将mat yuv编码为h264流, 使用ffmpeg, cpp代码, 以函数形式

以下是将mat yuv编码为h264流的cpp代码，使用ffmpeg库：

#include <iostream>
#include <string>
#include <opencv2/core.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgproc.hpp>
#include <libavcodec/avcodec.h>
#include <libavutil/opt.h>
#include <libavutil/imgutils.h>

using namespace std;
using namespace cv;

// Function to encode a YUV image to H264 stream
int encode_yuv_to_h264(Mat yuv_frame, AVCodecContext* codec_ctx, AVFrame* frame, AVPacket* pkt, FILE* outfile) {
    // Set the frame's data pointers to the YUV image data
    frame->data[0] = yuv_frame.data;
    frame->data[1] = yuv_frame.data + yuv_frame.rows * yuv_frame.cols;
    frame->data[2] = yuv_frame.data + yuv_frame.rows * yuv_frame.cols * 5 / 4;

    // Set the frame's line sizes to the YUV image line sizes
    frame->linesize[0] = yuv_frame.cols;
    frame->linesize[1] = yuv_frame.cols / 2;
    frame->linesize[2] = yuv_frame.cols / 2;

    // Encode the frame and write the packet to the output file
    int ret = avcodec_send_frame(codec_ctx, frame);
    if (ret < 0) {
        cerr << "Error sending frame to encoder: " << av_err2str(ret) << endl;
        return ret;
    }

    while (ret >= 0) {
        ret = avcodec_receive_packet(codec_ctx, pkt);
        if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
            return 0;
        } else if (ret < 0) {
            cerr << "Error receiving packet from encoder: " << av_err2str(ret) << endl;
            return ret;
        }

        fwrite(pkt->data, 1, pkt->size, outfile);
        av_packet_unref(pkt);
    }

    return 0;
}

int main(int argc, char* argv[]) {
    if (argc < 4) {
        cerr << "Usage: " << argv[0] << " <input_yuv_file> <output_h264_file> <output_width> <output_height>" << endl;
        return 1;
    }

    // Open the input file and read the YUV image
    FILE* infile = fopen(argv[1], "rb");
    if (!infile) {
        cerr << "Could not open input file: " << argv[1] << endl;
        return 1;
    }

    int width = stoi(argv[3]);
    int height = stoi(argv[4]);
    Mat yuv_frame(height * 3 / 2, width, CV_8UC1);
    fread(yuv_frame.data, 1, yuv_frame.total(), infile);
    fclose(infile);

    // Initialize the FFmpeg library
    avcodec_register_all();
    AVCodec* codec = avcodec_find_encoder(AV_CODEC_ID_H264);
    if (!codec) {
        cerr << "Could not find H264 encoder" << endl;
        return 1;
    }

    AVCodecContext* codec_ctx = avcodec_alloc_context3(codec);
    if (!codec_ctx) {
        cerr << "Could not allocate codec context" << endl;
        return 1;
    }

    // Set the codec context parameters
    codec_ctx->width = width;
    codec_ctx->height = height;
    codec_ctx->time_base = {1, 25};
    codec_ctx->framerate = {25, 1};
    codec_ctx->gop_size = 10;
    codec_ctx->max_b_frames = 1;
    codec_ctx->pix_fmt = AV_PIX_FMT_YUV420P;

    if (avcodec_open2(codec_ctx, codec, nullptr) < 0) {
        cerr << "Could not open codec" << endl;
        return 1;
    }

    // Create the output file and write the H264 stream header
    FILE* outfile = fopen(argv[2], "wb");
    if (!outfile) {
        cerr << "Could not open output file: " << argv[2] << endl;
        return 1;
    }

    AVFrame* frame = av_frame_alloc();
    frame->format = codec_ctx->pix_fmt;
    frame->width = codec_ctx->width;
    frame->height = codec_ctx->height;
    av_frame_get_buffer(frame, 0);

    AVPacket* pkt = av_packet_alloc();
    av_init_packet(pkt);

    avcodec_send_frame(codec_ctx, nullptr);
    while (avcodec_receive_packet(codec_ctx, pkt) == 0) {
        fwrite(pkt->data, 1, pkt->size, outfile);
        av_packet_unref(pkt);
    }

    // Encode the YUV image to H264 stream and write the output packets to the output file
    encode_yuv_to_h264(yuv_frame, codec_ctx, frame, pkt, outfile);

    // Flush the encoder and write any remaining packets to the output file
    while (avcodec_receive_packet(codec_ctx, pkt) == 0) {
        fwrite(pkt->data, 1, pkt->size, outfile);
        av_packet_unref(pkt);
    }

    // Close the output file and free resources
    fclose(outfile);
    av_packet_free(&pkt);
    av_frame_free(&frame);
    avcodec_free_context(&codec_ctx);

    return 0;
}

该代码中的主要函数是`encode_yuv_to_h264`，该函数接受一个`Mat`类型的YUV图像，一个AVCodecContext结构体指针，一个AVFrame结构体指针和一个AVPacket结构体指针，以及一个输出文件指针。该函数将YUV图像编码为H264流，并将输出数据写入输出文件。

要使用此代码，请将其保存为文件（例如“yuv_to_h264.cpp”），并使用以下命令编译：

g++ -o yuv_to_h264 yuv_to_h264.cpp `pkg-config --cflags --libs opencv` -lavcodec -lavutil

在编译后，您可以使用以下命令将YUV文件编码为H264文件：

./yuv_to_h264 input.yuv output.h264 width height

其中，`input.yuv`是输入YUV文件的路径，`output.h264`是输出H264文件的路径，`width`和`height`是输出视频的宽度和高度。