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  1. /*
  2.  * Nellymoser encoder
  3.  * This code is developed as part of Google Summer of Code 2008 Program.
  4.  *
  5.  * Copyright (c) 2008 Bartlomiej Wolowiec
  6.  *
  7.  * This file is part of FFmpeg.
  8.  *
  9.  * FFmpeg is free software; you can redistribute it and/or
  10.  * modify it under the terms of the GNU Lesser General Public
  11.  * License as published by the Free Software Foundation; either
  12.  * version 2.1 of the License, or (at your option) any later version.
  13.  *
  14.  * FFmpeg is distributed in the hope that it will be useful,
  15.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17.  * Lesser General Public License for more details.
  18.  *
  19.  * You should have received a copy of the GNU Lesser General Public
  20.  * License along with FFmpeg; if not, write to the Free Software
  21.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22.  */
  23.  
  24. /**
  25.  * @file
  26.  * Nellymoser encoder
  27.  * by Bartlomiej Wolowiec
  28.  *
  29.  * Generic codec information: libavcodec/nellymoserdec.c
  30.  *
  31.  * Some information also from: http://samples.mplayerhq.hu/A-codecs/Nelly_Moser/ASAO/ASAO.zip
  32.  *                             (Copyright Joseph Artsimovich and UAB "DKD")
  33.  *
  34.  * for more information about nellymoser format, visit:
  35.  * http://wiki.multimedia.cx/index.php?title=Nellymoser
  36.  */
  37.  
  38. #include "libavutil/common.h"
  39. #include "libavutil/float_dsp.h"
  40. #include "libavutil/mathematics.h"
  41.  
  42. #include "audio_frame_queue.h"
  43. #include "avcodec.h"
  44. #include "fft.h"
  45. #include "internal.h"
  46. #include "nellymoser.h"
  47. #include "sinewin.h"
  48.  
  49. #define BITSTREAM_WRITER_LE
  50. #include "put_bits.h"
  51.  
  52. #define POW_TABLE_SIZE (1<<11)
  53. #define POW_TABLE_OFFSET 3
  54. #define OPT_SIZE ((1<<15) + 3000)
  55.  
  56. typedef struct NellyMoserEncodeContext {
  57.     AVCodecContext  *avctx;
  58.     int             last_frame;
  59.     AVFloatDSPContext *fdsp;
  60.     FFTContext      mdct_ctx;
  61.     AudioFrameQueue afq;
  62.     DECLARE_ALIGNED(32, float, mdct_out)[NELLY_SAMPLES];
  63.     DECLARE_ALIGNED(32, float, in_buff)[NELLY_SAMPLES];
  64.     DECLARE_ALIGNED(32, float, buf)[3 * NELLY_BUF_LEN];     ///< sample buffer
  65.     float           (*opt )[OPT_SIZE];
  66.     uint8_t         (*path)[OPT_SIZE];
  67. } NellyMoserEncodeContext;
  68.  
  69. static float pow_table[POW_TABLE_SIZE];     ///< pow(2, -i / 2048.0 - 3.0);
  70.  
  71. static const uint8_t sf_lut[96] = {
  72.      0,  1,  1,  1,  1,  1,  1,  2,  2,  2,  2,  3,  3,  3,  4,  4,
  73.      5,  5,  5,  6,  7,  7,  8,  8,  9, 10, 11, 11, 12, 13, 13, 14,
  74.     15, 15, 16, 17, 17, 18, 19, 19, 20, 21, 22, 22, 23, 24, 25, 26,
  75.     27, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 37, 38, 39, 40,
  76.     41, 41, 42, 43, 44, 45, 45, 46, 47, 48, 49, 50, 51, 52, 52, 53,
  77.     54, 55, 55, 56, 57, 57, 58, 59, 59, 60, 60, 60, 61, 61, 61, 62,
  78. };
  79.  
  80. static const uint8_t sf_delta_lut[78] = {
  81.      0,  1,  1,  1,  1,  1,  1,  2,  2,  2,  2,  3,  3,  3,  4,  4,
  82.      4,  5,  5,  5,  6,  6,  7,  7,  8,  8,  9, 10, 10, 11, 11, 12,
  83.     13, 13, 14, 15, 16, 17, 17, 18, 19, 19, 20, 21, 21, 22, 22, 23,
  84.     23, 24, 24, 25, 25, 25, 26, 26, 26, 26, 27, 27, 27, 27, 27, 28,
  85.     28, 28, 28, 28, 28, 29, 29, 29, 29, 29, 29, 29, 29, 30,
  86. };
  87.  
