam_A = bptr [0] + apply_weight (weight_A, dpp->samples_A [0]);
update_weight_clip (weight_A, delta, dpp->samples_A [0], bptr [0]);
sam_B = bptr [1] + apply_weight (weight_B, dpp->samples_B [0]);
update_weight_clip (weight_B, delta, dpp->samples_B [0], bptr [1]);
bptr [0] = dpp->samples_B [0] = sam_A;
bptr [1] = dpp->samples_A [0] = sam_B;
}
break;
}
dpp->weight_A = weight_A;
dpp->weight_B = weight_B;
}
#if (!defined(CPU_COLDFIRE) && !defined(CPU_ARM)) || defined(SIMULATOR)
static void decorr_stereo_pass_cont (struct decorr_pass *dpp, int32_t *buffer, int32_t sample_count)
{
int32_t delta = dpp->delta, weight_A = dpp->weight_A, weight_B = dpp->weight_B;
int32_t *bptr, *tptr, *eptr = buffer + (sample_count * 2), sam_A, sam_B;
int k, i;
switch (dpp->term) {
case 17:
for (bptr = buffer; bptr < eptr; bptr += 2) {
sam_A = 2 * bptr [-2] - bptr [-4];
bptr [0] = apply_weight (weight_A, sam_A) + (sam_B = bptr [0]);
update_weight (weight_A, delta, sam_A, sam_B);
sam_A = 2 * bptr [-1] - bptr [-3];
bptr [1] = apply_weight (weight_B, sam_A) + (sam_B = bptr [1]);
update_weight (weight_B, delta, sam_A, sam_B);
}
dpp->samples_B [0] = bptr [-1];
dpp->samples_A [0] = bptr [-2];
dpp->samples_B [1] = bptr [-3];
dpp->samples_A [1] = bptr [-4];
break;
case 18:
for (bptr = buffer; bptr < eptr; bptr += 2) {
sam_A = (3 * bptr [-2] - bptr [-4]) >> 1;
bptr [0] = apply_weight (weight_A, sam_A) + (sam_B = bptr [0]);
update_weight (weight_A, delta, sam_A, sam_B);
sam_A = (3 * bptr [-1] - bptr [-3]) >> 1;
bptr [1] = apply_weight (weight_B, sam_A) + (sam_B = bptr [1]);
update_weight (weight_B, delta, sam_A, sam_B);
}
dpp->samples_B [0] = bptr [-1];
dpp->samples_A [0] = bptr [-2];
dpp->samples_B [1] = bptr [-3];
dpp->samples_A [1] = bptr [-4];
break;
default:
for (bptr = buffer, tptr = buffer - (dpp->term * 2); bptr < eptr; bptr += 2, tptr += 2) {
bptr [0] = apply_weight (weight_A, tptr [0]) + (sam_A = bptr [0]);
update_weight (weight_A, delta, tptr [0], sam_A);
bptr [1] = apply_weight (weight_B, tptr [1]) + (sam_A = bptr [1]);
update_weight (weight_B, delta, tptr [1], sam_A);
}
for (k = dpp->term - 1, i = 8; i--; k--) {
dpp->samples_B [k & (MAX_TERM - 1)] = *--bptr;
dpp->samples_A [k & (MAX_TERM - 1)] = *--bptr;
}
break;
case -1:
for (bptr = buffer; bptr < eptr; bptr += 2) {
bptr [0] = apply_weight (weight_A, bptr [-1]) + (sam_A = bptr [0]);
update_weight_clip (weight_A, delta, bptr [-1], sam_A);
bptr [1] = apply_weight (weight_B, bptr [0]) + (sam_A = bptr [1]);
update_weight_clip (weight_B, delta, bptr [0], sam_A);
}
dpp->samples_A [0] = bptr [-1];
break;
case -2:
for (bptr = buffer; bptr < eptr; bptr += 2) {
bptr [1] = apply_weight (weight_B, bptr [-2]) + (sam_A = bptr [1]);
update_weight_clip (weight_B, delta, bptr [-2], sam_A);
bptr [0] = apply_weight (weight_A, bptr [1]) + (sam_A = bptr [0]);
update_weight_clip (weight_A, delta, bptr [1], sam_A);
}
dpp->samples_B [0] = bptr [-2];
break;
case -3:
for (bptr = buffer; bptr < eptr; bptr += 2) {
bptr [0] = apply_weight (weight_A, bptr [-1]) + (sam_A = bptr [0]);
update_weight_clip (weight_A, delta, bptr [-1], sam_A);
bptr [1] = apply_weight (weight_B, bptr [-2]) + (sam_A = bptr [1]);
update_weight_clip (weight_B, delta, bptr [-2], sam_A);
}
dpp->samples_A [0] = bptr [-1];
dpp->samples_B [0] = bptr [-2];
break;
}
dpp->weight_A = weight_A;
dpp->weight_B = weight_B;
}
#endif
static void decorr_mono_pass (struct decorr_pass *dpp, int32_t *buffer, int32_t sample_count)
{
int32_t delta = dpp->delta, weight_A = dpp->weight_A;
int32_t *bptr, *eptr = buffer + sample_count, sam_A;
int m, k;
switch (dpp->term) {
case 17:
for (bptr = buffer; bptr < eptr; bptr++) {
