LCOV - code coverage report
Current view: top level - libavcodec - alac.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 228 291 78.4 %
Date: 2017-12-11 04:34:20 Functions: 11 11 100.0 %

          Line data    Source code
       1             : /*
       2             :  * ALAC (Apple Lossless Audio Codec) decoder
       3             :  * Copyright (c) 2005 David Hammerton
       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             : /**
      23             :  * @file
      24             :  * ALAC (Apple Lossless Audio Codec) decoder
      25             :  * @author 2005 David Hammerton
      26             :  * @see http://crazney.net/programs/itunes/alac.html
      27             :  *
      28             :  * Note: This decoder expects a 36-byte QuickTime atom to be
      29             :  * passed through the extradata[_size] fields. This atom is tacked onto
      30             :  * the end of an 'alac' stsd atom and has the following format:
      31             :  *
      32             :  * 32 bits  atom size
      33             :  * 32 bits  tag                  ("alac")
      34             :  * 32 bits  tag version          (0)
      35             :  * 32 bits  samples per frame    (used when not set explicitly in the frames)
      36             :  *  8 bits  compatible version   (0)
      37             :  *  8 bits  sample size
      38             :  *  8 bits  history mult         (40)
      39             :  *  8 bits  initial history      (10)
      40             :  *  8 bits  rice param limit     (14)
      41             :  *  8 bits  channels
      42             :  * 16 bits  maxRun               (255)
      43             :  * 32 bits  max coded frame size (0 means unknown)
      44             :  * 32 bits  average bitrate      (0 means unknown)
      45             :  * 32 bits  samplerate
      46             :  */
      47             : 
      48             : #include <inttypes.h>
      49             : 
      50             : #include "libavutil/channel_layout.h"
      51             : #include "libavutil/opt.h"
      52             : #include "avcodec.h"
      53             : #include "get_bits.h"
      54             : #include "bytestream.h"
      55             : #include "internal.h"
      56             : #include "thread.h"
      57             : #include "unary.h"
      58             : #include "mathops.h"
      59             : #include "alac_data.h"
      60             : #include "alacdsp.h"
      61             : 
      62             : #define ALAC_EXTRADATA_SIZE 36
      63             : 
      64             : typedef struct ALACContext {
      65             :     AVClass *class;
      66             :     AVCodecContext *avctx;
      67             :     GetBitContext gb;
      68             :     int channels;
      69             : 
      70             :     int32_t *predict_error_buffer[2];
      71             :     int32_t *output_samples_buffer[2];
      72             :     int32_t *extra_bits_buffer[2];
      73             : 
      74             :     uint32_t max_samples_per_frame;
      75             :     uint8_t  sample_size;
      76             :     uint8_t  rice_history_mult;
      77             :     uint8_t  rice_initial_history;
      78             :     uint8_t  rice_limit;
      79             :     int      sample_rate;
      80             : 
      81             :     int extra_bits;     /**< number of extra bits beyond 16-bit */
      82             :     int nb_samples;     /**< number of samples in the current frame */
      83             : 
      84             :     int direct_output;
      85             :     int extra_bit_bug;
      86             : 
      87             :     ALACDSPContext dsp;
      88             : } ALACContext;
      89             : 
      90    16507234 : static inline unsigned int decode_scalar(GetBitContext *gb, int k, int bps)
      91             : {
      92    16507234 :     unsigned int x = get_unary_0_9(gb);
      93             : 
      94    16507234 :     if (x > 8) { /* RICE THRESHOLD */
      95             :         /* use alternative encoding */
      96       27035 :         x = get_bits_long(gb, bps);
      97    16480199 :     } else if (k != 1) {
      98    16477495 :         int extrabits = show_bits(gb, k);
      99             : 
     100             :         /* multiply x by 2^k - 1, as part of their strange algorithm */
     101    16477495 :         x = (x << k) - x;
     102             : 
     103    16477495 :         if (extrabits > 1) {
     104    14896137 :             x += extrabits - 1;
     105    14896137 :             skip_bits(gb, k);
     106             :         } else
     107     1581358 :             skip_bits(gb, k - 1);
     108             :     }
     109    16507234 :     return x;
     110             : }
     111             : 
     112        4074 : static int rice_decompress(ALACContext *alac, int32_t *output_buffer,
