FFmpeg: libavcodec/dcaenc.c Source File

00001 /*
00002  * DCA encoder
00003  * Copyright (C) 2008 Alexander E. Patrakov
00004  *               2010 Benjamin Larsson
00005  *               2011 Xiang Wang
00006  *
00007  * This file is part of FFmpeg.
00008  *
00009  * FFmpeg is free software; you can redistribute it and/or
00010  * modify it under the terms of the GNU Lesser General Public
00011  * License as published by the Free Software Foundation; either
00012  * version 2.1 of the License, or (at your option) any later version.
00013  *
00014  * FFmpeg is distributed in the hope that it will be useful,
00015  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00016  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00017  * Lesser General Public License for more details.
00018  *
00019  * You should have received a copy of the GNU Lesser General Public
00020  * License along with FFmpeg; if not, write to the Free Software
00021  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00022  */
00023 
00024 #include "libavutil/common.h"
00025 #include "libavutil/avassert.h"
00026 #include "libavutil/audioconvert.h"
00027 #include "avcodec.h"
00028 #include "get_bits.h"
00029 #include "put_bits.h"
00030 #include "dcaenc.h"
00031 #include "dcadata.h"
00032 
00033 #undef NDEBUG
00034 
00035 #define MAX_CHANNELS 6
00036 #define DCA_SUBBANDS_32 32
00037 #define DCA_MAX_FRAME_SIZE 16383
00038 #define DCA_HEADER_SIZE 13
00039 
00040 #define DCA_SUBBANDS 32 
00041 #define QUANTIZER_BITS 16
00042 #define SUBFRAMES 1
00043 #define SUBSUBFRAMES 4
00044 #define PCM_SAMPLES (SUBFRAMES*SUBSUBFRAMES*8)
00045 #define LFE_BITS 8
00046 #define LFE_INTERPOLATION 64
00047 #define LFE_PRESENT 2
00048 #define LFE_MISSING 0
00049 
00050 static const int8_t dca_lfe_index[] = {
00051     1,2,2,2,2,3,2,3,2,3,2,3,1,3,2,3
00052 };
00053 
00054 static const int8_t dca_channel_reorder_lfe[][9] = {
00055     { 0, -1, -1, -1, -1, -1, -1, -1, -1 },
00056     { 0,  1, -1, -1, -1, -1, -1, -1, -1 },
00057     { 0,  1, -1, -1, -1, -1, -1, -1, -1 },
00058     { 0,  1, -1, -1, -1, -1, -1, -1, -1 },
00059     { 0,  1, -1, -1, -1, -1, -1, -1, -1 },
00060     { 1,  2,  0, -1, -1, -1, -1, -1, -1 },
00061     { 0,  1, -1,  2, -1, -1, -1, -1, -1 },
00062     { 1,  2,  0, -1,  3, -1, -1, -1, -1 },
00063     { 0,  1, -1,  2,  3, -1, -1, -1, -1 },
00064     { 1,  2,  0, -1,  3,  4, -1, -1, -1 },
00065     { 2,  3, -1,  0,  1,  4,  5, -1, -1 },
00066     { 1,  2,  0, -1,  3,  4,  5, -1, -1 },
00067     { 0, -1,  4,  5,  2,  3,  1, -1, -1 },
00068     { 3,  4,  1, -1,  0,  2,  5,  6, -1 },
00069     { 2,  3, -1,  5,  7,  0,  1,  4,  6 },
00070     { 3,  4,  1, -1,  0,  2,  5,  7,  6 },
00071 };
00072 
00073 static const int8_t dca_channel_reorder_nolfe[][9] = {
00074     { 0, -1, -1, -1, -1, -1, -1, -1, -1 },
00075     { 0,  1, -1, -1, -1, -1, -1, -1, -1 },
00076     { 0,  1, -1, -1, -1, -1, -1, -1, -1 },
00077     { 0,  1, -1, -1, -1, -1, -1, -1, -1 },
00078     { 0,  1, -1, -1, -1, -1, -1, -1, -1 },
00079     { 1,  2,  0, -1, -1, -1, -1, -1, -1 },
00080     { 0,  1,  2, -1, -1, -1, -1, -1, -1 },
00081     { 1,  2,  0,  3, -1, -1, -1, -1, -1 },
00082     { 0,  1,  2,  3, -1, -1, -1, -1, -1 },