sam_A = 2 * dpp->samples_A [0] - dpp->samples_A [1];
dpp->samples_A [1] = dpp->samples_A [0];
dpp->samples_A [0] = apply_weight (weight_A, sam_A) + bptr [0];
update_weight (weight_A, delta, sam_A, bptr [0]);
bptr [0] = dpp->samples_A [0];
}
break;
case 18:
for (bptr = buffer; bptr < eptr; bptr++) {
sam_A = (3 * dpp->samples_A [0] - dpp->samples_A [1]) >> 1;
dpp->samples_A [1] = dpp->samples_A [0];
dpp->samples_A [0] = apply_weight (weight_A, sam_A) + bptr [0];
update_weight (weight_A, delta, sam_A, bptr [0]);
bptr [0] = dpp->samples_A [0];
}
break;
default:
for (m = 0, k = dpp->term & (MAX_TERM - 1), bptr = buffer; bptr < eptr; bptr++) {
sam_A = dpp->samples_A [m];
dpp->samples_A [k] = apply_weight (weight_A, sam_A) + bptr [0];
update_weight (weight_A, delta, sam_A, bptr [0]);
bptr [0] = dpp->samples_A [k];
m = (m + 1) & (MAX_TERM - 1);
k = (k + 1) & (MAX_TERM - 1);
}
if (m) {
int32_t temp_samples [MAX_TERM];
memcpy (temp_samples, dpp->samples_A, sizeof (dpp->samples_A));
for (k = 0; k < MAX_TERM; k++, m++)
dpp->samples_A [k] = temp_samples [m & (MAX_TERM - 1)];
}
break;
}
dpp->weight_A = weight_A;
}
// This is a helper function for unpack_samples() that applies several final
// operations. First, if the data is 32-bit float data, then that conversion
// is done in the float.c module (whether lossy or lossless) and we return.
// Otherwise, if the extended integer data applies, then that operation is
// executed first. If the unpacked data is lossy (and not corrected) then
// it is clipped and shifted in a single operation. Otherwise, if it's
// lossless then the last step is to apply the final shift (if any).
// This function has been modified for RockBox to return all integer samples
// as 28-bits, and clipping (for lossy mode) has been eliminated because this
// now happens in the dsp module.
static void fixup_samples (WavpackStream *wps, int32_t *buffer, uint32_t sample_count)
{
uint32_t flags = wps->wphdr.flags;
int shift = (flags & SHIFT_MASK) >> SHIFT_LSB;
shift += 21 - (flags & BYTES_STORED) * 8; // this provides RockBox with 28-bit (+sign)
if (flags & FLOAT_DATA) {
float_values (wps, buffer, (flags & MONO_DATA) ? sample_count : sample_count * 2);
return;
}
if (flags & INT32_DATA) {
uint32_t count = (flags & MONO_DATA) ? sample_count : sample_count * 2;
int sent_bits = wps->int32_sent_bits, zeros = wps->int32_zeros;
int ones = wps->int32_ones, dups = wps->int32_dups;
int32_t *dptr = buffer;
if (!(flags & HYBRID_FLAG) && !sent_bits && (zeros + ones + dups))
while (count--) {
if (zeros)
*dptr <<= zeros;
else if (ones)
*dptr = ((*dptr + 1) << ones) - 1;
else if (dups)
*dptr = ((*dptr + (*dptr & 1)) << dups) - (*dptr & 1);
dptr++;
}
else
shift += zeros + sent_bits + ones + dups;
}
if (shift > 0) {
if (!(flags & MONO_DATA))
sample_count *= 2;
while (sample_count--)
*buffer++ <<= shift;
}
else if (shift < 0) {
shift = -shift;
if (!(flags & MONO_DATA))
sample_count *= 2;
while (sample_count--)
*buffer++ >>= shift;
}
}
// This function checks the crc value(s) for an unpacked block, returning the
// number of actual crc errors detected for the block. The block must be
// completely unpacked before this test is valid. For losslessly unpacked
// blocks of float or extended integer data the extended crc is also checked.
// Note that WavPack's crc is not a CCITT approved polynomial algorithm, but
// is a much simpler method that is virtually as robust for real world data.
int check_crc_error (WavpackContext *wpc)
{
WavpackStream *wps = &wpc->stream;
int result = 0;
if (wps->crc != wps->wphdr.crc)
++result;
return result;
}
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