视音频数据处理入门：AAC音频码流解析

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1. /**?
2. ?*?最简单的视音频数据处理示例?
3. ?*?Simplest?MediaData?Test?
4. ?*?
5. ?*?雷霄骅?Lei?Xiaohua?
6. ?*?leixiaohua1020@126.com?
7. ?*?中国传媒大学/数字电视技术?
8. ?*?Communication?University?of?China?/?Digital?TV?Technology?
9. ?*?http://blog.csdn.net/leixiaohua1020?
10. ?*?本项目包含如下几种视音频测试示例：?
11. ?*??(1)像素数据处理程序。包含RGB和YUV像素格式处理的函数。?
12. ?*??(2)音频采样数据处理程序。包含PCM音频采样格式处理的函数。?
13. ?*??(3)H.264码流分析程序。可以分离并解析NALU。?
14. ?*??(4)AAC码流分析程序。可以分离并解析ADTS帧。?
15. ?*??(5)FLV封装格式分析程序。可以将FLV中的MP3音频码流分离出来。?
16. ?*??(6)UDP-RTP协议分析程序。可以将分析UDP/RTP/MPEG-TS数据包。?
17. ?*?This?project?contains?following?samples?to?handling?multimedia?data:?
18. ?*??(1)?Video?pixel?data?handling?program.?It?contains?several?examples?to?handle?RGB?and?YUV?data.?
19. ?*??(2)?Audio?sample?data?handling?program.?It?contains?several?examples?to?handle?PCM?data.?
20. ?*??(3)?H.264?stream?analysis?program.?It?can?parse?H.264?bitstream?and?analysis?NALU?of?stream.?
21. ?*??(4)?AAC?stream?analysis?program.?It?can?parse?AAC?bitstream?and?analysis?ADTS?frame?of?stream.?
22. ?*??(5)?FLV?format?analysis?program.?It?can?analysis?FLV?file?and?extract?MP3?audio?stream.?
23. ?*??(6)?UDP-RTP?protocol?analysis?program.?It?can?analysis?UDP/RTP/MPEG-TS?Packet.?
24. ?*/??
25. #include?<stdio.h>??
26. #include?<stdlib.h>??
27. #include?<string.h>??
28. ??
29. ??
30. int?getADTSframe(unsigned?char*?buffer,?int?buf_size,?unsigned?char*?data?,int*?data_size){??
31. ????int?size?=?0;??
32. ????if(!buffer?||?!data?||?!data_size?){??
33. ????????return?-1;??
34. ????}??
35. while(1){??
36. if(buf_size??<?7?){??
37. ????????????return?-1;??
38. ????????}??
39. ????????//Sync?words??
40. if((buffer[0]?==?0xff)?&&?((buffer[1]?&?0xf0)?==?0xf0)?){??
41. ????????????size?|=?((buffer[3]?&?0x03)?<<11);?????//high?2?bit??
42. ????????????size?|=?buffer[4]<<3;????????????????//middle?8?bit??
43. ????????????size?|=?((buffer[5]?&?0xe0)>>5);????????//low?3bit??
44. ????????????break;??
45. ????????}??
46. ????????--buf_size;??
47. ????????++buffer;??
48. ????}??
49. ????if(buf_size?<?size){??
50. ????????return?1;??
51. ????memcpy(data,?buffer,?size);??
52. ????*data_size?=?size;??
53. return?0;??
54. }??
55. int?simplest_aac_parser(char?*url)??
56. {??
57. ????int?data_size?=?0;??
58. int?cnt=0;??
59. int?offset=0;??
60. ????//FILE?*myout=fopen("output_log.txt","wb+");??
61. FILE?*myout=stdout;??
62. ????unsigned?char?*aacframe=(unsigned?char?*)malloc(1024*5);??
63. ????unsigned?char?*aacbuffer=(unsigned?char?*)malloc(1024*1024);??
64. FILE?*ifile?=?fopen(url,?"rb");??
65. if(!ifile){??
66. ????????printf("Open?file?error");??
67. ????printf("-----+-?ADTS?Frame?Table?-+------+n");??
68. ????printf("?NUM?|?Profile?|?Frequency|?Size?|n");??
