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  1. /*
  2.  * FLAC audio encoder
  3.  * Copyright (c) 2006  Justin Ruggles <justin.ruggles@gmail.com>
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg is free software; you can redistribute it and/or
  8.  * modify it under the terms of the GNU Lesser General Public
  9.  * License as published by the Free Software Foundation; either
  10.  * version 2.1 of the License, or (at your option) any later version.
  11.  *
  12.  * FFmpeg is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15.  * Lesser General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU Lesser General Public
  18.  * License along with FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20.  */
  21.  
  22. #include "libavutil/avassert.h"
  23. #include "libavutil/crc.h"
  24. #include "libavutil/intmath.h"
  25. #include "libavutil/md5.h"
  26. #include "libavutil/opt.h"
  27. #include "avcodec.h"
  28. #include "dsputil.h"
  29. #include "put_bits.h"
  30. #include "golomb.h"
  31. #include "internal.h"
  32. #include "lpc.h"
  33. #include "flac.h"
  34. #include "flacdata.h"
  35. #include "flacdsp.h"
  36.  
  37. #define FLAC_SUBFRAME_CONSTANT  0
  38. #define FLAC_SUBFRAME_VERBATIM  1
  39. #define FLAC_SUBFRAME_FIXED     8
  40. #define FLAC_SUBFRAME_LPC      32
  41.  
  42. #define MAX_FIXED_ORDER     4
  43. #define MAX_PARTITION_ORDER 8
  44. #define MAX_PARTITIONS     (1 << MAX_PARTITION_ORDER)
  45. #define MAX_LPC_PRECISION  15
  46. #define MAX_LPC_SHIFT      15
  47.  
  48. enum CodingMode {
  49.     CODING_MODE_RICE  = 4,
  50.     CODING_MODE_RICE2 = 5,
  51. };
  52.  
  53. typedef struct CompressionOptions {
  54.     int compression_level;
  55.     int block_time_ms;
  56.     enum FFLPCType lpc_type;
  57.     int lpc_passes;
  58.     int lpc_coeff_precision;
  59.     int min_prediction_order;
  60.     int max_prediction_order;
  61.     int prediction_order_method;
  62.     int min_partition_order;
  63.     int max_partition_order;
  64.     int ch_mode;
  65. } CompressionOptions;
  66.  
  67. typedef struct RiceContext {
  68.     enum CodingMode coding_mode;
  69.     int porder;
  70.     int params[MAX_PARTITIONS];
  71. } RiceContext;
  72.  
  73. typedef struct FlacSubframe {
  74.     int type;
  75.     int type_code;
  76.     int obits;
  77.     int wasted;
  78.     int order;
  79.     int32_t coefs[MAX_LPC_ORDER];
  80.     int shift;
  81.     RiceContext rc;
  82.     int32_t samples[FLAC_MAX_BLOCKSIZE];
  83.     int32_t residual[FLAC_MAX_BLOCKSIZE+1];
  84. } FlacSubframe;
  85.  
  86. typedef struct FlacFrame {
  87.     FlacSubframe subframes[FLAC_MAX_CHANNELS];
  88.     int blocksize;
  89.     int bs_code[2];
  90.     uint8_t crc8;
  91.     int ch_mode;
  92.     int verbatim_only;
  93. } FlacFrame;
  94.  
  95. typedef struct FlacEncodeContext {
  96.     AVClass *class;
  97.     PutBitContext pb;
  98.     int channels;
  99.     int samplerate;
  100.     int sr_code[2];
  101.     int bps_code;
  102.     int max_blocksize;
  103.     int min_framesize;
  104.     int max_framesize;
  105.     int max_encoded_framesize;
  106.     uint32_t frame_count;
  107.     uint64_t sample_count;
  108.     uint8_t md5sum[16];
  109.     FlacFrame frame;
  110.     CompressionOptions options;
  111.     AVCodecContext *avctx;
  112.     LPCContext lpc_ctx;
  113.     struct AVMD5 *md5ctx;
  114.     uint8_t *md5_buffer;
  115.     unsigned int md5_buffer_size;
  116.     DSPContext dsp;
  117.     FLACDSPContext flac_dsp;
  118. } FlacEncodeContext;
  119.  
  120.  
  121. /**
  122.  * Write streaminfo metadata block to byte array.
  123.  */
  124. static void write_streaminfo(FlacEncodeContext *s, uint8_t *header)
  125. {
  126.     PutBitContext pb;
  127.  
  128.     memset(header, 0, FLAC_STREAMINFO_SIZE);
  129.     init_put_bits(&pb, header, FLAC_STREAMINFO_SIZE);
  130.  
  131.     /* streaminfo metadata block */
  132.     put_bits(&pb, 16, s->max_blocksize);
  133.     put_bits(&pb, 16, s->max_blocksize);
  134.     put_bits(&pb, 24, s->min_framesize);
  135.     put_bits(&pb, 24, s->max_framesize);
  136.     put_bits(&pb, 20, s->samplerate);
  137.     put_bits(&pb, 3, s->channels-1);
  138.     put_bits(&pb,  5, s->avctx->bits_per_raw_sample - 1);
  139.     /* write 36-bit sample count in 2 put_bits() calls */
  140.     put_bits(&pb, 24, (s->sample_count & 0xFFFFFF000LL) >> 12);
  141.     put_bits(&pb, 12,  s->sample_count & 0x000000FFFLL);
  142.     flush_put_bits(&pb);
  143.     memcpy(&header[18], s->md5sum, 16);
  144. }
  145.  
  146.  
  147. /**
  148.  * Set blocksize based on samplerate.
  149.  * Choose the closest predefined blocksize >= BLOCK_TIME_MS milliseconds.
  150.  */
  151. static int select_blocksize(int samplerate, int block_time_ms)
  152. {
  153.     int i;
  154.     int target;
  155.     int blocksize;
  156.  
  157.     av_assert0(samplerate > 0);
  158.     blocksize = ff_flac_blocksize_table[1];
  159.     target    = (samplerate * block_time_ms) / 1000;
  160.     for (i = 0; i < 16; i++) {
  161.         if (target >= ff_flac_blocksize_table[i] &&
  162.             ff_flac_blocksize_table[i] > blocksize) {
  163.             blocksize = ff_flac_blocksize_table[i];
  164.         }
  165.     }
  166.     return blocksize;
  167. }
  168.  
  169.  
  170. static av_cold void dprint_compression_options(FlacEncodeContext *s)
  171. {
  172.     AVCodecContext     *avctx = s->avctx;
  173.     CompressionOptions *opt   = &s->options;
  174.  
  175.     av_log(avctx, AV_LOG_DEBUG, " compression: %d\n", opt->compression_level);
  176.  
  177.     switch (opt->lpc_type) {
  178.     case FF_LPC_TYPE_NONE:
  179.         av_log(avctx, AV_LOG_DEBUG, " lpc type: None\n");
  180.         break;
  181.     case FF_LPC_TYPE_FIXED:
  182.         av_log(avctx, AV_LOG_DEBUG, " lpc type: Fixed pre-defined coefficients\n");
  183.         break;
  184.     case FF_LPC_TYPE_LEVINSON:
  185.         av_log(avctx, AV_LOG_DEBUG, " lpc type: Levinson-Durbin recursion with Welch window\n");
  186.         break;
  187.     case FF_LPC_TYPE_CHOLESKY:
  188.         av_log(avctx, AV_LOG_DEBUG, " lpc type: Cholesky factorization, %d pass%s\n",
  189.                opt->lpc_passes, opt->lpc_passes == 1 ? "" : "es");
  190.         break;
  191.     }
  192.  
  193.     av_log(avctx, AV_LOG_DEBUG, " prediction order: %d, %d\n",
  194.            opt->min_prediction_order, opt->max_prediction_order);
  195.  