  88. static const uint8_t quant_lut[230] = {
  89.      0,
  90.  
  91.      0,  1,  2,
  92.  
  93.      0,  1,  2,  3,  4,  5,  6,
  94.  
  95.      0,  1,  1,  2,  2,  3,  3,  4,  5,  6,  7,  8,  9, 10, 11, 11,
  96.     12, 13, 13, 13, 14,
  97.  
  98.      0,  1,  1,  2,  2,  2,  3,  3,  4,  4,  5,  5,  6,  6,  7,  8,
  99.      8,  9, 10, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,
  100.     22, 23, 23, 24, 24, 25, 25, 26, 26, 27, 27, 28, 28, 29, 29, 29,
  101.     30,
  102.  
  103.      0,  1,  1,  1,  1,  1,  1,  2,  2,  2,  2,  2,  3,  3,  3,  3,
  104.      4,  4,  4,  5,  5,  5,  6,  6,  7,  7,  7,  8,  8,  9,  9,  9,
  105.     10, 10, 11, 11, 11, 12, 12, 13, 13, 13, 13, 14, 14, 14, 15, 15,
  106.     15, 15, 16, 16, 16, 17, 17, 17, 18, 18, 18, 19, 19, 20, 20, 20,
  107.     21, 21, 22, 22, 23, 23, 24, 25, 26, 26, 27, 28, 29, 30, 31, 32,
  108.     33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 42, 43, 44, 44, 45, 45,
  109.     46, 47, 47, 48, 48, 49, 49, 50, 50, 50, 51, 51, 51, 52, 52, 52,
  110.     53, 53, 53, 54, 54, 54, 55, 55, 55, 56, 56, 56, 57, 57, 57, 57,
  111.     58, 58, 58, 58, 59, 59, 59, 59, 60, 60, 60, 60, 60, 61, 61, 61,
  112.     61, 61, 61, 61, 62,
  113. };
  114.  
  115. static const float quant_lut_mul[7] = { 0.0,  0.0,  2.0,  2.0,  5.0, 12.0,  36.6 };
  116. static const float quant_lut_add[7] = { 0.0,  0.0,  2.0,  7.0, 21.0, 56.0, 157.0 };
  117. static const uint8_t quant_lut_offset[8] = { 0, 0, 1, 4, 11, 32, 81, 230 };
  118.  
  119. static void apply_mdct(NellyMoserEncodeContext *s)
  120. {
  121.     float *in0 = s->buf;
  122.     float *in1 = s->buf + NELLY_BUF_LEN;
  123.     float *in2 = s->buf + 2 * NELLY_BUF_LEN;
  124.  
  125.     s->fdsp->vector_fmul        (s->in_buff,                 in0, ff_sine_128, NELLY_BUF_LEN);
  126.     s->fdsp->vector_fmul_reverse(s->in_buff + NELLY_BUF_LEN, in1, ff_sine_128, NELLY_BUF_LEN);
  127.     s->mdct_ctx.mdct_calc(&s->mdct_ctx, s->mdct_out, s->in_buff);
  128.  
  129.     s->fdsp->vector_fmul        (s->in_buff,                 in1, ff_sine_128, NELLY_BUF_LEN);
  130.     s->fdsp->vector_fmul_reverse(s->in_buff + NELLY_BUF_LEN, in2, ff_sine_128, NELLY_BUF_LEN);
  131.     s->mdct_ctx.mdct_calc(&s->mdct_ctx, s->mdct_out + NELLY_BUF_LEN, s->in_buff);
  132. }
  133.  
  134. static av_cold int encode_end(AVCodecContext *avctx)
  135. {
  136.     NellyMoserEncodeContext *s = avctx->priv_data;
  137.  
  138.     ff_mdct_end(&s->mdct_ctx);
  139.  
  140.     if (s->avctx->trellis) {
  141.         av_freep(&s->opt);
  142.         av_freep(&s->path);
  143.     }
  144.     ff_af_queue_close(&s->afq);
  145.     av_freep(&s->fdsp);
  146.  
  147.     return 0;
  148. }
  149.  
  150. static av_cold int encode_init(AVCodecContext *avctx)
  151. {
  152.     NellyMoserEncodeContext *s = avctx->priv_data;
  153.     int i, ret;
  154.  
