dlib/examples/ffmpeg_video_demuxing2_ex.cpp

84 lines
2.4 KiB
C++

// The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt
/*
This is an example illustrating the use of the ffmpeg wrappers,
in this case the demuxer API.
In this example, we show how to read both images and audio.
*/
#include <cstdio>
#include <dlib/media.h>
#include <dlib/gui_widgets.h>
#include <dlib/cmd_line_parser.h>
using namespace std;
using namespace dlib;
using namespace dlib::ffmpeg;
int main(const int argc, const char** argv)
try
{
command_line_parser parser;
parser.add_option("i", "input video", 1);
parser.add_option("verbose", "enable all internal ffmpeg logging");
parser.set_group_name("Help Options");
parser.add_option("h", "alias of --help");
parser.add_option("help", "display this message and exit");
parser.parse(argc, argv);
const char* one_time_opts[] = {"i"};
parser.check_one_time_options(one_time_opts);
if (parser.option("h") || parser.option("help"))
{
parser.print_options();
return 0;
}
const std::string filepath = parser.option("i").argument();
// We use the most simple constructor, the one that takes in filepath.
// By default, both images and audio are read.
demuxer cap(filepath);
if (!cap.is_open())
{
printf("%s is not a valid video file\n", filepath.c_str());
return EXIT_FAILURE;
}
// Read images and audio.
// Images are plotted, audio samples are counted.
frame f;
array2d<rgb_pixel> img;
image_window win;
int nsamples{0};
// When reading frames, we get exactly what's in the codec by default.
// To resize, change pixel format, resample or change sample format,
// you have to pass extra arguments to read() which either resize or resample
// the frame. Since we want rgb_pixel, we need to set the pixel format appropriately.
const resizing_args args_image {0, 0, pix_traits<rgb_pixel>::fmt};
while (cap.read(f, args_image))
{
if (f.is_image())
{
convert(f, img);
win.set_image(img);
}
else if (f.is_audio())
{
nsamples += f.nsamples();
}
}
printf("Read %i audio samples\n", nsamples);
return EXIT_SUCCESS;
}
catch (const std::exception& e)
{
printf("%s\n", e.what());
return EXIT_FAILURE;
}