  196.     switch (opt->prediction_order_method) {
  197.     case ORDER_METHOD_EST:
  198.         av_log(avctx, AV_LOG_DEBUG, " order method: %s\n", "estimate");
  199.         break;
  200.     case ORDER_METHOD_2LEVEL:
  201.         av_log(avctx, AV_LOG_DEBUG, " order method: %s\n", "2-level");
  202.         break;
  203.     case ORDER_METHOD_4LEVEL:
  204.         av_log(avctx, AV_LOG_DEBUG, " order method: %s\n", "4-level");
  205.         break;
  206.     case ORDER_METHOD_8LEVEL:
  207.         av_log(avctx, AV_LOG_DEBUG, " order method: %s\n", "8-level");
  208.         break;
  209.     case ORDER_METHOD_SEARCH:
  210.         av_log(avctx, AV_LOG_DEBUG, " order method: %s\n", "full search");
  211.         break;
  212.     case ORDER_METHOD_LOG:
  213.         av_log(avctx, AV_LOG_DEBUG, " order method: %s\n", "log search");
  214.         break;
  215.     }
  216.  
  217.  
  218.     av_log(avctx, AV_LOG_DEBUG, " partition order: %d, %d\n",
  219.            opt->min_partition_order, opt->max_partition_order);
  220.  
  221.     av_log(avctx, AV_LOG_DEBUG, " block size: %d\n", avctx->frame_size);
  222.  
  223.     av_log(avctx, AV_LOG_DEBUG, " lpc precision: %d\n",
  224.            opt->lpc_coeff_precision);
  225. }
  226.  
  227.  
  228. static av_cold int flac_encode_init(AVCodecContext *avctx)
  229. {
  230.     int freq = avctx->sample_rate;
  231.     int channels = avctx->channels;
  232.     FlacEncodeContext *s = avctx->priv_data;
  233.     int i, level, ret;
  234.     uint8_t *streaminfo;
  235.  
  236.     s->avctx = avctx;
  237.  
  238.     switch (avctx->sample_fmt) {
  239.     case AV_SAMPLE_FMT_S16:
  240.         avctx->bits_per_raw_sample = 16;
  241.         s->bps_code                = 4;
  242.         break;
  243.     case AV_SAMPLE_FMT_S32:
  244.         if (avctx->bits_per_raw_sample != 24)
  245.             av_log(avctx, AV_LOG_WARNING, "encoding as 24 bits-per-sample\n");
  246.         avctx->bits_per_raw_sample = 24;
  247.         s->bps_code                = 6;
  248.         break;
  249.     }
  250.  
  251.     if (channels < 1 || channels > FLAC_MAX_CHANNELS) {
  252.         av_log(avctx, AV_LOG_ERROR, "%d channels not supported (max %d)\n",
  253.                channels, FLAC_MAX_CHANNELS);
  254.         return AVERROR(EINVAL);
  255.     }
  256.     s->channels = channels;
  257.  
  258.     /* find samplerate in table */
  259.     if (freq < 1)
  260.         return -1;
  261.     for (i = 4; i < 12; i++) {
  262.         if (freq == ff_flac_sample_rate_table[i]) {
  263.             s->samplerate = ff_flac_sample_rate_table[i];
  264.             s->sr_code[0] = i;
  265.             s->sr_code[1] = 0;
  266.             break;
  267.         }
  268.     }
  269.     /* if not in table, samplerate is non-standard */
  270.     if (i == 12) {
  271.         if (freq % 1000 == 0 && freq < 255000) {
  272.             s->sr_code[0] = 12;
  273.             s->sr_code[1] = freq / 1000;
  274.         } else if (freq % 10 == 0 && freq < 655350) {
  275.             s->sr_code[0] = 14;
  276.             s->sr_code[1] = freq / 10;
  277.         } else if (freq < 65535) {
  278.             s->sr_code[0] = 13;
  279.             s->sr_code[1] = freq;
  280.         } else {
  281.             av_log(avctx, AV_LOG_ERROR, "%d Hz not supported\n", freq);
  282.             return AVERROR(EINVAL);
  283.         }
  284.         s->samplerate = freq;
  285.     }
  286.  
  287.     /* set compression option defaults based on avctx->compression_level */
  288.     if (avctx->compression_level < 0)
  289.         s->options.compression_level = 5;
  290.     else
  291.         s->options.compression_level = avctx->compression_level;
  292.  
  293.     level = s->options.compression_level;
  294.     if (level > 12) {
  295.         av_log(avctx, AV_LOG_ERROR, "invalid compression level: %d\n",
  296.                s->options.compression_level);
  297.         return AVERROR(EINVAL);
  298.     }
  299.  
  300.     s->options.block_time_ms = ((int[]){ 27, 27, 27,105,105,105,105,105,105,105,105,105,105})[level];
  301.  
  302.     if (s->options.lpc_type == FF_LPC_TYPE_DEFAULT)
  303.         s->options.lpc_type  = ((int[]){ FF_LPC_TYPE_FIXED,    FF_LPC_TYPE_FIXED,    FF_LPC_TYPE_FIXED,
  304.                                          FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON,
  305.                                          FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON,
  306.                                          FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON, FF_LPC_TYPE_LEVINSON,
  307.                                          FF_LPC_TYPE_LEVINSON})[level];
  308.  
  309.     s->options.min_prediction_order = ((int[]){  2,  0,  0,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1})[level];
  310.     s->options.max_prediction_order = ((int[]){  3,  4,  4,  6,  8,  8,  8,  8, 12, 12, 12, 32, 32})[level];
  311.  
  312.     if (s->options.prediction_order_method < 0)
  313.         s->options.prediction_order_method = ((int[]){ ORDER_METHOD_EST,    ORDER_METHOD_EST,    ORDER_METHOD_EST,
  314.                                                        ORDER_METHOD_EST,    ORDER_METHOD_EST,    ORDER_METHOD_EST,
  315.                                                        ORDER_METHOD_4LEVEL, ORDER_METHOD_LOG,    ORDER_METHOD_4LEVEL,
  316.                                                        ORDER_METHOD_LOG,    ORDER_METHOD_SEARCH, ORDER_METHOD_LOG,
  317.                                                        ORDER_METHOD_SEARCH})[level];
  318.  
  319.     if (s->options.min_partition_order > s->options.max_partition_order) {
  320.         av_log(avctx, AV_LOG_ERROR, "invalid partition orders: min=%d max=%d\n",
  321.                s->options.min_partition_order, s->options.max_partition_order);
  322.         return AVERROR(EINVAL);
  323.     }
  324.     if (s->options.min_partition_order < 0)
  325.         s->options.min_partition_order = ((int[]){  2,  2,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0})[level];
  326.     if (s->options.max_partition_order < 0)
  327.         s->options.max_partition_order = ((int[]){  2,  2,  3,  3,  3,  8,  8,  8,  8,  8,  8,  8,  8})[level];
  328.  
