diff options
Diffstat (limited to 'faad2/src/libfaad/lt_predict.c')
| -rw-r--r-- | faad2/src/libfaad/lt_predict.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/faad2/src/libfaad/lt_predict.c b/faad2/src/libfaad/lt_predict.c new file mode 100644 index 0000000..33defb4 --- /dev/null +++ b/faad2/src/libfaad/lt_predict.c @@ -0,0 +1,215 @@ +/*
+** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
+** Copyright (C) 2003-2005 M. Bakker, Nero AG, http://www.nero.com
+**
+** This program is free software; you can redistribute it and/or modify
+** it under the terms of the GNU General Public License as published by
+** the Free Software Foundation; either version 2 of the License, or
+** (at your option) any later version.
+**
+** This program is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+** GNU General Public License for more details.
+**
+** You should have received a copy of the GNU General Public License
+** along with this program; if not, write to the Free Software
+** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+**
+** Any non-GPL usage of this software or parts of this software is strictly
+** forbidden.
+**
+** The "appropriate copyright message" mentioned in section 2c of the GPLv2
+** must read: "Code from FAAD2 is copyright (c) Nero AG, www.nero.com"
+**
+** Commercial non-GPL licensing of this software is possible.
+** For more info contact Nero AG through Mpeg4AAClicense@nero.com.
+**
+** $Id: lt_predict.c,v 1.27 2007/11/01 12:33:31 menno Exp $
+**/
+
+
+#include "common.h"
+#include "structs.h"
+
+#ifdef LTP_DEC
+
+#include <stdlib.h>
+#include "syntax.h"
+#include "lt_predict.h"
+#include "filtbank.h"
+#include "tns.h"
+
+
+/* static function declarations */
+static int16_t real_to_int16(real_t sig_in);
+
+
+/* check if the object type is an object type that can have LTP */
+uint8_t is_ltp_ot(uint8_t object_type)
+{
+#ifdef LTP_DEC
+ if ((object_type == LTP)
+#ifdef ERROR_RESILIENCE
+ || (object_type == ER_LTP)
+#endif
+#ifdef LD_DEC
+ || (object_type == LD)
+#endif
+ )
+ {
+ return 1;
+ }
+#endif
+
+ return 0;
+}
+
+ALIGN static const real_t codebook[8] =
+{
+ REAL_CONST(0.570829),
+ REAL_CONST(0.696616),
+ REAL_CONST(0.813004),
+ REAL_CONST(0.911304),
+ REAL_CONST(0.984900),
+ REAL_CONST(1.067894),
+ REAL_CONST(1.194601),
+ REAL_CONST(1.369533)
+};
+
+void lt_prediction(ic_stream *ics, ltp_info *ltp, real_t *spec,
+ int16_t *lt_pred_stat, fb_info *fb, uint8_t win_shape,
+ uint8_t win_shape_prev, uint8_t sr_index,
+ uint8_t object_type, uint16_t frame_len)
+{
+ uint8_t sfb;
+ uint16_t bin, i, num_samples;
+ ALIGN real_t x_est[2048];
+ ALIGN real_t X_est[2048];
+
+ if (ics->window_sequence != EIGHT_SHORT_SEQUENCE)
+ {
+ if (ltp->data_present)
+ {
+ num_samples = frame_len << 1;
+
+ for(i = 0; i < num_samples; i++)
+ {
+ /* The extra lookback M (N/2 for LD, 0 for LTP) is handled
+ in the buffer updating */
+
+#if 0
+ x_est[i] = MUL_R_C(lt_pred_stat[num_samples + i - ltp->lag],
+ codebook[ltp->coef]);
+#else
+ /* lt_pred_stat is a 16 bit int, multiplied with the fixed point real
+ this gives a real for x_est
+ */
+ x_est[i] = (real_t)lt_pred_stat[num_samples + i - ltp->lag] * codebook[ltp->coef];
+#endif
+ }
+
+ filter_bank_ltp(fb, ics->window_sequence, win_shape, win_shape_prev,
+ x_est, X_est, object_type, frame_len);
+
+ tns_encode_frame(ics, &(ics->tns), sr_index, object_type, X_est,
+ frame_len);
+
+ for (sfb = 0; sfb < ltp->last_band; sfb++)
+ {
+ if (ltp->long_used[sfb])
+ {
+ uint16_t low = ics->swb_offset[sfb];
+ uint16_t high = min(ics->swb_offset[sfb+1], ics->swb_offset_max);
+
+ for (bin = low; bin < high; bin++)
+ {
+ spec[bin] += X_est[bin];
+ }
+ }
+ }
+ }
+ }
+}
+
+#ifdef FIXED_POINT
+static INLINE int16_t real_to_int16(real_t sig_in)
+{
+ if (sig_in >= 0)
+ {
+ sig_in += (1 << (REAL_BITS-1));
+ if (sig_in >= REAL_CONST(32768))
+ return 32767;
+ } else {
+ sig_in += -(1 << (REAL_BITS-1));
+ if (sig_in <= REAL_CONST(-32768))
+ return -32768;
+ }
+
+ return (sig_in >> REAL_BITS);
+}
+#else
+static INLINE int16_t real_to_int16(real_t sig_in)
+{
+ if (sig_in >= 0)
+ {
+#ifndef HAS_LRINTF
+ sig_in += 0.5f;
+#endif
+ if (sig_in >= 32768.0f)
+ return 32767;
+ } else {
+#ifndef HAS_LRINTF
+ sig_in += -0.5f;
+#endif
+ if (sig_in <= -32768.0f)
+ return -32768;
+ }
+
+ return lrintf(sig_in);
+}
+#endif
+
+void lt_update_state(int16_t *lt_pred_stat, real_t *time, real_t *overlap,
+ uint16_t frame_len, uint8_t object_type)
+{
+ uint16_t i;
+
+ /*
+ * The reference point for index i and the content of the buffer
+ * lt_pred_stat are arranged so that lt_pred_stat(0 ... N/2 - 1) contains the
+ * last aliased half window from the IMDCT, and lt_pred_stat(N/2 ... N-1)
+ * is always all zeros. The rest of lt_pred_stat (i<0) contains the previous
+ * fully reconstructed time domain samples, i.e., output of the decoder.
+ *
+ * These values are shifted up by N*2 to avoid (i<0)
+ *
+ * For the LD object type an extra 512 samples lookback is accomodated here.
+ */
+#ifdef LD_DEC
+ if (object_type == LD)
+ {
+ for (i = 0; i < frame_len; i++)
+ {
+ lt_pred_stat[i] /* extra 512 */ = lt_pred_stat[i + frame_len];
+ lt_pred_stat[frame_len + i] = lt_pred_stat[i + (frame_len * 2)];
+ lt_pred_stat[(frame_len * 2) + i] = real_to_int16(time[i]);
+ lt_pred_stat[(frame_len * 3) + i] = real_to_int16(overlap[i]);
+ }
+ } else {
+#endif
+ for (i = 0; i < frame_len; i++)
+ {
+ lt_pred_stat[i] = lt_pred_stat[i + frame_len];
+ lt_pred_stat[frame_len + i] = real_to_int16(time[i]);
+ lt_pred_stat[(frame_len * 2) + i] = real_to_int16(overlap[i]);
+#if 0 /* set to zero once upon initialisation */
+ lt_pred_stat[(frame_len * 3) + i] = 0;
+#endif
+ }
+#ifdef LD_DEC
+ }
+#endif
+}
+
+#endif
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