Intel C compiler warns on this assignment in this if(), probably
[libav.git] / libavcodec / h264_parser.c
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1/*
2 * H.26L/H.264/AVC/JVT/14496-10/... parser
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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20 */
21
22/**
23 * @file h264_parser.c
24 * H.264 / AVC / MPEG4 part10 parser.
25 * @author Michael Niedermayer <michaelni@gmx.at>
26 */
27
28#include "parser.h"
29#include "h264_parser.h"
30
31#include <assert.h>
32
33
34int ff_h264_find_frame_end(H264Context *h, const uint8_t *buf, int buf_size)
35{
36 int i;
37 uint32_t state;
38 ParseContext *pc = &(h->s.parse_context);
39//printf("first %02X%02X%02X%02X\n", buf[0], buf[1],buf[2],buf[3]);
40// mb_addr= pc->mb_addr - 1;
41 state= pc->state;
42 if(state>13)
43 state= 7;
44
45 for(i=0; i<buf_size; i++){
46 if(state==7){
47 for(; i<buf_size; i++){
48 if(!buf[i]){
49 state=2;
50 break;
51 }
52 }
53 }else if(state<=2){
54 if(buf[i]==1) state^= 5; //2->7, 1->4, 0->5
55 else if(buf[i]) state = 7;
56 else state>>=1; //2->1, 1->0, 0->0
57 }else if(state<=5){
58 int v= buf[i] & 0x1F;
59 if(v==7 || v==8 || v==9){
60 if(pc->frame_start_found){
61 i++;
62found:
63 pc->state=7;
64 pc->frame_start_found= 0;
65 return i-(state&5);
66 }
67 }else if(v==1 || v==2 || v==5){
68 if(pc->frame_start_found){
69 state+=8;
70 continue;
71 }else
72 pc->frame_start_found = 1;
73 }
74 state= 7;
75 }else{
76 if(buf[i] & 0x80)
77 goto found;
78 state= 7;
79 }
80 }
81 pc->state= state;
82 return END_NOT_FOUND;
83}
84
85static int h264_parse(AVCodecParserContext *s,
86 AVCodecContext *avctx,
87 const uint8_t **poutbuf, int *poutbuf_size,
88 const uint8_t *buf, int buf_size)
89{
90 H264Context *h = s->priv_data;
91 ParseContext *pc = &h->s.parse_context;
92 int next;
93
94 if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
95 next= buf_size;
96 }else{
97 next= ff_h264_find_frame_end(h, buf, buf_size);
98
99 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
100 *poutbuf = NULL;
101 *poutbuf_size = 0;
102 return buf_size;
103 }
104
105 if(next<0 && next != END_NOT_FOUND){
106 assert(pc->last_index + next >= 0 );
107 ff_h264_find_frame_end(h, &pc->buffer[pc->last_index + next], -next); //update state
108 }
109 }
110
111 *poutbuf = buf;
112 *poutbuf_size = buf_size;
113 return next;
114}
115
116static int h264_split(AVCodecContext *avctx,
117 const uint8_t *buf, int buf_size)
118{
119 int i;
120 uint32_t state = -1;
121 int has_sps= 0;
122
123 for(i=0; i<=buf_size; i++){
124 if((state&0xFFFFFF1F) == 0x107)
125 has_sps=1;
126/* if((state&0xFFFFFF1F) == 0x101 || (state&0xFFFFFF1F) == 0x102 || (state&0xFFFFFF1F) == 0x105){
127 }*/
128 if((state&0xFFFFFF00) == 0x100 && (state&0xFFFFFF1F) != 0x107 && (state&0xFFFFFF1F) != 0x108 && (state&0xFFFFFF1F) != 0x109){
129 if(has_sps){
130 while(i>4 && buf[i-5]==0) i--;
131 return i-4;
132 }
133 }
134 if (i<buf_size)
135 state= (state<<8) | buf[i];
136 }
137 return 0;
138}
139
140
141AVCodecParser h264_parser = {
142 { CODEC_ID_H264 },
143 sizeof(H264Context),
144 NULL,
145 h264_parse,
146 ff_parse_close,
147 h264_split,
148};