00083     { 1,  2,  0,  3,  4, -1, -1, -1, -1 },
00084     { 2,  3,  0,  1,  4,  5, -1, -1, -1 },
00085     { 1,  2,  0,  3,  4,  5, -1, -1, -1 },
00086     { 0,  4,  5,  2,  3,  1, -1, -1, -1 },
00087     { 3,  4,  1,  0,  2,  5,  6, -1, -1 },
00088     { 2,  3,  5,  7,  0,  1,  4,  6, -1 },
00089     { 3,  4,  1,  0,  2,  5,  7,  6, -1 },
00090 };
00091 
00092 typedef struct {
00093     PutBitContext pb;
00094     int32_t history[MAX_CHANNELS][512]; /* This is a circular buffer */
00095     int start[MAX_CHANNELS];
00096     int frame_size;
00097     int prim_channels;
00098     int lfe_channel;
00099     int sample_rate_code;
00100     int scale_factor[MAX_CHANNELS][DCA_SUBBANDS_32];
00101     int lfe_scale_factor;
00102     int lfe_data[SUBFRAMES*SUBSUBFRAMES*4];
00103 
00104     int a_mode;                         
00105     int num_channel;
00106     int lfe_state;
00107     int lfe_offset;
00108     const int8_t *channel_order_tab;    
00109 
00110     int32_t pcm[FFMAX(LFE_INTERPOLATION, DCA_SUBBANDS_32)];
00111     int32_t subband[PCM_SAMPLES][MAX_CHANNELS][DCA_SUBBANDS_32]; /* [sample][channel][subband] */
00112 } DCAContext;
00113 
00114 static int32_t cos_table[128];
00115 
00116 static inline int32_t mul32(int32_t a, int32_t b)
00117 {
00118     int64_t r = (int64_t) a * b;
00119     /* round the result before truncating - improves accuracy */
00120     return (r + 0x80000000) >> 32;
00121 }
00122 
00123 /* Integer version of the cosine modulated Pseudo QMF */
00124 
00125 static void qmf_init(void)
00126 {
00127     int i;
00128     int32_t c[17], s[17];
00129     s[0] = 0;           /* sin(index * PI / 64) * 0x7fffffff */
00130     c[0] = 0x7fffffff;  /* cos(index * PI / 64) * 0x7fffffff */
00131 
00132     for (i = 1; i <= 16; i++) {
00133         s[i] = 2 * (mul32(c[i - 1], 105372028)  + mul32(s[i - 1], 2144896908));
00134         c[i] = 2 * (mul32(c[i - 1], 2144896908) - mul32(s[i - 1], 105372028));
00135     }
00136 
00137     for (i = 0; i < 16; i++) {
00138         cos_table[i      ]  =  c[i]      >> 3; /* avoid output overflow */
00139         cos_table[i +  16]  =  s[16 - i] >> 3;
00140         cos_table[i +  32]  = -s[i]      >> 3;
00141         cos_table[i +  48]  = -c[16 - i] >> 3;
00142         cos_table[i +  64]  = -c[i]      >> 3;
00143         cos_table[i +  80]  = -s[16 - i] >> 3;
00144         cos_table[i +  96]  =  s[i]      >> 3;
00145         cos_table[i + 112]  =  c[16 - i] >> 3;
00146     }
00147 }
00148 
00149 static int32_t band_delta_factor(int band, int sample_num)
00150 {
00151     int index = band * (2 * sample_num + 1);
00152     if (band == 0)
00153         return 0x07ffffff;
00154     else
00155         return cos_table[index & 127];
00156 }
00157 
00158 static void add_new_samples(DCAContext *c, const int32_t *in,
00159                             int count, int channel)
00160 {
00161     int i;
00162 
00163     /* Place new samples into the history buffer */
00164     for (i = 0; i < count; i++) {
00165         c->history[channel][c->start[channel] + i] = in[i];
00166         av_assert0(c->start[channel] + i < 512);
00167     }
00168     c->start[channel] += count;
