1 /*
2 FFmpeg环境配置：
3 配置包含目录，库目录，附加依赖性
4 添加dll到工程debug文件下
5 */
6
7 /*
8 libavcodec encoding/decoding library
9 libavfilter graph-based frame editing library
10 libavformat I/O and muxing/demuxing library
11 libavdevice special devices muxing/demuxing library
12 libavutil common utility library
13 libswresample audio resampling, format conversion and mixing
14 libpostproc post processing library
15 libswscale color conversion and scaling library
16 */
17
18
19 #include <stdio.h>
20
21 extern "C" // 因为FFmpeg是纯C程序
22 {
23 // FFmpeg libraries
24 #include "libavcodec/avcodec.h"
25 #include "libavformat/avformat.h"
26 #include "libswscale/swscale.h"
27 };
28
29
30
31 //#define STEP1 // 视频文件解码为YUV420数据
32 #define STEP2 // YUV420P像素数据编码为JPEG图片
33
34
35 #ifdef STEP1
36
37 /////////////////////////////////////////////////////////////////////////////////////////
38 // 视频文件解码为YUV数据
39
40 int main(int argc, char* argv[])
41 {
42 AVFormatContext *pFormatCtx;
43 AVCodecContext *pCodecCtx;
44 AVCodec *pCodec;
45 AVFrame *pFrame, *pFrameYUV;
46 AVPacket *packet;
47 struct SwsContext *img_convert_ctx;
48 uint8_t *out_buffer;
49
50 int videoindex = -1;
51 int y_size;
52 int ret, got_picture;
53
54 char filepath[] = "video1.mkv";
55 FILE *fp_yuv = fopen("video1.yuv", "wb+");
56
57 av_register_all();
58 //avformat_network_init();
59 pFormatCtx = avformat_alloc_context();
60
61 if (avformat_open_input(&pFormatCtx, filepath, NULL, NULL) != 0)
62 {
63 printf("Couldn't open input stream.\n");
64 return -1;
65 }
66 if (avformat_find_stream_info(pFormatCtx, NULL) <0)
67 {
68 printf("Couldn't find stream information.\n");
69 return -1;
70 }
71
72 for (int i = 0; i < pFormatCtx->nb_streams; i++)
73 {
74 if (pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)
75 {
76 videoindex = i;
77 break;
78 }
79 }
80 if (videoindex == -1)
81 {
82 printf("Didn't find a video stream.\n");
83 return -1;
84 }
85
86 pCodecCtx = pFormatCtx->streams[videoindex]->codec;
87
88 // 根据编码器的ID查找FFmpeg的解码器
89 pCodec = avcodec_find_decoder(pCodecCtx->codec_id);
90 if (pCodec == NULL)
91 {
92 printf("Codec not found.\n");
93 return -1;
94 }
95 // 初始化一个视音频编解码器的AVCodecContext
96 if (avcodec_open2(pCodecCtx, pCodec, NULL)<0)
97 {
98 printf("Could not open codec.\n");
99 return -1;
100 }
101
102 // 一些内存分配
103 packet = (AVPacket *)av_malloc(sizeof(AVPacket));
104 pFrame = av_frame_alloc();
105 pFrameYUV = av_frame_alloc();
106 out_buffer = (uint8_t *)av_malloc(avpicture_get_size(AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height));
107 // 为已经分配空间的结构体AVPicture挂上一段用于保存数据的空间
108 // AVFrame/AVPicture有一个data[4]的数据字段,buffer里面存放的只是yuv这样排列的数据，
109 // 而经过fill 之后，会把buffer中的yuv分别放到data[0],data[1],data[2]中。
110 avpicture_fill((AVPicture *)pFrameYUV, out_buffer, AV_PIX_FMT_YUV420P, pCodecCtx->width, pCodecCtx->height);
111
112 //Output Info-----------------------------
113 printf("--------------- File Information ----------------\n");
114 av_dump_format(pFormatCtx, 0, filepath, 0);
115 printf("-------------------------------------------------\n");
