/*

 * Chinese AVS video (AVS1-P2, JiZhun profile) parser.

 * Copyright (c) 2006  Stefan Gehrer <stefan.gehrer@gmx.de>

 *

 * 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

 */

/**

 * @file

 * Chinese AVS video (AVS1-P2, JiZhun profile) parser

 * @author Stefan Gehrer <stefan.gehrer@gmx.de>

 */

#include "parser.h"

#include "cavs.h"

#include "get_bits.h"

#include "mpeg12data.h"

#include "parser_internal.h"

#include "startcode.h"

/**

 * Find the end of the current frame in the bitstream.

 * @return the position of the first byte of the next frame, or -1

 */

static int cavs_find_frame_end(ParseContext *pc, const uint8_t *buf,

                               int buf_size) {

    int pic_found, i;

    uint32_t state;

    pic_found= pc->frame_start_found;

    state= pc->state;

    i=0;

    if(!pic_found){

        for(i=0; i<buf_size; i++){

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

            if(state == PIC_I_START_CODE || state == PIC_PB_START_CODE){

                i++;

                pic_found=1;

                break;

            }

        }

    }

    if(pic_found){

        /* EOF considered as end of frame */

        if (buf_size == 0)

            return 0;

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

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

            if (state == PIC_I_START_CODE || state == PIC_PB_START_CODE ||

                    state == CAVS_START_CODE) {

                pc->frame_start_found=0;

                pc->state=-1;

                return i-3;

            }

        }

    }

    pc->frame_start_found= pic_found;

    pc->state= state;

    return END_NOT_FOUND;

}

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

                            GetBitContext *gb)

{

    int frame_rate_code;

    int width, height;

    int mb_width, mb_height;

    skip_bits(gb, 8); // profile

    skip_bits(gb, 8); // level

    skip_bits1(gb);   // progressive sequence

    width  = get_bits(gb, 14);

    height = get_bits(gb, 14);

    if (width <= 0 || height <= 0) {

        av_log(avctx, AV_LOG_ERROR, "Dimensions invalid\n");

        return AVERROR_INVALIDDATA;

    }

    mb_width  = (width  + 15) >> 4;

    mb_height = (height + 15) >> 4;

    skip_bits(gb, 2); // chroma format

    skip_bits(gb, 3); // sample_precision

    skip_bits(gb, 4); // aspect_ratio

    frame_rate_code = get_bits(gb, 4);

    if (frame_rate_code == 0 || frame_rate_code > 13) {

        av_log(avctx, AV_LOG_WARNING,

               "frame_rate_code %d is invalid\n", frame_rate_code);

        frame_rate_code = 1;

    }

    skip_bits(gb, 18); // bit_rate_lower

    skip_bits1(gb);    // marker_bit

    skip_bits(gb, 12); // bit_rate_upper

    skip_bits1(gb);    // low_delay

    s->width  = width;

    s->height = height;

    s->coded_width  = 16 * mb_width;

    s->coded_height = 16 * mb_height;

    avctx->framerate = ff_mpeg12_frame_rate_tab[frame_rate_code];

    return 0;

}

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

                            const uint8_t *buf, int buf_size)

{

    GetBitContext gb;

    const uint8_t *buf_end;

    const uint8_t *buf_ptr;

    uint32_t stc = -1;

    s->key_frame = 0;

    s->pict_type = AV_PICTURE_TYPE_NONE;

    if (buf_size == 0)

        return 0;

    buf_ptr = buf;

    buf_end = buf + buf_size;

    for (;;) {

        buf_ptr = avpriv_find_start_code(buf_ptr, buf_end, &stc);

        if ((stc & 0xFFFFFE00) || buf_ptr == buf_end)

            return 0;

        switch (stc) {

        case CAVS_START_CODE:

            if (init_get_bits8(&gb, buf_ptr, buf_end - buf_ptr) < 0)

                return 0;

            parse_seq_header(s, avctx, &gb);

            break;

        case PIC_I_START_CODE:

            s->key_frame = 1;

            s->pict_type = AV_PICTURE_TYPE_I;

            break;

        default:

            break;

        }

    }

}

static int cavsvideo_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= cavs_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;

        }

    }

    cavs_parse_frame(s, avctx, buf, buf_size);

    *poutbuf = buf;

    *poutbuf_size = buf_size;

    return next;

}

const FFCodecParser ff_cavsvideo_parser = {

    PARSER_CODEC_LIST(AV_CODEC_ID_CAVS),

    .priv_data_size = sizeof(ParseContext),

    .parse          = cavsvideo_parse,

    .close          = ff_parse_close,

};