将mat yuv编码为h264流, 使用ffmpeg, cpp代码

以下是将Mat YUV编码为H264流的C++代码示例，使用FFmpeg库：

#include <iostream>
#include <fstream>
#include <opencv2/opencv.hpp>
#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libavutil/imgutils.h>
#include <libswscale/swscale.h>

int main(int argc, char* argv[])
{
    // Check input arguments
    if (argc < 4) {
        std::cerr << "Usage: " << argv[0] << " input_file width height output_file" << std::endl;
        return 1;
    }

    // Initialize FFmpeg
    av_register_all();

    // Open input file
    const char* input_file = argv[1];
    int width = std::stoi(argv[2]);
    int height = std::stoi(argv[3]);
    cv::Mat yuv_image(height * 3 / 2, width, CV_8UC1);
    std::ifstream input_stream(input_file, std::ios::binary);
    if (!input_stream.is_open()) {
        std::cerr << "Failed to open input file" << std::endl;
        return 1;
    }

    // Open output file
    const char* output_file = argv[4];
    AVFormatContext* format_context = nullptr;
    if (avformat_alloc_output_context2(&format_context, nullptr, nullptr, output_file) < 0) {
        std::cerr << "Failed to allocate output context" << std::endl;
        return 1;
    }

    // Open output stream
    AVOutputFormat* output_format = format_context->oformat;
    AVStream* stream = avformat_new_stream(format_context, nullptr);
    if (!stream) {
        std::cerr << "Failed to create output stream" << std::endl;
        return 1;
    }
    stream->id = format_context->nb_streams - 1;
    AVCodecContext* codec_context = stream->codec;
    codec_context->codec_id = output_format->video_codec;
    codec_context->codec_type = AVMEDIA_TYPE_VIDEO;
    codec_context->width = width;
    codec_context->height = height;
    codec_context->pix_fmt = AV_PIX_FMT_YUV420P;
    codec_context->time_base = { 1, 25 };
    if (format_context->oformat->flags & AVFMT_GLOBALHEADER) {
        codec_context->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
    }
    AVCodec* codec = avcodec_find_encoder(codec_context->codec_id);
    if (!codec) {
        std::cerr << "Failed to find encoder" << std::endl;
        return 1;
    }
    if (avcodec_open2(codec_context, codec, nullptr) < 0) {
        std::cerr << "Failed to open codec" << std::endl;
        return 1;
    }
    av_dump_format(format_context, 0, output_file, 1);
    if (!(output_format->flags & AVFMT_NOFILE)) {
        if (avio_open(&format_context->pb, output_file, AVIO_FLAG_WRITE) < 0) {
            std::cerr << "Failed to open output file" << std::endl;
            return 1;
        }
    }
    if (avformat_write_header(format_context, nullptr) < 0) {
        std::cerr << "Failed to write header" << std::endl;
        return 1;
    }

    // Initialize video converter
    struct SwsContext* converter = sws_getContext(width, height, AV_PIX_FMT_GRAY8,
                                                  width, height, AV_PIX_FMT_YUV420P,
                                                  0, nullptr, nullptr, nullptr);
    if (!converter) {
        std::cerr << "Failed to create video converter" << std::endl;
        return 1;
    }

    // Encode frames
    AVFrame* frame = av_frame_alloc();
    frame->width = width;
    frame->height = height;
    frame->format = codec_context->pix_fmt;
    if (av_frame_get_buffer(frame, 0) < 0) {
        std::cerr << "Failed to allocate frame buffer" << std::endl;
        return 1;
    }
    AVPacket packet = { 0 };
    int frame_count = 0;
    while (input_stream.read(reinterpret_cast<char*>(yuv_image.data), yuv_image.total())) {
        // Convert YUV image to AVFrame
        sws_scale(converter, &yuv_image.data, &yuv_image.step, 0, height,
                  frame->data, frame->linesize);

        // Encode frame
        frame->pts = frame_count++;
        int result = avcodec_send_frame(codec_context, frame);
        if (result < 0) {
            std::cerr << "Failed to send frame" << std::endl;
            return 1;
        }
        while (result >= 0) {
            result = avcodec_receive_packet(codec_context, &packet);
            if (result == AVERROR(EAGAIN) || result == AVERROR_EOF) {
                break;
            }
            if (result < 0) {
                std::cerr << "Failed to receive packet" << std::endl;
                return 1;
            }
            av_packet_rescale_ts(&packet, codec_context->time_base, stream->time_base);
            packet.stream_index = stream->index;
            if (av_interleaved_write_frame(format_context, &packet) < 0) {
                std::cerr << "Failed to write packet" << std::endl;
                return 1;
            }
            av_packet_unref(&packet);
        }
    }

    // Flush encoder
    int result = avcodec_send_frame(codec_context, nullptr);
    if (result < 0) {
        std::cerr << "Failed to send frame" << std::endl;
        return 1;
    }
    while (result >= 0) {
        result = avcodec_receive_packet(codec_context, &packet);
        if (result == AVERROR(EAGAIN) || result == AVERROR_EOF) {
            break;
        }
        if (result < 0) {
            std::cerr << "Failed to receive packet" << std::endl;
            return 1;
        }
        av_packet_rescale_ts(&packet, codec_context->time_base, stream->time_base);
        packet.stream_index = stream->index;
        if (av_interleaved_write_frame(format_context, &packet) < 0) {
            std::cerr << "Failed to write packet" << std::endl;
            return 1;
        }
        av_packet_unref(&packet);
    }

    // Close output file
    av_write_trailer(format_context);
    if (format_context && !(output_format->flags & AVFMT_NOFILE)) {
        avio_close(format_context->pb);
    }
    avcodec_close(codec_context);
    avformat_free_context(format_context);
    av_frame_free(&frame);
    sws_freeContext(converter);
    input_stream.close();

    return 0;
}

请注意，此示例假设输入文件为YUV 4:2:0格式的二进制文件，其中Y，U和V平面以交替方式存储。如果您的输入格式不同，请根据需要进行修改。此外，此示例假设您已安装OpenCV和FFmpeg库。