00169     if (c->start[channel] == 512)
00170         c->start[channel] = 0;
00171     av_assert0(c->start[channel] < 512);
00172 }
00173 
00174 static void qmf_decompose(DCAContext *c, int32_t in[32], int32_t out[32],
00175                           int channel)
00176 {
00177     int band, i, j, k;
00178     int32_t resp;
00179     int32_t accum[DCA_SUBBANDS_32] = {0};
00180 
00181     add_new_samples(c, in, DCA_SUBBANDS_32, channel);
00182 
00183     /* Calculate the dot product of the signal with the (possibly inverted)
00184        reference decoder's response to this vector:
00185        (0.0, 0.0, ..., 0.0, -1.0, 1.0, 0.0, ..., 0.0)
00186        so that -1.0 cancels 1.0 from the previous step */
00187 
00188     for (k = 48, j = 0, i = c->start[channel]; i < 512; k++, j++, i++)
00189         accum[(k & 32) ? (31 - (k & 31)) : (k & 31)] += mul32(c->history[channel][i], UnQMF[j]);
00190     for (i = 0; i < c->start[channel]; k++, j++, i++)
00191         accum[(k & 32) ? (31 - (k & 31)) : (k & 31)] += mul32(c->history[channel][i], UnQMF[j]);
00192 
00193     resp = 0;
00194     /* TODO: implement FFT instead of this naive calculation */
00195     for (band = 0; band < DCA_SUBBANDS_32; band++) {
00196         for (j = 0; j < 32; j++)
00197             resp += mul32(accum[j], band_delta_factor(band, j));
00198 
00199         out[band] = (band & 2) ? (-resp) : resp;
00200     }
00201 }
00202 
00203 static int32_t lfe_fir_64i[512];
00204 static int lfe_downsample(DCAContext *c, int32_t in[LFE_INTERPOLATION])
00205 {
00206     int i, j;
00207     int channel = c->prim_channels;
00208     int32_t accum = 0;
00209 
00210     add_new_samples(c, in, LFE_INTERPOLATION, channel);
00211     for (i = c->start[channel], j = 0; i < 512; i++, j++)
00212         accum += mul32(c->history[channel][i], lfe_fir_64i[j]);
00213     for (i = 0; i < c->start[channel]; i++, j++)
00214         accum += mul32(c->history[channel][i], lfe_fir_64i[j]);
00215     return accum;
00216 }
00217 
00218 static void init_lfe_fir(void)
00219 {
00220     static int initialized = 0;
00221     int i;
00222     if (initialized)
00223         return;
00224 
00225     for (i = 0; i < 512; i++)
00226         lfe_fir_64i[i] = lfe_fir_64[i] * (1 << 25); //float -> int32_t
00227     initialized = 1;
00228 }
00229 
00230 static void put_frame_header(DCAContext *c)
00231 {
00232     /* SYNC */
00233     put_bits(&c->pb, 16, 0x7ffe);
00234     put_bits(&c->pb, 16, 0x8001);
00235 
00236     /* Frame type: normal */
00237     put_bits(&c->pb, 1, 1);
00238 
00239     /* Deficit sample count: none */
00240     put_bits(&c->pb, 5, 31);
00241 
00242     /* CRC is not present */
00243     put_bits(&c->pb, 1, 0);
00244 
00245     /* Number of PCM sample blocks */
00246     put_bits(&c->pb, 7, PCM_SAMPLES-1);
00247 
00248     /* Primary frame byte size */
00249     put_bits(&c->pb, 14, c->frame_size-1);
00250 
00251     /* Audio channel arrangement: L + R (stereo) */
00252     put_bits(&c->pb, 6, c->num_channel);
00253 
00254     /* Core audio sampling frequency */
00255     put_bits(&c->pb, 4, c->sample_rate_code);
00256 
00257     /* Transmission bit rate: 1411.2 kbps */
