yading@10: /*
yading@10:  * Opus decoder using libopus
yading@10:  * Copyright (c) 2012 Nicolas George
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #include <opus.h>
yading@10: #include <opus_multistream.h>
yading@10: 
yading@10: #include "libavutil/avassert.h"
yading@10: #include "libavutil/intreadwrite.h"
yading@10: #include "avcodec.h"
yading@10: #include "internal.h"
yading@10: #include "vorbis.h"
yading@10: #include "mathops.h"
yading@10: #include "libopus.h"
yading@10: 
yading@10: struct libopus_context {
yading@10:     OpusMSDecoder *dec;
yading@10:     int pre_skip;
yading@10: #ifndef OPUS_SET_GAIN
yading@10:     union { int i; double d; } gain;
yading@10: #endif
yading@10: };
yading@10: 
yading@10: #define OPUS_HEAD_SIZE 19
yading@10: 
yading@10: static av_cold int libopus_decode_init(AVCodecContext *avc)
yading@10: {
yading@10:     struct libopus_context *opus = avc->priv_data;
yading@10:     int ret, channel_map = 0, gain_db = 0, nb_streams, nb_coupled;
yading@10:     uint8_t mapping_arr[8] = { 0, 1 }, *mapping;
yading@10: 
yading@10:     avc->sample_rate    = 48000;
yading@10:     avc->sample_fmt     = avc->request_sample_fmt == AV_SAMPLE_FMT_FLT ?
yading@10:                           AV_SAMPLE_FMT_FLT : AV_SAMPLE_FMT_S16;
yading@10:     avc->channel_layout = avc->channels > 8 ? 0 :
yading@10:                           ff_vorbis_channel_layouts[avc->channels - 1];
yading@10: 
yading@10:     if (avc->extradata_size >= OPUS_HEAD_SIZE) {
yading@10:         opus->pre_skip = AV_RL16(avc->extradata + 10);
yading@10:         gain_db     = sign_extend(AV_RL16(avc->extradata + 16), 16);
yading@10:         channel_map = AV_RL8 (avc->extradata + 18);
yading@10:     }
yading@10:     if (avc->extradata_size >= OPUS_HEAD_SIZE + 2 + avc->channels) {
yading@10:         nb_streams = avc->extradata[OPUS_HEAD_SIZE + 0];
yading@10:         nb_coupled = avc->extradata[OPUS_HEAD_SIZE + 1];
yading@10:         if (nb_streams + nb_coupled != avc->channels)
yading@10:             av_log(avc, AV_LOG_WARNING, "Inconsistent channel mapping.\n");
yading@10:         mapping = avc->extradata + OPUS_HEAD_SIZE + 2;
yading@10:     } else {
yading@10:         if (avc->channels > 2 || channel_map) {
yading@10:             av_log(avc, AV_LOG_ERROR,
yading@10:                    "No channel mapping for %d channels.\n", avc->channels);
yading@10:             return AVERROR(EINVAL);
yading@10:         }
yading@10:         nb_streams = 1;
yading@10:         nb_coupled = avc->channels > 1;
yading@10:         mapping    = mapping_arr;
yading@10:     }
yading@10: 
yading@10:     if (avc->channels > 2 && avc->channels <= 8) {
yading@10:         const uint8_t *vorbis_offset = ff_vorbis_channel_layout_offsets[avc->channels - 1];
yading@10:         int ch;
yading@10: 
yading@10:         /* Remap channels from vorbis order to ffmpeg order */
yading@10:         for (ch = 0; ch < avc->channels; ch++)
yading@10:             mapping_arr[ch] = mapping[vorbis_offset[ch]];
yading@10:         mapping = mapping_arr;
yading@10:     }
yading@10: 
yading@10:     opus->dec = opus_multistream_decoder_create(avc->sample_rate, avc->channels,
yading@10:                                                 nb_streams, nb_coupled,
yading@10:                                                 mapping, &ret);
yading@10:     if (!opus->dec) {
yading@10:         av_log(avc, AV_LOG_ERROR, "Unable to create decoder: %s\n",
yading@10:                opus_strerror(ret));
yading@10:         return ff_opus_error_to_averror(ret);
yading@10:     }
yading@10: 
yading@10: #ifdef OPUS_SET_GAIN
yading@10:     ret = opus_multistream_decoder_ctl(opus->dec, OPUS_SET_GAIN(gain_db));
yading@10:     if (ret != OPUS_OK)
yading@10:         av_log(avc, AV_LOG_WARNING, "Failed to set gain: %s\n",
yading@10:                opus_strerror(ret));
yading@10: #else
yading@10:     {
yading@10:         double gain_lin = pow(10, gain_db / (20.0 * 256));
yading@10:         if (avc->sample_fmt == AV_SAMPLE_FMT_FLT)
yading@10:             opus->gain.d = gain_lin;