  329.     if (s->options.lpc_type == FF_LPC_TYPE_NONE) {
  330.         s->options.min_prediction_order = 0;
  331.     } else if (avctx->min_prediction_order >= 0) {
  332.         if (s->options.lpc_type == FF_LPC_TYPE_FIXED) {
  333.             if (avctx->min_prediction_order > MAX_FIXED_ORDER) {
  334.                 av_log(avctx, AV_LOG_ERROR, "invalid min prediction order: %d\n",
  335.                        avctx->min_prediction_order);
  336.                 return AVERROR(EINVAL);
  337.             }
  338.         } else if (avctx->min_prediction_order < MIN_LPC_ORDER ||
  339.                    avctx->min_prediction_order > MAX_LPC_ORDER) {
  340.             av_log(avctx, AV_LOG_ERROR, "invalid min prediction order: %d\n",
  341.                    avctx->min_prediction_order);
  342.             return AVERROR(EINVAL);
  343.         }
  344.         s->options.min_prediction_order = avctx->min_prediction_order;
  345.     }
  346.     if (s->options.lpc_type == FF_LPC_TYPE_NONE) {
  347.         s->options.max_prediction_order = 0;
  348.     } else if (avctx->max_prediction_order >= 0) {
  349.         if (s->options.lpc_type == FF_LPC_TYPE_FIXED) {
  350.             if (avctx->max_prediction_order > MAX_FIXED_ORDER) {
  351.                 av_log(avctx, AV_LOG_ERROR, "invalid max prediction order: %d\n",
  352.                        avctx->max_prediction_order);
  353.                 return AVERROR(EINVAL);
  354.             }
  355.         } else if (avctx->max_prediction_order < MIN_LPC_ORDER ||
  356.                    avctx->max_prediction_order > MAX_LPC_ORDER) {
  357.             av_log(avctx, AV_LOG_ERROR, "invalid max prediction order: %d\n",
  358.                    avctx->max_prediction_order);
  359.             return AVERROR(EINVAL);
  360.         }
  361.         s->options.max_prediction_order = avctx->max_prediction_order;
  362.     }
  363.     if (s->options.max_prediction_order < s->options.min_prediction_order) {
  364.         av_log(avctx, AV_LOG_ERROR, "invalid prediction orders: min=%d max=%d\n",
  365.                s->options.min_prediction_order, s->options.max_prediction_order);
  366.         return AVERROR(EINVAL);
  367.     }
  368.  
  369.     if (avctx->frame_size > 0) {
  370.         if (avctx->frame_size < FLAC_MIN_BLOCKSIZE ||
  371.                 avctx->frame_size > FLAC_MAX_BLOCKSIZE) {
  372.             av_log(avctx, AV_LOG_ERROR, "invalid block size: %d\n",
  373.                    avctx->frame_size);
  374.             return AVERROR(EINVAL);
  375.         }
  376.     } else {
  377.         s->avctx->frame_size = select_blocksize(s->samplerate, s->options.block_time_ms);
  378.     }
  379.     s->max_blocksize = s->avctx->frame_size;
  380.  
  381.     /* set maximum encoded frame size in verbatim mode */
  382.     s->max_framesize = ff_flac_get_max_frame_size(s->avctx->frame_size,
  383.                                                   s->channels,
  384.                                                   s->avctx->bits_per_raw_sample);
  385.  
  386.     /* initialize MD5 context */
  387.     s->md5ctx = av_md5_alloc();
  388.     if (!s->md5ctx)
  389.         return AVERROR(ENOMEM);
  390.     av_md5_init(s->md5ctx);
  391.  
  392.     streaminfo = av_malloc(FLAC_STREAMINFO_SIZE);
  393.     if (!streaminfo)
  394.         return AVERROR(ENOMEM);
  395.     write_streaminfo(s, streaminfo);
  396.     avctx->extradata = streaminfo;
  397.     avctx->extradata_size = FLAC_STREAMINFO_SIZE;
  398.  
  399.     s->frame_count   = 0;
  400.     s->min_framesize = s->max_framesize;
  401.  
  402.     if (channels == 3 &&
  403.             avctx->channel_layout != (AV_CH_LAYOUT_STEREO|AV_CH_FRONT_CENTER) ||
  404.         channels == 4 &&
  405.             avctx->channel_layout != AV_CH_LAYOUT_2_2 &&
  406.             avctx->channel_layout != AV_CH_LAYOUT_QUAD ||
  407.         channels == 5 &&
  408.             avctx->channel_layout != AV_CH_LAYOUT_5POINT0 &&
  409.             avctx->channel_layout != AV_CH_LAYOUT_5POINT0_BACK ||
  410.         channels == 6 &&
  411.             avctx->channel_layout != AV_CH_LAYOUT_5POINT1 &&
  412.             avctx->channel_layout != AV_CH_LAYOUT_5POINT1_BACK) {
  413.         if (avctx->channel_layout) {
  414.             av_log(avctx, AV_LOG_ERROR, "Channel layout not supported by Flac, "
  415.                                              "output stream will have incorrect "
  416.                                              "channel layout.\n");
  417.         } else {
  418.             av_log(avctx, AV_LOG_WARNING, "No channel layout specified. The encoder "
  419.                                                "will use Flac channel layout for "
  420.                                                "%d channels.\n", channels);
  421.         }
  422.     }
  423.  
  424.     ret = ff_lpc_init(&s->lpc_ctx, avctx->frame_size,
  425.                       s->options.max_prediction_order, FF_LPC_TYPE_LEVINSON);
  426.  
  427.     ff_dsputil_init(&s->dsp, avctx);
  428.     ff_flacdsp_init(&s->flac_dsp, avctx->sample_fmt,
  429.                     avctx->bits_per_raw_sample);
  430.  
  431.     dprint_compression_options(s);
  432.  
  433.     return ret;
  434. }
  435.  
  436.  
  437. static void init_frame(FlacEncodeContext *s, int nb_samples)
  438. {
  439.     int i, ch;
  440.     FlacFrame *frame;
  441.  
  442.     frame = &s->frame;
  443.  
  444.     for (i = 0; i < 16; i++) {
  445.         if (nb_samples == ff_flac_blocksize_table[i]) {
  446.             frame->blocksize  = ff_flac_blocksize_table[i];
  447.             frame->bs_code[0] = i;
  448.             frame->bs_code[1] = 0;
  449.             break;
  450.         }
  451.     }
  452.     if (i == 16) {
  453.         frame->blocksize = nb_samples;
  454.         if (frame->blocksize <= 256) {
  455.             frame->bs_code[0] = 6;
  456.             frame->bs_code[1] = frame->blocksize-1;
  457.         } else {
  458.             frame->bs_code[0] = 7;
  459.             frame->bs_code[1] = frame->blocksize-1;
  460.         }
  461.     }
  462.  
  463.     for (ch = 0; ch < s->channels; ch++) {
  464.         FlacSubframe *sub = &frame->subframes[ch];
  465.  
  466.         sub->wasted = 0;
  467.         sub->obits  = s->avctx->bits_per_raw_sample;
  468.  
  469.         if (sub->obits > 16)
  470.             sub->rc.coding_mode = CODING_MODE_RICE2;
  471.         else
  472.             sub->rc.coding_mode = CODING_MODE_RICE;
  473.     }
  474.  
  475.     frame->verbatim_only = 0;
  476. }
  477.  
  478.  
  479. /**
  480.  * Copy channel-interleaved input samples into separate subframes.
  481.  */
  482. static void copy_samples(FlacEncodeContext *s, const void *samples)
  483. {
  484.     int i, j, ch;
  485.     FlacFrame *frame;
  486.     int shift = av_get_bytes_per_sample(s->avctx->sample_fmt) * 8 -
  487.                 s->avctx->bits_per_raw_sample;
  488.  
  489. #define COPY_SAMPLES(bits) do {                                     \
  490.     const int ## bits ## _t *samples0 = samples;                    \
  491.     frame = &s->frame;                                              \
  492.     for (i = 0, j = 0; i < frame->blocksize; i++)                   \
  493.         for (ch = 0; ch < s->channels; ch++, j++)                   \
  494.             frame->subframes[ch].samples[i] = samples0[j] >> shift; \
  495. } while (0)
  496.  
  497.     if (s->avctx->sample_fmt == AV_SAMPLE_FMT_S16)
  498.         COPY_SAMPLES(16);
  499.     else
  500.         COPY_SAMPLES(32);
  501. }
  502.  
  503.  
  504. static uint64_t rice_count_exact(int32_t *res, int n, int k)
  505. {
  506.     int i;
  507.     uint64_t count = 0;
  508.  
  509.     for (i = 0; i < n; i++) {
  510.         int32_t v = -2 * res[i] - 1;
  511.         v ^= v >> 31;
  512.         count += (v >> k) + 1 + k;
  513.     }
  514.     return count;
  515. }
  516.  
  517.  