  155.     if (avctx->channels != 1) {
  156.         av_log(avctx, AV_LOG_ERROR, "Nellymoser supports only 1 channel\n");
  157.         return AVERROR(EINVAL);
  158.     }
  159.  
  160.     if (avctx->sample_rate != 8000 && avctx->sample_rate != 16000 &&
  161.         avctx->sample_rate != 11025 &&
  162.         avctx->sample_rate != 22050 && avctx->sample_rate != 44100 &&
  163.         avctx->strict_std_compliance >= FF_COMPLIANCE_NORMAL) {
  164.         av_log(avctx, AV_LOG_ERROR, "Nellymoser works only with 8000, 16000, 11025, 22050 and 44100 sample rate\n");
  165.         return AVERROR(EINVAL);
  166.     }
  167.  
  168.     avctx->frame_size = NELLY_SAMPLES;
  169.     avctx->initial_padding = NELLY_BUF_LEN;
  170.     ff_af_queue_init(avctx, &s->afq);
  171.     s->avctx = avctx;
  172.     if ((ret = ff_mdct_init(&s->mdct_ctx, 8, 0, 32768.0)) < 0)
  173.         goto error;
  174.     s->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
  175.     if (!s->fdsp) {
  176.         ret = AVERROR(ENOMEM);
  177.         goto error;
  178.     }
  179.  
  180.     /* Generate overlap window */
  181.     ff_init_ff_sine_windows(7);
  182.     for (i = 0; i < POW_TABLE_SIZE; i++)
  183.         pow_table[i] = pow(2, -i / 2048.0 - 3.0 + POW_TABLE_OFFSET);
  184.  
  185.     if (s->avctx->trellis) {
  186.         s->opt  = av_malloc(NELLY_BANDS * OPT_SIZE * sizeof(float  ));
  187.         s->path = av_malloc(NELLY_BANDS * OPT_SIZE * sizeof(uint8_t));
  188.         if (!s->opt || !s->path) {
  189.             ret = AVERROR(ENOMEM);
  190.             goto error;
  191.         }
  192.     }
  193.  
  194.     return 0;
  195. error:
  196.     encode_end(avctx);
  197.     return ret;
  198. }
  199.  
  200. #define find_best(val, table, LUT, LUT_add, LUT_size) \
  201.     best_idx = \
  202.         LUT[av_clip ((lrintf(val) >> 8) + LUT_add, 0, LUT_size - 1)]; \
  203.     if (fabs(val - table[best_idx]) > fabs(val - table[best_idx + 1])) \
  204.         best_idx++;
  205.  
  206. static void get_exponent_greedy(NellyMoserEncodeContext *s, float *cand, int *idx_table)
  207. {
  208.     int band, best_idx, power_idx = 0;
  209.     float power_candidate;
  210.  
  211.     //base exponent
  212.     find_best(cand[0], ff_nelly_init_table, sf_lut, -20, 96);
  213.     idx_table[0] = best_idx;
  214.     power_idx = ff_nelly_init_table[best_idx];
  215.  
  216.     for (band = 1; band < NELLY_BANDS; band++) {
  217.         power_candidate = cand[band] - power_idx;
  218.         find_best(power_candidate, ff_nelly_delta_table, sf_delta_lut, 37, 78);
  219.         idx_table[band] = best_idx;
  220.         power_idx += ff_nelly_delta_table[best_idx];
  221.     }
  222. }
  223.  
  224. static inline float distance(float x, float y, int band)
  225. {
  226.     //return pow(fabs(x-y), 2.0);
  227.     float tmp = x - y;
  228.     return tmp * tmp;
  229. }
  230.  
  231. static void get_exponent_dynamic(NellyMoserEncodeContext *s, float *cand, int *idx_table)
  232. {
  233.     int i, j, band, best_idx;
  234.     float power_candidate, best_val;
  235.  
  236.     float  (*opt )[OPT_SIZE] = s->opt ;
  237.     uint8_t(*path)[OPT_SIZE] = s->path;
  238.  
  239.     for (i = 0; i < NELLY_BANDS * OPT_SIZE; i++) {
  240.         opt[0][i] = INFINITY;
  241.     }
  242.  
  243.     for (i = 0; i < 64; i++) {
  244.         opt[0][ff_nelly_init_table[i]] = distance(cand[0], ff_nelly_init_table[i], 0);
  245.         path[0][ff_nelly_init_table[i]] = i;
  246.     }
  247.  
