使用X264编码yuv格式的视频帧使用ffmpeg解码h264视频帧

https://www.bbsmax.com/A/n2d9pVjQ5D/

 

前面一篇博客介绍在centos上搭建点击打开链接ffmpeg及x264开发环境。以下就来问个样例：

1、利用x264库将YUV格式视频文件编码为h264格式视频文件

2、利用ffmpeh库将h264格式的视频文件解码为yuv格式视频文件

解码和编码前后对文件大小进行比較，如图：

当中yuv420p.yuv为原始文件，大小77M

encode.h264为H264编码后的视频文件，大小1.4M

decode.yuv为ffmpeg解码后的视频文件，大小77M。

从文件的大小非常明显能够看出h264压缩率。在Ｗｉｎｄｏｗｓ平台分辨播放了三个文件，画面看不出差别。

以下是代码＂

 

1. /*File : yuvTO264.c
2. *Auth : sjin
3. *Date : 20141115
4. *Mail : [email protected]
5. */
6.  
7. /*利用x264库将YUV文件编码为h264文件
8. *
9. */
10.  
11. #include
12. #include
13. #include
14. #include
15. #include
16. #include
17. #include
18.  
19. #define CLEAR(x) (memset((&x),0,sizeof(x)))
20. #define IMAGE_WIDTH 176
21. #define IMAGE_HEIGHT 144
22. #define ENCODER_PRESET "veryfast"
23.  
24. /*配置參数
25. * 使用默认參数，在这里使用了zerolatency的选项，使用这个选项之后，就不会有
26. * delayed_frames，假设你使用不是这个的话，还须要在编码完毕之后得到缓存的
27. * 编码帧
28. */
29. #define ENCODER_TUNE "zerolatency"
30. #define ENCODER_PROFILE "baseline"
31. #define ENCODER_COLORSPACE X264_CSP_I420
32.  
33. typedef struct my_x264_encoder{
34. x264_param_t * x264_parameter;
35. char parameter_preset[20];
36. char parameter_tune[20];
37. char parameter_profile[20];
38. x264_t * x264_encoder;
39. x264_picture_t * yuv420p_picture;
40. long colorspace;
41. unsigned char *yuv;
42. x264_nal_t * nal;
43. } my_x264_encoder;
44.  
45. char *read_filename="yuv420p.yuv";
46. char *write_filename="encode.h264";
47.  
48. int main(int argc ,char **argv)
49. {
50. int ret;
51. int fd_read,fd_write;
52. my_x264_encoder * encoder = (my_x264_encoder *)malloc(sizeof(my_x264_encoder));
53. if(!encoder){
54. printf("cannot malloc my_x264_encoder !\n");
55. exit(EXIT_FAILURE);
56. }
57. CLEAR(*encoder);
58.  
59. /****************************************************************************
60. * Advanced parameter handling functions
61. ****************************************************************************/
62.  
63. /* These functions expose the full power of x264's preset-tune-profile system for
64. * easy adjustment of large numbers //free(encoder->yuv420p_picture);of internal parameters.
65. *
66. * In order to replicate x264CLI's option handling, these functions MUST be called
67. * in the following order:
68. * 1) x264_param_default_preset
69. * 2) Custom user options (via param_parse or directly assigned variables)
70. * 3) x264_param_apply_fastfirstpass
71. * 4) x264_param_apply_profile
72. *
73. * Additionally, x264CLI does not apply step 3 if the preset chosen is "placebo"
74. * or --slow-firstpass is set. */
75. strcpy(encoder->parameter_preset,ENCODER_PRESET);
76. strcpy(encoder->parameter_tune,ENCODER_TUNE);
77.  
78. encoder->x264_parameter = (x264_param_t *)malloc(sizeof(x264_param_t));
79. if(!encoder->x264_parameter){
80. printf("malloc x264_parameter error!\n");
81. exit(EXIT_FAILURE);
82. }
83.  
84. /*初始化编码器*/
85. CLEAR(*(encoder->x264_parameter));
86. x264_param_default(encoder->x264_parameter);
87.  
88. if((ret = x264_param_default_preset(encoder->x264_parameter,encoder->parameter_preset,encoder->parameter_tune))<0){
89. printf("x264_param_default_preset error!\n");
90. exit(EXIT_FAILURE);
91. }
92.  
93. /*cpuFlags 去空缓冲区继续使用不死锁保证*/
94. encoder->x264_parameter->i_threads =X264_SYNC_LOOKAHEAD_AUTO;
95. /*视频选项*/
96. encoder->x264_parameter->i_width =IMAGE_WIDTH;//要编码的图像的宽度
97. encoder->x264_parameter->i_height =IMAGE_HEIGHT;//要编码的图像的高度
