Statistics
| Branch: | Revision:

ffmpeg / libavformat / avc.c @ bd51c013

History | View | Annotate | Download (4.59 KB)

1
/*
2
 * AVC helper functions for muxers
3
 * Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com>
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
20
 */
21

    
22
#include "libavutil/intreadwrite.h"
23
#include "avformat.h"
24
#include "avio.h"
25

    
26
const uint8_t *ff_avc_find_startcode(const uint8_t *p, const uint8_t *end)
27
{
28
    const uint8_t *a = p + 4 - ((long)p & 3);
29

    
30
    for( end -= 3; p < a && p < end; p++ ) {
31
        if( p[0] == 0 && p[1] == 0 && p[2] == 1 )
32
            return p;
33
    }
34

    
35
    for( end -= 3; p < end; p += 4 ) {
36
        uint32_t x = *(const uint32_t*)p;
37
//      if( (x - 0x01000100) & (~x) & 0x80008000 ) // little endian
38
//      if( (x - 0x00010001) & (~x) & 0x00800080 ) // big endian
39
        if( (x - 0x01010101) & (~x) & 0x80808080 ) { // generic
40
            if( p[1] == 0 ) {
41
                if( p[0] == 0 && p[2] == 1 )
42
                    return p-1;
43
                if( p[2] == 0 && p[3] == 1 )
44
                    return p;
45
            }
46
            if( p[3] == 0 ) {
47
                if( p[2] == 0 && p[4] == 1 )
48
                    return p+1;
49
                if( p[4] == 0 && p[5] == 1 )
50
                    return p+2;
51
            }
52
        }
53
    }
54

    
55
    for( end += 3; p < end; p++ ) {
56
        if( p[0] == 0 && p[1] == 0 && p[2] == 1 )
57
            return p;
58
    }
59

    
60
    return end + 3;
61
}
62

    
63
int ff_avc_parse_nal_units(ByteIOContext *pb, const uint8_t *buf_in, int size)
64
{
65
    const uint8_t *p = buf_in;
66
    const uint8_t *end = p + size;
67
    const uint8_t *nal_start, *nal_end;
68

    
69
    size = 0;
70
    nal_start = ff_avc_find_startcode(p, end);
71
    while (nal_start < end) {
72
        while(!*(nal_start++));
73
        nal_end = ff_avc_find_startcode(nal_start, end);
74
        put_be32(pb, nal_end - nal_start);
75
        put_buffer(pb, nal_start, nal_end - nal_start);
76
        size += 4 + nal_end - nal_start;
77
        nal_start = nal_end;
78
    }
79
    return size;
80
}
81

    
82
int ff_avc_parse_nal_units_buf(const uint8_t *buf_in, uint8_t **buf, int *size)
83
{
84
    ByteIOContext *pb;
85
    int ret = url_open_dyn_buf(&pb);
86
    if(ret < 0)
87
        return ret;
88

    
89
    ff_avc_parse_nal_units(pb, buf_in, *size);
90

    
91
    av_freep(buf);
92
    *size = url_close_dyn_buf(pb, buf);
93
    return 0;
94
}
95

    
96
int ff_isom_write_avcc(ByteIOContext *pb, const uint8_t *data, int len)
97
{
98
    if (len > 6) {
99
        /* check for h264 start code */
100
        if (AV_RB32(data) == 0x00000001 ||
101
            AV_RB24(data) == 0x000001) {
102
            uint8_t *buf=NULL, *end, *start;
103
            uint32_t sps_size=0, pps_size=0;
104
            uint8_t *sps=0, *pps=0;
105

    
106
            int ret = ff_avc_parse_nal_units_buf(data, &buf, &len);
107
            if (ret < 0)
108
                return ret;
109
            start = buf;
110
            end = buf + len;
111

    
112
            /* look for sps and pps */
113
            while (buf < end) {
114
                unsigned int size;
115
                uint8_t nal_type;
116
                size = AV_RB32(buf);
117
                nal_type = buf[4] & 0x1f;
118
                if (nal_type == 7) { /* SPS */
119
                    sps = buf + 4;
120
                    sps_size = size;
121
                } else if (nal_type == 8) { /* PPS */
122
                    pps = buf + 4;
123
                    pps_size = size;
124
                }
125
                buf += size + 4;
126
            }
127
            assert(sps);
128
            assert(pps);
129

    
130
            put_byte(pb, 1); /* version */
131
            put_byte(pb, sps[1]); /* profile */
132
            put_byte(pb, sps[2]); /* profile compat */
133
            put_byte(pb, sps[3]); /* level */
134
            put_byte(pb, 0xff); /* 6 bits reserved (111111) + 2 bits nal size length - 1 (11) */
135
            put_byte(pb, 0xe1); /* 3 bits reserved (111) + 5 bits number of sps (00001) */
136

    
137
            put_be16(pb, sps_size);
138
            put_buffer(pb, sps, sps_size);
139
            put_byte(pb, 1); /* number of pps */
140
            put_be16(pb, pps_size);
141
            put_buffer(pb, pps, pps_size);
142
            av_free(start);
143
        } else {
144
            put_buffer(pb, data, len);
145
        }
146
    }
147
    return 0;
148
}