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
26const 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
63int 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
82int 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
96int 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}
149