Libav
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00001 /* 00002 * AVC helper functions for muxers 00003 * Copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@smartjog.com> 00004 * 00005 * This file is part of FFmpeg. 00006 * 00007 * FFmpeg is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * FFmpeg is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with FFmpeg; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 00022 #include "libavutil/intreadwrite.h" 00023 #include "avformat.h" 00024 #include "avio.h" 00025 #include "avc.h" 00026 00027 static const uint8_t *ff_avc_find_startcode_internal(const uint8_t *p, const uint8_t *end) 00028 { 00029 const uint8_t *a = p + 4 - ((intptr_t)p & 3); 00030 00031 for (end -= 3; p < a && p < end; p++) { 00032 if (p[0] == 0 && p[1] == 0 && p[2] == 1) 00033 return p; 00034 } 00035 00036 for (end -= 3; p < end; p += 4) { 00037 uint32_t x = *(const uint32_t*)p; 00038 // if ((x - 0x01000100) & (~x) & 0x80008000) // little endian 00039 // if ((x - 0x00010001) & (~x) & 0x00800080) // big endian 00040 if ((x - 0x01010101) & (~x) & 0x80808080) { // generic 00041 if (p[1] == 0) { 00042 if (p[0] == 0 && p[2] == 1) 00043 return p; 00044 if (p[2] == 0 && p[3] == 1) 00045 return p+1; 00046 } 00047 if (p[3] == 0) { 00048 if (p[2] == 0 && p[4] == 1) 00049 return p+2; 00050 if (p[4] == 0 && p[5] == 1) 00051 return p+3; 00052 } 00053 } 00054 } 00055 00056 for (end += 3; p < end; p++) { 00057 if (p[0] == 0 && p[1] == 0 && p[2] == 1) 00058 return p; 00059 } 00060 00061 return end + 3; 00062 } 00063 00064 const uint8_t *ff_avc_find_startcode(const uint8_t *p, const uint8_t *end){ 00065 const uint8_t *out= ff_avc_find_startcode_internal(p, end); 00066 if(p<out && out<end && !out[-1]) out--; 00067 return out; 00068 } 00069 00070 int ff_avc_parse_nal_units(ByteIOContext *pb, const uint8_t *buf_in, int size) 00071 { 00072 const uint8_t *p = buf_in; 00073 const uint8_t *end = p + size; 00074 const uint8_t *nal_start, *nal_end; 00075 00076 size = 0; 00077 nal_start = ff_avc_find_startcode(p, end); 00078 while (nal_start < end) { 00079 while(!*(nal_start++)); 00080 nal_end = ff_avc_find_startcode(nal_start, end); 00081 put_be32(pb, nal_end - nal_start); 00082 put_buffer(pb, nal_start, nal_end - nal_start); 00083 size += 4 + nal_end - nal_start; 00084 nal_start = nal_end; 00085 } 00086 return size; 00087 } 00088 00089 int ff_avc_parse_nal_units_buf(const uint8_t *buf_in, uint8_t **buf, int *size) 00090 { 00091 ByteIOContext *pb; 00092 int ret = url_open_dyn_buf(&pb); 00093 if(ret < 0) 00094 return ret; 00095 00096 ff_avc_parse_nal_units(pb, buf_in, *size); 00097 00098 av_freep(buf); 00099 *size = url_close_dyn_buf(pb, buf); 00100 return 0; 00101 } 00102 00103 int ff_isom_write_avcc(ByteIOContext *pb, const uint8_t *data, int len) 00104 { 00105 if (len > 6) { 00106 /* check for h264 start code */ 00107 if (AV_RB32(data) == 0x00000001 || 00108 AV_RB24(data) == 0x000001) { 00109 uint8_t *buf=NULL, *end, *start; 00110 uint32_t sps_size=0, pps_size=0; 00111 uint8_t *sps=0, *pps=0; 00112 00113 int ret = ff_avc_parse_nal_units_buf(data, &buf, &len); 00114 if (ret < 0) 00115 return ret; 00116 start = buf; 00117 end = buf + len; 00118 00119 /* look for sps and pps */ 00120 while (buf < end) { 00121 unsigned int size; 00122 uint8_t nal_type; 00123 size = AV_RB32(buf); 00124 nal_type = buf[4] & 0x1f; 00125 if (nal_type == 7) { /* SPS */ 00126 sps = buf + 4; 00127 sps_size = size; 00128 } else if (nal_type == 8) { /* PPS */ 00129 pps = buf + 4; 00130 pps_size = size; 00131 } 00132 buf += size + 4; 00133 } 00134 assert(sps); 00135 assert(pps); 00136 00137 put_byte(pb, 1); /* version */ 00138 put_byte(pb, sps[1]); /* profile */ 00139 put_byte(pb, sps[2]); /* profile compat */ 00140 put_byte(pb, sps[3]); /* level */ 00141 put_byte(pb, 0xff); /* 6 bits reserved (111111) + 2 bits nal size length - 1 (11) */ 00142 put_byte(pb, 0xe1); /* 3 bits reserved (111) + 5 bits number of sps (00001) */ 00143 00144 put_be16(pb, sps_size); 00145 put_buffer(pb, sps, sps_size); 00146 put_byte(pb, 1); /* number of pps */ 00147 put_be16(pb, pps_size); 00148 put_buffer(pb, pps, pps_size); 00149 av_free(start); 00150 } else { 00151 put_buffer(pb, data, len); 00152 } 00153 } 00154 return 0; 00155 }