《最简单的基于FFMPEG的视频编码器（YUV编码为H.264）》，它介绍的是使用FFMPEG将YUV420 数据编码成H.264数据。在它的博客中，没有介绍到YUYV数据格式的编码，但是我们在实际应用中，有时候摄像头只能输出YUYV数据格式，这样他的工程就不能使用了。经过一通折腾，终于在他的基础上实现了使用FFMPEG将YUYV编码成H264数据。
因为YUYV数据是属于YUV422格式，而FFMPEG的编码器又不支持AV_PIX_FMT_YUYV422 编码格式。因此我们需要做的是将YUYV数据格式转换为YUV422P数据格式，然后再进行编码。因为YUYV转YUV422P比较简单，因此我这里没有调用FFMPEG的转换器而是直接转换了。这里需要注意一下，我使用的FFMPEG版本是ffmpeg-3.2.4 ，因为版本的更新，有些接口可能改变了，也正是因为这样，在调试的时候出现了不少的问题。代码如下：
- /*=============================================================================
- # FileName: ffmpeg_encoder.c
- # Desc: an example of ffmpeg fileter
- # Author: licaibiao
- # LastChange: 2017-03-18
- =============================================================================*/
- #include <stdio.h>
- #define __STDC_CONSTANT_MACROS
- #include <libavutil/opt.h>
- #include <libavcodec/avcodec.h>
- #include <libavformat/avformat.h>
- //#define ENCODE_YUV
- #ifdef ENCODE_YUV
- #define INPUT_FILE "yuv_512_288.yuv"
- #define INPUT_WIDTH 512
- #define INPUT_HEIGHT 288
- #else
- #define INPUT_FILE "yuyv_640_480.yuyv"
- #define INPUT_WIDTH 640
- #define INPUT_HEIGHT 480
- #endif
- #define OUTPUT_FILE "ds.h264"
- #define FRAMENUM 300
- int flush_encoder(AVFormatContext *fmt_ctx,unsigned int stream_index){
- int ret;
- int got_frame;
- AVPacket enc_pkt;
- if (!(fmt_ctx->streams[stream_index]->codec->codec->capabilities &
- CODEC_CAP_DELAY))
- return 0;
- while (1) {
- enc_pkt.data = NULL;
- enc_pkt.size = 0;
- av_init_packet(&enc_pkt);
- ret = avcodec_encode_video2 (fmt_ctx->streams[stream_index]->codec, &enc_pkt,
- NULL, &got_frame);
- av_frame_free(NULL);
- if (ret < 0)
- break;
- if (!got_frame){
- ret=0;
- break;
- }
- printf("Flush Encoder: Succeed to encode 1 frame!\tsize:%5d\n",enc_pkt.size);
- /* mux encoded frame */
- ret = av_write_frame(fmt_ctx, &enc_pkt);
- if (ret < 0)
- break;
- }
- return ret;
- }
- int main(int argc, char* argv[])
- {
- AVFormatContext* pFormatCtx;
- AVOutputFormat* fmt;
- AVStream* video_st;
- AVCodecContext* pCodecCtx;
- AVCodec* pCodec;
- AVPacket pkt;
- uint8_t* picture_buf;
- AVFrame* pFrame;
- int picture_size;
- int y_size;
- int framecnt=0;
- FILEFILE *in_file ; //Input raw YUV data
- int in_w=INPUT_WIDTH, in_h=INPUT_HEIGHT; //Input data's width and height
- int framenum=FRAMENUM; //Frames to encode
- const char* out_file = OUTPUT_FILE;
- int i,j,k;
- int num;
- int index_y, index_u, index_v;
- uint8_t *y_, *u_, *v_, *in;
- int got_picture =0;
- int ret;
- in_file = fopen(INPUT_FILE, "rb"); //Input raw YUV data
- av_register_all();
- //Method1.
- pFormatCtx = avformat_alloc_context();
- //Guess Format
- fmt = av_guess_format(NULL, out_file, NULL);
- pFormatCtx->oformat = fmt;
- //Method 2.