00258     put_bits(&c->pb, 5, 0x16); /* FIXME: magic number */
00259 
00260     /* Embedded down mix: disabled */
00261     put_bits(&c->pb, 1, 0);
00262 
00263     /* Embedded dynamic range flag: not present */
00264     put_bits(&c->pb, 1, 0);
00265 
00266     /* Embedded time stamp flag: not present */
00267     put_bits(&c->pb, 1, 0);
00268 
00269     /* Auxiliary data flag: not present */
00270     put_bits(&c->pb, 1, 0);
00271 
00272     /* HDCD source: no */
00273     put_bits(&c->pb, 1, 0);
00274 
00275     /* Extension audio ID: N/A */
00276     put_bits(&c->pb, 3, 0);
00277 
00278     /* Extended audio data: not present */
00279     put_bits(&c->pb, 1, 0);
00280 
00281     /* Audio sync word insertion flag: after each sub-frame */
00282     put_bits(&c->pb, 1, 0);
00283 
00284     /* Low frequency effects flag: not present or interpolation factor=64 */
00285     put_bits(&c->pb, 2, c->lfe_state);
00286 
00287     /* Predictor history switch flag: on */
00288     put_bits(&c->pb, 1, 1);
00289 
00290     /* No CRC */
00291     /* Multirate interpolator switch: non-perfect reconstruction */
00292     put_bits(&c->pb, 1, 0);
00293 
00294     /* Encoder software revision: 7 */
00295     put_bits(&c->pb, 4, 7);
00296 
00297     /* Copy history: 0 */
00298     put_bits(&c->pb, 2, 0);
00299 
00300     /* Source PCM resolution: 16 bits, not DTS ES */
00301     put_bits(&c->pb, 3, 0);
00302 
00303     /* Front sum/difference coding: no */
00304     put_bits(&c->pb, 1, 0);
00305 
00306     /* Surrounds sum/difference coding: no */
00307     put_bits(&c->pb, 1, 0);
00308 
00309     /* Dialog normalization: 0 dB */
00310     put_bits(&c->pb, 4, 0);
00311 }
00312 
00313 static void put_primary_audio_header(DCAContext *c)
00314 {
00315     static const int bitlen[11] = { 0, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3 };
00316     static const int thr[11]    = { 0, 1, 3, 3, 3, 3, 7, 7, 7, 7, 7 };
00317 
00318     int ch, i;
00319     /* Number of subframes */
00320     put_bits(&c->pb, 4, SUBFRAMES - 1);
00321 
00322     /* Number of primary audio channels */
00323     put_bits(&c->pb, 3, c->prim_channels - 1);
00324 
00325     /* Subband activity count */
00326     for (ch = 0; ch < c->prim_channels; ch++)
00327         put_bits(&c->pb, 5, DCA_SUBBANDS - 2);
00328 
00329     /* High frequency VQ start subband */
00330     for (ch = 0; ch < c->prim_channels; ch++)
00331         put_bits(&c->pb, 5, DCA_SUBBANDS - 1);
00332 
00333     /* Joint intensity coding index: 0, 0 */
00334     for (ch = 0; ch < c->prim_channels; ch++)
00335         put_bits(&c->pb, 3, 0);
00336 
00337     /* Transient mode codebook: A4, A4 (arbitrary) */
00338     for (ch = 0; ch < c->prim_channels; ch++)
00339         put_bits(&c->pb, 2, 0);
00340 
00341     /* Scale factor code book: 7 bit linear, 7-bit sqrt table (for each channel) */
00342     for (ch = 0; ch < c->prim_channels; ch++)
00343         put_bits(&c->pb, 3, 6);
00344 
00345     /* Bit allocation quantizer select: linear 5-bit */
00346     for (ch = 0; ch < c->prim_channels; ch++)
00347         put_bits(&c->pb, 3, 6);
00348 
00349     /* Quantization index codebook select: dummy data
