/*

 * 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/opt.h"

#include "libavcodec/apv.h"

#include "libavcodec/bytestream.h"

#include "avformat.h"

#include "avio_internal.h"

#include "demux.h"

#include "internal.h"

typedef struct APVDemuxerContext {

    const AVClass *class;     /**< Class for private options. */

    AVRational framerate;    /**< AVRational describing framerate, set by a private option. */

} APVDemuxerContext;

typedef struct APVHeaderInfo {

    uint8_t  pbu_type;

    uint16_t group_id;

    uint8_t  profile_idc;

    uint8_t  level_idc;

    uint8_t  band_idc;

    int      frame_width;

    int      frame_height;

    uint8_t  bit_depth_minus8;

} APVHeaderInfo;

static int apv_extract_header_info(GetByteContext *gbc)

{

    APVHeaderInfo header, *info = &header;

    int zero, byte;

    info->pbu_type = bytestream2_get_byte(gbc);

    info->group_id = bytestream2_get_be16(gbc);

    zero = bytestream2_get_byte(gbc);

    if (zero != 0)

        return AVERROR_INVALIDDATA;

    if (info->pbu_type == APV_PBU_ACCESS_UNIT_INFORMATION) {

        unsigned int num_frames = bytestream2_get_be16(gbc);

        if (num_frames < 1)

            return AVERROR_INVALIDDATA;

        info->pbu_type = bytestream2_get_byte(gbc);

        if (info->pbu_type != APV_PBU_PRIMARY_FRAME &&

            info->pbu_type != APV_PBU_NON_PRIMARY_FRAME &&

            (info->pbu_type < APV_PBU_PREVIEW_FRAME || info->pbu_type > APV_PBU_ALPHA_FRAME))

            return AVERROR_INVALIDDATA;

        bytestream2_skip(gbc, 2); // group_id

        zero = bytestream2_get_byte(gbc);

        if (zero != 0)

            return AVERROR_INVALIDDATA;

    } else if (info->pbu_type != APV_PBU_PRIMARY_FRAME)

        return AVERROR_INVALIDDATA;

    info->profile_idc = bytestream2_get_byte(gbc);

    info->level_idc   = bytestream2_get_byte(gbc);

    byte = bytestream2_get_byte(gbc);

    info->band_idc = byte >> 3;

    zero = byte & 7;

    if (zero != 0)

        return AVERROR_INVALIDDATA;

    info->frame_width  = bytestream2_get_be24(gbc);

    info->frame_height = bytestream2_get_be24(gbc);

    if (info->frame_width  < 1 || info->frame_width  > 65536 ||

        info->frame_height < 1 || info->frame_height > 65536)

        return AVERROR_INVALIDDATA;

    byte = bytestream2_get_byte(gbc);

    info->bit_depth_minus8  = byte & 0xf;

    if (info->bit_depth_minus8 > 8) {

        return AVERROR_INVALIDDATA;

    }

    if (info->bit_depth_minus8 % 2) {

        // Odd bit depths are technically valid but not useful here.

        return AVERROR_INVALIDDATA;

    }

    // Ignore capture_time_distance.

    bytestream2_skip(gbc, 1);

    zero = bytestream2_get_byte(gbc);

    if (zero != 0)

        return AVERROR_INVALIDDATA;

    return 1;

}

static int apv_probe(const AVProbeData *p)

{

    GetByteContext gbc;

    uint32_t au_size, signature, pbu_size;

    int err;

    if (p->buf_size < 28) {

        // Too small to fit an APV header.

        return 0;

    }

    bytestream2_init(&gbc, p->buf, p->buf_size);

    au_size = bytestream2_get_be32(&gbc);

    if (au_size < 24) {

        // Too small.

        return 0;

    }

    signature = bytestream2_get_be32(&gbc);

    if (signature != APV_SIGNATURE) {

        // Signature is mandatory.

        return 0;

