FFmpeg YUV编码为H264

使用FFmpeg库把YUV420P文件编码为H264文件，FFmpeg版本为4.4.2-0。

需要yuv测试文件的，可以从我上传的MP4文件中用ffmpeg提取，命令如下：

ffmpeg -i <input.mp4> -pix_fmt yuv420p <output.yuv>

代码如下：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libavutil/opt.h>
#include <libavutil/mem.h>
#include <libavutil/imgutils.h>
#include <libswscale/swscale.h>int main(int argc, char *argv[])
{int ret = -1;int frame_index = 0;const char *input_file = argv[1];const char *output_file = argv[2];FILE *input_yuv = NULL;AVFormatContext *format_context = NULL;AVCodecContext *codec_context = NULL;AVStream *stream = NULL;AVCodec *codec = NULL;AVFrame *frame = NULL;AVPacket *packet = NULL;const AVOutputFormat *ofmt = NULL;int in_width = 1280;                                // 输入YUV文件的宽度int in_height = 720;                                // 输入YUV文件的高度enum AVPixelFormat in_pix_fmt = AV_PIX_FMT_YUV420P; // 输入YUV文件的像素格式int frame_rate = 24;                                // 输出视频帧率if (argc < 3){fprintf(stderr, "Usage: %s <input file> <output file>\n", argv[0]);return -1;}input_yuv = fopen(input_file, "rb");if (!input_yuv){fprintf(stderr, "open input file failed\n");goto end;}// 分配输出格式上下文avformat_alloc_output_context2(&format_context, NULL, NULL, output_file);if (!format_context){fprintf(stderr, "avformat_alloc_output_context2 failed\n");goto end;}ofmt = format_context->oformat;// 查找编码器codec = avcodec_find_encoder(AV_CODEC_ID_H264);if (!codec){fprintf(stderr, "Codec not found\n");goto end;}printf("codec name: %s\n", codec->name);// 创建新的视频流stream = avformat_new_stream(format_context, NULL);if (!stream){fprintf(stderr, "avformat_new_stream failed\n");goto end;}// 分配编码器上下文codec_context = avcodec_alloc_context3(codec);if (!codec_context){fprintf(stderr, "avcodec_alloc_context3 failed\n");goto end;}/* 设置编码器参数 */codec_context->codec_id = AV_CODEC_ID_H264;codec_context->codec_type = AVMEDIA_TYPE_VIDEO;codec_context->pix_fmt = AV_PIX_FMT_YUV420P;codec_context->width = in_width;codec_context->height = in_height;codec_context->time_base = (AVRational){1, frame_rate};     // 设置时间基codec_context->framerate = (AVRational){frame_rate, 1};     // 设置帧率codec_context->bit_rate = 1456 * 1000;                      // 设置比特率codec_context->gop_size = frame_rate;                       // 设置GOP大小codec_context->max_b_frames = 1;                            // 设置最大B帧数，不需要B帧时设置为0av_opt_set(codec_context->priv_data, "profile", "main", 0); // 设置h264画质级别// 打开编码器if (avcodec_open2(codec_context, codec, NULL) < 0){fprintf(stderr, "avcodec_open2 failed\n");goto end;}// 将编码器参数复制到流int result = avcodec_parameters_from_context(stream->codecpar, codec_context);if (result < 0){fprintf(stderr, "avcodec_parameters_from_context failed\n");goto end;}// 打开输出文件if (!(ofmt->flags & AVFMT_NOFILE)) // 检查输出格式是否需要文件存储{result = avio_open(&format_context->pb, output_file, AVIO_FLAG_WRITE);if (result < 0){fprintf(stderr, "open output file failed\n");goto end;}}// 写文件头result = avformat_write_header(format_context, NULL);if (result < 0){fprintf(stderr, "avformat_write_header failed\n");goto end;}frame = av_frame_alloc();packet = av_packet_alloc();if (!frame || !packet){fprintf(stderr, "allocate frame or packet failed\n");goto end;}// 设置帧参数frame->format = codec_context->pix_fmt;frame->width = codec_context->width;frame->height = codec_context->height;// 分配帧数据缓冲区result = av_frame_get_buffer(frame, 0);if (result < 0){fprintf(stderr, "av_frame_get_buffer failed\n");goto end;}// 计算输入缓冲区大小int input_buffer_size = av_image_get_buffer_size(in_pix_fmt, in_width, in_height, 1);uint8_t *input_buffer = (uint8_t *)av_malloc(input_buffer_size);if (!input_buffer){fprintf(stderr, "av_malloc failed\n");goto end;}// 编码循环while (1){// 读取YUV数据到缓冲区result = fread(input_buffer, 1, input_buffer_size, input_yuv);if (result <= 0){break;}// 填充帧数据av_image_fill_arrays(frame->data, frame->linesize, input_buffer, in_pix_fmt, in_width, in_height, 1);frame->pts = frame_index;frame_index++;// 发送帧到编码器result = avcodec_send_frame(codec_context, frame);if (result < 0){fprintf(stderr, "avcodec_send_frame error (errmsg '%s')\n", av_err2str(result));goto end;}// 接收编码后的数据包while (result >= 0){result = avcodec_receive_packet(codec_context, packet);if (result == AVERROR(EAGAIN) || result == AVERROR_EOF){break;}else if (result < 0){fprintf(stderr, "avcodec_receive_packet error (errmsg '%s')\n", av_err2str(result));goto end;}packet->stream_index = stream->index;// 将时间戳从编码器时间基转换到流时间基av_packet_rescale_ts(packet, codec_context->time_base, stream->time_base);// 写数据包到输出文件result = av_interleaved_write_frame(format_context, packet);if (result < 0){fprintf(stderr, "av_interleaved_write_frame failed\n");av_packet_unref(packet);goto end;}av_packet_unref(packet);}}av_free(input_buffer);// 发送NULL帧到编码器，刷新编码器内部缓冲区result = avcodec_send_frame(codec_context, NULL);while (result >= 0){result = avcodec_receive_packet(codec_context, packet);if (result == AVERROR_EOF){break;}else if (result < 0){fprintf(stderr, "avcodec_receive_packet error (errmsg '%s')\n", av_err2str(result));goto end;}packet->stream_index = stream->index;av_packet_rescale_ts(packet, codec_context->time_base, stream->time_base);result = av_interleaved_write_frame(format_context, packet);if (result < 0){fprintf(stderr, "av_interleaved_write_frame failed\n");av_packet_unref(packet);goto end;}av_packet_unref(packet);}// 写文件尾av_write_trailer(format_context);ret = 0;end:if (frame)av_frame_free(&frame);if (packet)av_packet_free(&packet);if (codec_context)avcodec_free_context(&codec_context);if (ofmt && !(ofmt->flags & AVFMT_NOFILE))avio_close(format_context->pb);if (format_context)avformat_free_context(format_context);if (input_yuv)fclose(input_yuv);return ret;
}