I am reading a mpeg4 video stream using ffmpeg. I use some of its properties and do some processes using those properties. What I want is to play the opened video using a player like vlc. And then consequently I need to play the output video after processing in order to check whether there is a latency. Is it possible to give the video to a port. So that I can get the video as a input to the vlc player from the specific port.
This is my code up to now. I use MV_generation method to extract features from it and to do a comparison from it.
static int MV_generation(const AVPacket *pkt)
{
std::vector<unsigned long long> vl = File_read();
std::hash<string> hash1;
std::ios_base::app);
double x_src_val = 0;
double y_src_val = 0;
double x_dst_val = 0;
double y_dst_val = 0;
int ret = avcodec_send_packet(video_dec_ctx, pkt);
if (ret < 0) {
//fprintf(stderr, "Error while sending a packet to the decoder: %s\n", av_err2str(ret));
return ret;
}
video_frame_count++;
while (ret >= 0){
ret = avcodec_receive_frame(video_dec_ctx, frame);
if (ret == AVERROR(EAGAIN) || ret == AVERROR_EOF) {
break;
}
else if (ret < 0) {
return ret;
}
if (ret >= 0) {
AVFrameSideData *sd;
sd = av_frame_get_side_data(frame, AV_FRAME_DATA_MOTION_VECTORS);
if (sd) {
const AVMotionVector *mvs = (const AVMotionVector *)sd->data;
int size_sd = sd->size;
//outData << size_sd << endl;
string str = "", str1, str2, str3, str4;
for (int i = 0; i < size_sd / sizeof(*mvs); i++) {
const AVMotionVector *mv = &mvs[i];
int x_src = mv->src_x;
int y_src = mv->src_y;
int x_dst = mv->dst_x;
int y_dst = mv->dst_y;
if (x_src != x_dst || y_src != y_dst || x_src > 100 || y_src > 100 || x_dst > 100 || y_dst > 100){
str1 = to_string(x_src);
str2 = to_string(y_src);
str3 = to_string(x_dst);
str4 = to_string(y_dst);
str = str.append(str1).append(str2).append(str3).append(str4);
}
}
for (unsigned long long y : vl)
{
// Check if any of the numbers are equal to x
if (hash1(str) == y)
{
cout << "matched frame_no : " << video_frame_count << endl;
}
}
}
av_frame_unref(frame);
}
}
outData.close();
return 0;
}
This method can also used once the frame is converted to a mat
int ShowVideo(Mat mRGB, string textOnVideo, string windowName){
namedWindow(windowName, 1);
Pict_type = frame->pict_type;
//cout << av_get_picture_type_char(Pict_type); //I P or B frame
if (AV_PICTURE_TYPE_NONE != Pict_type)
{
namedWindow(windowName, 1);
mRGB = Mat(dec_ctx->height, dec_ctx->width, CV_8UC3);
Mat mYUV(dec_ctx->height + dec_ctx->height / 2, dec_ctx->width, CV_8UC1, (void*)buff);
cvtColor(mYUV, mRGB, CV_YUV2RGB_YV12, 3);
putText(mRGB, textOnVideo,
Point(100, 100), FONT_HERSHEY_PLAIN, 1, Scalar(0, 0, 255, 255));
imshow(windowName, mRGB);
waitKey(1);
}
return 0;
}