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
28struct libcelt_context {
29    CELTMode *mode;
30    CELTDecoder *dec;
31    int discard;
32};
33
34static 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
52static 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
59static 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
96static 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
105static 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
130AVCodec 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