| 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 | }; |