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https://github.com/FFmpeg/FFmpeg.git
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e930b834a9
H.264 and mpeg12 parsers need to be adjusted at the same time to stop using the value of AVCodecContext.ticks_per_frame, because it is not set correctly unless the codec has been opened. Previously this would result in both the parser and lavf seeing the same incorrect value, which would cancel out. Updating lavf and not the parsers would result in correct value in lavf, but the wrong one in parsers, which would break some tests.
291 lines
11 KiB
C
291 lines
11 KiB
C
/*
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* MPEG-1 / MPEG-2 video parser
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* Copyright (c) 2000,2001 Fabrice Bellard
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* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/avassert.h"
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#include "decode.h"
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#include "parser.h"
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#include "mpeg12.h"
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#include "mpeg12data.h"
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#include "startcode.h"
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struct MpvParseContext {
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ParseContext pc;
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AVRational frame_rate;
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int progressive_sequence;
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int width, height;
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};
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/**
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* Find the end of the current frame in the bitstream.
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* @return the position of the first byte of the next frame, or -1
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*/
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static int mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf,
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int buf_size, AVCodecParserContext *s)
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{
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int i;
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uint32_t state = pc->state;
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/* EOF considered as end of frame */
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if (buf_size == 0)
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return 0;
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/*
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0 frame start -> 1/4
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1 first_SEQEXT -> 0/2
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2 first field start -> 3/0
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3 second_SEQEXT -> 2/0
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4 searching end
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*/
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for (i = 0; i < buf_size; i++) {
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av_assert1(pc->frame_start_found >= 0 && pc->frame_start_found <= 4);
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if (pc->frame_start_found & 1) {
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if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80)
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pc->frame_start_found--;
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else if (state == EXT_START_CODE + 2) {
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if ((buf[i] & 3) == 3)
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pc->frame_start_found = 0;
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else
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pc->frame_start_found = (pc->frame_start_found + 1) & 3;
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}
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state++;
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} else {
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i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1;
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if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) {
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i++;
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pc->frame_start_found = 4;
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}
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if (state == SEQ_END_CODE) {
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pc->frame_start_found = 0;
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pc->state = -1;
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return i + 1;
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}
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if (pc->frame_start_found == 2 && state == SEQ_START_CODE)
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pc->frame_start_found = 0;
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if (pc->frame_start_found < 4 && state == EXT_START_CODE)
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pc->frame_start_found++;
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if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) {
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if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) {
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pc->frame_start_found = 0;
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pc->state = -1;
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return i - 3;
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}
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}
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if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) {
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ff_fetch_timestamp(s, i - 3, 1, i > 3);
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}
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}
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}
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pc->state = state;
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return END_NOT_FOUND;
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}
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static void mpegvideo_extract_headers(AVCodecParserContext *s,
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AVCodecContext *avctx,
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const uint8_t *buf, int buf_size)
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{
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struct MpvParseContext *pc = s->priv_data;
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const uint8_t *buf_end = buf + buf_size;
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uint32_t start_code;
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int frame_rate_index, ext_type, bytes_left;
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int frame_rate_ext_n, frame_rate_ext_d;
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int top_field_first, repeat_first_field, progressive_frame;
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int horiz_size_ext, vert_size_ext, bit_rate_ext;
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int did_set_size=0;
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int set_dim_ret = 0;
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int bit_rate = 0;
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int vbv_delay = 0;
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int chroma_format;
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enum AVPixelFormat pix_fmt = AV_PIX_FMT_NONE;
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//FIXME replace the crap with get_bits()
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s->repeat_pict = 0;
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while (buf < buf_end) {
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start_code= -1;
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buf= avpriv_find_start_code(buf, buf_end, &start_code);
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bytes_left = buf_end - buf;
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switch(start_code) {
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case PICTURE_START_CODE:
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if (bytes_left >= 2) {
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s->pict_type = (buf[1] >> 3) & 7;
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if (bytes_left >= 4)
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vbv_delay = ((buf[1] & 0x07) << 13) | (buf[2] << 5) | (buf[3] >> 3);
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s->repeat_pict = 1;
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}
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break;
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case SEQ_START_CODE:
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if (bytes_left >= 7) {
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pc->width = (buf[0] << 4) | (buf[1] >> 4);
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pc->height = ((buf[1] & 0x0f) << 8) | buf[2];
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if(!avctx->width || !avctx->height || !avctx->coded_width || !avctx->coded_height){
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set_dim_ret = ff_set_dimensions(avctx, pc->width, pc->height);
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did_set_size=1;
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}
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pix_fmt = AV_PIX_FMT_YUV420P;
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frame_rate_index = buf[3] & 0xf;
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pc->frame_rate = avctx->framerate = ff_mpeg12_frame_rate_tab[frame_rate_index];
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bit_rate = (buf[4]<<10) | (buf[5]<<2) | (buf[6]>>6);
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avctx->codec_id = AV_CODEC_ID_MPEG1VIDEO;
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avctx->ticks_per_frame = 1;
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}
