1/* 2 * AVC helper functions for muxers 3 * Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com> 4 * 5 * This file is part of Libav. 6 * 7 * Libav 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 * Libav 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 Libav; 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