116
117 // 初始化一个SwsContext
118 // 参数：源图像的宽，源图像的高，源图像的像素格式，目标图像的宽，目标图像的高，目标图像的像素格式，设定图像拉伸使用的算法
119 img_convert_ctx = sws_getContext(pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,
120 pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_YUV420P, SWS_BICUBIC, NULL, NULL, NULL);
121
122 while (av_read_frame(pFormatCtx, packet) >= 0)
123 {
124 if (packet->stream_index == videoindex)
125 {
126 // 解码一帧视频数据。输入一个压缩编码的结构体AVPacket，输出一个解码后的结构体AVFrame
127 ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);
128 if (ret < 0)
129 {
130 printf("Decode Error.\n");
131 return -1;
132 }
133 if (got_picture)
134 {
135 // 转换像素
136 sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,
137 pFrameYUV->data, pFrameYUV->linesize);
138
139 y_size = pCodecCtx->width * pCodecCtx->height;
140 // 向文件写入一个数据块
141 fwrite(pFrameYUV->data[0], 1, y_size, fp_yuv); //Y
142 fwrite(pFrameYUV->data[1], 1, y_size / 4, fp_yuv); //U
143 fwrite(pFrameYUV->data[2], 1, y_size / 4, fp_yuv); //V
144 //printf("Succeed to decode 1 frame!\n");
145
146 }
147 }
148 av_free_packet(packet);
149 }
150
151 //flush decoder
152 //FIX: Flush Frames remained in Codec
153 while (1)
154 {
155 ret = avcodec_decode_video2(pCodecCtx, pFrame, &got_picture, packet);
156 if (ret < 0)
157 break;
158 if (!got_picture)
159 break;
160 sws_scale(img_convert_ctx, (const uint8_t* const*)pFrame->data, pFrame->linesize, 0, pCodecCtx->height,
161 pFrameYUV->data, pFrameYUV->linesize);
162
163 int y_size = pCodecCtx->width*pCodecCtx->height;
164
165 fwrite(pFrameYUV->data[0], 1, y_size, fp_yuv); //Y
166 fwrite(pFrameYUV->data[1], 1, y_size / 4, fp_yuv); //U
167 fwrite(pFrameYUV->data[2], 1, y_size / 4, fp_yuv); //V
168 //printf("Flush Decoder: Succeed to decode 1 frame!\n");
169 }
170
171 sws_freeContext(img_convert_ctx);
172 fclose(fp_yuv);
173 av_frame_free(&pFrameYUV);
174 av_frame_free(&pFrame);
175 avcodec_close(pCodecCtx);
176 avformat_close_input(&pFormatCtx);
177
178 return 0;
179 }
180
181 #endif
182
183
184
185 #ifdef STEP2
186
187 /////////////////////////////////////////////////////////////////////////////////////////
188 // YUV420P像素数据编码为JPEG图片
189
190 int main(int argc, char* argv[])
191 {
192 AVFormatContext* pFormatCtx;
193 AVOutputFormat* fmt;
194 AVStream* video_st;
195 AVCodecContext* pCodecCtx;
196 AVCodec* pCodec;
197
198 uint8_t* picture_buf;
199 AVFrame* picture;
200 AVPacket pkt;
201 int y_size;
202 int got_picture = 0;
203 int size;
204 int ret = 0;
205 //int in_w = 480, in_h = 272;
206 int in_w = 720, in_h = 480;
207 int frame_num = 1;
208
209 FILE *in_file = NULL;
210 const char* out_file = "new1.jpg";
211
212 in_file = fopen("video1.yuv", "rb");
213
214 // 计算YUV420帧数量
215 const int WIDTH = 720;
216 const int HEIGHT = 480;
217 const int EachFrameSize = (int)(WIDTH*HEIGHT*1.5);
218 if (in_file == NULL)
219 {
220 printf("couldn't open file.\n");
221 return -1;
222 }
223 // 将文件指针移到文件末尾
224 fseek(in_file, 0, SEEK_END);
225 // 得到文件尾相对于文件首的位移，即文件的总字节数
226 // 该函数对大于2^31 -1文件，即2.1G以上的文件操作时可能出错
