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1 | /* |
2 | * Opus decoder using libopus | |
3 | * Copyright (c) 2012 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 <opus.h> | |
23 | #include <opus_multistream.h> | |
24 | ||
25 | #include "libavutil/avassert.h" | |
26 | #include "libavutil/intreadwrite.h" | |
27 | #include "avcodec.h" | |
28 | #include "internal.h" | |
29 | #include "vorbis.h" | |
30 | #include "mathops.h" | |
31 | #include "libopus.h" | |
32 | ||
33 | struct libopus_context { | |
34 | OpusMSDecoder *dec; | |
35 | int pre_skip; | |
36 | #ifndef OPUS_SET_GAIN | |
37 | union { int i; double d; } gain; | |
38 | #endif | |
39 | }; | |
40 | ||
41 | #define OPUS_HEAD_SIZE 19 | |
42 | ||
43 | static av_cold int libopus_decode_init(AVCodecContext *avc) | |
44 | { | |
45 | struct libopus_context *opus = avc->priv_data; | |
46 | int ret, channel_map = 0, gain_db = 0, nb_streams, nb_coupled; | |
47 | uint8_t mapping_arr[8] = { 0, 1 }, *mapping; | |
48 | ||
49 | avc->sample_rate = 48000; | |
50 | avc->sample_fmt = avc->request_sample_fmt == AV_SAMPLE_FMT_FLT ? | |
51 | AV_SAMPLE_FMT_FLT : AV_SAMPLE_FMT_S16; | |
52 | avc->channel_layout = avc->channels > 8 ? 0 : | |
53 | ff_vorbis_channel_layouts[avc->channels - 1]; | |
54 | ||
55 | if (avc->extradata_size >= OPUS_HEAD_SIZE) { | |
56 | opus->pre_skip = AV_RL16(avc->extradata + 10); | |
57 | gain_db = sign_extend(AV_RL16(avc->extradata + 16), 16); | |
58 | channel_map = AV_RL8 (avc->extradata + 18); | |
59 | } | |
60 | if (avc->extradata_size >= OPUS_HEAD_SIZE + 2 + avc->channels) { | |
61 | nb_streams = avc->extradata[OPUS_HEAD_SIZE + 0]; | |
62 | nb_coupled = avc->extradata[OPUS_HEAD_SIZE + 1]; | |
63 | if (nb_streams + nb_coupled != avc->channels) | |
64 | av_log(avc, AV_LOG_WARNING, "Inconsistent channel mapping.\n"); | |
65 | mapping = avc->extradata + OPUS_HEAD_SIZE + 2; | |
66 | } else { | |
67 | if (avc->channels > 2 || channel_map) { | |
68 | av_log(avc, AV_LOG_ERROR, | |
69 | "No channel mapping for %d channels.\n", avc->channels); | |
70 | return AVERROR(EINVAL); | |
71 | } | |
72 | nb_streams = 1; | |
73 | nb_coupled = avc->channels > 1; | |
74 | mapping = mapping_arr; | |
75 | } | |
76 | ||
77 | if (avc->channels > 2 && avc->channels <= 8) { | |
78 | const uint8_t *vorbis_offset = ff_vorbis_channel_layout_offsets[avc->channels - 1]; | |
79 | int ch; | |
80 | ||
81 | /* Remap channels from vorbis order to ffmpeg order */ | |
82 | for (ch = 0; ch < avc->channels; ch++) | |
83 | mapping_arr[ch] = mapping[vorbis_offset[ch]]; | |
84 | mapping = mapping_arr; | |
85 | } | |
86 | ||
87 | opus->dec = opus_multistream_decoder_create(avc->sample_rate, avc->channels, | |
88 | nb_streams, nb_coupled, | |
89 | mapping, &ret); | |
90 | if (!opus->dec) { | |
91 | av_log(avc, AV_LOG_ERROR, "Unable to create decoder: %s\n", | |
92 | opus_strerror(ret)); | |
93 | return ff_opus_error_to_averror(ret); | |
94 | } | |
95 | ||
96 | #ifdef OPUS_SET_GAIN | |
97 | ret = opus_multistream_decoder_ctl(opus->dec, OPUS_SET_GAIN(gain_db)); | |
98 | if (ret != OPUS_OK) | |
99 | av_log(avc, AV_LOG_WARNING, "Failed to set gain: %s\n", | |
100 | opus_strerror(ret)); | |
101 | #else | |
102 | { | |
103 | double gain_lin = pow(10, gain_db / (20.0 * 256)); | |