  518. static uint64_t subframe_count_exact(FlacEncodeContext *s, FlacSubframe *sub,
  519.                                      int pred_order)
  520. {
  521.     int p, porder, psize;
  522.     int i, part_end;
  523.     uint64_t count = 0;
  524.  
  525.     /* subframe header */
  526.     count += 8;
  527.  
  528.     /* subframe */
  529.     if (sub->type == FLAC_SUBFRAME_CONSTANT) {
  530.         count += sub->obits;
  531.     } else if (sub->type == FLAC_SUBFRAME_VERBATIM) {
  532.         count += s->frame.blocksize * sub->obits;
  533.     } else {
  534.         /* warm-up samples */
  535.         count += pred_order * sub->obits;
  536.  
  537.         /* LPC coefficients */
  538.         if (sub->type == FLAC_SUBFRAME_LPC)
  539.             count += 4 + 5 + pred_order * s->options.lpc_coeff_precision;
  540.  
  541.         /* rice-encoded block */
  542.         count += 2;
  543.  
  544.         /* partition order */
  545.         porder = sub->rc.porder;
  546.         psize  = s->frame.blocksize >> porder;
  547.         count += 4;
  548.  
  549.         /* residual */
  550.         i        = pred_order;
  551.         part_end = psize;
  552.         for (p = 0; p < 1 << porder; p++) {
  553.             int k = sub->rc.params[p];
  554.             count += sub->rc.coding_mode;
  555.             count += rice_count_exact(&sub->residual[i], part_end - i, k);
  556.             i = part_end;
  557.             part_end = FFMIN(s->frame.blocksize, part_end + psize);
  558.         }
  559.     }
  560.  
  561.     return count;
  562. }
  563.  
  564.  
  565. #define rice_encode_count(sum, n, k) (((n)*((k)+1))+((sum-(n>>1))>>(k)))
  566.  
  567. /**
  568.  * Solve for d/dk(rice_encode_count) = n-((sum-(n>>1))>>(k+1)) = 0.
  569.  */
  570. static int find_optimal_param(uint64_t sum, int n, int max_param)
  571. {
  572.     int k;
  573.     uint64_t sum2;
  574.  
  575.     if (sum <= n >> 1)
  576.         return 0;
  577.     sum2 = sum - (n >> 1);
  578.     k    = av_log2(av_clipl_int32(sum2 / n));
  579.     return FFMIN(k, max_param);
  580. }
  581.  
  582.  
  583. static uint64_t calc_optimal_rice_params(RiceContext *rc, int porder,
  584.                                          uint64_t *sums, int n, int pred_order)
  585. {
  586.     int i;
  587.     int k, cnt, part, max_param;
  588.     uint64_t all_bits;
  589.  
  590.     max_param = (1 << rc->coding_mode) - 2;
  591.  
  592.     part     = (1 << porder);
  593.     all_bits = 4 * part;
  594.  
  595.     cnt = (n >> porder) - pred_order;
  596.     for (i = 0; i < part; i++) {
  597.         k = find_optimal_param(sums[i], cnt, max_param);
  598.         rc->params[i] = k;
  599.         all_bits += rice_encode_count(sums[i], cnt, k);
  600.         cnt = n >> porder;
  601.     }
  602.  
  603.     rc->porder = porder;
  604.  
  605.     return all_bits;
  606. }
  607.  
  608.  
  609. static void calc_sums(int pmin, int pmax, uint32_t *data, int n, int pred_order,
  610.                       uint64_t sums[][MAX_PARTITIONS])
  611. {
  612.     int i, j;
  613.     int parts;
  614.     uint32_t *res, *res_end;
  615.  
  616.     /* sums for highest level */
  617.     parts   = (1 << pmax);
  618.     res     = &data[pred_order];
  619.     res_end = &data[n >> pmax];
  620.     for (i = 0; i < parts; i++) {
  621.         uint64_t sum = 0;
  622.         while (res < res_end)
  623.             sum += *(res++);
  624.         sums[pmax][i] = sum;
  625.         res_end += n >> pmax;
  626.     }
  627.     /* sums for lower levels */
  628.     for (i = pmax - 1; i >= pmin; i--) {
  629.         parts = (1 << i);
  630.         for (j = 0; j < parts; j++)
  631.             sums[i][j] = sums[i+1][2*j] + sums[i+1][2*j+1];
  632.     }
  633. }
  634.  
  635.  
  636. static uint64_t calc_rice_params(RiceContext *rc, int pmin, int pmax,
  637.                                  int32_t *data, int n, int pred_order)
  638. {
  639.     int i;
  640.     uint64_t bits[MAX_PARTITION_ORDER+1];
  641.     int opt_porder;
  642.     RiceContext tmp_rc;
  643.     uint32_t *udata;
  644.     uint64_t sums[MAX_PARTITION_ORDER+1][MAX_PARTITIONS];
  645.  
  646.     av_assert1(pmin >= 0 && pmin <= MAX_PARTITION_ORDER);
  647.     av_assert1(pmax >= 0 && pmax <= MAX_PARTITION_ORDER);
  648.     av_assert1(pmin <= pmax);
  649.  
  650.     tmp_rc.coding_mode = rc->coding_mode;
  651.  
  652.     udata = av_malloc(n * sizeof(uint32_t));
  653.     for (i = 0; i < n; i++)
  654.         udata[i] = (2*data[i]) ^ (data[i]>>31);
  655.  
  656.     calc_sums(pmin, pmax, udata, n, pred_order, sums);
  657.  
  658.     opt_porder = pmin;
  659.     bits[pmin] = UINT32_MAX;
  660.     for (i = pmin; i <= pmax; i++) {
  661.         bits[i] = calc_optimal_rice_params(&tmp_rc, i, sums[i], n, pred_order);
  662.         if (bits[i] <= bits[opt_porder]) {
  663.             opt_porder = i;
  664.             *rc = tmp_rc;
  665.         }
  666.     }
  667.  
  668.     av_freep(&udata);
  669.     return bits[opt_porder];
  670. }
  671.  
  672.  
  673. static int get_max_p_order(int max_porder, int n, int order)
  674. {
  675.     int porder = FFMIN(max_porder, av_log2(n^(n-1)));
  676.     if (order > 0)
  677.         porder = FFMIN(porder, av_log2(n/order));
  678.     return porder;
  679. }
  680.  
  681.  
  682. static uint64_t find_subframe_rice_params(FlacEncodeContext *s,
  683.                                           FlacSubframe *sub, int pred_order)
  684. {
  685.     int pmin = get_max_p_order(s->options.min_partition_order,
  686.                                s->frame.blocksize, pred_order);
  687.     int pmax = get_max_p_order(s->options.max_partition_order,
  688.                                s->frame.blocksize, pred_order);
  689.  
  690.     uint64_t bits = 8 + pred_order * sub->obits + 2 + sub->rc.coding_mode;
  691.     if (sub->type == FLAC_SUBFRAME_LPC)
  692.         bits += 4 + 5 + pred_order * s->options.lpc_coeff_precision;
  693.     bits += calc_rice_params(&sub->rc, pmin, pmax, sub->residual,
  694.                              s->frame.blocksize, pred_order);
  695.     return bits;
  696. }
  697.  
  698.  
  699. static void encode_residual_fixed(int32_t *res, const int32_t *smp, int n,
  700.                                   int order)
  701. {
  702.     int i;
  703.  
  704.     for (i = 0; i < order; i++)
  705.         res[i] = smp[i];
  706.  
