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  • Insert text on sequence of image and create video using imagemagick or graphicsmagick with node.js

    12 décembre 2015, par Keyur Sakaria

    I am trying to create a sequence of image with dynamic text using imagemagick and then convert into video using ffmpeg. The issue I am facing right now:

    1. I was able to put text on image but now I want to move that text and sync with the character on image. Below is the link of what I have achieved

    http://tinypic.com/player.php?v=2ciic8g%3E&s=9#.VmrAZUp97Dc

    The bright white "text goes here" text should sync with the character behind

    Below is the code which I have written

    gm("original_images/moving/" + text + ".png")
    .fill("#FCF7FB")
    .fontSize(40)
    .drawText(x, moveY, "text goes here", "center")
    .font("font/BTTTRIAL_1.ttf")
    .write("newImages/demo" + i + ".png", function(err)
    {
        count++;
        console.log("success : " + err);
        console.log("i : " + i);
        console.log("moving : " + moveX);

        if(count == 72)
        {
            console.log(count);
            var date = moment().format('MMMMDDYYYYhmmssa');
            var cmd = 'ffmpeg -r 17 -i newImages/demo%d.png -c:v libx264 -r 24 -pix_fmt yuv420p output/' + date + '.mp4';

            exec(cmd, function(error, stdout, stderr)
            {
                console.log(error)
                console.log(stdout)
                console.log(stderr)
            });
        }
    });

    I am trying to calculate x and y according to image and im getting the values in decimal, which graphicsmagick is not considering and rounding it thus text is not syncing with image and goes up and down

    If you have any other suggestions or ways to achieve what im trying to do please let me know.

    Thanks in advance.

  • A bug in CV::VideoCapture::open() ?

    12 décembre 2015, par wking

    I am using CV::VideoCapture to capture frames from an IP camera. It works most of time, however, sometimes it reports the error:

    [mjpeg @ 0x233aea0] overread 8

    And when this error occurred, my program just stuck there. This might explain why. But how can I solve it in C++ code? Can OpenCV handle this error without terminate the program?

    p.s. I found that if I didn't call CV::VideoCapture::read() immediately, but wait for a while, like 60 seconds, after CV::VideoCapture::open(), this error occurred everytime! Is it a bug of OpenCV?

    #include 
#include highgui/highgui.hpp>
#include 

int main(int argc, char* argv[]) {
  // argv[1] is a valid url, like "http://xxxx/mjpg/video.mjpg"
  cv::VideoCapture cap(argv[1]);
  if (!cap.isOpened()) {
    std::cout << "Cannot Open Camera!" << std::endl;
    return -1;
  }
  // The error occures if I pause for a while.
  // But it is okay when I capture frames from video files intead of IP camera.
  sleep(60);
  while (static_cast(cv::waitKey(1)) != 'q') {
    cv::Mat frame;
    cap >> frame;
    if (frame.empty()) break;
    cv::imshow("frame", frame);
  }
}

  • Placing an image inside another image [on hold]

    12 décembre 2015, par George R.

    I'm trying to place an image (small PNG file) inside a larger image (JPEG). Can I do this and choose where in the larger image the smaller gets positioned? Thanks

  • Merge 2 videos like PIP (pitcher in pitcher) using ffmpeg

    12 décembre 2015, par Karthikeya Vaidya

    I am using ffmpeg to merge 2 videos as shown in below image. but the problem is both the videos are not in sync. To be more specific lets consider video1.mp4 starts at 00:01:00 and ends at 00:10:00 and video2.mp4 starts at 00:02:13 and ends at 00:10:00. Now I merge video1.mp4 and video2.mp4 to get pip.mp4 using below command 

    ffmpeg -i video1.mp4 -i video2.mp4 -filter_complex "[1]scale=iw/5:ih/5 [pip]; [0][pip] overlay=main_w-overlay_w-10:main_h-overlay_h-10" -profile:v main -level 3.1 -b:v 440k -ar 44100 -ab 128k -s 720x400 -vcodec h264 -acodec aac -strict experimental  pip.mp4

    The problem is time gap of 1 min 13 sec remains for entire output video. ffmpeg is maintaining the end time of both videos. How can I mix both the videos so that starting time difference is eliminated (from lengthy video) from video1.mp4 and after that mixing of videos begins at same time frame and output video will be in sync.