104 | if (avc->sample_fmt == AV_SAMPLE_FMT_FLT) | |
105 | opus->gain.d = gain_lin; | |
106 | else | |
107 | opus->gain.i = FFMIN(gain_lin * 65536, INT_MAX); | |
108 | } | |
109 | #endif | |
110 | ||
111 | /* Decoder delay (in samples) at 48kHz */ | |
112 | avc->delay = avc->internal->skip_samples = opus->pre_skip; | |
113 | ||
114 | return 0; | |
115 | } | |
116 | ||
117 | static av_cold int libopus_decode_close(AVCodecContext *avc) | |
118 | { | |
119 | struct libopus_context *opus = avc->priv_data; | |
120 | ||
121 | opus_multistream_decoder_destroy(opus->dec); | |
122 | return 0; | |
123 | } | |
124 | ||
125 | #define MAX_FRAME_SIZE (960 * 6) | |
126 | ||
127 | static int libopus_decode(AVCodecContext *avc, void *data, | |
128 | int *got_frame_ptr, AVPacket *pkt) | |
129 | { | |
130 | struct libopus_context *opus = avc->priv_data; | |
131 | AVFrame *frame = data; | |
132 | int ret, nb_samples; | |
133 | ||
134 | frame->nb_samples = MAX_FRAME_SIZE; | |
135 | if ((ret = ff_get_buffer(avc, frame, 0)) < 0) | |
136 | return ret; | |
137 | ||
138 | if (avc->sample_fmt == AV_SAMPLE_FMT_S16) | |
139 | nb_samples = opus_multistream_decode(opus->dec, pkt->data, pkt->size, | |
140 | (opus_int16 *)frame->data[0], | |
141 | frame->nb_samples, 0); | |
142 | else | |
143 | nb_samples = opus_multistream_decode_float(opus->dec, pkt->data, pkt->size, | |
144 | (float *)frame->data[0], | |
145 | frame->nb_samples, 0); | |
146 | ||
147 | if (nb_samples < 0) { | |
148 | av_log(avc, AV_LOG_ERROR, "Decoding error: %s\n", | |
149 | opus_strerror(nb_samples)); | |
150 | return ff_opus_error_to_averror(nb_samples); | |
151 | } | |
152 | ||
153 | #ifndef OPUS_SET_GAIN | |
154 | { | |
155 | int i = avc->channels * nb_samples; | |
156 | if (avc->sample_fmt == AV_SAMPLE_FMT_FLT) { | |
157 | float *pcm = (float *)frame->data[0]; | |
158 | for (; i > 0; i--, pcm++) | |
159 | *pcm = av_clipf(*pcm * opus->gain.d, -1, 1); | |
160 | } else { | |
161 | int16_t *pcm = (int16_t *)frame->data[0]; | |
162 | for (; i > 0; i--, pcm++) | |
163 | *pcm = av_clip_int16(((int64_t)opus->gain.i * *pcm) >> 16); | |
164 | } | |
165 | } | |
166 | #endif | |
167 | ||
168 | frame->nb_samples = nb_samples; | |
169 | *got_frame_ptr = 1; | |
170 | ||
171 | return pkt->size; | |
172 | } | |
173 | ||
174 | static void libopus_flush(AVCodecContext *avc) | |
175 | { | |
176 | struct libopus_context *opus = avc->priv_data; | |
177 | ||
178 | opus_multistream_decoder_ctl(opus->dec, OPUS_RESET_STATE); | |
179 | /* The stream can have been extracted by a tool that is not Opus-aware. | |
180 | Therefore, any packet can become the first of the stream. */ | |
181 | avc->internal->skip_samples = opus->pre_skip; | |
182 | } | |
183 | ||
184 | AVCodec ff_libopus_decoder = { | |
185 | .name = "libopus", | |
186 | .long_name = NULL_IF_CONFIG_SMALL("libopus Opus"), | |
187 | .type = AVMEDIA_TYPE_AUDIO, | |
188 | .id = AV_CODEC_ID_OPUS, | |
189 | .priv_data_size = sizeof(struct libopus_context), | |
190 | .init = libopus_decode_init, | |
191 | .close = libopus_decode_close, | |
192 | .decode = libopus_decode, | |
193 | .flush = libopus_flush, | |
194 | .capabilities = CODEC_CAP_DR1, | |
195 | .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLT, | |
196 | AV_SAMPLE_FMT_S16, | |
197 | AV_SAMPLE_FMT_NONE }, | |
198 | }; |