  248.     for (band = 1; band < NELLY_BANDS; band++) {
  249.         int q, c = 0;
  250.         float tmp;
  251.         int idx_min, idx_max, idx;
  252.         power_candidate = cand[band];
  253.         for (q = 1000; !c && q < OPT_SIZE; q <<= 2) {
  254.             idx_min = FFMAX(0, cand[band] - q);
  255.             idx_max = FFMIN(OPT_SIZE, cand[band - 1] + q);
  256.             for (i = FFMAX(0, cand[band - 1] - q); i < FFMIN(OPT_SIZE, cand[band - 1] + q); i++) {
  257.                 if ( isinf(opt[band - 1][i]) )
  258.                     continue;
  259.                 for (j = 0; j < 32; j++) {
  260.                     idx = i + ff_nelly_delta_table[j];
  261.                     if (idx > idx_max)
  262.                         break;
  263.                     if (idx >= idx_min) {
  264.                         tmp = opt[band - 1][i] + distance(idx, power_candidate, band);
  265.                         if (opt[band][idx] > tmp) {
  266.                             opt[band][idx] = tmp;
  267.                             path[band][idx] = j;
  268.                             c = 1;
  269.                         }
  270.                     }
  271.                 }
  272.             }
  273.         }
  274.         av_assert1(c); //FIXME
  275.     }
  276.  
  277.     best_val = INFINITY;
  278.     best_idx = -1;
  279.     band = NELLY_BANDS - 1;
  280.     for (i = 0; i < OPT_SIZE; i++) {
  281.         if (best_val > opt[band][i]) {
  282.             best_val = opt[band][i];
  283.             best_idx = i;
  284.         }
  285.     }
  286.     for (band = NELLY_BANDS - 1; band >= 0; band--) {
  287.         idx_table[band] = path[band][best_idx];
  288.         if (band) {
  289.             best_idx -= ff_nelly_delta_table[path[band][best_idx]];
  290.         }
  291.     }
  292. }
  293.  
  294. /**
  295.  * Encode NELLY_SAMPLES samples. It assumes, that samples contains 3 * NELLY_BUF_LEN values
  296.  *  @param s               encoder context
  297.  *  @param output          output buffer
  298.  *  @param output_size     size of output buffer
  299.  */
  300. static void encode_block(NellyMoserEncodeContext *s, unsigned char *output, int output_size)
  301. {
  302.     PutBitContext pb;
  303.     int i, j, band, block, best_idx, power_idx = 0;
  304.     float power_val, coeff, coeff_sum;
  305.     float pows[NELLY_FILL_LEN];
  306.     int bits[NELLY_BUF_LEN], idx_table[NELLY_BANDS];
  307.     float cand[NELLY_BANDS];
  308.  
  309.     apply_mdct(s);
  310.  
  311.     init_put_bits(&pb, output, output_size);
  312.  
  313.     i = 0;
  314.     for (band = 0; band < NELLY_BANDS; band++) {
  315.         coeff_sum = 0;
  316.         for (j = 0; j < ff_nelly_band_sizes_table[band]; i++, j++) {
  317.             coeff_sum += s->mdct_out[i                ] * s->mdct_out[i                ]
  318.                        + s->mdct_out[i + NELLY_BUF_LEN] * s->mdct_out[i + NELLY_BUF_LEN];
  319.         }
  320.         cand[band] =
  321.             log(FFMAX(1.0, coeff_sum / (ff_nelly_band_sizes_table[band] << 7))) * 1024.0 / M_LN2;
  322.     }
  323.  
  324.     if (s->avctx->trellis) {
  325.         get_exponent_dynamic(s, cand, idx_table);
  326.     } else {
  327.         get_exponent_greedy(s, cand, idx_table);
  328.     }
  329.  
  330.     i = 0;
  331.     for (band = 0; band < NELLY_BANDS; band++) {
  332.         if (band) {
  333.             power_idx += ff_nelly_delta_table[idx_table[band]];
  334.             put_bits(&pb, 5, idx_table[band]);
  335.         } else {
  336.             power_idx = ff_nelly_init_table[idx_table[0]];
  337.             put_bits(&pb, 6, idx_table[0]);
  338.         }
  339.         power_val = pow_table[power_idx & 0x7FF] / (1 << ((power_idx >> 11) + POW_TABLE_OFFSET));
  340.         for (j = 0; j < ff_nelly_band_sizes_table[band]; i++, j++) {
  341.             s->mdct_out[i] *= power_val;
  342.             s->mdct_out[i + NELLY_BUF_LEN] *= power_val;
  343.             pows[i] = power_idx;
  344.         }
  345.     }
  346.  
