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libcelt_dec.c
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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 };
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