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  1. /*
  2.  * Xiph CELT decoder using libcelt
  3.  * Copyright (c) 2011 Nicolas George
  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 <celt/celt.h>
  23. #include <celt/celt_header.h>
  24. #include "avcodec.h"
  25. #include "internal.h"
  26. #include "libavutil/intreadwrite.h"
  27.  
  28. struct libcelt_context {
  29.     CELTMode *mode;
  30.     CELTDecoder *dec;
  31.     int discard;
  32. };
  33.  
  34. static int ff_celt_error_to_averror(int err)
  35. {
  36.     switch (err) {
  37.         case CELT_BAD_ARG:          return AVERROR(EINVAL);
  38. #ifdef CELT_BUFFER_TOO_SMALL
  39.         case CELT_BUFFER_TOO_SMALL: return AVERROR(ENOBUFS);
  40. #endif
  41.         case CELT_INTERNAL_ERROR:   return AVERROR(EFAULT);
  42.         case CELT_CORRUPTED_DATA:   return AVERROR_INVALIDDATA;
  43.         case CELT_UNIMPLEMENTED:    return AVERROR(ENOSYS);
  44. #ifdef ENOTRECOVERABLE
  45.         case CELT_INVALID_STATE:    return AVERROR(ENOTRECOVERABLE);
  46. #endif
  47.         case CELT_ALLOC_FAIL:       return AVERROR(ENOMEM);
  48.         default:                    return AVERROR(EINVAL);
  49.     }
  50. }
  51.  
  52. static int ff_celt_bitstream_version_hack(CELTMode *mode)
  53. {
  54.     CELTHeader header = { .version_id = 0 };
  55.     celt_header_init(&header, mode, 960, 2);
  56.     return header.version_id;
  57. }
  58.  
  59. static av_cold int libcelt_dec_init(AVCodecContext *c)
  60. {
  61.     struct libcelt_context *celt = c->priv_data;
  62.     int err;
  63.  
  64.     if (!c->channels || !c->frame_size ||
  65.         c->frame_size > INT_MAX / sizeof(int16_t) / c->channels)
  66.         return AVERROR(EINVAL);
  67.     celt->mode = celt_mode_create(c->sample_rate, c->frame_size, &err);
  68.     if (!celt->mode)
  69.         return ff_celt_error_to_averror(err);
  70.     celt->dec = celt_decoder_create_custom(celt->mode, c->channels, &err);
  71.     if (!celt->dec) {
  72.         celt_mode_destroy(celt->mode);
  73.         return ff_celt_error_to_averror(err);
  74.     }
  75.     if (c->extradata_size >= 4) {
  76.         celt->discard = AV_RL32(c->extradata);
  77.         if (celt->discard < 0 || celt->discard >= c->frame_size) {
  78.             av_log(c, AV_LOG_WARNING,
  79.                    "Invalid overlap (%d), ignored.\n", celt->discard);
  80.             celt->discard = 0;
  81.         }
  82.     }
  83.     if (c->extradata_size >= 8) {
  84.         unsigned version = AV_RL32(c->extradata + 4);
  85.         unsigned lib_version = ff_celt_bitstream_version_hack(celt->mode);
  86.         if (version != lib_version)
  87.             av_log(c, AV_LOG_WARNING,
  88.                    "CELT bitstream version 0x%x may be "
  89.                    "improperly decoded by libcelt for version 0x%x.\n",
  90.                    version, lib_version);
  91.     }
  92.     c->sample_fmt = AV_SAMPLE_FMT_S16;
  93.     return 0;
  94. }
  95.  
  96. static av_cold int libcelt_dec_close(AVCodecContext *c)
  97. {
  98.     struct libcelt_context *celt = c->priv_data;
  99.  
  100.     celt_decoder_destroy(celt->dec);
  101.     celt_mode_destroy(celt->mode);
  102.     return 0;
  103. }
  104.  
  105. static int libcelt_dec_decode(AVCodecContext *c, void *data,
  106.                               int *got_frame_ptr, AVPacket *pkt)
  107. {
  108.     struct libcelt_context *celt = c->priv_data;
  109.     AVFrame *frame = data;
  110.     int err;
  111.     int16_t *pcm;
  112.  
  113.     frame->nb_samples = c->frame_size;
  114.     if ((err = ff_get_buffer(c, frame, 0)) < 0)
  115.         return err;
  116.     pcm = (int16_t *)frame->data[0];
  117.     err = celt_decode(celt->dec, pkt->data, pkt->size, pcm, c->frame_size);
  118.     if (err < 0)
  119.         return ff_celt_error_to_averror(err);
  120.     if (celt->discard) {
  121.         frame->nb_samples -= celt->discard;
  122.         memmove(pcm, pcm + celt->discard * c->channels,
  123.                 frame->nb_samples * c->channels * sizeof(int16_t));
  124.         celt->discard = 0;
  125.     }
  126.     *got_frame_ptr = 1;
  127.     return pkt->size;
  128. }
  129.  
  130. AVCodec ff_libcelt_decoder = {
  131.     .name           = "libcelt",
  132.     .long_name      = NULL_IF_CONFIG_SMALL("Xiph CELT decoder using libcelt"),
  133.     .type           = AVMEDIA_TYPE_AUDIO,
  134.     .id             = AV_CODEC_ID_CELT,
  135.     .priv_data_size = sizeof(struct libcelt_context),
  136.     .init           = libcelt_dec_init,
  137.     .close          = libcelt_dec_close,
  138.     .decode         = libcelt_dec_decode,
  139.     .capabilities   = CODEC_CAP_DR1,
  140. };
  141.