     113             :                             int nb_samples, int bps, int rice_history_mult)
     114             : {
     115             :     int i;
     116        4074 :     unsigned int history = alac->rice_initial_history;
     117        4074 :     int sign_modifier = 0;
     118             : 
     119    16511147 :     for (i = 0; i < nb_samples; i++) {
     120             :         int k;
     121             :         unsigned int x;
     122             : 
     123    16507073 :         if(get_bits_left(&alac->gb) <= 0)
     124           0 :             return -1;
     125             : 
     126             :         /* calculate rice param and decode next value */
     127    16507073 :         k = av_log2((history >> 9) + 3);
     128    16507073 :         k = FFMIN(k, alac->rice_limit);
     129    16507073 :         x = decode_scalar(&alac->gb, k, bps);
     130    16507073 :         x += sign_modifier;
     131    16507073 :         sign_modifier = 0;
     132    16507073 :         output_buffer[i] = (x >> 1) ^ -(x & 1);
     133             : 
     134             :         /* update the history */
     135    16507073 :         if (x > 0xffff)
     136       11363 :             history = 0xffff;
     137             :         else
     138    32991420 :             history +=         x * rice_history_mult -
     139    16495710 :                        ((history * rice_history_mult) >> 9);
     140             : 
     141             :         /* special case: there may be compressed blocks of 0 */
     142    16507073 :         if ((history < 128) && (i + 1 < nb_samples)) {
     143             :             int block_size;
     144             : 
     145             :             /* calculate rice param and decode block size */
     146         161 :             k = 7 - av_log2(history) + ((history + 16) >> 6);
     147         161 :             k = FFMIN(k, alac->rice_limit);
     148         161 :             block_size = decode_scalar(&alac->gb, k, 16);
     149             : 
     150         161 :             if (block_size > 0) {
     151          65 :                 if (block_size >= nb_samples - i) {
     152           0 :                     av_log(alac->avctx, AV_LOG_ERROR,
     153             :                            "invalid zero block size of %d %d %d\n", block_size,
     154             :                            nb_samples, i);
     155           0 :                     block_size = nb_samples - i - 1;
     156             :                 }
     157          65 :                 memset(&output_buffer[i + 1], 0,
     158             :                        block_size * sizeof(*output_buffer));
     159          65 :                 i += block_size;
     160             :             }
     161         161 :             if (block_size <= 0xffff)
     162         161 :                 sign_modifier = 1;
     163         161 :             history = 0;
     164             :         }
     165             :     }
     166        4074 :     return 0;
     167             : }
     168             : 
     169    86321215 : static inline int sign_only(int v)
     170             : {
     171    86321215 :     return v ? FFSIGN(v) : 0;
     172             : }
     173             : 
     174        4074 : static void lpc_prediction(int32_t *error_buffer, int32_t *buffer_out,
     175             :                            int nb_samples, int bps, int16_t *lpc_coefs,
     176             :                            int lpc_order, int lpc_quant)
     177             : {
     178             :     int i;
     179        4074 :     int32_t *pred = buffer_out;
     180             : 
     181             :     /* first sample always copies */
     182        4074 :     *buffer_out = *error_buffer;
     183             : 
     184        4074 :     if (nb_samples <= 1)
     185           0 :         return;
     186             : 
     187        4074 :     if (!lpc_order) {
     188           0 :         memcpy(&buffer_out[1], &error_buffer[1],
     189           0 :                (nb_samples - 1) * sizeof(*buffer_out));
     190           0 :         return;
     191             :     }
     192             : 
     193        4074 :     if (lpc_order == 31) {
     194             :         /* simple 1st-order prediction */
     195           0 :         for (i = 1; i < nb_samples; i++) {
     196           0 :             buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i],
     197             :                                         bps);
     198             :         }
     199           0 :         return;
     200             :     }
     201             : 
     202             :     /* read warm-up samples */
     203       37687 :     for (i = 1; i <= lpc_order && i < nb_samples; i++)
     204       33613 :         buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i], bps);
     205             : 
     206             :     /* NOTE: 4 and 8 are very common cases that could be optimized. */
