/*

 * Opus parser for Ogg

 * 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 <string.h>

#include "libavutil/intreadwrite.h"

#include "libavutil/mem.h"

#include "avformat.h"

#include "internal.h"

#include "oggdec.h"

struct oggopus_private {

    int need_comments;

    unsigned pre_skip;

    int64_t cur_dts;

};

#define OPUS_SEEK_PREROLL_MS 80

#define OPUS_HEAD_SIZE 19

static int opus_header(AVFormatContext *avf, int idx)

{

    struct ogg *ogg              = avf->priv_data;

    struct ogg_stream *os        = &ogg->streams[idx];

    AVStream *st                 = avf->streams[idx];

    struct oggopus_private *priv = os->private;

    uint8_t *packet              = os->buf + os->pstart;

    int ret;

    if (!priv) {

        priv = os->private = av_mallocz(sizeof(*priv));

        if (!priv)

            return AVERROR(ENOMEM);

    }

    if (os->flags & OGG_FLAG_BOS) {

        if (os->psize < OPUS_HEAD_SIZE || (AV_RL8(packet + 8) & 0xF0) != 0)

            return AVERROR_INVALIDDATA;

        st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;

        st->codecpar->codec_id   = AV_CODEC_ID_OPUS;

        st->codecpar->ch_layout.nb_channels = AV_RL8(packet + 9);

        priv->pre_skip        = AV_RL16(packet + 10);

        st->codecpar->initial_padding = priv->pre_skip;

        os->start_trimming = priv->pre_skip;

        /*orig_sample_rate    = AV_RL32(packet + 12);*/

        /*gain                = AV_RL16(packet + 16);*/

        /*channel_map         = AV_RL8 (packet + 18);*/

        if ((ret = ff_alloc_extradata(st->codecpar, os->psize)) < 0)

            return ret;

        memcpy(st->codecpar->extradata, packet, os->psize);

        st->codecpar->sample_rate = 48000;

        st->codecpar->seek_preroll = av_rescale(OPUS_SEEK_PREROLL_MS,

                                                st->codecpar->sample_rate, 1000);

        avpriv_set_pts_info(st, 64, 1, 48000);

        priv->need_comments = 1;

        return 1;

    }

    if (priv->need_comments) {

        if (os->psize < 8 || memcmp(packet, "OpusTags", 8))

            return AVERROR_INVALIDDATA;

        ff_vorbis_stream_comment(avf, st, packet + 8, os->psize - 8);

        priv->need_comments--;

        return 1;

    }

    return 0;

}

static int opus_duration(uint8_t *src, int size)

{

    unsigned nb_frames  = 1;

    unsigned toc        = src[0];

    unsigned toc_config = toc >> 3;

    unsigned toc_count  = toc & 3;

    unsigned frame_size = toc_config < 12 ? FFMAX(480, 960 * (toc_config & 3)) :

                          toc_config < 16 ? 480 << (toc_config & 1) :

                                            120 << (toc_config & 3);

    if (toc_count == 3) {

        if (size<2)

            return AVERROR_INVALIDDATA;

        nb_frames = src[1] & 0x3F;

    } else if (toc_count) {

        nb_frames = 2;

    }

    return frame_size * nb_frames;

}

static int opus_packet(AVFormatContext *avf, int idx)

{

    struct ogg *ogg              = avf->priv_data;

    struct ogg_stream *os        = &ogg->streams[idx];

    AVStream *st                 = avf->streams[idx];

    struct oggopus_private *priv = os->private;

    uint8_t *packet              = os->buf + os->pstart;

    int ret;

    if (!os->psize)

        return AVERROR_INVALIDDATA;

    if (os->granule > (1LL << 62)) {

        av_log(avf, AV_LOG_ERROR, "Unsupported huge granule pos %"PRId64 "\n", os->granule);

        return AVERROR_INVALIDDATA;

    }

    if ((!os->lastpts || os->lastpts == AV_NOPTS_VALUE) && !(os->flags & OGG_FLAG_EOS)) {

        int seg, d;

        int duration;

        uint8_t *last_pkt  = os->buf + os->pstart;

        uint8_t *next_pkt  = last_pkt;

        duration = 0;

        seg = os->segp;

        d = opus_duration(last_pkt, os->psize);

        if (d < 0) {

            os->pflags |= AV_PKT_FLAG_CORRUPT;

            return 0;

        }

        duration += d;

        last_pkt = next_pkt =  next_pkt + os->psize;

        for (; seg < os->nsegs; seg++) {

            next_pkt += os->segments[seg];

            if (os->segments[seg] < 255 && next_pkt != last_pkt) {

                int d = opus_duration(last_pkt, next_pkt - last_pkt);

                if (d > 0)

                    duration += d;

                last_pkt = next_pkt;

            }

        }

        os->lastpts                 =

        os->lastdts                 = os->granule - duration;

    }

    if ((ret = opus_duration(packet, os->psize)) < 0)

        return ret;

    os->pduration = ret;

    if (os->lastpts != AV_NOPTS_VALUE) {

        if (st->start_time == AV_NOPTS_VALUE)

            st->start_time = os->lastpts;

        priv->cur_dts = os->lastdts = os->lastpts -= priv->pre_skip;

    }

    priv->cur_dts += os->pduration;

    if ((os->flags & OGG_FLAG_EOS)) {

        int64_t skip = priv->cur_dts - os->granule + priv->pre_skip;

        skip = FFMIN(skip, os->pduration);

        if (skip > 0) {

            os->pduration = skip < os->pduration ? os->pduration - skip : 1;

            os->end_trimming = skip;

            av_log(avf, AV_LOG_DEBUG,

                   "Last packet was truncated to %d due to end trimming.\n",

                   os->pduration);

        }

    }

    return 0;

}

const struct ogg_codec ff_opus_codec = {

    .name             = "Opus",

    .magic            = "OpusHead",

    .magicsize        = 8,

    .header           = opus_header,

    .packet           = opus_packet,

    .nb_header        = 1,

};