227 long total_size = ftell(in_file);
228 // 重置文件指针指向文件头部
229 rewind(in_file);
230
231 // size/(WIDTH*HEIGHT*1.5)可获得了yuv420文件的总帧数
232 long nFrame = total_size / EachFrameSize;
233 printf("该YUV420总帧数:%ld\n\n", nFrame);
234
235 printf("转换第几帧？ 请输入： ");
236 scanf("%d", &frame_num);
237 printf("\n");
238
239 fseek(in_file, (frame_num-1) * EachFrameSize, SEEK_SET);
240
241
242 av_register_all();
243 pFormatCtx = avformat_alloc_context();
244
245 // 返回一个已经注册的最合适的输出格式
246 fmt = av_guess_format("mjpeg", NULL, NULL);
247 pFormatCtx->oformat = fmt;
248
249 if (avio_open(&pFormatCtx->pb, out_file, AVIO_FLAG_READ_WRITE) < 0)
250 {
251 printf("Couldn't open output file.");
252 return -1;
253 }
254
255 // 上述更简单的方法：
256 //avformat_alloc_output_context2(&pFormatCtx, NULL, NULL, out_file);
257 //fmt = pFormatCtx->oformat;
258
259 video_st = avformat_new_stream(pFormatCtx, 0);
260 if (video_st == NULL)
261 {
262 return -1;
263 }
264 pCodecCtx = video_st->codec;
265 pCodecCtx->codec_id = fmt->video_codec;
266 pCodecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
267 pCodecCtx->pix_fmt = AV_PIX_FMT_YUVJ420P;
268
269 pCodecCtx->width = in_w;
270 pCodecCtx->height = in_h;
271
272 pCodecCtx->time_base.num = 1;
273 pCodecCtx->time_base.den = 25;
274
275 // Output some information
276 av_dump_format(pFormatCtx, 0, out_file, 1);
277
278 pCodec = avcodec_find_encoder(pCodecCtx->codec_id);
279 if (!pCodec)
280 {
281 printf("Codec not found.");
282 return -1;
283 }
284 if (avcodec_open2(pCodecCtx, pCodec, NULL) < 0)
285 {
286 printf("Could not open codec.");
287 return -1;
288 }
289 picture = av_frame_alloc();
290 size = avpicture_get_size(pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);
291 picture_buf = (uint8_t *)av_malloc(size);
292 if (!picture_buf)
293 {
294 return -1;
295 }
296
297 avpicture_fill((AVPicture *)picture, picture_buf, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);
298
299 // 写头部
300 avformat_write_header(pFormatCtx, NULL);
301
302 y_size = pCodecCtx->width * pCodecCtx->height;
303 av_new_packet(&pkt, y_size * 3);
304
305
306
307
308 // Read YUV
309 if (fread(picture_buf, 1, y_size * 3 / 2, in_file) <= 0)
310 {
311 printf("Could not read input file.");
312 return -1;
313 }
314 picture->data[0] = picture_buf; // Y
315 picture->data[1] = picture_buf + y_size; // U
316 picture->data[2] = picture_buf + y_size * 5 / 4; // V
317
318 // 编码
319 ret = avcodec_encode_video2(pCodecCtx, &pkt, picture, &got_picture);
320 if (ret < 0)
321 {
322 printf("Encode Error.\n");
323 return -1;
324 }
325 if (got_picture == 1)
326 {
327 pkt.stream_index = video_st->index;
328 ret = av_write_frame(pFormatCtx, &pkt);
329 }
330
331 av_free_packet(&pkt);
332
333 av_write_trailer(pFormatCtx);
334
335 printf("Encode Successful.\n");
336
337 if (video_st)
338 {
339 avcodec_close(video_st->codec);
340 av_free(picture);
341 av_free(picture_buf);
342 }
343 avio_close(pFormatCtx->pb);
344 avformat_free_context(pFormatCtx);
345 fclose(in_file);
346
347 return 0;
348 }
349
350 #endif