     207             : 
     208    16626395 :     for (; i < nb_samples; i++) {
     209             :         int j;
     210    16622321 :         int val = 0;
     211    16622321 :         int error_val = error_buffer[i];
     212             :         int error_sign;
     213    16622321 :         int d = *pred++;
     214             : 
     215             :         /* LPC prediction */
     216   153619021 :         for (j = 0; j < lpc_order; j++)
     217   136996700 :             val += (pred[j] - d) * lpc_coefs[j];
     218    16622321 :         val = (val + (1 << (lpc_quant - 1))) >> lpc_quant;
     219    16622321 :         val += d + error_val;
     220    16622321 :         buffer_out[i] = sign_extend(val, bps);
     221             : 
     222             :         /* adapt LPC coefficients */
     223    16622321 :         error_sign = sign_only(error_val);
     224    16622321 :         if (error_sign) {
     225    85499474 :             for (j = 0; j < lpc_order && error_val * error_sign > 0; j++) {
     226             :                 int sign;
     227    69698894 :                 val  = d - pred[j];
     228    69698894 :                 sign = sign_only(val) * error_sign;
     229    69698894 :                 lpc_coefs[j] -= sign;
     230    69698894 :                 val *= sign;
     231    69698894 :                 error_val -= (val >> lpc_quant) * (j + 1);
     232             :             }
     233             :         }
     234             :     }
     235             : }
     236             : 
     237        2609 : static int decode_element(AVCodecContext *avctx, AVFrame *frame, int ch_index,
     238             :                           int channels)
     239             : {
     240        2609 :     ALACContext *alac = avctx->priv_data;
     241             :     int has_size, bps, is_compressed, decorr_shift, decorr_left_weight, ret;
     242             :     uint32_t output_samples;
     243             :     int i, ch;
     244             : 
     245        2609 :     skip_bits(&alac->gb, 4);  /* element instance tag */
     246        2609 :     skip_bits(&alac->gb, 12); /* unused header bits */
     247             : 
     248             :     /* the number of output samples is stored in the frame */
     249        2609 :     has_size = get_bits1(&alac->gb);
     250             : 
     251        2609 :     alac->extra_bits = get_bits(&alac->gb, 2) << 3;
     252        2609 :     bps = alac->sample_size - alac->extra_bits + channels - 1;
     253        2609 :     if (bps > 32U) {
     254           0 :         avpriv_report_missing_feature(avctx, "bps %d", bps);
     255           0 :         return AVERROR_PATCHWELCOME;
     256             :     }
     257             : 
     258             :     /* whether the frame is compressed */
     259        2609 :     is_compressed = !get_bits1(&alac->gb);
     260             : 
     261        2609 :     if (has_size)
     262          11 :         output_samples = get_bits_long(&alac->gb, 32);
     263             :     else
     264        2598 :         output_samples = alac->max_samples_per_frame;
     265        2609 :     if (!output_samples || output_samples > alac->max_samples_per_frame) {
     266           0 :         av_log(avctx, AV_LOG_ERROR, "invalid samples per frame: %"PRIu32"\n",
     267             :                output_samples);
     268           0 :         return AVERROR_INVALIDDATA;
     269             :     }
     270        2609 :     if (!alac->nb_samples) {
     271        2609 :         ThreadFrame tframe = { .f = frame };
     272             :         /* get output buffer */
     273        2609 :         frame->nb_samples = output_samples;
     274        2609 :         if ((ret = ff_thread_get_buffer(avctx, &tframe, 0)) < 0)
     275           0 :             return ret;
     276           0 :     } else if (output_samples != alac->nb_samples) {
     277           0 :         av_log(avctx, AV_LOG_ERROR, "sample count mismatch: %"PRIu32" != %d\n",
     278             :                output_samples, alac->nb_samples);
     279           0 :         return AVERROR_INVALIDDATA;
     280             :     }
     281        2609 :     alac->nb_samples = output_samples;
     282        2609 :     if (alac->direct_output) {
     283        5628 :         for (ch = 0; ch < channels; ch++)
     284        3752 :             alac->output_samples_buffer[ch] = (int32_t *)frame->extended_data[ch_index + ch];
     285             :     }
     286             : 
     287        2609 :     if (is_compressed) {
     288             :         int16_t lpc_coefs[2][32];
     289             :         int lpc_order[2];
     290             :         int prediction_type[2];
     291             :         int lpc_quant[2];
     292             :         int rice_history_mult[2];
     293             : 
     294        2037 :         if (!alac->rice_limit) {