00350        to avoid transmission of scale factor adjustment */
00351 
00352     for (i = 1; i < 11; i++)
00353         for (ch = 0; ch < c->prim_channels; ch++)
00354             put_bits(&c->pb, bitlen[i], thr[i]);
00355 
00356     /* Scale factor adjustment index: not transmitted */
00357 }
00358 
00364 static inline uint32_t quantize(int32_t sample, int bits)
00365 {
00366     av_assert0(sample <    1 << (bits - 1));
00367     av_assert0(sample >= -(1 << (bits - 1)));
00368     return sample & ((1 << bits) - 1);
00369 }
00370 
00371 static inline int find_scale_factor7(int64_t max_value, int bits)
00372 {
00373     int i = 0, j = 128, q;
00374     max_value = ((max_value << 15) / lossy_quant[bits + 3]) >> (bits - 1);
00375     while (i < j) {
00376         q = (i + j) >> 1;
00377         if (max_value < scale_factor_quant7[q])
00378             j = q;
00379         else
00380             i = q + 1;
00381     }
00382     av_assert1(i < 128);
00383     return i;
00384 }
00385 
00386 static inline void put_sample7(DCAContext *c, int64_t sample, int bits,
00387                                int scale_factor)
00388 {
00389     sample = (sample << 15) / ((int64_t) lossy_quant[bits + 3] * scale_factor_quant7[scale_factor]);
00390     put_bits(&c->pb, bits, quantize((int) sample, bits));
00391 }
00392 
00393 static void put_subframe(DCAContext *c,
00394                          int32_t subband_data[8 * SUBSUBFRAMES][MAX_CHANNELS][32],
00395                          int subframe)
00396 {
00397     int i, sub, ss, ch, max_value;
00398     int32_t *lfe_data = c->lfe_data + 4 * SUBSUBFRAMES * subframe;
00399 
00400     /* Subsubframes count */
00401     put_bits(&c->pb, 2, SUBSUBFRAMES -1);
00402 
00403     /* Partial subsubframe sample count: dummy */
00404     put_bits(&c->pb, 3, 0);
00405 
00406     /* Prediction mode: no ADPCM, in each channel and subband */
00407     for (ch = 0; ch < c->prim_channels; ch++)
00408         for (sub = 0; sub < DCA_SUBBANDS; sub++)
00409             put_bits(&c->pb, 1, 0);
00410 
00411     /* Prediction VQ addres: not transmitted */
00412     /* Bit allocation index */
00413     for (ch = 0; ch < c->prim_channels; ch++)
00414         for (sub = 0; sub < DCA_SUBBANDS; sub++)
00415             put_bits(&c->pb, 5, QUANTIZER_BITS+3);
00416 
00417     if (SUBSUBFRAMES > 1) {
00418         /* Transition mode: none for each channel and subband */
00419         for (ch = 0; ch < c->prim_channels; ch++)
00420             for (sub = 0; sub < DCA_SUBBANDS; sub++)
00421                 put_bits(&c->pb, 1, 0); /* codebook A4 */
00422     }
00423 
00424     /* Determine scale_factor */
00425     for (ch = 0; ch < c->prim_channels; ch++)
00426         for (sub = 0; sub < DCA_SUBBANDS; sub++) {
00427             max_value = 0;
00428             for (i = 0; i < 8 * SUBSUBFRAMES; i++)
00429                 max_value = FFMAX(max_value, FFABS(subband_data[i][ch][sub]));
00430             c->scale_factor[ch][sub] = find_scale_factor7(max_value, QUANTIZER_BITS);
00431         }
00432 
00433     if (c->lfe_channel) {
00434         max_value = 0;
00435         for (i = 0; i < 4 * SUBSUBFRAMES; i++)