  707.     if (order == 0) {
  708.         for (i = order; i < n; i++)
  709.             res[i] = smp[i];
  710.     } else if (order == 1) {
  711.         for (i = order; i < n; i++)
  712.             res[i] = smp[i] - smp[i-1];
  713.     } else if (order == 2) {
  714.         int a = smp[order-1] - smp[order-2];
  715.         for (i = order; i < n; i += 2) {
  716.             int b    = smp[i  ] - smp[i-1];
  717.             res[i]   = b - a;
  718.             a        = smp[i+1] - smp[i  ];
  719.             res[i+1] = a - b;
  720.         }
  721.     } else if (order == 3) {
  722.         int a = smp[order-1] -   smp[order-2];
  723.         int c = smp[order-1] - 2*smp[order-2] + smp[order-3];
  724.         for (i = order; i < n; i += 2) {
  725.             int b    = smp[i  ] - smp[i-1];
  726.             int d    = b - a;
  727.             res[i]   = d - c;
  728.             a        = smp[i+1] - smp[i  ];
  729.             c        = a - b;
  730.             res[i+1] = c - d;
  731.         }
  732.     } else {
  733.         int a = smp[order-1] -   smp[order-2];
  734.         int c = smp[order-1] - 2*smp[order-2] +   smp[order-3];
  735.         int e = smp[order-1] - 3*smp[order-2] + 3*smp[order-3] - smp[order-4];
  736.         for (i = order; i < n; i += 2) {
  737.             int b    = smp[i  ] - smp[i-1];
  738.             int d    = b - a;
  739.             int f    = d - c;
  740.             res[i  ] = f - e;
  741.             a        = smp[i+1] - smp[i  ];
  742.             c        = a - b;
  743.             e        = c - d;
  744.             res[i+1] = e - f;
  745.         }
  746.     }
  747. }
  748.  
  749.  
  750. static int encode_residual_ch(FlacEncodeContext *s, int ch)
  751. {
  752.     int i, n;
  753.     int min_order, max_order, opt_order, omethod;
  754.     FlacFrame *frame;
  755.     FlacSubframe *sub;
  756.     int32_t coefs[MAX_LPC_ORDER][MAX_LPC_ORDER];
  757.     int shift[MAX_LPC_ORDER];
  758.     int32_t *res, *smp;
  759.  
  760.     frame = &s->frame;
  761.     sub   = &frame->subframes[ch];
  762.     res   = sub->residual;
  763.     smp   = sub->samples;
  764.     n     = frame->blocksize;
  765.  
  766.     /* CONSTANT */
  767.     for (i = 1; i < n; i++)
  768.         if(smp[i] != smp[0])
  769.             break;
  770.     if (i == n) {
  771.         sub->type = sub->type_code = FLAC_SUBFRAME_CONSTANT;
  772.         res[0] = smp[0];
  773.         return subframe_count_exact(s, sub, 0);
  774.     }
  775.  
  776.     /* VERBATIM */
  777.     if (frame->verbatim_only || n < 5) {
  778.         sub->type = sub->type_code = FLAC_SUBFRAME_VERBATIM;
  779.         memcpy(res, smp, n * sizeof(int32_t));
  780.         return subframe_count_exact(s, sub, 0);
  781.     }
  782.  
  783.     min_order  = s->options.min_prediction_order;
  784.     max_order  = s->options.max_prediction_order;
  785.     omethod    = s->options.prediction_order_method;
  786.  
  787.     /* FIXED */
  788.     sub->type = FLAC_SUBFRAME_FIXED;
  789.     if (s->options.lpc_type == FF_LPC_TYPE_NONE  ||
  790.         s->options.lpc_type == FF_LPC_TYPE_FIXED || n <= max_order) {
  791.         uint64_t bits[MAX_FIXED_ORDER+1];
  792.         if (max_order > MAX_FIXED_ORDER)
  793.             max_order = MAX_FIXED_ORDER;
  794.         opt_order = 0;
  795.         bits[0]   = UINT32_MAX;
  796.         for (i = min_order; i <= max_order; i++) {
  797.             encode_residual_fixed(res, smp, n, i);
  798.             bits[i] = find_subframe_rice_params(s, sub, i);
  799.             if (bits[i] < bits[opt_order])
  800.                 opt_order = i;
  801.         }
  802.         sub->order     = opt_order;
  803.         sub->type_code = sub->type | sub->order;
  804.         if (sub->order != max_order) {
  805.             encode_residual_fixed(res, smp, n, sub->order);
  806.             find_subframe_rice_params(s, sub, sub->order);
  807.         }
  808.         return subframe_count_exact(s, sub, sub->order);
  809.     }
  810.  
  811.     /* LPC */
  812.     sub->type = FLAC_SUBFRAME_LPC;
  813.     opt_order = ff_lpc_calc_coefs(&s->lpc_ctx, smp, n, min_order, max_order,
  814.                                   s->options.lpc_coeff_precision, coefs, shift, s->options.lpc_type,
  815.                                   s->options.lpc_passes, omethod,
  816.                                   MAX_LPC_SHIFT, 0);
  817.  
  818.     if (omethod == ORDER_METHOD_2LEVEL ||
  819.         omethod == ORDER_METHOD_4LEVEL ||
  820.         omethod == ORDER_METHOD_8LEVEL) {
  821.         int levels = 1 << omethod;
  822.         uint64_t bits[1 << ORDER_METHOD_8LEVEL];
  823.         int order       = -1;
  824.         int opt_index   = levels-1;
  825.         opt_order       = max_order-1;
  826.         bits[opt_index] = UINT32_MAX;
  827.         for (i = levels-1; i >= 0; i--) {
  828.             int last_order = order;
  829.             order = min_order + (((max_order-min_order+1) * (i+1)) / levels)-1;
  830.             order = av_clip(order, min_order - 1, max_order - 1);
  831.             if (order == last_order)
  832.                 continue;
  833.             s->flac_dsp.lpc_encode(res, smp, n, order+1, coefs[order],
  834.                                    shift[order]);
  835.             bits[i] = find_subframe_rice_params(s, sub, order+1);
  836.             if (bits[i] < bits[opt_index]) {
  837.                 opt_index = i;
  838.                 opt_order = order;
  839.             }
  840.         }
  841.         opt_order++;
  842.     } else if (omethod == ORDER_METHOD_SEARCH) {
  843.         // brute-force optimal order search
  844.         uint64_t bits[MAX_LPC_ORDER];
  845.         opt_order = 0;
  846.         bits[0]   = UINT32_MAX;
  847.         for (i = min_order-1; i < max_order; i++) {
  848.             s->flac_dsp.lpc_encode(res, smp, n, i+1, coefs[i], shift[i]);
  849.             bits[i] = find_subframe_rice_params(s, sub, i+1);
  850.             if (bits[i] < bits[opt_order])
  851.                 opt_order = i;
  852.         }
  853.         opt_order++;
  854.     } else if (omethod == ORDER_METHOD_LOG) {
  855.         uint64_t bits[MAX_LPC_ORDER];
  856.         int step;
  857.  
  858.         opt_order = min_order - 1 + (max_order-min_order)/3;
  859.         memset(bits, -1, sizeof(bits));
  860.  
  861.         for (step = 16; step; step >>= 1) {
  862.             int last = opt_order;
  863.             for (i = last-step; i <= last+step; i += step) {
  864.                 if (i < min_order-1 || i >= max_order || bits[i] < UINT32_MAX)
  865.                     continue;
  866.                 s->flac_dsp.lpc_encode(res, smp, n, i+1, coefs[i], shift[i]);
  867.                 bits[i] = find_subframe_rice_params(s, sub, i+1);
  868.                 if (bits[i] < bits[opt_order])
  869.                     opt_order = i;
  870.             }
  871.         }
  872.         opt_order++;
  873.     }
  874.  
  875.     sub->order     = opt_order;
  876.     sub->type_code = sub->type | (sub->order-1);
  877.     sub->shift     = shift[sub->order-1];
  878.     for (i = 0; i < sub->order; i++)
  879.         sub->coefs[i] = coefs[sub->order-1][i];
  880.  
  881.     s->flac_dsp.lpc_encode(res, smp, n, sub->order, sub->coefs, sub->shift);
  882.  
  883.     find_subframe_rice_params(s, sub, sub->order);
  884.  
  885.     return subframe_count_exact(s, sub, sub->order);
  886. }
  887.  