     295           0 :             avpriv_request_sample(alac->avctx,
     296             :                                   "Compression with rice limit 0");
     297           0 :             return AVERROR(ENOSYS);
     298             :         }
     299             : 
     300        2037 :         decorr_shift       = get_bits(&alac->gb, 8);
     301        2037 :         decorr_left_weight = get_bits(&alac->gb, 8);
     302             : 
     303        6111 :         for (ch = 0; ch < channels; ch++) {
     304        4074 :             prediction_type[ch]   = get_bits(&alac->gb, 4);
     305        4074 :             lpc_quant[ch]         = get_bits(&alac->gb, 4);
     306        4074 :             rice_history_mult[ch] = get_bits(&alac->gb, 3);
     307        4074 :             lpc_order[ch]         = get_bits(&alac->gb, 5);
     308             : 
     309        4074 :             if (lpc_order[ch] >= alac->max_samples_per_frame)
     310           0 :                 return AVERROR_INVALIDDATA;
     311             : 
     312             :             /* read the predictor table */
     313       37687 :             for (i = lpc_order[ch] - 1; i >= 0; i--)
     314       33613 :                 lpc_coefs[ch][i] = get_sbits(&alac->gb, 16);
     315             :         }
     316             : 
     317        2037 :         if (alac->extra_bits) {
     318     5761407 :             for (i = 0; i < alac->nb_samples; i++) {
     319     5760000 :                 if(get_bits_left(&alac->gb) <= 0)
     320           0 :                     return -1;
     321    17280000 :                 for (ch = 0; ch < channels; ch++)
     322    11520000 :                     alac->extra_bits_buffer[ch][i] = get_bits(&alac->gb, alac->extra_bits);
     323             :             }
     324             :         }
     325        6111 :         for (ch = 0; ch < channels; ch++) {
     326        4074 :             int ret=rice_decompress(alac, alac->predict_error_buffer[ch],
     327             :                             alac->nb_samples, bps,
     328        4074 :                             rice_history_mult[ch] * alac->rice_history_mult / 4);
     329        4074 :             if(ret<0)
     330           0 :                 return ret;
     331             : 
     332             :             /* adaptive FIR filter */
     333        4074 :             if (prediction_type[ch] == 15) {
     334             :                 /* Prediction type 15 runs the adaptive FIR twice.
     335             :                  * The first pass uses the special-case coef_num = 31, while
     336             :                  * the second pass uses the coefs from the bitstream.
     337             :                  *
     338             :                  * However, this prediction type is not currently used by the
     339             :                  * reference encoder.
     340             :                  */
     341           0 :                 lpc_prediction(alac->predict_error_buffer[ch],
     342             :                                alac->predict_error_buffer[ch],
     343             :                                alac->nb_samples, bps, NULL, 31, 0);
     344        4074 :             } else if (prediction_type[ch] > 0) {
     345           0 :                 av_log(avctx, AV_LOG_WARNING, "unknown prediction type: %i\n",
     346             :                        prediction_type[ch]);
     347             :             }
     348        8148 :             lpc_prediction(alac->predict_error_buffer[ch],
     349             :                            alac->output_samples_buffer[ch], alac->nb_samples,
     350        4074 :                            bps, lpc_coefs[ch], lpc_order[ch], lpc_quant[ch]);
     351             :         }
     352             :     } else {
     353             :         /* not compressed, easy case */
     354     2339522 :         for (i = 0; i < alac->nb_samples; i++) {
     355     2338950 :             if(get_bits_left(&alac->gb) <= 0)
     356           0 :                 return -1;
     357     7016850 :             for (ch = 0; ch < channels; ch++) {
     358     9355800 :                 alac->output_samples_buffer[ch][i] =
     359     9355800 :                          get_sbits_long(&alac->gb, alac->sample_size);
     360             :             }
     361             :         }
     362         572 :         alac->extra_bits   = 0;
     363         572 :         decorr_shift       = 0;
     364         572 :         decorr_left_weight = 0;
     365             :     }
     366             : 
     367        2609 :     if (channels == 2) {
     368        2609 :         if (alac->extra_bits && alac->extra_bit_bug) {
     369           0 :             alac->dsp.append_extra_bits[1](alac->output_samples_buffer, alac->extra_bits_buffer,
     370             :                                            alac->extra_bits, channels, alac->nb_samples);
