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#include "avc.h"
26
27static const uint8_t *ff_avc_find_startcode_internal(const uint8_t *p, const uint8_t *end)
28{
29    const uint8_t *a = p + 4 - ((intptr_t)p & 3);
30
31    for (end -= 3; p < a && p < end; p++) {
32        if (p[0] == 0 && p[1] == 0 && p[2] == 1)
33            return p;
34    }
35
36    for (end -= 3; p < end; p += 4) {
37        uint32_t x = *(const uint32_t*)p;
38//      if ((x - 0x01000100) & (~x) & 0x80008000) // little endian
39//      if ((x - 0x00010001) & (~x) & 0x00800080) // big endian
40        if ((x - 0x01010101) & (~x) & 0x80808080) { // generic
41            if (p[1] == 0) {
42                if (p[0] == 0 && p[2] == 1)
43                    return p;
44                if (p[2] == 0 && p[3] == 1)
45                    return p+1;
46            }
47            if (p[3] == 0) {
48                if (p[2] == 0 && p[4] == 1)
49                    return p+2;
50                if (p[4] == 0 && p[5] == 1)
51                    return p+3;
52            }
53        }
54    }
55
56    for (end += 3; p < end; p++) {
57        if (p[0] == 0 && p[1] == 0 && p[2] == 1)
58            return p;
59    }
60
61    return end + 3;
62}
63
64const uint8_t *ff_avc_find_startcode(const uint8_t *p, const uint8_t *end){
65    const uint8_t *out= ff_avc_find_startcode_internal(p, end);
66    if(p<out && out<end && !out[-1]) out--;
67    return out;
68}
69
70int ff_avc_parse_nal_units(AVIOContext *pb, const uint8_t *buf_in, int size)
71{
72    const uint8_t *p = buf_in;
73    const uint8_t *end = p + size;
74    const uint8_t *nal_start, *nal_end;
75
76    size = 0;
77    nal_start = ff_avc_find_startcode(p, end);
78    for (;;) {
79        while (nal_start < end && !*(nal_start++));
80        if (nal_start == end)
81            break;
82
83        nal_end = ff_avc_find_startcode(nal_start, end);
84        avio_wb32(pb, nal_end - nal_start);
85        avio_write(pb, nal_start, nal_end - nal_start);
86        size += 4 + nal_end - nal_start;
87        nal_start = nal_end;
88    }
89    return size;
90}
91
92int ff_avc_parse_nal_units_buf(const uint8_t *buf_in, uint8_t **buf, int *size)
93{
94    AVIOContext *pb;
95    int ret = avio_open_dyn_buf(&pb);
96    if(ret < 0)
97        return ret;
98
99    ff_avc_parse_nal_units(pb, buf_in, *size);
100
101    av_freep(buf);
102    *size = avio_close_dyn_buf(pb, buf);
103    return 0;
104}
105
106int ff_isom_write_avcc(AVIOContext *pb, const uint8_t *data, int len)
107{
108    if (len > 6) {
109        /* check for h264 start code */
110        if (AV_RB32(data) == 0x00000001 ||
111            AV_RB24(data) == 0x000001) {
112            uint8_t *buf=NULL, *end, *start;
113            uint32_t sps_size=0, pps_size=0;
114            uint8_t *sps=0, *pps=0;
115
116            int ret = ff_avc_parse_nal_units_buf(data, &buf, &len);
117            if (ret < 0)
118                return ret;
119            start = buf;
120            end = buf + len;
121
122            /* look for sps and pps */
123            while (end - buf > 4) {
124                uint32_t size;
125                uint8_t nal_type;
126                size = FFMIN(AV_RB32(buf), end - buf - 4);
127                buf += 4;
128                nal_type = buf[0] & 0x1f;
129
130                if (nal_type == 7) { /* SPS */
131                    sps = buf;
132                    sps_size = size;
133                } else if (nal_type == 8) { /* PPS */
134                    pps = buf;
135                    pps_size = size;
136                }
137
138                buf += size;
139            }
140
141            if (!sps || !pps || sps_size < 4 || sps_size > UINT16_MAX || pps_size > UINT16_MAX)
142                return AVERROR_INVALIDDATA;
143
144            avio_w8(pb, 1); /* version */
145            avio_w8(pb, sps[1]); /* profile */
146            avio_w8(pb, sps[2]); /* profile compat */
147            avio_w8(pb, sps[3]); /* level */
148            avio_w8(pb, 0xff); /* 6 bits reserved (111111) + 2 bits nal size length - 1 (11) */
149            avio_w8(pb, 0xe1); /* 3 bits reserved (111) + 5 bits number of sps (00001) */
150
151            avio_wb16(pb, sps_size);
152            avio_write(pb, sps, sps_size);
153            avio_w8(pb, 1); /* number of pps */
154            avio_wb16(pb, pps_size);
155            avio_write(pb, pps, pps_size);
156            av_free(start);
157        } else {
158            avio_write(pb, data, len);
159        }
160    }
161    return 0;
162}
163
164int ff_avc_write_annexb_extradata(const uint8_t *in, uint8_t **buf, int *size)
165{
166    uint16_t sps_size, pps_size;
167    uint8_t *out;
168    int out_size;
169
170    *buf = NULL;
171    if (*size >= 4 && (AV_RB32(in) == 0x00000001 || AV_RB24(in) == 0x000001))
172        return 0;
173    if (*size < 11 || in[0] != 1)
174        return AVERROR_INVALIDDATA;
175
176    sps_size = AV_RB16(&in[6]);
177    if (11 + sps_size > *size)
178        return AVERROR_INVALIDDATA;
179    pps_size = AV_RB16(&in[9 + sps_size]);
180    if (11 + sps_size + pps_size > *size)
181        return AVERROR_INVALIDDATA;
182    out_size = 8 + sps_size + pps_size;
183    out = av_mallocz(out_size);
184    if (!out)
185        return AVERROR(ENOMEM);
186    AV_WB32(&out[0], 0x00000001);
187    memcpy(out + 4, &in[8], sps_size);
188    AV_WB32(&out[4 + sps_size], 0x00000001);
189    memcpy(out + 8 + sps_size, &in[11 + sps_size], pps_size);
190    *buf = out;
191    *size = out_size;
192    return 0;
193}
194