/*

 * Opus decoder using libopus

 * Copyright (c) 2012 Nicolas George

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include <opus.h>

#include <opus_multistream.h>

#include "libavutil/internal.h"

#include "libavutil/intreadwrite.h"

#include "libavutil/ffmath.h"

#include "libavutil/opt.h"

#include "avcodec.h"

#include "codec_internal.h"

#include "decode.h"

#include "internal.h"

#include "mathops.h"

#include "libopus.h"

#include "vorbis_data.h"

struct libopus_context {

    AVClass *class;

    OpusMSDecoder *dec;

    int pre_skip;

#ifndef OPUS_SET_GAIN

    union { int i; double d; } gain;

#endif

#ifdef OPUS_SET_PHASE_INVERSION_DISABLED_REQUEST

    int apply_phase_inv;

#endif

};

#define OPUS_HEAD_SIZE 19

static av_cold int libopus_decode_init(AVCodecContext *avc)

{

    struct libopus_context *opus = avc->priv_data;

    int ret, channel_map = 0, gain_db = 0, nb_streams, nb_coupled, channels;

    uint8_t mapping_arr[8] = { 0, 1 }, *mapping;

    channels = avc->extradata_size >= 10 ? avc->extradata[9] : (avc->ch_layout.nb_channels == 1) ? 1 : 2;

    if (channels <= 0) {

        av_log(avc, AV_LOG_WARNING,

               "Invalid number of channels %d, defaulting to stereo\n", channels);

        channels = 2;

    }

    avc->sample_rate    = 48000;

    avc->sample_fmt     = avc->request_sample_fmt == AV_SAMPLE_FMT_FLT ?

                          AV_SAMPLE_FMT_FLT : AV_SAMPLE_FMT_S16;

    av_channel_layout_uninit(&avc->ch_layout);

    if (channels > 8) {

        avc->ch_layout.order       = AV_CHANNEL_ORDER_UNSPEC;

        avc->ch_layout.nb_channels = channels;

    } else {

        av_channel_layout_copy(&avc->ch_layout, &ff_vorbis_ch_layouts[channels - 1]);

    }

    if (avc->extradata_size >= OPUS_HEAD_SIZE) {

        opus->pre_skip = AV_RL16(avc->extradata + 10);

        gain_db     = sign_extend(AV_RL16(avc->extradata + 16), 16);

        channel_map = AV_RL8 (avc->extradata + 18);

    }

    if (avc->extradata_size >= OPUS_HEAD_SIZE + 2 + channels) {

        nb_streams = avc->extradata[OPUS_HEAD_SIZE + 0];

        nb_coupled = avc->extradata[OPUS_HEAD_SIZE + 1];

        if (nb_streams + nb_coupled != channels)

            av_log(avc, AV_LOG_WARNING, "Inconsistent channel mapping.\n");

        mapping = avc->extradata + OPUS_HEAD_SIZE + 2;

    } else {

        if (channels > 2 || channel_map) {

            av_log(avc, AV_LOG_ERROR,

                   "No channel mapping for %d channels.\n", channels);

            return AVERROR(EINVAL);

        }

        nb_streams = 1;

        nb_coupled = channels > 1;

        mapping    = mapping_arr;

    }

    if (channels > 2 && channels <= 8) {

        const uint8_t *vorbis_offset = ff_vorbis_channel_layout_offsets[channels - 1];

        int ch;

        /* Remap channels from Vorbis order to ffmpeg order */

        for (ch = 0; ch < channels; ch++)

            mapping_arr[ch] = mapping[vorbis_offset[ch]];

        mapping = mapping_arr;

    }

    opus->dec = opus_multistream_decoder_create(avc->sample_rate, channels,

                                                nb_streams, nb_coupled,

                                                mapping, &ret);

    if (!opus->dec) {

        av_log(avc, AV_LOG_ERROR, "Unable to create decoder: %s\n",

               opus_strerror(ret));

        return ff_opus_error_to_averror(ret);

    }

#ifdef OPUS_SET_GAIN

    ret = opus_multistream_decoder_ctl(opus->dec, OPUS_SET_GAIN(gain_db));

    if (ret != OPUS_OK)

        av_log(avc, AV_LOG_WARNING, "Failed to set gain: %s\n",

               opus_strerror(ret));

#else

    {

        double gain_lin = ff_exp10(gain_db / (20.0 * 256));

        if (avc->sample_fmt == AV_SAMPLE_FMT_FLT)

            opus->gain.d = gain_lin;

        else

            opus->gain.i = FFMIN(gain_lin * 65536, INT_MAX);