69. ????printf("-----+---------+----------+------+n");??
70. while(!feof(ifile)){??
71. ????????data_size?=?fread(aacbuffer+offset,?1,?1024*1024-offset,?ifile);??
72. ????????unsigned?char*?input_data?=?aacbuffer;??
73. while(1)??
74. ????????{??
75. ????????????int?ret=getADTSframe(input_data,?data_size,?aacframe,?&size);??
76. if(ret==-1){??
77. ????????????????break;??
78. ????????????}else?if(ret==1){??
79. ????????????????memcpy(aacbuffer,input_data,data_size);??
80. ????????????????offset=data_size;??
81. ????????????}??
82. ????????????char?profile_str[10]={0};??
83. char?frequence_str[10]={0};??
84. ????????????unsigned?char?profile=aacframe[2]&0xC0;??
85. ????????????profile=profile>>6;??
86. switch(profile){??
87. case?0:?sprintf(profile_str,"Main");case?1:?sprintf(profile_str,"LC");case?2:?sprintf(profile_str,"SSR");default:sprintf(profile_str,"unknown"); ????????????unsigned?char?sampling_frequency_index=aacframe[2]&0x3C;??
88. ????????????sampling_frequency_index=sampling_frequency_index>>2;??
89. switch(sampling_frequency_index){??
90. case?0:?sprintf(frequence_str,"96000Hz");case?1:?sprintf(frequence_str,"88200Hz");case?2:?sprintf(frequence_str,"64000Hz");case?3:?sprintf(frequence_str,"48000Hz");case?4:?sprintf(frequence_str,"44100Hz");case?5:?sprintf(frequence_str,"32000Hz");case?6:?sprintf(frequence_str,"24000Hz");case?7:?sprintf(frequence_str,"22050Hz");case?8:?sprintf(frequence_str,"16000Hz");case?9:?sprintf(frequence_str,"12000Hz");case?10:?sprintf(frequence_str,"11025Hz");case?11:?sprintf(frequence_str,"8000Hz");default:sprintf(frequence_str,248); line-height:18px; margin:0px!important; padding:0px 3px 0px 10px!important; list-style-position:outside!important"> ????????????fprintf(myout,"%5d|?%8s|??%8s|?%5d|n",cnt,profile_str?,frequence_str,size);??
91. ????????????data_size?-=?size;??
92. ????????????input_data?+=?size;??
93. ????????????cnt++;??
94. ????????}?????
95. ????fclose(ifile);??
96. ????free(aacbuffer);??
97. ????free(aacframe);??
98. return?0;??
99. }??

上文中的函数调用方法如下所示。

结果

本程序的输入为一个AAC原始码流（裸流）的文件路径，输出为该码流中ADTS frame的统计数据，如下图所示。

下载

Simplest mediadata test

项目主页
SourceForge：https://sourceforge.net/projects/simplest-mediadata-test/

Github：https://github.com/leixiaohua1020/simplest_mediadata_test

开源中国： http://git.oschina.net/leixiaohua1020/simplest_mediadata_test

CSDN下载地址： http://download.csdn.net/detail/leixiaohua1020/9422409
本项目包含如下几种视音频数据解析示例：
?(1)像素数据处理程序。包含RGB和YUV像素格式处理的函数。
?(2)音频采样数据处理程序。包含PCM音频采样格式处理的函数。
?(3)H.264码流分析程序。可以分离并解析NALU。
?(4)AAC码流分析程序。可以分离并解析ADTS帧。
?(5)FLV封装格式分析程序。可以将FLV中的MP3音频码流分离出来。
?(6)UDP-RTP协议分析程序。可以将分析UDP/RTP/MPEG-TS数据包。
雷霄骅 (Lei Xiaohua)
leixiaohua1020@126.com

http://blog.csdn.net/leixiaohua1020

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