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break;
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case EXT_START_CODE:
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if (bytes_left >= 1) {
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ext_type = (buf[0] >> 4);
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switch(ext_type) {
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case 0x1: /* sequence extension */
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if (bytes_left >= 6) {
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horiz_size_ext = ((buf[1] & 1) << 1) | (buf[2] >> 7);
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vert_size_ext = (buf[2] >> 5) & 3;
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bit_rate_ext = ((buf[2] & 0x1F)<<7) | (buf[3]>>1);
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frame_rate_ext_n = (buf[5] >> 5) & 3;
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frame_rate_ext_d = (buf[5] & 0x1f);
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pc->progressive_sequence = buf[1] & (1 << 3);
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avctx->has_b_frames= !(buf[5] >> 7);
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chroma_format = (buf[1] >> 1) & 3;
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switch (chroma_format) {
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case 1: pix_fmt = AV_PIX_FMT_YUV420P; break;
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case 2: pix_fmt = AV_PIX_FMT_YUV422P; break;
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case 3: pix_fmt = AV_PIX_FMT_YUV444P; break;
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}
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pc->width = (pc->width & 0xFFF) | (horiz_size_ext << 12);
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pc->height = (pc->height& 0xFFF) | ( vert_size_ext << 12);
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bit_rate = (bit_rate&0x3FFFF) | (bit_rate_ext << 18);
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if(did_set_size)
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set_dim_ret = ff_set_dimensions(avctx, pc->width, pc->height);
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avctx->framerate.num = pc->frame_rate.num * (frame_rate_ext_n + 1);
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avctx->framerate.den = pc->frame_rate.den * (frame_rate_ext_d + 1);
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avctx->codec_id = AV_CODEC_ID_MPEG2VIDEO;
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avctx->ticks_per_frame = 2;
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}
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break;
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case 0x8: /* picture coding extension */
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if (bytes_left >= 5) {
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top_field_first = buf[3] & (1 << 7);
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repeat_first_field = buf[3] & (1 << 1);
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progressive_frame = buf[4] & (1 << 7);
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/* check if we must repeat the frame */
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if (repeat_first_field) {
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if (pc->progressive_sequence) {
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if (top_field_first)
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s->repeat_pict = 5;
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else
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s->repeat_pict = 3;
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} else if (progressive_frame) {
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s->repeat_pict = 2;
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}
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}
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if (!pc->progressive_sequence && !progressive_frame) {
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if (top_field_first)
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s->field_order = AV_FIELD_TT;
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else
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s->field_order = AV_FIELD_BB;
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} else
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s->field_order = AV_FIELD_PROGRESSIVE;
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}
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break;
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}
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}
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break;
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case -1:
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goto the_end;
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default:
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/* we stop parsing when we encounter a slice. It ensures
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that this function takes a negligible amount of time */
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if (start_code >= SLICE_MIN_START_CODE &&
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start_code <= SLICE_MAX_START_CODE)
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goto the_end;
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break;
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}
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}
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the_end:
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if (set_dim_ret < 0)
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av_log(avctx, AV_LOG_ERROR, "Failed to set dimensions\n");
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if (avctx->codec_id == AV_CODEC_ID_MPEG2VIDEO && bit_rate) {
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avctx->rc_max_rate = 400LL*bit_rate;
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}
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if (bit_rate &&
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((avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO && bit_rate != 0x3FFFF) || vbv_delay != 0xFFFF)) {
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avctx->bit_rate = 400LL*bit_rate;
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}
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if (pix_fmt != AV_PIX_FMT_NONE) {
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s->format = pix_fmt;
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s->width = pc->width;
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s->height = pc->height;
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s->coded_width = FFALIGN(pc->width, 16);
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s->coded_height = FFALIGN(pc->height, 16);
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}
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}
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static int mpegvideo_parse(AVCodecParserContext *s,
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AVCodecContext *avctx,
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const uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size)
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{
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struct MpvParseContext *pc1 = s->priv_data;
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ParseContext *pc= &pc1->pc;
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int next;
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if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
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next= buf_size;
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}else{
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next = mpeg1_find_frame_end(pc, buf, buf_size, s);
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if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
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*poutbuf = NULL;
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*poutbuf_size = 0;
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return buf_size;
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}
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}
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/* we have a full frame : we just parse the first few MPEG headers
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to have the full timing information. The time take by this
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function should be negligible for uncorrupted streams */
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mpegvideo_extract_headers(s, avctx, buf, buf_size);
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ff_dlog(NULL, "pict_type=%d frame_rate=%0.3f repeat_pict=%d\n",
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s->pict_type, av_q2d(avctx->framerate), s->repeat_pict);
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*poutbuf = buf;
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*poutbuf_size = buf_size;
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return next;
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}
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static int mpegvideo_parse_init(AVCodecParserContext *s)
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{
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s->pict_type = AV_PICTURE_TYPE_NONE; // first frame might be partial
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return 0;
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}
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const AVCodecParser ff_mpegvideo_parser = {
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.codec_ids = { AV_CODEC_ID_MPEG1VIDEO, AV_CODEC_ID_MPEG2VIDEO },
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.priv_data_size = sizeof(struct MpvParseContext),
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.parser_init = mpegvideo_parse_init,
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.parser_parse = mpegvideo_parse,
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.parser_close = ff_parse_close,
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};
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