     371             :         }
     372             : 
     373        2609 :         if (decorr_left_weight) {
     374         596 :             alac->dsp.decorrelate_stereo(alac->output_samples_buffer, alac->nb_samples,
     375             :                                          decorr_shift, decorr_left_weight);
     376             :         }
     377             : 
     378        2609 :         if (alac->extra_bits && !alac->extra_bit_bug) {
     379        1407 :             alac->dsp.append_extra_bits[1](alac->output_samples_buffer, alac->extra_bits_buffer,
     380             :                                            alac->extra_bits, channels, alac->nb_samples);
     381             :         }
     382           0 :     } else if (alac->extra_bits) {
     383           0 :         alac->dsp.append_extra_bits[0](alac->output_samples_buffer, alac->extra_bits_buffer,
     384             :                                        alac->extra_bits, channels, alac->nb_samples);
     385             :     }
     386             : 
     387        2609 :     switch(alac->sample_size) {
     388         733 :     case 16: {
     389        2199 :         for (ch = 0; ch < channels; ch++) {
     390        1466 :             int16_t *outbuffer = (int16_t *)frame->extended_data[ch_index + ch];
     391     5979374 :             for (i = 0; i < alac->nb_samples; i++)
     392     5977908 :                 *outbuffer++ = alac->output_samples_buffer[ch][i];
     393             :         }}
     394         733 :         break;
     395           0 :     case 20: {
     396           0 :         for (ch = 0; ch < channels; ch++) {
     397           0 :             for (i = 0; i < alac->nb_samples; i++)
     398           0 :                 alac->output_samples_buffer[ch][i] <<= 12;
     399             :         }}
     400           0 :         break;
     401        1876 :     case 24: {
     402        5628 :         for (ch = 0; ch < channels; ch++) {
     403    15363752 :             for (i = 0; i < alac->nb_samples; i++)
     404    15360000 :                 alac->output_samples_buffer[ch][i] <<= 8;
     405             :         }}
     406        1876 :         break;
     407             :     }
     408             : 
     409        2609 :     return 0;
     410             : }
     411             : 
     412        2609 : static int alac_decode_frame(AVCodecContext *avctx, void *data,
     413             :                              int *got_frame_ptr, AVPacket *avpkt)
     414             : {
     415        2609 :     ALACContext *alac = avctx->priv_data;
     416        2609 :     AVFrame *frame    = data;
     417             :     enum AlacRawDataBlockType element;
     418             :     int channels;
     419             :     int ch, ret, got_end;
     420             : 
     421        2609 :     if ((ret = init_get_bits8(&alac->gb, avpkt->data, avpkt->size)) < 0)
     422           0 :         return ret;
     423             : 
     424        2609 :     got_end = 0;
     425        2609 :     alac->nb_samples = 0;
     426        2609 :     ch = 0;
     427        7827 :     while (get_bits_left(&alac->gb) >= 3) {
     428        5218 :         element = get_bits(&alac->gb, 3);
     429        5218 :         if (element == TYPE_END) {
     430        2609 :             got_end = 1;
     431        2609 :             break;
     432             :         }
     433        2609 :         if (element > TYPE_CPE && element != TYPE_LFE) {
     434           0 :             avpriv_report_missing_feature(avctx, "Syntax element %d", element);
     435           0 :             return AVERROR_PATCHWELCOME;
     436             :         }
     437             : 
     438        2609 :         channels = (element == TYPE_CPE) ? 2 : 1;
     439        5218 :         if (ch + channels > alac->channels ||
     440        2609 :             ff_alac_channel_layout_offsets[alac->channels - 1][ch] + channels > alac->channels) {
     441           0 :             av_log(avctx, AV_LOG_ERROR, "invalid element channel count\n");
     442           0 :             return AVERROR_INVALIDDATA;
     443             :         }
     444             : 
     445        2609 :         ret = decode_element(avctx, frame,
     446        2609 :                              ff_alac_channel_layout_offsets[alac->channels - 1][ch],
     447             :                              channels);
     448        2609 :         if (ret < 0 && get_bits_left(&alac->gb))
     449           0 :             return ret;
     450             : 
     451        2609 :         ch += channels;
     452             :     }
     453        2609 :     if (!got_end) {
     454           0 :         av_log(avctx, AV_LOG_ERROR, "no end tag found. incomplete packet.\n");
     455           0 :         return AVERROR_INVALIDDATA;
     456             :     }
     457             : 
