diff options
Diffstat (limited to 'ffmpeg1/libavcodec/mpegvideo_parser.c')
| -rw-r--r-- | ffmpeg1/libavcodec/mpegvideo_parser.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/ffmpeg1/libavcodec/mpegvideo_parser.c b/ffmpeg1/libavcodec/mpegvideo_parser.c new file mode 100644 index 0000000..35a9160 --- /dev/null +++ b/ffmpeg1/libavcodec/mpegvideo_parser.c @@ -0,0 +1,208 @@ +/* + * 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" + +struct MpvParseContext { + ParseContext pc; + AVRational frame_rate; + int progressive_sequence; + int width, height; +}; + + +static void mpegvideo_extract_headers(AVCodecParserContext *s, + AVCodecContext *avctx, + const uint8_t *buf, int buf_size) +{ + struct MpvParseContext *pc = s->priv_data; + const uint8_t *buf_end = buf + buf_size; + uint32_t start_code; + int frame_rate_index, ext_type, bytes_left; + int frame_rate_ext_n, frame_rate_ext_d; + int top_field_first, repeat_first_field, progressive_frame; + int horiz_size_ext, vert_size_ext, bit_rate_ext; + int did_set_size=0; + int bit_rate = 0; + int vbv_delay = 0; +//FIXME replace the crap with get_bits() + s->repeat_pict = 0; + + while (buf < buf_end) { + start_code= -1; + buf= avpriv_mpv_find_start_code(buf, buf_end, &start_code); + bytes_left = buf_end - buf; + switch(start_code) { + case PICTURE_START_CODE: + if (bytes_left >= 2) { + s->pict_type = (buf[1] >> 3) & 7; + if (bytes_left >= 4) + vbv_delay = ((buf[1] & 0x07) << 13) | (buf[2] << 5) | (buf[3] >> 3); + } + 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]; + if(!avctx->width || !avctx->height || !avctx->coded_width || !avctx->coded_height){ + avcodec_set_dimensions(avctx, pc->width, pc->height); + did_set_size=1; + } + frame_rate_index = buf[3] & 0xf; + pc->frame_rate.den = avctx->time_base.den = ff_mpeg12_frame_rate_tab[frame_rate_index].num; + pc->frame_rate.num = avctx->time_base.num = ff_mpeg12_frame_rate_tab[frame_rate_index].den; + bit_rate = (buf[4]<<10) | (buf[5]<<2) | (buf[6]>>6); + avctx->codec_id = AV_CODEC_ID_MPEG1VIDEO; + } + 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); + bit_rate = (bit_rate&0x3FFFF) | (bit_rate_ext << 18); + if(did_set_size) + avcodec_set_dimensions(avctx, pc->width, pc->height); + avctx->time_base.den = pc->frame_rate.den * (frame_rate_ext_n + 1) * 2; + avctx->time_base.num = pc->frame_rate.num * (frame_rate_ext_d + 1); + avctx->codec_id = AV_CODEC_ID_MPEG2VIDEO; + } + break; + case 0x8: /* picture coding extension */ + if (bytes_left >= 5) { + 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 */ + s->repeat_pict = 1; + if (repeat_first_field) { + if (pc->progressive_sequence) { + if (top_field_first) + s->repeat_pict = 5; + else + s->repeat_pict = 3; + } else if (progressive_frame) { + s->repeat_pict = 2; + } + } + } + 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: ; + if (avctx->codec_id == AV_CODEC_ID_MPEG2VIDEO && bit_rate) { + avctx->rc_max_rate = 400*bit_rate; + } else if (avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO && bit_rate && + (bit_rate != 0x3FFFF || vbv_delay != 0xFFFF)) { + avctx->bit_rate = 400*bit_rate; + } +} + +static int mpegvideo_parse(AVCodecParserContext *s, + AVCodecContext *avctx, + const uint8_t **poutbuf, int *poutbuf_size, + const uint8_t *buf, int buf_size) +{ + struct MpvParseContext *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, s); + + 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); + av_dlog(NULL, "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); + + *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; + int found=0; + + for(i=0; i<buf_size; i++){ + state= (state<<8) | buf[i]; + if(state == 0x1B3){ + found=1; + }else if(found && state != 0x1B5 && state < 0x200 && state >= 0x100) + return i-3; + } + return 0; +} + +static int mpegvideo_parse_init(AVCodecParserContext *s) +{ + s->pict_type = AV_PICTURE_TYPE_NONE; // first frame might be partial + return 0; +} + +AVCodecParser ff_mpegvideo_parser = { + .codec_ids = { AV_CODEC_ID_MPEG1VIDEO, AV_CODEC_ID_MPEG2VIDEO }, + .priv_data_size = sizeof(struct MpvParseContext), + .parser_init = mpegvideo_parse_init, + .parser_parse = mpegvideo_parse, + .parser_close = ff_parse_close, + .split = mpegvideo_split, +}; |