/*

 * On2 VP8 parser for Ogg

 * Copyright (C) 2013 James Almer

 *

 * 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 "libavutil/intreadwrite.h"

#include "avformat.h"

#include "internal.h"

#include "oggdec.h"

#define VP8_HEADER_SIZE 26

static int vp8_header(AVFormatContext *s, int idx)

{

    struct ogg *ogg = s->priv_data;

    struct ogg_stream *os = ogg->streams + idx;

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

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

    AVRational framerate;

    if (os->psize < 7 || p[0] != 0x4f)

        return 0;

    switch (p[5]){

    case 0x01:

        if (os->psize < VP8_HEADER_SIZE) {

            av_log(s, AV_LOG_ERROR, "Invalid OggVP8 header packet");

            return AVERROR_INVALIDDATA;

        }

        if (p[6] != 1) {

            av_log(s, AV_LOG_WARNING,

                   "Unknown OggVP8 version %d.%d\n", p[6], p[7]);

            return AVERROR_INVALIDDATA;

        }

        st->codecpar->width         = AV_RB16(p +  8);

        st->codecpar->height        = AV_RB16(p + 10);

        st->sample_aspect_ratio.num = AV_RB24(p + 12);

        st->sample_aspect_ratio.den = AV_RB24(p + 15);

        framerate.num               = AV_RB32(p + 18);

        framerate.den               = AV_RB32(p + 22);

        avpriv_set_pts_info(st, 64, framerate.den, framerate.num);

        st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;

        st->codecpar->codec_id   = AV_CODEC_ID_VP8;

        ffstream(st)->need_parsing = AVSTREAM_PARSE_HEADERS;

        break;

    case 0x02:

        if (p[6] != 0x20)

            return AVERROR_INVALIDDATA;

        ff_vorbis_stream_comment(s, st, p + 7, os->psize - 7);

        break;

    default:

        av_log(s, AV_LOG_ERROR, "Unknown VP8 header type 0x%02X\n", p[5]);

        return AVERROR_INVALIDDATA;

    }

    return 1;

}

static uint64_t vp8_gptopts(AVFormatContext *s, int idx,

                            uint64_t granule, int64_t *dts)

{

    struct ogg *ogg = s->priv_data;

    struct ogg_stream *os = ogg->streams + idx;

    int invcnt    = !((granule >> 30) & 3);

    // If page granule is that of an invisible vp8 frame, its pts will be

    // that of the end of the next visible frame. We subtract 1 for those

    // to prevent messing up pts calculations.

    uint64_t pts  = (granule >> 32) - invcnt;

    uint32_t dist = (granule >>  3) & 0x07ffffff;

    if (!dist)

        os->pflags |= AV_PKT_FLAG_KEY;

    if (dts)

        *dts = pts;

    return pts;

}

static int vp8_packet(AVFormatContext *s, int idx)

{

    struct ogg *ogg = s->priv_data;

    struct ogg_stream *os = ogg->streams + idx;

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

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

        !(os->flags & OGG_FLAG_EOS)) {

        int seg;

        int duration;

        uint8_t *last_pkt = p;

        uint8_t *next_pkt;

        seg = os->segp;

        duration = (last_pkt[0] >> 4) & 1;

        next_pkt = last_pkt += os->psize;

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

            if (os->segments[seg] < 255) {

                duration += (last_pkt[0] >> 4) & 1;

                last_pkt  = next_pkt + os->segments[seg];

            }

            next_pkt += os->segments[seg];

        }

        os->lastpts =

        os->lastdts = vp8_gptopts(s, idx, os->granule, NULL) - duration;

        if(s->streams[idx]->start_time == AV_NOPTS_VALUE) {

            s->streams[idx]->start_time = os->lastpts;

            if (s->streams[idx]->duration && s->streams[idx]->duration != AV_NOPTS_VALUE)

                s->streams[idx]->duration -= s->streams[idx]->start_time;

        }

    }

    if (os->psize > 0)

        os->pduration = (p[0] >> 4) & 1;

    return 0;

}

const struct ogg_codec ff_vp8_codec = {

    .magic     = "OVP80",

    .magicsize = 5,

    .header    = vp8_header,

    .packet    = vp8_packet,

    .gptopts   = vp8_gptopts,

    .nb_header = 1,

};