- /* 初始化输出码流的AVFormatContext */
- //avformat_alloc_output_context2(&pFormatCtx, NULL, NULL, out_file);
- //fmt = pFormatCtx->oformat;
- //Open output URL
- if (avio_open(&pFormatCtx->pb,out_file, AVIO_FLAG_READ_WRITE) < 0){
- printf("Failed to open output file! \n");
- return -1;
- }
- /* 创建输出码流的AVStream */
- video_st = avformat_new_stream(pFormatCtx, 0);
- //video_st->time_base.num = 1;
- //video_st->time_base.den = 25;
- if (video_st==NULL){
- return -1;
- }
- //Param that must set
- pCodecCtx = video_st->codec;
- //pCodecCtx->codec_id =AV_CODEC_ID_HEVC;
- pCodecCtx->codec_id = fmt->video_codec;
- pCodecCtx->codec_type = AVMEDIA_TYPE_VIDEO;
- #ifdef ENCODE_YUV
- pCodecCtx->pix_fmt = AV_PIX_FMT_YUV420P;
- #else
- pCodecCtx->pix_fmt = AV_PIX_FMT_YUV422P;
- #endif
- pCodecCtx->width = in_w;
- pCodecCtx->height = in_h;
- pCodecCtx->bit_rate = 2000000;
- pCodecCtx->gop_size=10;
- pCodecCtx->time_base.num = 1;
- pCodecCtx->time_base.den = 25;
- //H264
- //pCodecCtx->me_range = 16;
- //pCodecCtx->max_qdiff = 4;
- //pCodecCtx->qcompress = 0.6;
- pCodecCtx->qmin = 10;
- pCodecCtx->qmax = 51;
- //Optional Param
- pCodecCtx->max_b_frames=3;
- // Set Option
- AVDictionary *param = 0;
- //H.264
- if(pCodecCtx->codec_id == AV_CODEC_ID_H264) {
- av_dict_set(¶m, "preset", "slow", 0);
- /* 这个可以让libav不缓存视频帧 */
- av_dict_set(¶m, "tune", "zerolatency", 0);
- //av_dict_set(¶m, "profile", "main", 0);
- }
- //Show some Information
- av_dump_format(pFormatCtx, 0, out_file, 1);
- /* 查找编码器 */
- pCodec = avcodec_find_encoder(pCodecCtx->codec_id);
- if (!pCodec){
- printf("Can not find encoder! \n");
- return -1;
- }
- /* 打开编码器 */
- if (avcodec_open2(pCodecCtx, pCodec,¶m) < 0){
- printf("Failed to open encoder! \n");
- return -1;
- }
- pFrame = av_frame_alloc();
- picture_size = avpicture_get_size(pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);
- picture_buf = (uint8_t *)av_malloc(picture_size);
- #ifdef ENCODE_YUV
- avpicture_fill((AVPicture *)pFrame, picture_buf, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);
- #else
- pFrame->format = pCodecCtx->pix_fmt;
- pFrame->width = pCodecCtx->width;
- pFrame->height = pCodecCtx->height;
- av_image_alloc(pFrame->data, pFrame->linesize, pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, 32);
- #endif
- //Write File Header
- /* 写文件头（对于某些没有文件头的封装格式，不需要此函数。比如说MPEG2TS） */
- avformat_write_header(pFormatCtx,NULL);
- /* Allocate the payload of a packet and initialize its fields with default values. */
- av_new_packet(&pkt,picture_size);
- y_size = pCodecCtx->width * pCodecCtx->height;
- for (j=0; j< framenum; j++){
- //Read raw YUV data
- #ifdef ENCODE_YUV
- if (fread(picture_buf, 1, y_size*3/2, in_file) <= 0){
- #else
- if (fread(picture_buf, 1, y_size*2, in_file) <= 0){
- #endif
- printf("Failed to read raw data! \n");
- return -1;
- }else if(feof(in_file)){
- break;