00436             max_value = FFMAX(max_value, FFABS(lfe_data[i]));
00437         c->lfe_scale_factor = find_scale_factor7(max_value, LFE_BITS);
00438     }
00439 
00440     /* Scale factors: the same for each channel and subband,
00441        encoded according to Table D.1.2 */
00442     for (ch = 0; ch < c->prim_channels; ch++)
00443         for (sub = 0; sub < DCA_SUBBANDS; sub++)
00444             put_bits(&c->pb, 7, c->scale_factor[ch][sub]);
00445 
00446     /* Joint subband scale factor codebook select: not transmitted */
00447     /* Scale factors for joint subband coding: not transmitted */
00448     /* Stereo down-mix coefficients: not transmitted */
00449     /* Dynamic range coefficient: not transmitted */
00450     /* Stde information CRC check word: not transmitted */
00451     /* VQ encoded high frequency subbands: not transmitted */
00452 
00453     /* LFE data */
00454     if (c->lfe_channel) {
00455         for (i = 0; i < 4 * SUBSUBFRAMES; i++)
00456             put_sample7(c, lfe_data[i], LFE_BITS, c->lfe_scale_factor);
00457         put_bits(&c->pb, 8, c->lfe_scale_factor);
00458     }
00459 
00460     /* Audio data (subsubframes) */
00461 
00462     for (ss = 0; ss < SUBSUBFRAMES ; ss++)
00463         for (ch = 0; ch < c->prim_channels; ch++)
00464             for (sub = 0; sub < DCA_SUBBANDS; sub++)
00465                 for (i = 0; i < 8; i++)
00466                     put_sample7(c, subband_data[ss * 8 + i][ch][sub], QUANTIZER_BITS, c->scale_factor[ch][sub]);
00467 
00468     /* DSYNC */
00469     put_bits(&c->pb, 16, 0xffff);
00470 }
00471 
00472 static void put_frame(DCAContext *c,
00473                       int32_t subband_data[PCM_SAMPLES][MAX_CHANNELS][32],
00474                       uint8_t *frame)
00475 {
00476     int i;
00477     init_put_bits(&c->pb, frame + DCA_HEADER_SIZE, DCA_MAX_FRAME_SIZE-DCA_HEADER_SIZE);
00478 
00479     put_primary_audio_header(c);
00480     for (i = 0; i < SUBFRAMES; i++)
00481         put_subframe(c, &subband_data[SUBSUBFRAMES * 8 * i], i);
00482 
00483     flush_put_bits(&c->pb);
00484     c->frame_size = (put_bits_count(&c->pb) >> 3) + DCA_HEADER_SIZE;
00485 
00486     init_put_bits(&c->pb, frame, DCA_HEADER_SIZE);
00487     put_frame_header(c);
00488     flush_put_bits(&c->pb);
00489 }
00490 
00491 static int encode_frame(AVCodecContext *avctx, uint8_t *frame,
00492                         int buf_size, void *data)
00493 {
00494     int i, k, channel;
00495     DCAContext *c = avctx->priv_data;
00496     int16_t *samples = data;
00497     int real_channel = 0;
00498 
00499     for (i = 0; i < PCM_SAMPLES; i ++) { /* i is the decimated sample number */
00500         for (channel = 0; channel < c->prim_channels + 1; channel++) {
00501             /* Get 32 PCM samples */
00502             for (k = 0; k < 32; k++) { /* k is the sample number in a 32-sample block */
00503                 c->pcm[k] = samples[avctx->channels * (32 * i + k) + channel] << 16;
00504             }
00505             /* Put subband samples into the proper place */
00506             real_channel = c->channel_order_tab[channel];
00507             if (real_channel >= 0) {
00508                 qmf_decompose(c, c->pcm, &c->subband[i][real_channel][0], real_channel);
