CODEWITHSUNDEEP
c++opencvmemory-leaksffmpegopencv3.0
Pavel
Pavel

Reputation: 277

OpenCV Mat to ffmpeg AVPicture conversion memory leak

I have next code:

void matToAvPicture(cv::Mat frame, AVPicture *picture)
{
    cv::resize(frame, frame, cv::Size(m_streamWidth, m_streamHeight));
    uint8_t* buf = (uint8_t*)malloc(avpicture_get_size(AV_PIX_FMT_BGR24, m_streamWidth, m_streamHeight)); // 3 bytes per pixel
    for(int i = 0; i < m_streamHeight; i++)
    {
        memcpy(&(buf[i * m_streamWidth * 3]), &(frame.data[i * frame.step]), m_streamWidth * 3);
    }
    AVPicture bgrPicture;
    avpicture_alloc(&bgrPicture, AV_PIX_FMT_BGR24, m_streamWidth, m_streamHeight);
    avpicture_fill(&bgrPicture, buf, AV_PIX_FMT_BGR24, m_streamWidth, m_streamHeight);
    sws_scale(rgbToYuvContext, (const uint8_t * const *)bgrPicture.data, bgrPicture.linesize, 0, m_streamHeight, picture->data, picture->linesize);
    avpicture_free(&bgrPicture);
//    free(buf);
}

But call of avpicture_free(&bgrPicture) doesn't free memory completely. If I commented line avpicture_fill(&bgrPicture, buf, AV_PIX_FMT_BGR24, m_streamWidth, m_streamHeight); and uncommented line
free(buf)
memory leak doesn't appear. What is the problem?

Upvotes: 0

Views: 491

Answers (1)

Ronald S. Bultje
Ronald S. Bultje

Reputation: 11174

uint8_t* buf = (uint8_t*)malloc(avpicture_get_size(AV_PIX_FMT_BGR24, m_streamWidth, m_streamHeight)); // 3 bytes per pixel
avpicture_alloc(&bgrPicture, AV_PIX_FMT_BGR24, m_streamWidth, m_streamHeight);
avpicture_fill(&bgrPicture, buf, AV_PIX_FMT_BGR24, m_streamWidth, m_streamHeight);

That's doing the same thing twice. avpicture_alloc allocates and fills the data array in a picture with a self-allocated buffer (free'ed with avpicture_free), and avpicture_fill fills the data structure with some buffer that you control yourself (in your case: malloc/free manually). Use either malloc+avpicture_fill+free, or use avpicture_alloc+avpicture_free. Don't use both.

Upvotes: 1

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