     458        2609 :     if (avpkt->size * 8 - get_bits_count(&alac->gb) > 8) {
     459           0 :         av_log(avctx, AV_LOG_ERROR, "Error : %d bits left\n",
     460           0 :                avpkt->size * 8 - get_bits_count(&alac->gb));
     461             :     }
     462             : 
     463        2609 :     if (alac->channels == ch && alac->nb_samples)
     464        2609 :         *got_frame_ptr = 1;
     465             :     else
     466           0 :         av_log(avctx, AV_LOG_WARNING, "Failed to decode all channels\n");
     467             : 
     468        2609 :     return avpkt->size;
     469             : }
     470             : 
     471          25 : static av_cold int alac_decode_close(AVCodecContext *avctx)
     472             : {
     473          25 :     ALACContext *alac = avctx->priv_data;
     474             : 
     475             :     int ch;
     476          75 :     for (ch = 0; ch < FFMIN(alac->channels, 2); ch++) {
     477          50 :         av_freep(&alac->predict_error_buffer[ch]);
     478          50 :         if (!alac->direct_output)
     479          34 :             av_freep(&alac->output_samples_buffer[ch]);
     480          50 :         av_freep(&alac->extra_bits_buffer[ch]);
     481             :     }
     482             : 
     483          25 :     return 0;
     484             : }
     485             : 
     486          25 : static int allocate_buffers(ALACContext *alac)
     487             : {
     488             :     int ch;
     489          25 :     int buf_size = alac->max_samples_per_frame * sizeof(int32_t);
     490             : 
     491          75 :     for (ch = 0; ch < 2; ch++) {
     492          50 :         alac->predict_error_buffer[ch]  = NULL;
     493          50 :         alac->output_samples_buffer[ch] = NULL;
     494          50 :         alac->extra_bits_buffer[ch]     = NULL;
     495             :     }
     496             : 
     497          75 :     for (ch = 0; ch < FFMIN(alac->channels, 2); ch++) {
     498          50 :         FF_ALLOC_OR_GOTO(alac->avctx, alac->predict_error_buffer[ch],
     499             :                          buf_size, buf_alloc_fail);
     500             : 
     501          50 :         alac->direct_output = alac->sample_size > 16;
     502          50 :         if (!alac->direct_output) {
     503          34 :             FF_ALLOC_OR_GOTO(alac->avctx, alac->output_samples_buffer[ch],
     504             :                              buf_size + AV_INPUT_BUFFER_PADDING_SIZE, buf_alloc_fail);
     505             :         }
     506             : 
     507          50 :         FF_ALLOC_OR_GOTO(alac->avctx, alac->extra_bits_buffer[ch],
     508             :                          buf_size + AV_INPUT_BUFFER_PADDING_SIZE, buf_alloc_fail);
     509             :     }
     510          25 :     return 0;
     511           0 : buf_alloc_fail:
     512           0 :     alac_decode_close(alac->avctx);
     513           0 :     return AVERROR(ENOMEM);
     514             : }
     515             : 
     516          24 : static int alac_set_info(ALACContext *alac)
     517             : {
     518             :     GetByteContext gb;
     519             : 
     520          24 :     bytestream2_init(&gb, alac->avctx->extradata,
     521          24 :                      alac->avctx->extradata_size);
     522             : 
     523          24 :     bytestream2_skipu(&gb, 12); // size:4, alac:4, version:4
     524             : 
     525          24 :     alac->max_samples_per_frame = bytestream2_get_be32u(&gb);
     526          48 :     if (!alac->max_samples_per_frame ||
     527          24 :         alac->max_samples_per_frame > 4096 * 4096) {
     528           0 :         av_log(alac->avctx, AV_LOG_ERROR,
     529             :                "max samples per frame invalid: %"PRIu32"\n",
     530             :                alac->max_samples_per_frame);
     531           0 :         return AVERROR_INVALIDDATA;
     532             :     }
     533          24 :     bytestream2_skipu(&gb, 1);  // compatible version
     534          24 :     alac->sample_size          = bytestream2_get_byteu(&gb);
     535          24 :     alac->rice_history_mult    = bytestream2_get_byteu(&gb);
     536          24 :     alac->rice_initial_history = bytestream2_get_byteu(&gb);
     537          24 :     alac->rice_limit           = bytestream2_get_byteu(&gb);
     538          24 :     alac->channels             = bytestream2_get_byteu(&gb);
     539          24 :     bytestream2_get_be16u(&gb); // maxRun
     540          24 :     bytestream2_get_be32u(&gb); // max coded frame size
     541          24 :     bytestream2_get_be32u(&gb); // average bitrate
     542          24 :     alac->sample_rate          = bytestream2_get_be32u(&gb);
     543             : 
     544          24 :     return 0;
     545             : }
     546             : 
     547          24 : static av_cold int alac_decode_init(AVCodecContext * avctx)