    enter image description here

    Can anyone please suggest me how to achieve this

    Many Thanks

    Karthik Vaidya

  • How to compile ffmpeg with x11grab ? xlib missing

    12 décembre 2015, par Shuman

    I am compiling ffmpeg on centos 7.1 x64. The error message I got is 

    #### FFmpeg static build, by STVS SA ####
*** Building FFmpeg ***
ERROR: Xlib not found

    config.log

    gcc -D_ISOC99_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_POSIX_C_SOURCE=200112 -D_XOPEN_SOURCE=600 -I/home/shuman/github/ffmpeg-static/target/include -I/home/shuman/github/ffmpeg-static/target/include -static --static -std=c99 -fomit-frame-pointer -pthread -I/home/shuman/github/ffmpeg-static/target/include/opus -I/home/shuman/github/ffmpeg-static/target/include -I/home/shuman/github/ffmpeg-static/target/include -I/home/shuman/github/ffmpeg-static/target/include -I/home/shuman/github/ffmpeg-static/target/include -I/home/shuman/github/ffmpeg-static/target/include -I/home/shuman/github/ffmpeg-static/target/include -c -o /tmp/ffconf.eYdD6TBQ.o /tmp/ffconf.UnBT7bp1.c
gcc -L/home/shuman/github/ffmpeg-static/target/lib -lm -L/home/shuman/github/ffmpeg-static/target/lib -lm -static -Wl,--as-needed -Wl,-z,noexecstack -o /tmp/ffconf.6gKhjd90 /tmp/ffconf.eYdD6TBQ.o -lxcb -lxvidcore -L/home/shuman/github/ffmpeg-static/target/lib -lx264 -lpthread -lm -L/home/shuman/github/ffmpeg-static/target/lib -lvpx -lm -L/home/shuman/github/ffmpeg-static/target/lib -lvpx -lm -L/home/shuman/github/ffmpeg-static/target/lib -lvpx -lm -L/home/shuman/github/ffmpeg-static/target/lib -lvpx -lm -lvorbisenc -lvorbis -logg -ltheoraenc -ltheoradec -logg -L/home/shuman/github/ffmpeg-static/target/lib -lrtmp -lz -lssl -lcrypto -L/home/shuman/github/ffmpeg-static/target/lib -lopus -lmp3lame -lfaac -lm -lbz2 -lz -pthread -ldl -lXext
/usr/bin/ld: cannot find -lxcb
collect2: error: ld returned 1 exit status
ERROR: Xlib not found

    but I have yum installed libxcb, what could be the reason for this?

    edit:

    $ rpm -qa | grep libxcb
libxcb-devel-1.11-4.el7.x86_64
libxcb-1.11-4.el7.i686
libxcb-1.11-4.el7.x86_64
compat-libxcb-1.9-1.el7.x86_64

$ locate xcb.h
/home/shuman/Downloads/buildroot/package/x11r7/libxcb/libxcb.hash
/usr/include/X11/Xlib-xcb.h
/usr/include/cairo/cairo-xcb.h
/usr/include/xcb/xcb.h

$ locate xcb.so
/home/shuman/.dropbox-dist/dropbox-lnx.x86_64-3.10.11/libX11-xcb.so.1
/home/shuman/.dropbox-dist/dropbox-lnx.x86_64-3.10.11/plugins/platforms/libqxcb.so
/usr/lib/libX11-xcb.so
/usr/lib/libX11-xcb.so.1
/usr/lib/libX11-xcb.so.1.0.0
/usr/lib/libxcb.so.1
/usr/lib/libxcb.so.1.1.0
/usr/lib64/libX11-xcb.so
/usr/lib64/libX11-xcb.so.1
/usr/lib64/libX11-xcb.so.1.0.0
/usr/lib64/libxcb.so
/usr/lib64/libxcb.so.1
/usr/lib64/libxcb.so.1.1.0

    edit: it turns out that it's because I'm not using the correct configure commandline, after following this guide, it works now

    CFLAGS="-I$TARGET_DIR/include" LDFLAGS="-L$TARGET_DIR/lib" ./configure --prefix=${OUTPUT_DIR:-$TARGET_DIR} --extra-cflags="-I$TARGET_DIR/include" --extra-ldflags="-L$TARGET_DIR/lib"  --pkg-config-flags="--static" --enable-gpl --enable-nonfree --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-librtmp

    in which, $TARGET_DIR is where all the dependency libs installed, this is part of my static ffmpeg build script ( with librtmp and libx265 and x11grab)

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