98. encoder->x264_parameter->i_frame_total =0;//要编码的总帧数，不知道用0
99. encoder->x264_parameter->i_keyint_max =25;
100. /*流參数*/
101. encoder->x264_parameter->i_bframe =5;
102. encoder->x264_parameter->b_open_gop =0;
103. encoder->x264_parameter->i_bframe_pyramid=0;
104. encoder->x264_parameter->i_bframe_adaptive=X264_B_ADAPT_TRELLIS;
105.  
106. /*log參数，不须要打印编码信息时直接凝视掉*/
107. encoder->x264_parameter->i_log_level =X264_LOG_DEBUG;
108.  
109. encoder->x264_parameter->i_fps_den =1;//码率分母
110. encoder->x264_parameter->i_fps_num =25;//码率分子
111. encoder->x264_parameter->b_intra_refresh =1;
112. encoder->x264_parameter->b_annexb =1;
113.  
114. strcpy(encoder->parameter_profile,ENCODER_PROFILE);
115. if((ret=x264_param_apply_profile(encoder->x264_parameter,encoder->parameter_profile))<0){
116. printf("x264_param_apply_profile error!\n");
117. exit(EXIT_FAILURE);
118. }
119. /*打开编码器*/
120. encoder->x264_encoder = x264_encoder_open(encoder->x264_parameter);
121. encoder->colorspace = ENCODER_COLORSPACE;
122.  
123. /*初始化pic*/
124. encoder->yuv420p_picture = (x264_picture_t *)malloc(sizeof(x264_picture_t ));
125. if(!encoder->yuv420p_picture){
126. printf("malloc encoder->yuv420p_picture error!\n");
127. exit(EXIT_FAILURE);
128. }
129. if((ret = x264_picture_alloc(encoder->yuv420p_picture,encoder->colorspace,IMAGE_WIDTH,IMAGE_HEIGHT))<0){
130. printf("ret=%d\n",ret);
131. printf("x264_picture_alloc error!\n");
132. exit(EXIT_FAILURE);
133. }
134.  
135. encoder->yuv420p_picture->img.i_csp = encoder->colorspace;
136. encoder->yuv420p_picture->img.i_plane = 3;
137. encoder->yuv420p_picture->i_type = X264_TYPE_AUTO;
138.  
139. /*申请YUV buffer*/
140. encoder->yuv = (uint8_t *)malloc(IMAGE_WIDTH*IMAGE_HEIGHT*3/2);
141. if(!encoder->yuv){
142. printf("malloc yuv error!\n");
143. exit(EXIT_FAILURE);
144. }
145. CLEAR(*(encoder->yuv));
146. encoder->yuv420p_picture->img.plane[0] = encoder->yuv;
147. encoder->yuv420p_picture->img.plane[1] = encoder->yuv+IMAGE_WIDTH*IMAGE_HEIGHT;
148. encoder->yuv420p_picture->img.plane[2] = encoder->yuv+IMAGE_WIDTH*IMAGE_HEIGHT+IMAGE_WIDTH*IMAGE_HEIGHT/4;
149.  
150. if((fd_read = open(read_filename,O_RDONLY))<0){
151. printf("cannot open input file!\n");
152. exit(EXIT_FAILURE);
153. }
154.  
155. if((fd_write = open(write_filename,O_WRONLY | O_APPEND | O_CREAT,0777))<0){
156. printf("cannot open output file!\n");
157. exit(EXIT_FAILURE);
158. }
159.  
160. int n_nal = 0;
161. x264_picture_t pic_out;
162. x264_nal_t *my_nal;
163. encoder->nal = (x264_nal_t *)malloc(sizeof(x264_nal_t ));
164. if(!encoder->nal){
165. printf("malloc x264_nal_t error!\n");
166. exit(EXIT_FAILURE);
167. }
168. CLEAR(*(encoder->nal));
169.  
170. /*编码*/
171. while(read(fd_read,encoder->yuv,IMAGE_WIDTH*IMAGE_HEIGHT*3/2)>0){
172. encoder->yuv420p_picture->i_pts++;
173. if((ret = x264_encoder_encode(encoder->x264_encoder,&encoder->nal,&n_nal,encoder->yuv420p_picture,&pic_out))<0){
174. printf("x264_encoder_encode error!\n");
175. exit(EXIT_FAILURE);
176. }
177.  
178. for(my_nal = encoder->nal; my_nalnal+n_nal; ++my_nal){
179. write(fd_write,my_nal->p_payload,my_nal->i_payload);
180. }
181. }
182.  
183. free(encoder->yuv);
184. free(encoder->yuv420p_picture);
185. free(encoder->x264_parameter);
186. x264_encoder_close(encoder->x264_encoder);
187. free(encoder);
188. close(fd_read);
189. close(fd_write);
190.  
191. return 0;
192. }

