/* * MPEG1 / MPEG2 video parser * Copyright (c) 2000,2001 Fabrice Bellard. * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at> * * 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 "parser.h"#include "mpegvideo.h"static void mpegvideo_extract_headers(AVCodecParserContext *s,                                      AVCodecContext *avctx,                                      const uint8_t *buf, int buf_size){    ParseContext1 *pc = s->priv_data;    const uint8_t *buf_end;    const uint8_t *buf_start= buf;    uint32_t start_code;    int frame_rate_index, ext_type, bytes_left;    int frame_rate_ext_n, frame_rate_ext_d;    int picture_structure, top_field_first, repeat_first_field, progressive_frame;    int horiz_size_ext, vert_size_ext, bit_rate_ext;//FIXME replace the crap with get_bits()    s->repeat_pict = 0;    buf_end = buf + buf_size;    while (buf < buf_end) {        start_code= -1;        buf= ff_find_start_code(buf, buf_end, &start_code);        bytes_left = buf_end - buf;        switch(start_code) {        case PICTURE_START_CODE:            ff_fetch_timestamp(s, buf-buf_start-4, 1);            if (bytes_left >= 2) {                s->pict_type = (buf[1] >> 3) & 7;            }            break;        case SEQ_START_CODE:            if (bytes_left >= 7) {                pc->width  = (buf[0] << 4) | (buf[1] >> 4);                pc->height = ((buf[1] & 0x0f) << 8) | buf[2];                avcodec_set_dimensions(avctx, pc->width, pc->height);                frame_rate_index = buf[3] & 0xf;                pc->frame_rate.den = avctx->time_base.den = ff_frame_rate_tab[frame_rate_index].num;                pc->frame_rate.num = avctx->time_base.num = ff_frame_rate_tab[frame_rate_index].den;                avctx->bit_rate = ((buf[4]<<10) | (buf[5]<<2) | (buf[6]>>6))*400;                avctx->codec_id = CODEC_ID_MPEG1VIDEO;                avctx->sub_id = 1;            }            break;        case EXT_START_CODE:            if (bytes_left >= 1) {                ext_type = (buf[0] >> 4);                switch(ext_type) {                case 0x1: /* sequence extension */                    if (bytes_left >= 6) {                        horiz_size_ext = ((buf[1] & 1) << 1) | (buf[2] >> 7);                        vert_size_ext = (buf[2] >> 5) & 3;                        bit_rate_ext = ((buf[2] & 0x1F)<<7) | (buf[3]>>1);                        frame_rate_ext_n = (buf[5] >> 5) & 3;                        frame_rate_ext_d = (buf[5] & 0x1f);                        pc->progressive_sequence = buf[1] & (1 << 3);                        avctx->has_b_frames= !(buf[5] >> 7);                        pc->width  |=(horiz_size_ext << 12);                        pc->height |=( vert_size_ext << 12);                        avctx->bit_rate += (bit_rate_ext << 18) * 400;                        avcodec_set_dimensions(avctx, pc->width, pc->height);                        avctx->time_base.den = pc->frame_rate.den * (frame_rate_ext_n + 1);                        avctx->time_base.num = pc->frame_rate.num * (frame_rate_ext_d + 1);                        avctx->codec_id = CODEC_ID_MPEG2VIDEO;                        avctx->sub_id = 2; /* forces MPEG2 */                    }                    break;                case 0x8: /* picture coding extension */                    if (bytes_left >= 5) {                        picture_structure = buf[2]&3;                        top_field_first = buf[3] & (1 << 7);                        repeat_first_field = buf[3] & (1 << 1);                        progressive_frame = buf[4] & (1 << 7);                        /* check if we must repeat the frame */                        if (repeat_first_field) {                            if (pc->progressive_sequence) {                                if (top_field_first)                                    s->repeat_pict = 4;                                else                                    s->repeat_pict = 2;                            } else if (progressive_frame) {                                s->repeat_pict = 1;                            }                        }                    }                    break;                }            }            break;        case -1:            goto the_end;        default:            /* we stop parsing when we encounter a slice. It ensures               that this function takes a negligible amount of time */            if (start_code >= SLICE_MIN_START_CODE &&                start_code <= SLICE_MAX_START_CODE)                goto the_end;            break;        }    } the_end: ;}static int mpegvideo_parse(AVCodecParserContext *s,                           AVCodecContext *avctx,                           const uint8_t **poutbuf, int *poutbuf_size,                           const uint8_t *buf, int buf_size){    ParseContext1 *pc1 = s->priv_data;    ParseContext *pc= &pc1->pc;    int next;    if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){        next= buf_size;    }else{        next= ff_mpeg1_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;        }    }    /* we have a full frame : we just parse the first few MPEG headers       to have the full timing information. The time take by this       function should be negligible for uncorrupted streams */    mpegvideo_extract_headers(s, avctx, buf, buf_size);#if 0    printf("pict_type=%d frame_rate=%0.3f repeat_pict=%d\n",           s->pict_type, (double)avctx->time_base.den / avctx->time_base.num, s->repeat_pict);#endif    *poutbuf = buf;    *poutbuf_size = buf_size;    return next;}static int mpegvideo_split(AVCodecContext *avctx,                           const uint8_t *buf, int buf_size){    int i;    uint32_t state= -1;    for(i=0; i<buf_size; i++){        state= (state<<8) | buf[i];        if(state != 0x1B3 && state != 0x1B5 && state < 0x200 && state >= 0x100)            return i-3;    }    return 0;}AVCodecParser mpegvideo_parser = {    { CODEC_ID_MPEG1VIDEO, CODEC_ID_MPEG2VIDEO },    sizeof(ParseContext1),    NULL,    mpegvideo_parse,    ff_parse1_close,};