00509             }
00510         }
00511     }
00512 
00513     if (c->lfe_channel) {
00514         for (i = 0; i < PCM_SAMPLES / 2; i++) {
00515             for (k = 0; k < LFE_INTERPOLATION; k++) /* k is the sample number in a 32-sample block */
00516                 c->pcm[k] = samples[avctx->channels * (LFE_INTERPOLATION*i+k) + c->lfe_offset] << 16;
00517             c->lfe_data[i] = lfe_downsample(c, c->pcm);
00518         }
00519     }
00520 
00521     put_frame(c, c->subband, frame);
00522 
00523     return c->frame_size;
00524 }
00525 
00526 static int encode_init(AVCodecContext *avctx)
00527 {
00528     DCAContext *c = avctx->priv_data;
00529     int i;
00530 
00531     c->prim_channels = avctx->channels;
00532     c->lfe_channel   = (avctx->channels == 3 || avctx->channels == 6);
00533 
00534     switch (avctx->channel_layout) {
00535     case AV_CH_LAYOUT_STEREO:       c->a_mode = 2; c->num_channel = 2; break;
00536     case AV_CH_LAYOUT_5POINT0:      c->a_mode = 9; c->num_channel = 9; break;
00537     case AV_CH_LAYOUT_5POINT1:      c->a_mode = 9; c->num_channel = 9; break;
00538     case AV_CH_LAYOUT_5POINT0_BACK: c->a_mode = 9; c->num_channel = 9; break;
00539     case AV_CH_LAYOUT_5POINT1_BACK: c->a_mode = 9; c->num_channel = 9; break;
00540     default:
00541     av_log(avctx, AV_LOG_ERROR,
00542            "Only stereo, 5.0, 5.1 channel layouts supported at the moment!\n");
00543     return AVERROR_PATCHWELCOME;
00544     }
00545 
00546     if (c->lfe_channel) {
00547         init_lfe_fir();
00548         c->prim_channels--;
00549         c->channel_order_tab = dca_channel_reorder_lfe[c->a_mode];
00550         c->lfe_state         = LFE_PRESENT;
00551         c->lfe_offset        = dca_lfe_index[c->a_mode];
00552     } else {
00553         c->channel_order_tab = dca_channel_reorder_nolfe[c->a_mode];
00554         c->lfe_state         = LFE_MISSING;
00555     }
00556 
00557     for (i = 0; i < 16; i++) {
00558         if (dca_sample_rates[i] && (dca_sample_rates[i] == avctx->sample_rate))
00559             break;
00560     }
00561     if (i == 16) {
00562         av_log(avctx, AV_LOG_ERROR, "Sample rate %iHz not supported, only ", avctx->sample_rate);
00563         for (i = 0; i < 16; i++)
00564             av_log(avctx, AV_LOG_ERROR, "%d, ", dca_sample_rates[i]);
00565         av_log(avctx, AV_LOG_ERROR, "supported.\n");
00566         return -1;
00567     }
00568     c->sample_rate_code = i;
00569 
00570     avctx->frame_size = 32 * PCM_SAMPLES;
00571 
00572     if (!cos_table[127])
00573         qmf_init();
00574     return 0;
00575 }
00576 
00577 AVCodec ff_dca_encoder = {
00578     .name           = "dca",
00579     .type           = AVMEDIA_TYPE_AUDIO,
00580     .id             = CODEC_ID_DTS,
00581     .priv_data_size = sizeof(DCAContext),
00582     .init           = encode_init,
00583     .encode         = encode_frame,
00584     .capabilities   = CODEC_CAP_EXPERIMENTAL,
00585     .sample_fmts    = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16,AV_SAMPLE_FMT_NONE},
00586     .long_name      = NULL_IF_CONFIG_SMALL("DCA (DTS Coherent Acoustics)"),
00587 };