    }

    pbu_size = bytestream2_get_be32(&gbc);

    if (pbu_size < 16) {

        // Too small.

        return 0;

    }

    err = apv_extract_header_info(&gbc);

    if (err < 0) {

        // Header does not look like APV.

        return 0;

    }

    return AVPROBE_SCORE_MAX;

}

static int apv_read_header(AVFormatContext *s)

{

    APVDemuxerContext *apv = s->priv_data;

    AVStream *st;

    GetByteContext gbc;

    uint8_t buffer[12];

    uint32_t au_size, signature, pbu_size;

    int err, size;

    err = ffio_ensure_seekback(s->pb, sizeof(buffer));

    if (err < 0)

        return err;

    size = ffio_read_size(s->pb, buffer, sizeof(buffer));

    if (size < 0)

        return size;

    bytestream2_init(&gbc, buffer, sizeof(buffer));

    au_size = bytestream2_get_be32(&gbc);

    if (au_size < 24) {

        // Too small.

        return AVERROR_INVALIDDATA;

    }

    signature = bytestream2_get_be32(&gbc);

    if (signature != APV_SIGNATURE) {

        // Signature is mandatory.

        return AVERROR_INVALIDDATA;

    }

    pbu_size = bytestream2_get_be32(&gbc);

    if (pbu_size < 16) {

        // Too small.

        return AVERROR_INVALIDDATA;

    }

    st = avformat_new_stream(s, NULL);

    if (!st)

        return AVERROR(ENOMEM);

    st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;

    st->codecpar->codec_id   = AV_CODEC_ID_APV;

    ffstream(st)->need_parsing = AVSTREAM_PARSE_HEADERS;

    st->avg_frame_rate = apv->framerate;

    avpriv_set_pts_info(st, 64, apv->framerate.den, apv->framerate.num);

    avio_seek(s->pb, -size, SEEK_CUR);

    return 0;

}

static int apv_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    uint32_t au_size, signature;

    int ret;

    au_size = avio_rb32(s->pb);

    if (au_size == 0 && avio_feof(s->pb))

        return AVERROR_EOF;

    if (au_size < 24 || au_size > 1 << 26) {

        av_log(s, AV_LOG_ERROR,

               "APV AU has invalid size: %"PRIu32"\n", au_size);

        return AVERROR_INVALIDDATA;

    }

    ret = av_get_packet(s->pb, pkt, au_size);

    if (ret < 0)

        return ret;

    pkt->pos  -= 4;

    pkt->flags = AV_PKT_FLAG_KEY;

    signature = AV_RB32(pkt->data);

    if (signature != APV_SIGNATURE) {

        av_log(s, AV_LOG_ERROR, "APV AU has invalid signature.\n");

        return AVERROR_INVALIDDATA;

    }

    return 0;

}

#define OFFSET(x) offsetof(APVDemuxerContext, x)

#define DEC AV_OPT_FLAG_DECODING_PARAM

static const AVOption apv_options[] = {

    { "framerate", "set frame rate", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, { .str = "30" }, 0, INT_MAX, DEC },

    { NULL },

};

static const AVClass apv_demuxer_class = {

    .class_name = "apv demuxer",

    .item_name  = av_default_item_name,

    .option     = apv_options,

    .version    = LIBAVUTIL_VERSION_INT,

};

const FFInputFormat ff_apv_demuxer = {

    .p.name         = "apv",

    .p.long_name    = NULL_IF_CONFIG_SMALL("APV raw bitstream"),

    .p.extensions   = "apv",

    .p.flags        = AVFMT_GENERIC_INDEX | AVFMT_NOTIMESTAMPS,

    .p.priv_class   = &apv_demuxer_class,

    .priv_data_size = sizeof(APVDemuxerContext),

    .read_probe     = apv_probe,

    .read_header    = apv_read_header,

    .read_packet    = apv_read_packet,

};