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Libavformat

AVFrame to IplImage 

#include <libavutil/pixdesc.h>
IplImage * createRgb24CvImage(int const & pixel_format, AVFrame const * frame)
{
    if (pixel_format != PIX_FMT_BGR24) {
        return nullptr;
    }

    AVPixFmtDescriptor const * desc = av_pix_fmt_desc_get(static_cast<AVPixelFormat>(pixel_format));
    int depth = av_get_bits_per_pixel(desc); // maybe 8
    int width = frame->width;
    int height = frame->height;
    int linesize = frame->linesize[0];
    int channel = frame->channels; // maybe 3

    uint8_t * frame_data = NULL;
    uint8_t * cvframe_date = NULL;

    IplImage * image = cvCreateImage(cvSize(width, height), depth, channel);
    for (int y = 0; y < height; y++) {
        frame_data = (frame->data[0] + y * linesize);
        cvframe_date = (uint8_t *) (image->imageData + y * image->widthStep);

        for (int x = 0; x < width; x++) {
            // BGR24 Format Copy.
            cvframe_date[3 * x + 2] = frame_data[3 * x + 2]; // r
            cvframe_date[3 * x + 1] = frame_data[3 * x + 1]; // g
            cvframe_date[3 * x + 0] = frame_data[3 * x + 0]; // b
        }
    }

    return image;
}

Duration 구하기 

AVFormatContext*  pFC;
int ret;
pFC = avformat_alloc_context();
ret  = avformat_open_input(&pFC, filename, NULL, NULL);
if (ret < 0) {
    // fail .
}
ret  = avformat_find_stream_info(pFC, NULL);
if (ret < 0) {
    // fail
}
printf("duration %ld", pFC->duration);

FFMPEG Custom IO

check the AVFMT_FLAG_CUSTOM_IO macro.

How to get the duration and frame rate using libavformat 

int64_t AVFormatContext::duration
AVRational AVStream::avg_frame_rate
static double av_q2d ( AVRational a )

See also