  888.  
  889. static int count_frame_header(FlacEncodeContext *s)
  890. {
  891.     uint8_t av_unused tmp;
  892.     int count;
  893.  
  894.     /*
  895.     <14> Sync code
  896.     <1>  Reserved
  897.     <1>  Blocking strategy
  898.     <4>  Block size in inter-channel samples
  899.     <4>  Sample rate
  900.     <4>  Channel assignment
  901.     <3>  Sample size in bits
  902.     <1>  Reserved
  903.     */
  904.     count = 32;
  905.  
  906.     /* coded frame number */
  907.     PUT_UTF8(s->frame_count, tmp, count += 8;)
  908.  
  909.     /* explicit block size */
  910.     if (s->frame.bs_code[0] == 6)
  911.         count += 8;
  912.     else if (s->frame.bs_code[0] == 7)
  913.         count += 16;
  914.  
  915.     /* explicit sample rate */
  916.     count += ((s->sr_code[0] == 12) + (s->sr_code[0] > 12)) * 8;
  917.  
  918.     /* frame header CRC-8 */
  919.     count += 8;
  920.  
  921.     return count;
  922. }
  923.  
  924.  
  925. static int encode_frame(FlacEncodeContext *s)
  926. {
  927.     int ch;
  928.     uint64_t count;
  929.  
  930.     count = count_frame_header(s);
  931.  
  932.     for (ch = 0; ch < s->channels; ch++)
  933.         count += encode_residual_ch(s, ch);
  934.  
  935.     count += (8 - (count & 7)) & 7; // byte alignment
  936.     count += 16;                    // CRC-16
  937.  
  938.     count >>= 3;
  939.     if (count > INT_MAX)
  940.         return AVERROR_BUG;
  941.     return count;
  942. }
  943.  
  944.  
  945. static void remove_wasted_bits(FlacEncodeContext *s)
  946. {
  947.     int ch, i;
  948.  
  949.     for (ch = 0; ch < s->channels; ch++) {
  950.         FlacSubframe *sub = &s->frame.subframes[ch];
  951.         int32_t v         = 0;
  952.  
  953.         for (i = 0; i < s->frame.blocksize; i++) {
  954.             v |= sub->samples[i];
  955.             if (v & 1)
  956.                 break;
  957.         }
  958.  
  959.         if (v && !(v & 1)) {
  960.             v = av_ctz(v);
  961.  
  962.             for (i = 0; i < s->frame.blocksize; i++)
  963.                 sub->samples[i] >>= v;
  964.  
  965.             sub->wasted = v;
  966.             sub->obits -= v;
  967.  
  968.             /* for 24-bit, check if removing wasted bits makes the range better
  969.                suited for using RICE instead of RICE2 for entropy coding */
  970.             if (sub->obits <= 17)
  971.                 sub->rc.coding_mode = CODING_MODE_RICE;
  972.         }
  973.     }
  974. }
  975.  
  976.  
  977. static int estimate_stereo_mode(int32_t *left_ch, int32_t *right_ch, int n,
  978.                                 int max_rice_param)
  979. {
  980.     int i, best;
  981.     int32_t lt, rt;
  982.     uint64_t sum[4];
  983.     uint64_t score[4];
  984.     int k;
  985.  
  986.     /* calculate sum of 2nd order residual for each channel */
  987.     sum[0] = sum[1] = sum[2] = sum[3] = 0;
  988.     for (i = 2; i < n; i++) {
  989.         lt = left_ch[i]  - 2*left_ch[i-1]  + left_ch[i-2];
  990.         rt = right_ch[i] - 2*right_ch[i-1] + right_ch[i-2];
  991.         sum[2] += FFABS((lt + rt) >> 1);
  992.         sum[3] += FFABS(lt - rt);
  993.         sum[0] += FFABS(lt);
  994.         sum[1] += FFABS(rt);
  995.     }
  996.     /* estimate bit counts */
  997.     for (i = 0; i < 4; i++) {
  998.         k      = find_optimal_param(2 * sum[i], n, max_rice_param);
  999.         sum[i] = rice_encode_count( 2 * sum[i], n, k);
  1000.     }
  1001.  
  1002.     /* calculate score for each mode */
  1003.     score[0] = sum[0] + sum[1];
  1004.     score[1] = sum[0] + sum[3];
  1005.     score[2] = sum[1] + sum[3];
  1006.     score[3] = sum[2] + sum[3];
  1007.  
  1008.     /* return mode with lowest score */
  1009.     best = 0;
  1010.     for (i = 1; i < 4; i++)
  1011.         if (score[i] < score[best])
  1012.             best = i;
  1013.  
  1014.     return best;
  1015. }
  1016.  
  1017.  
  1018. /**
  1019.  * Perform stereo channel decorrelation.
  1020.  */
  1021. static void channel_decorrelation(FlacEncodeContext *s)
  1022. {
  1023.     FlacFrame *frame;
  1024.     int32_t *left, *right;
  1025.     int i, n;
  1026.  
  1027.     frame = &s->frame;
  1028.     n     = frame->blocksize;
  1029.     left  = frame->subframes[0].samples;
  1030.     right = frame->subframes[1].samples;
  1031.  
  1032.     if (s->channels != 2) {
  1033.         frame->ch_mode = FLAC_CHMODE_INDEPENDENT;
  1034.         return;
  1035.     }
  1036.  
  1037.     if (s->options.ch_mode < 0) {
  1038.         int max_rice_param = (1 << frame->subframes[0].rc.coding_mode) - 2;
  1039.         frame->ch_mode = estimate_stereo_mode(left, right, n, max_rice_param);
  1040.     } else
  1041.         frame->ch_mode = s->options.ch_mode;
  1042.  
  1043.     /* perform decorrelation and adjust bits-per-sample */
  1044.     if (frame->ch_mode == FLAC_CHMODE_INDEPENDENT)
  1045.         return;
  1046.     if (frame->ch_mode == FLAC_CHMODE_MID_SIDE) {
  1047.         int32_t tmp;
  1048.         for (i = 0; i < n; i++) {
  1049.             tmp      = left[i];
  1050.             left[i]  = (tmp + right[i]) >> 1;
  1051.             right[i] =  tmp - right[i];
  1052.         }
  1053.         frame->subframes[1].obits++;
  1054.     } else if (frame->ch_mode == FLAC_CHMODE_LEFT_SIDE) {
  1055.         for (i = 0; i < n; i++)
  1056.             right[i] = left[i] - right[i];
  1057.         frame->subframes[1].obits++;
  1058.     } else {
  1059.         for (i = 0; i < n; i++)
  1060.             left[i] -= right[i];
  1061.         frame->subframes[0].obits++;
  1062.     }
  1063. }
  1064.  
  1065.  
  1066. static void write_utf8(PutBitContext *pb, uint32_t val)
  1067. {
  1068.     uint8_t tmp;
  1069.     PUT_UTF8(val, tmp, put_bits(pb, 8, tmp);)
  1070. }
  1071.  
  1072.  
  1073. static void write_frame_header(FlacEncodeContext *s)
  1074. {
  1075.     FlacFrame *frame;
  1076.     int crc;
  1077.  
  1078.     frame = &s->frame;
  1079.  
  1080.     put_bits(&s->pb, 16, 0xFFF8);
  1081.     put_bits(&s->pb, 4, frame->bs_code[0]);
  1082.     put_bits(&s->pb, 4, s->sr_code[0]);
  1083.  
  1084.     if (frame->ch_mode == FLAC_CHMODE_INDEPENDENT)
  1085.         put_bits(&s->pb, 4, s->channels-1);
  1086.     else
  1087.         put_bits(&s->pb, 4, frame->ch_mode + FLAC_MAX_CHANNELS - 1);
  1088.  
  1089.     put_bits(&s->pb, 3, s->bps_code);
  1090.     put_bits(&s->pb, 1, 0);
  1091.     write_utf8(&s->pb, s->frame_count);
  1092.  