     548             : {
     549             :     int ret;
     550          24 :     ALACContext *alac = avctx->priv_data;
     551          24 :     alac->avctx = avctx;
     552             : 
     553             :     /* initialize from the extradata */
     554          24 :     if (alac->avctx->extradata_size < ALAC_EXTRADATA_SIZE) {
     555           0 :         av_log(avctx, AV_LOG_ERROR, "extradata is too small\n");
     556           0 :         return AVERROR_INVALIDDATA;
     557             :     }
     558          24 :     if (alac_set_info(alac)) {
     559           0 :         av_log(avctx, AV_LOG_ERROR, "set_info failed\n");
     560           0 :         return -1;
     561             :     }
     562             : 
     563          24 :     switch (alac->sample_size) {
     564          16 :     case 16: avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
     565          16 :              break;
     566           8 :     case 20:
     567             :     case 24:
     568           8 :     case 32: avctx->sample_fmt = AV_SAMPLE_FMT_S32P;
     569           8 :              break;
     570           0 :     default: avpriv_request_sample(avctx, "Sample depth %d", alac->sample_size);
     571           0 :              return AVERROR_PATCHWELCOME;
     572             :     }
     573          24 :     avctx->bits_per_raw_sample = alac->sample_size;
     574          24 :     avctx->sample_rate         = alac->sample_rate;
     575             : 
     576          24 :     if (alac->channels < 1) {
     577           0 :         av_log(avctx, AV_LOG_WARNING, "Invalid channel count\n");
     578           0 :         alac->channels = avctx->channels;
     579             :     } else {
     580          24 :         if (alac->channels > ALAC_MAX_CHANNELS)
     581           0 :             alac->channels = avctx->channels;
     582             :         else
     583          24 :             avctx->channels = alac->channels;
     584             :     }
     585          24 :     if (avctx->channels > ALAC_MAX_CHANNELS || avctx->channels <= 0 ) {
     586           0 :         avpriv_report_missing_feature(avctx, "Channel count %d",
     587             :                                       avctx->channels);
     588           0 :         return AVERROR_PATCHWELCOME;
     589             :     }
     590          24 :     avctx->channel_layout = ff_alac_channel_layouts[alac->channels - 1];
     591             : 
     592          24 :     if ((ret = allocate_buffers(alac)) < 0) {
     593           0 :         av_log(avctx, AV_LOG_ERROR, "Error allocating buffers\n");
     594           0 :         return ret;
     595             :     }
     596             : 
     597          24 :     ff_alacdsp_init(&alac->dsp);
     598             : 
     599          24 :     return 0;
     600             : }
     601             : 
     602             : #if HAVE_THREADS
     603           1 : static int init_thread_copy(AVCodecContext *avctx)
     604             : {
     605           1 :     ALACContext *alac = avctx->priv_data;
     606           1 :     alac->avctx = avctx;
     607           1 :     return allocate_buffers(alac);
     608             : }
     609             : #endif
     610             : 
     611             : static const AVOption options[] = {
     612             :     { "extra_bits_bug", "Force non-standard decoding process",
     613             :       offsetof(ALACContext, extra_bit_bug), AV_OPT_TYPE_BOOL, { .i64 = 0 },
     614             :       0, 1, AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM },
     615             :     { NULL },
     616             : };
     617             : 
     618             : static const AVClass alac_class = {
     619             :     .class_name = "alac",
     620             :     .item_name  = av_default_item_name,
     621             :     .option     = options,
     622             :     .version    = LIBAVUTIL_VERSION_INT,
     623             : };
     624             : 
     625             : AVCodec ff_alac_decoder = {
     626             :     .name           = "alac",
     627             :     .long_name      = NULL_IF_CONFIG_SMALL("ALAC (Apple Lossless Audio Codec)"),
     628             :     .type           = AVMEDIA_TYPE_AUDIO,
     629             :     .id             = AV_CODEC_ID_ALAC,
     630             :     .priv_data_size = sizeof(ALACContext),
     631             :     .init           = alac_decode_init,
     632             :     .close          = alac_decode_close,
     633             :     .decode         = alac_decode_frame,
     634             :     .init_thread_copy = ONLY_IF_THREADS_ENABLED(init_thread_copy),
     635             :     .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS,
     636             :     .priv_class     = &alac_class
     637             : };

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