ffmpeg Windows下采集摄像头一帧数据，并保存为bmp图片

柔光的暖阳◎ 2022-04-03 01:27 375阅读 0赞

这里请注意，在编译ffmpeg时，不要使用--disable-devices选项。

使用

\--enable-encoder=rawvideo  
\--enable-decoder=rawvideo

启用rawvideo codec。

代码如下：

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1.  \#include <stdlib.h>
2.  \#include <stdio.h>
3.  \#include <string.h>
4.  
5.  \#include <libavformat/avformat.h>
6.  \#include <libavcodec/avcodec.h>
7.  \#include <libavdevice/avdevice.h>
8.  \#include <libswscale/swscale.h>
9.  
10. \#include <windows.h>
11. 
12. \#include <time.h>
13. 
14. \#define MAX\_INPUT\_DEVICE\_NUM 10
15. 
16. \#ifdef \_WIN32
17. **int** strcasecmp(**const****char** \*s1, **const****char** \*s2) 
18. \{ 
19. **while** ((\*s1 != '\\0') 
20.  && (tolower(\*(unsigned **char** \*) s1) == 
21.  tolower(\*(unsigned **char** \*) s2))) 
22.  \{ 
23.  s1++; 
24.  s2++; 
25.  \} 
26. **return** tolower(\*(unsigned **char** \*) s1) - tolower(\*(unsigned **char** \*) s2); 
27. \} 
28. **int** strncasecmp(**const****char** \*s1, **const****char** \*s2, unsigned **int** n) 
29. \{ 
30. **if** (n == 0) 
31. **return** 0; 
32. **while** ((n-- != 0) 
33.  && (tolower(\*(unsigned **char** \*) s1) == 
34.  tolower(\*(unsigned **char** \*) s2))) \{ 
35. **if** (n == 0 || \*s1 == '\\0' || \*s2 == '\\0') 
36. **return** 0; 
37.  s1++; 
38.  s2++; 
39.  \} 
40. **return** tolower(\*(unsigned **char** \*) s1) - tolower(\*(unsigned **char** \*) s2); 
41. \} 
42. \#endif
43. 
44. **void** save\_bmp(unsigned **char** \* data,**int** data\_size,**int** w,**int** h,**FILE** \* out) 
45. \{ 
46. // 位图文件头
47.  BITMAPFILEHEADER bmpheader; 
48.  BITMAPINFO bmpinfo; 
49. **int** bit = 24; 
50. 
51.  bmpheader.bfType = ('M' <<8)|'B'; 
52.  bmpheader.bfReserved1 = 0; 
53.  bmpheader.bfReserved2 = 0; 
54.  bmpheader.bfOffBits = **sizeof**(BITMAPFILEHEADER) + **sizeof**(BITMAPINFOHEADER); 
55.  bmpheader.bfSize = bmpheader.bfOffBits + w\*h\*bit/8; 
56. 
57.  bmpinfo.bmiHeader.biSize = **sizeof**(BITMAPINFOHEADER); 
58.  bmpinfo.bmiHeader.biWidth = w; 
59.  bmpinfo.bmiHeader.biHeight = 0-h; 
60.  bmpinfo.bmiHeader.biPlanes = 1; 
61.  bmpinfo.bmiHeader.biBitCount = bit; 
62.  bmpinfo.bmiHeader.biCompression = BI\_RGB; 
63.  bmpinfo.bmiHeader.biSizeImage = 0; 
64.  bmpinfo.bmiHeader.biXPelsPerMeter = 100; 
65.  bmpinfo.bmiHeader.biYPelsPerMeter = 100; 
66.  bmpinfo.bmiHeader.biClrUsed = 0; 
67.  bmpinfo.bmiHeader.biClrImportant = 0; 
68. 
69.  fwrite(&bmpheader,**sizeof**(BITMAPFILEHEADER),1,out); 
70.  fwrite(&bmpinfo.bmiHeader,**sizeof**(BITMAPINFOHEADER),1,out); 
71.  fwrite(data,data\_size,1,out); 
72. \} 
73. **int** CaptureFromLocalCamera() 
74. \{ 
75.  AVFormatContext \*ic = NULL; 
76.  AVFormatParameters in\_fmt\_para=\{0\}; 
77.  AVPacket packet; 
78. **char** buffer\[MAX\_PATH\]=\{0\}; 
79. **int** width = 0,height = 0; 
80. **int** ret,video\_stream = -1,i=0; 
81. 
82. //查找输入（vfwcap）格式
83.  AVInputFormat \*in\_fmt = av\_find\_input\_format ("vfwcap"); 
84. **if** (in\_fmt == NULL) 
85.  \{ 
86.  printf("not support input device vfwcap.\\n"); 
87. **return** \-1; 
88.  \} 
89.  memset (&in\_fmt\_para, 0, **sizeof**(in\_fmt\_para)); 
90. //指定需要采集图像的高度
91.  in\_fmt\_para.height = height; 
92. //指定需要采集图像的宽度
93.  in\_fmt\_para.width = width; 
94. 
95. //设置帧率
96.  av\_parse\_video\_frame\_rate(&in\_fmt\_para.time\_base,"20"); 
97. 
98. //打开摄像头设备,从"0"到MAX\_INPUT\_DEVICE\_NUM依次尝试打开
99. **for**( i=0 ; i < MAX\_INPUT\_DEVICE\_NUM + 1; i++ ) 
100.  \{ 
101.  sprintf(buffer,"%d",i); 
102.  ret = av\_open\_input\_file ( &ic, buffer, in\_fmt,**sizeof**(in\_fmt\_para),&in\_fmt\_para); 
103. **if** ( ret == 0 && ic) 
104.  \{ 
105. **break**; 