  1093.     if (frame->bs_code[0] == 6)
  1094.         put_bits(&s->pb, 8, frame->bs_code[1]);
  1095.     else if (frame->bs_code[0] == 7)
  1096.         put_bits(&s->pb, 16, frame->bs_code[1]);
  1097.  
  1098.     if (s->sr_code[0] == 12)
  1099.         put_bits(&s->pb, 8, s->sr_code[1]);
  1100.     else if (s->sr_code[0] > 12)
  1101.         put_bits(&s->pb, 16, s->sr_code[1]);
  1102.  
  1103.     flush_put_bits(&s->pb);
  1104.     crc = av_crc(av_crc_get_table(AV_CRC_8_ATM), 0, s->pb.buf,
  1105.                  put_bits_count(&s->pb) >> 3);
  1106.     put_bits(&s->pb, 8, crc);
  1107. }
  1108.  
  1109.  
  1110. static void write_subframes(FlacEncodeContext *s)
  1111. {
  1112.     int ch;
  1113.  
  1114.     for (ch = 0; ch < s->channels; ch++) {
  1115.         FlacSubframe *sub = &s->frame.subframes[ch];
  1116.         int i, p, porder, psize;
  1117.         int32_t *part_end;
  1118.         int32_t *res       =  sub->residual;
  1119.         int32_t *frame_end = &sub->residual[s->frame.blocksize];
  1120.  
  1121.         /* subframe header */
  1122.         put_bits(&s->pb, 1, 0);
  1123.         put_bits(&s->pb, 6, sub->type_code);
  1124.         put_bits(&s->pb, 1, !!sub->wasted);
  1125.         if (sub->wasted)
  1126.             put_bits(&s->pb, sub->wasted, 1);
  1127.  
  1128.         /* subframe */
  1129.         if (sub->type == FLAC_SUBFRAME_CONSTANT) {
  1130.             put_sbits(&s->pb, sub->obits, res[0]);
  1131.         } else if (sub->type == FLAC_SUBFRAME_VERBATIM) {
  1132.             while (res < frame_end)
  1133.                 put_sbits(&s->pb, sub->obits, *res++);
  1134.         } else {
  1135.             /* warm-up samples */
  1136.             for (i = 0; i < sub->order; i++)
  1137.                 put_sbits(&s->pb, sub->obits, *res++);
  1138.  
  1139.             /* LPC coefficients */
  1140.             if (sub->type == FLAC_SUBFRAME_LPC) {
  1141.                 int cbits = s->options.lpc_coeff_precision;
  1142.                 put_bits( &s->pb, 4, cbits-1);
  1143.                 put_sbits(&s->pb, 5, sub->shift);
  1144.                 for (i = 0; i < sub->order; i++)
  1145.                     put_sbits(&s->pb, cbits, sub->coefs[i]);
  1146.             }
  1147.  
  1148.             /* rice-encoded block */
  1149.             put_bits(&s->pb, 2, sub->rc.coding_mode - 4);
  1150.  
  1151.             /* partition order */
  1152.             porder  = sub->rc.porder;
  1153.             psize   = s->frame.blocksize >> porder;
  1154.             put_bits(&s->pb, 4, porder);
  1155.  
  1156.             /* residual */
  1157.             part_end  = &sub->residual[psize];
  1158.             for (p = 0; p < 1 << porder; p++) {
  1159.                 int k = sub->rc.params[p];
  1160.                 put_bits(&s->pb, sub->rc.coding_mode, k);
  1161.                 while (res < part_end)
  1162.                     set_sr_golomb_flac(&s->pb, *res++, k, INT32_MAX, 0);
  1163.                 part_end = FFMIN(frame_end, part_end + psize);
  1164.             }
  1165.         }
  1166.     }
  1167. }
  1168.  
  1169.  
  1170. static void write_frame_footer(FlacEncodeContext *s)
  1171. {
  1172.     int crc;
  1173.     flush_put_bits(&s->pb);
  1174.     crc = av_bswap16(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, s->pb.buf,
  1175.                             put_bits_count(&s->pb)>>3));
  1176.     put_bits(&s->pb, 16, crc);
  1177.     flush_put_bits(&s->pb);
  1178. }
  1179.  
  1180.  
  1181. static int write_frame(FlacEncodeContext *s, AVPacket *avpkt)
  1182. {
  1183.     init_put_bits(&s->pb, avpkt->data, avpkt->size);
  1184.     write_frame_header(s);
  1185.     write_subframes(s);
  1186.     write_frame_footer(s);
  1187.     return put_bits_count(&s->pb) >> 3;
  1188. }
  1189.  
  1190.  
  1191. static int update_md5_sum(FlacEncodeContext *s, const void *samples)
  1192. {
  1193.     const uint8_t *buf;
  1194.     int buf_size = s->frame.blocksize * s->channels *
  1195.                    ((s->avctx->bits_per_raw_sample + 7) / 8);
  1196.  
  1197.     if (s->avctx->bits_per_raw_sample > 16 || HAVE_BIGENDIAN) {
  1198.         av_fast_malloc(&s->md5_buffer, &s->md5_buffer_size, buf_size);
  1199.         if (!s->md5_buffer)
  1200.             return AVERROR(ENOMEM);
  1201.     }
  1202.  
  1203.     if (s->avctx->bits_per_raw_sample <= 16) {
  1204.         buf = (const uint8_t *)samples;
  1205. #if HAVE_BIGENDIAN
  1206.         s->dsp.bswap16_buf((uint16_t *)s->md5_buffer,
  1207.                            (const uint16_t *)samples, buf_size / 2);
  1208.         buf = s->md5_buffer;
  1209. #endif
  1210.     } else {
  1211.         int i;
  1212.         const int32_t *samples0 = samples;
  1213.         uint8_t *tmp            = s->md5_buffer;
  1214.  
  1215.         for (i = 0; i < s->frame.blocksize * s->channels; i++) {
  1216.             int32_t v = samples0[i] >> 8;
  1217.             *tmp++    = (v      ) & 0xFF;
  1218.             *tmp++    = (v >>  8) & 0xFF;
  1219.             *tmp++    = (v >> 16) & 0xFF;
  1220.         }
  1221.         buf = s->md5_buffer;
  1222.     }
  1223.     av_md5_update(s->md5ctx, buf, buf_size);
  1224.  
  1225.     return 0;
  1226. }
  1227.  
  1228.  
  1229. static int flac_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
  1230.                              const AVFrame *frame, int *got_packet_ptr)
  1231. {
  1232.     FlacEncodeContext *s;
  1233.     int frame_bytes, out_bytes, ret;
  1234.  
  1235.     s = avctx->priv_data;
  1236.  
  1237.     /* when the last block is reached, update the header in extradata */
  1238.     if (!frame) {
  1239.         s->max_framesize = s->max_encoded_framesize;
  1240.         av_md5_final(s->md5ctx, s->md5sum);
  1241.         write_streaminfo(s, avctx->extradata);
  1242.         return 0;
  1243.     }
  1244.  
  1245.     /* change max_framesize for small final frame */
  1246.     if (frame->nb_samples < s->frame.blocksize) {
  1247.         s->max_framesize = ff_flac_get_max_frame_size(frame->nb_samples,
  1248.                                                       s->channels,
  1249.                                                       avctx->bits_per_raw_sample);
  1250.     }
  1251.  
  1252.     init_frame(s, frame->nb_samples);
  1253.  
  1254.     copy_samples(s, frame->data[0]);
  1255.  
  1256.     channel_decorrelation(s);
  1257.  
  1258.     remove_wasted_bits(s);
  1259.  
  1260.     frame_bytes = encode_frame(s);
  1261.  
