c++ - 如何在 C++ 中读取文本文件？

Question

我想检测视频中预定义的特定内容。为此，我分别使用已识别的一段视频和另一个输入视频。我已经阅读了识别视频中的数据，并且咬数组保存在文本文件中。现在我想将保存的文本文件的内容与输入的视频内容进行比较。

这是我的代码

    void CFfmpegmethods::VideoRead(){
    av_register_all();
    avformat_network_init();
    ifstream inFile;
    inFile.open("H:\\Sanduni_projects\\sample_ad.txt");
    const char *url = "H:\\Sanduni_projects\\ad_1.mp4";
    AVDictionary *options = NULL;
    AVFormatContext *s = avformat_alloc_context();

    AVPacket *pkt = new AVPacket(); //this structure stores compressed data

    //open an input stream and read the header
    int ret = avformat_open_input(&s, url, NULL,NULL);

    //avformat_find_stream_info(s, &options); //finding the missing information 

    if (ret < 0)
        abort();

    if (!inFile) {
        cerr << "Unable to open file datafile.txt";
        exit(1);   // call system to stop
    }

    av_dict_set(&options, "video_size", "640x480", 0);
    av_dict_set(&options, "pixel_format", "rgb24", 0);

    if (avformat_open_input(&s, url, NULL, &options) < 0){
        abort();
    }
    av_dict_free(&options);
    AVDictionaryEntry *e;

    if (e = av_dict_get(options, "", NULL, AV_DICT_IGNORE_SUFFIX)) {
        fprintf(stderr, "Option %s not recognized by the demuxer.\n", e->key);
        abort();
    }

    int i = 1;
    int64_t duration = 0;
    int size = 0;
    uint8_t *data; //Unsigned integer type with a width of exactly 8 bits.
    int sum = 0;

    int total_size = 0;
    int64_t total_duration = 0;
    int packet_size = 0;
    int64_t stream_index = 0;
    int64_t bit_rate = 0;
    AVBufferRef *buf;

    //writing data to a file
    outdata.open("H:\\Sanduni_projects\\sample_ad.txt");
    //outdata.open("H:\\Sanduni_projects\\log.txt");

    if (!outdata){
        cerr << "Error: file could not be opened" << endl;
        exit(1);
    }

    //Split what is stored in the file into frames and return one for each call
    //returns the next frame of the stream

    while(1){
        int frame = av_read_frame(s, pkt); //one frame is readed.
        if (frame < 0) break;
        size = pkt->size;
        data = pkt->data;

        for (int j = 0; j < size; j++){
            for (int k = 0; k < 12; k++){
                while (!inFile.eof){


                }
                //if (data[j] != ) break;
            }
        }

        //int decode = avcodec_send_packet(avctx, pkt);
    }

    //make the packet free
    av_packet_unref(pkt);
    delete pkt;

    cout << "total size: " << total_size << endl;
    cout << "total duration:" << total_duration << endl;

    outdata.close();

    //Close the file after reading
    avformat_close_input(&s);
}


void CFfmpegmethods::SampleAdCreation(){
    av_register_all();
    const char *url_ref = "H:\\Sanduni_projects\\sample_ad.mp4";
    AVDictionary *options = NULL;
    AVDictionary *options_ref = NULL;
    AVFormatContext *s = avformat_alloc_context();
    AVPacket *pkt = new AVPacket(); //this structure stores compressed data


    //open an input stream and read the header
    int ret = avformat_open_input(&s, url_ref, NULL, NULL);

    if (ret < 0)
        abort();

    av_dict_set(&options, "video_size", "640x480", 0);
    av_dict_set(&options, "pixel_format", "rgb24", 0);

    if (avformat_open_input(&s, url_ref, NULL, &options) < 0){
        abort();
    }

    av_dict_free(&options);
    AVDictionaryEntry *e;

    if (e = av_dict_get(options, "", NULL, AV_DICT_IGNORE_SUFFIX)) {
        fprintf(stderr, "Option %s not recognized by the demuxer.\n", e->key);
        abort();
    }

    uint8_t *data; 

    //writing data to a file
    outdata.open("H:\\Sanduni_projects\\sample_ad.txt");

    if (!outdata){
        cerr << "Error: file could not be opened" << endl;
        exit(1);
    }

    for (int m = 0; m < 12; m++){
        int size = pkt->size;
        int frame = av_read_frame(s, pkt); 
        if (frame < 0) break;

        data = pkt->data;

        for (int j = 0; j < size; j++){
            outdata << data[j];
        } outdata<<endl;
    }

    //make the packet free
    av_packet_unref(pkt);
    delete pkt;

    outdata.close();

    //Close the file after reading
    avformat_close_input(&s);
}

Answer 1

当您输出 outdata您应该用空格分隔字节:

    for (int j = 0; j < size; j++){
        outdata << data[j] << ' ';
    }

否则字节 {11, 1} 将产生与 {1, 11} 相同的输出。

然后你可以从你的 inFile 中读取这些字节:

unsigned char dataByte;
while (inFile >> dataByte)
{
    do something with dataByte;
}