  347.     ff_nelly_get_sample_bits(pows, bits);
  348.  
  349.     for (block = 0; block < 2; block++) {
  350.         for (i = 0; i < NELLY_FILL_LEN; i++) {
  351.             if (bits[i] > 0) {
  352.                 const float *table = ff_nelly_dequantization_table + (1 << bits[i]) - 1;
  353.                 coeff = s->mdct_out[block * NELLY_BUF_LEN + i];
  354.                 best_idx =
  355.                     quant_lut[av_clip (
  356.                             coeff * quant_lut_mul[bits[i]] + quant_lut_add[bits[i]],
  357.                             quant_lut_offset[bits[i]],
  358.                             quant_lut_offset[bits[i]+1] - 1
  359.                             )];
  360.                 if (fabs(coeff - table[best_idx]) > fabs(coeff - table[best_idx + 1]))
  361.                     best_idx++;
  362.  
  363.                 put_bits(&pb, bits[i], best_idx);
  364.             }
  365.         }
  366.         if (!block)
  367.             put_bits(&pb, NELLY_HEADER_BITS + NELLY_DETAIL_BITS - put_bits_count(&pb), 0);
  368.     }
  369.  
  370.     flush_put_bits(&pb);
  371.     memset(put_bits_ptr(&pb), 0, output + output_size - put_bits_ptr(&pb));
  372. }
  373.  
  374. static int encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
  375.                         const AVFrame *frame, int *got_packet_ptr)
  376. {
  377.     NellyMoserEncodeContext *s = avctx->priv_data;
  378.     int ret;
  379.  
  380.     if (s->last_frame)
  381.         return 0;
  382.  
  383.     memcpy(s->buf, s->buf + NELLY_SAMPLES, NELLY_BUF_LEN * sizeof(*s->buf));
  384.     if (frame) {
  385.         memcpy(s->buf + NELLY_BUF_LEN, frame->data[0],
  386.                frame->nb_samples * sizeof(*s->buf));
  387.         if (frame->nb_samples < NELLY_SAMPLES) {
  388.             memset(s->buf + NELLY_BUF_LEN + frame->nb_samples, 0,
  389.                    (NELLY_SAMPLES - frame->nb_samples) * sizeof(*s->buf));
  390.             if (frame->nb_samples >= NELLY_BUF_LEN)
  391.                 s->last_frame = 1;
  392.         }
  393.         if ((ret = ff_af_queue_add(&s->afq, frame)) < 0)
  394.             return ret;
  395.     } else {
  396.         memset(s->buf + NELLY_BUF_LEN, 0, NELLY_SAMPLES * sizeof(*s->buf));
  397.         s->last_frame = 1;
  398.     }
  399.  
  400.     if ((ret = ff_alloc_packet2(avctx, avpkt, NELLY_BLOCK_LEN, 0)) < 0)
  401.         return ret;
  402.     encode_block(s, avpkt->data, avpkt->size);
  403.  
  404.     /* Get the next frame pts/duration */
  405.     ff_af_queue_remove(&s->afq, avctx->frame_size, &avpkt->pts,
  406.                        &avpkt->duration);
  407.  
  408.     *got_packet_ptr = 1;
  409.     return 0;
  410. }
  411.  
  412. AVCodec ff_nellymoser_encoder = {
  413.     .name           = "nellymoser",
  414.     .long_name      = NULL_IF_CONFIG_SMALL("Nellymoser Asao"),
  415.     .type           = AVMEDIA_TYPE_AUDIO,
  416.     .id             = AV_CODEC_ID_NELLYMOSER,
  417.     .priv_data_size = sizeof(NellyMoserEncodeContext),
  418.     .init           = encode_init,
  419.     .encode2        = encode_frame,
  420.     .close          = encode_end,
  421.     .capabilities   = AV_CODEC_CAP_SMALL_LAST_FRAME | AV_CODEC_CAP_DELAY,
  422.     .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLT,
  423.                                                      AV_SAMPLE_FMT_NONE },
  424. };
  425.