- }
- #ifdef ENCODE_YUV
- pFrame->data[0] = picture_buf; // Y
- pFrame->data[1] = picture_buf + y_size; // U
- pFrame->data[2] = picture_buf + y_size*5/4; // V
- #else
- num = y_size * 2 - 4;
- index_y = 0;
- index_u = 0;
- index_v = 0;
- y_ = pFrame->data[0];
- u_ = pFrame->data[1];
- v_ = pFrame->data[2];
- in = picture_buf;
- for(i=0; i<num; i=i+4)
- {
- *(y_ + (index_y++)) = *(in + i);
- *(u_ + (index_u++)) = *(in + i + 1);
- *(y_ + (index_y++)) = *(in + i + 2);
- *(v_ + (index_v++)) = *(in + i + 3);
- }
- #endif
- //PTS
- //pFrame->pts=i;
- pFrame->pts=j*(video_st->time_base.den)/((video_st->time_base.num)*25);
- //Encode
- /* 编码一帧视频。即将AVFrame（存储YUV像素数据）编码为AVPacket（存储H.264等格式的码流数据） */
- int ret = avcodec_encode_video2(pCodecCtx, &pkt,pFrame, &got_picture);
- if(ret < 0){
- printf("Failed to encode! \n");
- return -1;
- }
- if (got_picture==1){
- //printf("Succeed to encode frame: %5d\tsize:%5d\n",framecnt,pkt.size);
- framecnt++;
- pkt.stream_index = video_st->index;
- /* 将编码后的视频码流写入文件 */
- ret = av_write_frame(pFormatCtx, &pkt);
- av_free_packet(&pkt);
- }
- }
- //Flush Encoder
- /* 输入的像素数据读取完成后调用此函数。用于输出编码器中剩余的AVPacket */
- ret = flush_encoder(pFormatCtx,0);
- if (ret < 0) {
- printf("Flushing encoder failed\n");
- return -1;
- }
- //Write file trailer
- /* 写文件尾（对于某些没有文件头的封装格式，不需要此函数。比如说MPEG2TS） */
- av_write_trailer(pFormatCtx);
- //Clean
- if (video_st){
- avcodec_close(video_st->codec);
- av_free(pFrame);
- av_free(picture_buf);
- }
- avio_close(pFormatCtx->pb);
- avformat_free_context(pFormatCtx);
- fclose(in_file);
- return 0;
- }
Makefile文件书写如下：
- OUT_APP = test
- INCLUDE_PATH = /usr/local/include/
- INCLUDE = -I$(INCLUDE_PATH)libavutil/ -I$(INCLUDE_PATH)libavdevice/ \
- -I$(INCLUDE_PATH)libavcodec/ -I$(INCLUDE_PATH)libswresample \
- -I$(INCLUDE_PATH)libavfilter/ -I$(INCLUDE_PATH)libavformat \
- -I$(INCLUDE_PATH)libswscale/
- FFMPEG_LIBS = -lavformat -lavutil -lavdevice -lavcodec -lswresample -lavfilter -lswscale
- SDL_LIBS =
- LIBS = $(FFMPEG_LIBS)$(SDL_LIBS)
- COMPILE_OPTS = $(INCLUDE)
- C = c
- OBJ = o
- C_COMPILER = cc
- C_FLAGS = $(COMPILE_OPTS) $(CPPFLAGS) $(CFLAGS)
- LINK = cc -o
- LINK_OPTS = -lz -lm -lpthread
- LINK_OBJ = test.o
- .$(C).$(OBJ):
- $(C_COMPILER) -c -g $(C_FLAGS) $<
- $(OUT_APP): $(LINK_OBJ)
- $(LINK)$@ $(LINK_OBJ) $(LIBS) $(LINK_OPTS)
- clean:
- rm -rf *.$(OBJ) $(OUT_APP) core *.core *~ *.h264 yuyv.yuyv
- licaibiao@ubuntu:~/test/FFMPEG/encoder$ ls
- Makefile test test.c test.o yuv_512_288.yuv yuyv_640_480.yuyv
- licaibiao@ubuntu:~/test/FFMPEG/encoder$ ./test
- Output #0, h264, to 'ds.h264':
- Stream #0:0: Unknown: none
- [libx264 @ 0xbe7140] using cpu capabilities: none!
- [libx264 @ 0xbe7140] profile High 4:2:2, level 3.0, 4:2:2 8-bit
- [h264 @ 0xbde240] Using AVStream.codec.time_base as a timebase hint to the muxer is deprecated. Set AVStream.time_base instead.