yading@10:         else
yading@10:             opus->gain.i = FFMIN(gain_lin * 65536, INT_MAX);
yading@10:     }
yading@10: #endif
yading@10: 
yading@10:     avc->internal->skip_samples = opus->pre_skip;
yading@10:     avc->delay = 3840;  /* Decoder delay (in samples) at 48kHz */
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static av_cold int libopus_decode_close(AVCodecContext *avc)
yading@10: {
yading@10:     struct libopus_context *opus = avc->priv_data;
yading@10: 
yading@10:     opus_multistream_decoder_destroy(opus->dec);
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: #define MAX_FRAME_SIZE (960 * 6)
yading@10: 
yading@10: static int libopus_decode(AVCodecContext *avc, void *data,
yading@10:                           int *got_frame_ptr, AVPacket *pkt)
yading@10: {
yading@10:     struct libopus_context *opus = avc->priv_data;
yading@10:     AVFrame *frame               = data;
yading@10:     int ret, nb_samples;
yading@10: 
yading@10:     frame->nb_samples = MAX_FRAME_SIZE;
yading@10:     if ((ret = ff_get_buffer(avc, frame, 0)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     if (avc->sample_fmt == AV_SAMPLE_FMT_S16)
yading@10:         nb_samples = opus_multistream_decode(opus->dec, pkt->data, pkt->size,
yading@10:                                              (opus_int16 *)frame->data[0],
yading@10:                                              frame->nb_samples, 0);
yading@10:     else
yading@10:         nb_samples = opus_multistream_decode_float(opus->dec, pkt->data, pkt->size,
yading@10:                                                    (float *)frame->data[0],
yading@10:                                                    frame->nb_samples, 0);
yading@10: 
yading@10:     if (nb_samples < 0) {
yading@10:         av_log(avc, AV_LOG_ERROR, "Decoding error: %s\n",
yading@10:                opus_strerror(nb_samples));
yading@10:         return ff_opus_error_to_averror(nb_samples);
yading@10:     }
yading@10: 
yading@10: #ifndef OPUS_SET_GAIN
yading@10:     {
yading@10:         int i = avc->channels * nb_samples;
yading@10:         if (avc->sample_fmt == AV_SAMPLE_FMT_FLT) {
yading@10:             float *pcm = (float *)frame->data[0];
yading@10:             for (; i > 0; i--, pcm++)
yading@10:                 *pcm = av_clipf(*pcm * opus->gain.d, -1, 1);
yading@10:         } else {
yading@10:             int16_t *pcm = (int16_t *)frame->data[0];
yading@10:             for (; i > 0; i--, pcm++)
yading@10:                 *pcm = av_clip_int16(((int64_t)opus->gain.i * *pcm) >> 16);
yading@10:         }
yading@10:     }
yading@10: #endif
yading@10: 
yading@10:     frame->nb_samples = nb_samples;
yading@10:     *got_frame_ptr    = 1;
yading@10: 
yading@10:     return pkt->size;
yading@10: }
yading@10: 
yading@10: static void libopus_flush(AVCodecContext *avc)
yading@10: {
yading@10:     struct libopus_context *opus = avc->priv_data;
yading@10: 
yading@10:     opus_multistream_decoder_ctl(opus->dec, OPUS_RESET_STATE);
yading@10:     /* The stream can have been extracted by a tool that is not Opus-aware.
yading@10:        Therefore, any packet can become the first of the stream. */
yading@10:     avc->internal->skip_samples = opus->pre_skip;
yading@10: }
yading@10: 
yading@10: AVCodec ff_libopus_decoder = {
yading@10:     .name           = "libopus",
yading@10:     .type           = AVMEDIA_TYPE_AUDIO,
yading@10:     .id             = AV_CODEC_ID_OPUS,
yading@10:     .priv_data_size = sizeof(struct libopus_context),
yading@10:     .init           = libopus_decode_init,
yading@10:     .close          = libopus_decode_close,
yading@10:     .decode         = libopus_decode,
yading@10:     .flush          = libopus_flush,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("libopus Opus"),
yading@10:     .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLT,
yading@10:                                                      AV_SAMPLE_FMT_S16,
yading@10:                                                      AV_SAMPLE_FMT_NONE },
yading@10: };