 

1. /*File : decode_h264.c
2. *Auth : sjin
3. *Date : 20141115
4. *Mail : [email protected]
5. */
6.  
7. /*将h264解码为yuv文件*/
8.  
9. #include
10. #include
11. #include
12. #include
13. #include
14. #include
15. #include
16. #include
17.  
18. #define DECODED_OUTPUT_FORMAT AV_PIX_FMT_YUV420P
19. #define INPUT_FILE_NAME "encode.h264"
20. #define OUTPUT_FILE_NAME "decode.yuv"
21. /*h264文件的宽度和高度，必须和实际的宽度和高度一致
22. *否则将出错
23. * */
24. #define IMAGE_WIDTH 176
25. #define IMAGE_HEIGHT 144
26.  
27. void error_handle(const char *errorInfo )
28. {
29. printf("%s error!\n",errorInfo);
30. exit(EXIT_FAILURE);
31. }
32.  
33. int main(int argc,char ** argv)
34. {
35. int write_fd,ret,videoStream;
36. AVFormatContext * formatContext=NULL;
37. AVCodec * codec;
38. AVCodecContext * codecContext;
39. AVFrame * decodedFrame;
40. AVPacket packet;
41. uint8_t *decodedBuffer;
42. unsigned int decodedBufferSize;
43. int finishedFrame;
44.  
45. //初始化环境
46. av_register_all();
47.  
48. write_fd = open(OUTPUT_FILE_NAME,O_RDWR | O_CREAT,0666);
49. if(write_fd<0){
50. perror("open");
51. exit(1);
52. }
53.  
54. ret = avformat_open_input(&formatContext, INPUT_FILE_NAME, NULL,NULL);
55. if(ret<0)
56. error_handle("avformat_open_input error");
57.  
58. ret = avformat_find_stream_info(formatContext,NULL);
59. if(ret<0)
60. error_handle("av_find_stream_info");
61.  
62. //打印输入文件的具体信息
63. av_dump_format(formatContext,0,INPUT_FILE_NAME,0);
64.  
65. videoStream = 0;
66. codecContext = formatContext->streams[videoStream]->codec;
67.  
68. codec = avcodec_find_decoder(AV_CODEC_ID_H264);
69. if(codec == NULL)
70. error_handle("avcodec_find_decoder error!\n");
71.  
72. ret = avcodec_open2(codecContext,codec,NULL);
73. if(ret<0)
74. error_handle("avcodec_open2");
75.  
76. //分配保存视频帧的空间
77. decodedFrame = avcodec_alloc_frame();
78. if(!decodedFrame)
79. error_handle("avcodec_alloc_frame!");
80.  
81. //分配解码后视频帧的空间
82. decodedBufferSize = avpicture_get_size(DECODED_OUTPUT_FORMAT,IMAGE_WIDTH,IMAGE_HEIGHT);
83. decodedBuffer = (uint8_t *)malloc(decodedBufferSize);
84. if(!decodedBuffer)
85. error_handle("malloc decodedBuffer error!");
86.  
87. av_init_packet(&packet);