    }

#endif

#ifdef OPUS_SET_PHASE_INVERSION_DISABLED_REQUEST

    ret = opus_multistream_decoder_ctl(opus->dec,

                                       OPUS_SET_PHASE_INVERSION_DISABLED(!opus->apply_phase_inv));

    if (ret != OPUS_OK)

        av_log(avc, AV_LOG_WARNING,

               "Unable to set phase inversion: %s\n",

               opus_strerror(ret));

#endif

    /* Decoder delay (in samples) at 48kHz */

    avc->delay = avc->internal->skip_samples = opus->pre_skip;

    return 0;

}

static av_cold int libopus_decode_close(AVCodecContext *avc)

{

    struct libopus_context *opus = avc->priv_data;

    if (opus->dec) {

        opus_multistream_decoder_destroy(opus->dec);

        opus->dec = NULL;

    }

    return 0;

}

#define MAX_FRAME_SIZE (960 * 6)

static int libopus_decode(AVCodecContext *avc, AVFrame *frame,

                          int *got_frame_ptr, AVPacket *pkt)

{

    struct libopus_context *opus = avc->priv_data;

    int ret, nb_samples;

    frame->nb_samples = MAX_FRAME_SIZE;

    if ((ret = ff_get_buffer(avc, frame, 0)) < 0)

        return ret;

    if (avc->sample_fmt == AV_SAMPLE_FMT_S16)

        nb_samples = opus_multistream_decode(opus->dec, pkt->data, pkt->size,

                                             (opus_int16 *)frame->data[0],

                                             frame->nb_samples, 0);

    else

        nb_samples = opus_multistream_decode_float(opus->dec, pkt->data, pkt->size,

                                                   (float *)frame->data[0],

                                                   frame->nb_samples, 0);

    if (nb_samples < 0) {

        av_log(avc, AV_LOG_ERROR, "Decoding error: %s\n",

               opus_strerror(nb_samples));

        return ff_opus_error_to_averror(nb_samples);

    }

#ifndef OPUS_SET_GAIN

    {

        int i = avc->ch_layout.nb_channels * nb_samples;

        if (avc->sample_fmt == AV_SAMPLE_FMT_FLT) {

            float *pcm = (float *)frame->data[0];

            for (; i > 0; i--, pcm++)

                *pcm = av_clipf(*pcm * opus->gain.d, -1, 1);

        } else {

            int16_t *pcm = (int16_t *)frame->data[0];

            for (; i > 0; i--, pcm++)

                *pcm = av_clip_int16(((int64_t)opus->gain.i * *pcm) >> 16);

        }

    }

#endif

    frame->nb_samples = nb_samples;

    *got_frame_ptr    = 1;

    return pkt->size;

}

static void libopus_flush(AVCodecContext *avc)

{

    struct libopus_context *opus = avc->priv_data;

    opus_multistream_decoder_ctl(opus->dec, OPUS_RESET_STATE);

    /* The stream can have been extracted by a tool that is not Opus-aware.

       Therefore, any packet can become the first of the stream. */

    avc->internal->skip_samples = opus->pre_skip;

}

#define OFFSET(x) offsetof(struct libopus_context, x)

#define FLAGS AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM

static const AVOption libopusdec_options[] = {

#ifdef OPUS_SET_PHASE_INVERSION_DISABLED_REQUEST

    { "apply_phase_inv", "Apply intensity stereo phase inversion", OFFSET(apply_phase_inv), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, FLAGS },

#endif

    { NULL },

};

static const AVClass libopusdec_class = {

    .class_name = "libopusdec",

    .item_name  = av_default_item_name,

    .option     = libopusdec_options,

    .version    = LIBAVUTIL_VERSION_INT,

};

const FFCodec ff_libopus_decoder = {

    .p.name         = "libopus",

    CODEC_LONG_NAME("libopus Opus"),

    .p.type         = AVMEDIA_TYPE_AUDIO,

    .p.id           = AV_CODEC_ID_OPUS,

    .priv_data_size = sizeof(struct libopus_context),

    .init           = libopus_decode_init,

    .close          = libopus_decode_close,

    FF_CODEC_DECODE_CB(libopus_decode),

    .flush          = libopus_flush,

    .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,

    .caps_internal  = FF_CODEC_CAP_NOT_INIT_THREADSAFE |

                      FF_CODEC_CAP_INIT_CLEANUP,

    CODEC_SAMPLEFMTS(AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_S16),

    .p.priv_class   = &libopusdec_class,

    .p.wrapper_name = "libopus",

};