  1262.     /* Fall back on verbatim mode if the compressed frame is larger than it
  1263.        would be if encoded uncompressed. */
  1264.     if (frame_bytes < 0 || frame_bytes > s->max_framesize) {
  1265.         s->frame.verbatim_only = 1;
  1266.         frame_bytes = encode_frame(s);
  1267.         if (frame_bytes < 0) {
  1268.             av_log(avctx, AV_LOG_ERROR, "Bad frame count\n");
  1269.             return frame_bytes;
  1270.         }
  1271.     }
  1272.  
  1273.     if ((ret = ff_alloc_packet2(avctx, avpkt, frame_bytes)) < 0)
  1274.         return ret;
  1275.  
  1276.     out_bytes = write_frame(s, avpkt);
  1277.  
  1278.     s->frame_count++;
  1279.     s->sample_count += frame->nb_samples;
  1280.     if ((ret = update_md5_sum(s, frame->data[0])) < 0) {
  1281.         av_log(avctx, AV_LOG_ERROR, "Error updating MD5 checksum\n");
  1282.         return ret;
  1283.     }
  1284.     if (out_bytes > s->max_encoded_framesize)
  1285.         s->max_encoded_framesize = out_bytes;
  1286.     if (out_bytes < s->min_framesize)
  1287.         s->min_framesize = out_bytes;
  1288.  
  1289.     avpkt->pts      = frame->pts;
  1290.     avpkt->duration = ff_samples_to_time_base(avctx, frame->nb_samples);
  1291.     avpkt->size     = out_bytes;
  1292.     *got_packet_ptr = 1;
  1293.     return 0;
  1294. }
  1295.  
  1296.  
  1297. static av_cold int flac_encode_close(AVCodecContext *avctx)
  1298. {
  1299.     if (avctx->priv_data) {
  1300.         FlacEncodeContext *s = avctx->priv_data;
  1301.         av_freep(&s->md5ctx);
  1302.         av_freep(&s->md5_buffer);
  1303.         ff_lpc_end(&s->lpc_ctx);
  1304.     }
  1305.     av_freep(&avctx->extradata);
  1306.     avctx->extradata_size = 0;
  1307.     return 0;
  1308. }
  1309.  
  1310. #define FLAGS AV_OPT_FLAG_ENCODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM
  1311. static const AVOption options[] = {
  1312. { "lpc_coeff_precision", "LPC coefficient precision", offsetof(FlacEncodeContext, options.lpc_coeff_precision), AV_OPT_TYPE_INT, {.i64 = 15 }, 0, MAX_LPC_PRECISION, FLAGS },
  1313. { "lpc_type", "LPC algorithm", offsetof(FlacEncodeContext, options.lpc_type), AV_OPT_TYPE_INT, {.i64 = FF_LPC_TYPE_DEFAULT }, FF_LPC_TYPE_DEFAULT, FF_LPC_TYPE_NB-1, FLAGS, "lpc_type" },
  1314. { "none",     NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_LPC_TYPE_NONE },     INT_MIN, INT_MAX, FLAGS, "lpc_type" },
  1315. { "fixed",    NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_LPC_TYPE_FIXED },    INT_MIN, INT_MAX, FLAGS, "lpc_type" },
  1316. { "levinson", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_LPC_TYPE_LEVINSON }, INT_MIN, INT_MAX, FLAGS, "lpc_type" },
  1317. { "cholesky", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = FF_LPC_TYPE_CHOLESKY }, INT_MIN, INT_MAX, FLAGS, "lpc_type" },
  1318. { "lpc_passes", "Number of passes to use for Cholesky factorization during LPC analysis", offsetof(FlacEncodeContext, options.lpc_passes),  AV_OPT_TYPE_INT, {.i64 = 2 }, 1, INT_MAX, FLAGS },
  1319. { "min_partition_order",  NULL, offsetof(FlacEncodeContext, options.min_partition_order),  AV_OPT_TYPE_INT, {.i64 = -1 },      -1, MAX_PARTITION_ORDER, FLAGS },
  1320. { "max_partition_order",  NULL, offsetof(FlacEncodeContext, options.max_partition_order),  AV_OPT_TYPE_INT, {.i64 = -1 },      -1, MAX_PARTITION_ORDER, FLAGS },
  1321. { "prediction_order_method", "Search method for selecting prediction order", offsetof(FlacEncodeContext, options.prediction_order_method), AV_OPT_TYPE_INT, {.i64 = -1 }, -1, ORDER_METHOD_LOG, FLAGS, "predm" },
  1322. { "estimation", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = ORDER_METHOD_EST },    INT_MIN, INT_MAX, FLAGS, "predm" },
  1323. { "2level",     NULL, 0, AV_OPT_TYPE_CONST, {.i64 = ORDER_METHOD_2LEVEL }, INT_MIN, INT_MAX, FLAGS, "predm" },
  1324. { "4level",     NULL, 0, AV_OPT_TYPE_CONST, {.i64 = ORDER_METHOD_4LEVEL }, INT_MIN, INT_MAX, FLAGS, "predm" },
  1325. { "8level",     NULL, 0, AV_OPT_TYPE_CONST, {.i64 = ORDER_METHOD_8LEVEL }, INT_MIN, INT_MAX, FLAGS, "predm" },
  1326. { "search",     NULL, 0, AV_OPT_TYPE_CONST, {.i64 = ORDER_METHOD_SEARCH }, INT_MIN, INT_MAX, FLAGS, "predm" },
  1327. { "log",        NULL, 0, AV_OPT_TYPE_CONST, {.i64 = ORDER_METHOD_LOG },    INT_MIN, INT_MAX, FLAGS, "predm" },
  1328. { "ch_mode", "Stereo decorrelation mode", offsetof(FlacEncodeContext, options.ch_mode), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, FLAC_CHMODE_MID_SIDE, FLAGS, "ch_mode" },
  1329. { "auto",       NULL, 0, AV_OPT_TYPE_CONST, { .i64 = -1                      }, INT_MIN, INT_MAX, FLAGS, "ch_mode" },
  1330. { "indep",      NULL, 0, AV_OPT_TYPE_CONST, { .i64 = FLAC_CHMODE_INDEPENDENT }, INT_MIN, INT_MAX, FLAGS, "ch_mode" },
  1331. { "left_side",  NULL, 0, AV_OPT_TYPE_CONST, { .i64 = FLAC_CHMODE_LEFT_SIDE   }, INT_MIN, INT_MAX, FLAGS, "ch_mode" },
  1332. { "right_side", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = FLAC_CHMODE_RIGHT_SIDE  }, INT_MIN, INT_MAX, FLAGS, "ch_mode" },
  1333. { "mid_side",   NULL, 0, AV_OPT_TYPE_CONST, { .i64 = FLAC_CHMODE_MID_SIDE    }, INT_MIN, INT_MAX, FLAGS, "ch_mode" },
  1334. { NULL },
  1335. };
  1336.  
  1337. static const AVClass flac_encoder_class = {
  1338.     "FLAC encoder",
  1339.     av_default_item_name,
  1340.     options,
  1341.     LIBAVUTIL_VERSION_INT,
  1342. };
  1343.  
  1344. AVCodec ff_flac_encoder = {
  1345.     .name           = "flac",
  1346.     .long_name      = NULL_IF_CONFIG_SMALL("FLAC (Free Lossless Audio Codec)"),
  1347.     .type           = AVMEDIA_TYPE_AUDIO,
  1348.     .id             = AV_CODEC_ID_FLAC,
  1349.     .priv_data_size = sizeof(FlacEncodeContext),
  1350.     .init           = flac_encode_init,
  1351.     .encode2        = flac_encode_frame,
  1352.     .close          = flac_encode_close,
  1353.     .capabilities   = CODEC_CAP_SMALL_LAST_FRAME | CODEC_CAP_DELAY | CODEC_CAP_LOSSLESS,
  1354.     .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
  1355.                                                      AV_SAMPLE_FMT_S32,
  1356.                                                      AV_SAMPLE_FMT_NONE },
  1357.     .priv_class     = &flac_encoder_class,
  1358. };
  1359.