/*

 * AVS3-P2/IEEE1857.10 video parser.

 * Copyright (c) 2020 Zhenyu Wang <wangzhenyu@pkusz.edu.cn>

 *                    Bingjie Han <hanbj@pkusz.edu.cn>

 *                    Huiwen Ren  <hwrenx@gmail.com>

 *

 * 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 "avs3.h"

#include "get_bits.h"

#include "parser.h"

#include "parser_internal.h"

static int avs3_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)

{

    int pic_found  = pc->frame_start_found;

    uint32_t state = pc->state;

    int cur = 0;

    if (!pic_found) {

        for (; cur < buf_size; ++cur) {

            state = (state << 8) | buf[cur];

            if (AVS3_ISPIC(buf[cur])){

                cur++;

                pic_found = 1;

                break;

            }

        }

    }

    if (pic_found) {

        if (!buf_size)

            return END_NOT_FOUND;

        for (; cur < buf_size; ++cur) {

            state = (state << 8) | buf[cur];

            if ((state & 0xFFFFFF00) == 0x100 && AVS3_ISUNIT(state & 0xFF)) {

                pc->frame_start_found = 0;

                pc->state = -1;

                return cur - 3;

            }

        }

    }

    pc->frame_start_found = pic_found;

    pc->state = state;

    return END_NOT_FOUND;

}

static void parse_avs3_nal_units(AVCodecParserContext *s, const uint8_t *buf,

                           int buf_size, AVCodecContext *avctx)

{

    if (buf_size < 5) {

        return;

    }

    if (buf[0] == 0x0 && buf[1] == 0x0 && buf[2] == 0x1) {

        if (buf[3] == AVS3_SEQ_START_CODE) {

            GetBitContext gb;

            int profile, ratecode, low_delay;

            av_unused int ret = init_get_bits(&gb, buf + 4, 100);

            av_assert1(ret >= 0);

            s->key_frame = 1;

            s->pict_type = AV_PICTURE_TYPE_I;

            profile = get_bits(&gb, 8);

            // Skip bits: level(8)

            //            progressive(1)

            //            field(1)

            //            library(2)

            //            resv(1)

            //            width(14)

            //            resv(1)

            //            height(14)

            //            chroma(2)

            //            sampe_precision(3)

            skip_bits(&gb, 47);

            if (profile == AVS3_PROFILE_BASELINE_MAIN10) {

                int sample_precision = get_bits(&gb, 3);

                if (sample_precision == 1) {

                    avctx->pix_fmt = AV_PIX_FMT_YUV420P;

                } else if (sample_precision == 2) {

                    avctx->pix_fmt = AV_PIX_FMT_YUV420P10;

                } else {

                    avctx->pix_fmt = AV_PIX_FMT_NONE;

                }

            }

            // Skip bits: resv(1)

            //            aspect(4)

            skip_bits(&gb, 5);

            ratecode = get_bits(&gb, 4);

            // Skip bits: resv(1)

            //            bitrate_low(18)

            //            resv(1)

            //            bitrate_high(12)

            skip_bits(&gb, 32);

            low_delay = get_bits(&gb, 1);

            avctx->has_b_frames = FFMAX(avctx->has_b_frames, !low_delay);

            avctx->framerate.num = ff_avs3_frame_rate_tab[ratecode].num;

            avctx->framerate.den = ff_avs3_frame_rate_tab[ratecode].den;

            s->width  = s->coded_width = avctx->width;

            s->height = s->coded_height = avctx->height;

            av_log(avctx, AV_LOG_DEBUG,

                   "AVS3 parse seq HDR: profile %d; coded size: %dx%d; frame rate code: %d\n",

                   profile, avctx->width, avctx->height, ratecode);

        } else if (buf[3] == AVS3_INTRA_PIC_START_CODE) {

            s->key_frame = 1;

            s->pict_type = AV_PICTURE_TYPE_I;

        } else if (buf[3] == AVS3_INTER_PIC_START_CODE){

            s->key_frame = 0;

            if (buf_size > 9) {

                int pic_code_type = buf[8] & 0x3;

                if (pic_code_type == 1 || pic_code_type == 3) {

                    s->pict_type = AV_PICTURE_TYPE_P;

                } else {

                    s->pict_type = AV_PICTURE_TYPE_B;

                }

            }

        }

    }

}

static int avs3_parse(AVCodecParserContext *s, AVCodecContext *avctx,

                      const uint8_t **poutbuf, int *poutbuf_size,

                      const uint8_t *buf, int buf_size)

{

    ParseContext *pc = s->priv_data;

    int next;

    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES)  {

        next = buf_size;

    } else {

        next = avs3_find_frame_end(pc, buf, buf_size);

        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {

            *poutbuf = NULL;

            *poutbuf_size = 0;

            return buf_size;

        }

    }

    parse_avs3_nal_units(s, buf, buf_size, avctx);

    *poutbuf = buf;

    *poutbuf_size = buf_size;

    return next;

}

const FFCodecParser ff_avs3_parser = {

    PARSER_CODEC_LIST(AV_CODEC_ID_AVS3),

    .priv_data_size = sizeof(ParseContext),

    .parse          = avs3_parse,

    .close          = ff_parse_close,

};