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 "codec_internal.h"
26#include "internal.h"
27#include "libavutil/intreadwrite.h"
28
29struct libcelt_context {
30    CELTMode *mode;
31    CELTDecoder *dec;
32    int discard;
33};
34
35static int ff_celt_error_to_averror(int err)
36{
37    switch (err) {
38        case CELT_BAD_ARG:          return AVERROR(EINVAL);
39#ifdef CELT_BUFFER_TOO_SMALL
40        case CELT_BUFFER_TOO_SMALL: return AVERROR(ENOBUFS);
41#endif
42        case CELT_INTERNAL_ERROR:   return AVERROR(EFAULT);
43        case CELT_CORRUPTED_DATA:   return AVERROR_INVALIDDATA;
44        case CELT_UNIMPLEMENTED:    return AVERROR(ENOSYS);
45#ifdef ENOTRECOVERABLE
46        case CELT_INVALID_STATE:    return AVERROR(ENOTRECOVERABLE);
47#endif
48        case CELT_ALLOC_FAIL:       return AVERROR(ENOMEM);
49        default:                    return AVERROR(EINVAL);
50    }
51}
52
53static int ff_celt_bitstream_version_hack(CELTMode *mode)
54{
55    CELTHeader header = { .version_id = 0 };
56    celt_header_init(&header, mode, 960, 2);
57    return header.version_id;
58}
59
60static av_cold int libcelt_dec_init(AVCodecContext *c)
61{
62    struct libcelt_context *celt = c->priv_data;
63    int err;
64
65    if (!c->ch_layout.nb_channels || !c->frame_size ||
66        c->frame_size > INT_MAX / sizeof(int16_t) / c->ch_layout.nb_channels)
67        return AVERROR(EINVAL);
68    celt->mode = celt_mode_create(c->sample_rate, c->frame_size, &err);
69    if (!celt->mode)
70        return ff_celt_error_to_averror(err);
71    celt->dec = celt_decoder_create_custom(celt->mode, c->ch_layout.nb_channels, &err);
72    if (!celt->dec) {
73        celt_mode_destroy(celt->mode);
74        return ff_celt_error_to_averror(err);
75    }
76    if (c->extradata_size >= 4) {
77        celt->discard = AV_RL32(c->extradata);
78        if (celt->discard < 0 || celt->discard >= c->frame_size) {
79            av_log(c, AV_LOG_WARNING,
80                   "Invalid overlap (%d), ignored.\n", celt->discard);
81            celt->discard = 0;
82        }
83    }
84    if (c->extradata_size >= 8) {
85        unsigned version = AV_RL32(c->extradata + 4);
86        unsigned lib_version = ff_celt_bitstream_version_hack(celt->mode);
87        if (version != lib_version)
88            av_log(c, AV_LOG_WARNING,
89                   "CELT bitstream version 0x%x may be "
90                   "improperly decoded by libcelt for version 0x%x.\n",
91                   version, lib_version);
92    }
93    c->sample_fmt = AV_SAMPLE_FMT_S16;
94    return 0;
95}
96
97static av_cold int libcelt_dec_close(AVCodecContext *c)
98{
99    struct libcelt_context *celt = c->priv_data;
100
101    celt_decoder_destroy(celt->dec);
102    celt_mode_destroy(celt->mode);
103    return 0;
104}
105
106static int libcelt_dec_decode(AVCodecContext *c, AVFrame *frame,
107                              int *got_frame_ptr, AVPacket *pkt)
108{
109    struct libcelt_context *celt = c->priv_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->ch_layout.nb_channels,
123                frame->nb_samples * c->ch_layout.nb_channels * sizeof(int16_t));
124        celt->discard = 0;
125    }
126    *got_frame_ptr = 1;
127    return pkt->size;
128}
129
130const FFCodec ff_libcelt_decoder = {
131    .p.name         = "libcelt",
132    .p.long_name    = NULL_IF_CONFIG_SMALL("Xiph CELT decoder using libcelt"),
133    .p.type         = AVMEDIA_TYPE_AUDIO,
134    .p.id           = AV_CODEC_ID_CELT,
135    .p.capabilities = AV_CODEC_CAP_DR1,
136    .p.wrapper_name = "libcelt",
137    .priv_data_size = sizeof(struct libcelt_context),
138    .init           = libcelt_dec_init,
139    .close          = libcelt_dec_close,
140    FF_CODEC_DECODE_CB(libcelt_dec_decode),
141};
142