88. while(av_read_frame(formatContext,&packet)>=0){
89. ret = avcodec_decode_video2(codecContext,decodedFrame,&finishedFrame,&packet);
90. if(ret<0)
91. error_handle("avcodec_decode_video2 error!");
92. if(finishedFrame){
93. avpicture_layout((AVPicture*)decodedFrame,DECODED_OUTPUT_FORMAT,IMAGE_WIDTH,IMAGE_HEIGHT,decodedBuffer,decodedBufferSize);
94. ret = write(write_fd,decodedBuffer,decodedBufferSize);
95. if(ret<0)
96. error_handle("write yuv stream error!");
97. }
98.  
99. av_free_packet(&packet);
100. }
101.  
102. /*防止视频解码完毕后丢帧的情况*/
103. while(1){
104. packet.data = NULL;
105. packet.size = 0;
106. ret = avcodec_decode_video2(codecContext,decodedFrame,&finishedFrame,&packet);
107. if(ret<=0 && (finishedFrame<=0))
108. break;
109. if(finishedFrame){
110. avpicture_layout((AVPicture*)decodedFrame,DECODED_OUTPUT_FORMAT,IMAGE_WIDTH,IMAGE_HEIGHT,decodedBuffer,decodedBufferSize);
111. ret = write(write_fd,decodedBuffer,decodedBufferSize);
112. if(ret<0)
113. error_handle("write yuv stream error!");
114. }
115.  
116. av_free_packet(&packet);
117. }
118.  
119. avformat_close_input(&formatContext);
120. free(decodedBuffer);
121. av_free(decodedFrame);
122. avcodec_close(codecContext);
123.  
124. return 0;
125. }

Makefile:

1. # use pkg-config for getting CFLAGS and LDLIBS
2. FFMPEG_LIBS= libavdevice \
3. libavformat \
4. libavfilter \
5. libavcodec \
6. libswresample \
7. libswscale \
8. libavutil \
9.  
10. CFLAGS += -Wall -O2 -g
11. CFLAGS := $(shell pkg-config --cflags $(FFMPEG_LIBS)) $(CFLAGS)
12. LDLIBS := $(shell pkg-config --libs $(FFMPEG_LIBS)) $(LDLIBS)
13.  
14. EXAMPLES= decode_h264 yuvTO264
15.  
16. OBJS=$(addsuffix .o,$(EXAMPLES))
17.  
18. # the following examples make explicit use of the math library
19. LDLIBS += -lx264 -m32 -pthread -lm -ldl
20.  
21. .phony:all clean
22.  
23. all: $(OBJS) $(EXAMPLES)
24.  
25. clean:
26. rm $(EXAMPLES) $(OBJS)

參考资料：

參考资料
1、http://blog.csdn.net/liushu1231/article/details/9203239
2、http://www.cnblogs.com/fojian/archive/2012/09/01/2666627.html
3、http://stackoverflow.com/questions/2940671/how-does-one-encode-a-series-of-images-into-h264-using-the-x264-c-api
4、http://blog.yikuyiku.com/?p=3486