- [h264 @ 0xbde240] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
- Flush Encoder: Succeed to encode 1 frame! size: 3131
- Flush Encoder: Succeed to encode 1 frame! size: 5618
- Flush Encoder: Succeed to encode 1 frame! size:16635
- [libx264 @ 0xbe7140] frame I:30 Avg QP:18.56 size: 31571
- [libx264 @ 0xbe7140] frame P:61 Avg QP:19.89 size: 15100
- [libx264 @ 0xbe7140] frame B:209 Avg QP:21.10 size: 5299
- [libx264 @ 0xbe7140] consecutive B-frames: 0.7% 19.3% 0.0% 80.0%
- [libx264 @ 0xbe7140] mb I I16..4: 14.0% 40.4% 45.6%
- [libx264 @ 0xbe7140] mb P I16..4: 8.7% 15.4% 9.8% P16..4: 36.2% 15.1% 5.2% 0.0% 0.0% skip: 9.6%
- [libx264 @ 0xbe7140] mb B I16..4: 1.0% 4.0% 1.7% B16..8: 27.6% 9.3% 1.6% direct:10.3% skip:44.5% L0:41.6% L1:42.2% BI:16.2%
- [libx264 @ 0xbe7140] final ratefactor: 17.64
- [libx264 @ 0xbe7140] 8x8 transform intra:46.1% inter:53.3%
- [libx264 @ 0xbe7140] direct mvs spatial:99.5% temporal:0.5%
- [libx264 @ 0xbe7140] coded y,uvDC,uvAC intra: 74.5% 88.9% 70.6% inter: 14.6% 34.0% 5.8%
- [libx264 @ 0xbe7140] i16 v,h,dc,p: 48% 9% 2% 42%
- [libx264 @ 0xbe7140] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 12% 13% 6% 11% 11% 13% 10% 12% 11%
- [libx264 @ 0xbe7140] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 12% 21% 6% 9% 14% 13% 10% 9% 7%
- [libx264 @ 0xbe7140] i8c dc,h,v,p: 41% 24% 22% 13%
- [libx264 @ 0xbe7140] Weighted P-Frames: Y:41.0% UV:19.7%
- [libx264 @ 0xbe7140] kb/s:1983.80
- licaibiao@ubuntu:~/test/FFMPEG/encoder$ ll
- total 413032
- drwxrwxr-x 2 licaibiao licaibiao 4096 Mar 18 04:24 ./
- drwxrwxr-x 10 licaibiao licaibiao 4096 Mar 17 03:46 ../
- -rw-rw-r-- 1 licaibiao licaibiao 2975705 Mar 18 04:24 ds.h264
- -rwxrwxr-x 1 licaibiao licaibiao 800 Mar 18 01:40 Makefile*
- -rwxrwxr-x 1 licaibiao licaibiao 61800 Mar 18 04:01 test*
- -rw-rw-r-- 1 licaibiao licaibiao 7131 Mar 18 04:22 test.c
- -rw-rw-r-- 1 licaibiao licaibiao 95184 Mar 18 04:01 test.o
- -rw-r--r-- 1 licaibiao licaibiao 112582656 Mar 16 18:35 yuv_512_288.yuv
- -rw-r--r-- 1 licaibiao licaibiao 307200000 Mar 17 04:25 yuyv_640_480.yuyv
- licaibiao@ubuntu:~/test/FFMPEG/encoder$
这里需要特别注意：在雷神的例子中，他是这样初始化frame的：
avpicture_fill((AVPicture *)pFrame, picture_buf, pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height);
按照他的例子设置，编码YUV420P数据是没有问题，但是当编码YUV422P的时候，它就会出现花屏的问题，下面的这张图。
出现这样的原因是，在它的工程中没有设置帧的帧类型，默认它是按YUV420P分配空间的。因为YUYV会比YUV420P多出1/4的数据，所以会造成有1/4的数据是异常的。我将他的例子该部分修改如下：
- pFrame->format = pCodecCtx->pix_fmt;
- pFrame->width = pCodecCtx->width;
- pFrame->height = pCodecCtx->height;
- av_image_alloc(pFrame->data, pFrame->linesize, pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt, 32);
- for(i=0; i<num; i=i+4)
- {
- *(y_ + (index_y++)) = *(in + i);
- *(u_ + (index_u++)) = *(in + i + 1);
- *(y_ + (index_y++)) = *(in + i + 2);
- *(v_ + (index_v++)) = *(in + i + 3);
- }