106.  \} 
107.  \} 
108. //open success?
109. **if**(!ic || ret != 0) 
110.  \{ 
111. **if**(ic) 
112.  av\_close\_input\_file(ic); 
113.  printf("can not open input file.\\n"); 
114. **return** \-2; 
115.  \} 
116.  printf("input device no. is %d\\n",i); 
117. //find the video stream
118. **for**(i=0;i<ic ->nb\_streams;i++) 
119.  \{ 
120. **if** ( CODEC\_TYPE\_VIDEO == ic ->streams\[i\] ->codec ->codec\_type ) 
121.  \{ 
122.  video\_stream = i; 
123. **break**; 
124.  \} 
125.  \} 
126. **if**(video\_stream < 0) 
127.  \{ 
128.  av\_close\_input\_file(ic); 
129.  printf("can not find a video stream.\\n"); 
130. **return** \-3; 
131.  \} 
132. //获取视频时间宽度和高度
133.  width = ic ->streams\[video\_stream\] ->codec ->width; 
134.  height = ic ->streams\[video\_stream\] ->codec ->height; 
135.  printf("video size: %dx%d\\n",width,height); 
136. //从摄像头获取图像数据
137. **if**( 0 == av\_read\_frame(ic,&packet)) 
138.  \{ 
139. //find the decode codec
140.  AVCodec \* decodec = avcodec\_find\_decoder(ic ->streams\[video\_stream\] ->codec ->codec\_id); 
141. **if**(decodec) 
142.  \{ 
143. //open the decode codec
144. **if**( 0 == avcodec\_open(ic ->streams\[video\_stream\] ->codec,decodec) ) 
145.  \{ 
146. **int** got\_picture = 0; 
147.  AVFrame \* frame = avcodec\_alloc\_frame(); 
148.  avcodec\_decode\_video2(ic ->streams\[video\_stream\] ->codec,frame,&got\_picture,&packet); 
149. //decode success
150. **if**(got\_picture) 
151.  \{ 
152.  uint8\_t \* buffer = NULL; 
153. **size\_t** buffer\_size = 0; 
154. **struct** SwsContext \*pSwsCtx=NULL; 
155.  AVFrame \* rgb\_frame = avcodec\_alloc\_frame(); 
156.  buffer\_size = avpicture\_get\_size(PIX\_FMT\_BGR24,width,height); 
157.  buffer = (uint8\_t \*)av\_malloc(buffer\_size); 
158.  avpicture\_fill((AVPicture\*)rgb\_frame,(uint8\_t \*)buffer,PIX\_FMT\_BGR24,width,height); 
159. //get swscale ctx
160.  pSwsCtx = sws\_getContext( 
161.  ic ->streams\[video\_stream\] ->codec ->width, 
162.  ic ->streams\[video\_stream\] ->codec ->height, 
163.  ic ->streams\[video\_stream\] ->codec ->pix\_fmt, 
164.  width, 
165.  height, 
166.  PIX\_FMT\_BGR24, 
167.  SWS\_BILINEAR, 
168.  NULL, 
169.  NULL, 
170.  NULL); 
171. **if**(pSwsCtx) 
172.  \{ 
173. **FILE** \*fp = NULL; 
174.  SYSTEMTIME dt=\{0\}; 
175. //图像格式转换
176.  sws\_scale( 
177.  pSwsCtx, 
178.  frame ->data, 
179.  frame ->linesize, 
180.  0, 
181.  ic ->streams\[video\_stream\] ->codec ->height, 
182.  rgb\_frame ->data, 
183.  rgb\_frame ->linesize); 
184. //create the image file name
185.  GetLocalTime(&dt); 
186.  srand(0); 
187.  sprintf(buffer,"imgs/%04d\_%02d\_%02d %02d\_%02d\_%02d %02d.bmp",dt.wYear,dt.wMonth,dt.wDay,dt.wHour,dt.wMinute,dt.wSecond,rand()%30); 
188. //
189.  CreateDirectoryA("imgs",NULL); 
190. //open file
191.  fp = fopen(buffer, "wb"); 
192. **if**(fp) 
193.  \{ 
194.  save\_bmp(rgb\_frame ->data\[0\],rgb\_frame ->linesize\[0\]\*height,width,height,fp); 
195.  fclose(fp); 
196.  \} 
197. //free sws ctx
198.  sws\_freeContext(pSwsCtx); 
199.  \} 
200. //free buffer
201.  av\_free(rgb\_frame); 
202.  av\_free(buffer); 
203.  \} 
204. //free buffer
205.  av\_free(frame); 
206. //close the decode codec
207.  avcodec\_close(ic ->streams\[video\_stream\] ->codec); 
208.  \} 
209.  \} 
210.  \} 
211. 
212. //close the input device
213.  av\_close\_input\_file(ic); 
214. 
215. **return** 0; 
216. \} 
217. 
218. 
219. **int** main() 
220. \{ 
221. //avcodec\_init(); 
222.  avcodec\_register\_all(); 
223.  avdevice\_register\_all(); 
224.  CaptureFromLocalCamera(); 
225. 
226. **return** 0; 
227. \} 
228.

[view plain]: http://blog.csdn.net/zxwangyun/article/details/8191059#