Implemented a video reader and writer with OpenCV.

The program now works as a video cat or converter :
./prpa -c MP42 -o /tmp/bar.avi /tmp/foo.flv
-c specify a 4-letter codec to be used for the output file and follow a strict
code defined on this page : http://www.fourcc.org/codecs.php
The file output extension *does* matter and must match the selected output
codec.

Makefile.am

@@ -27,4 +27,7 @@ prpa_SOURCES = src/main.cc
 
 prpa_LDFLAGS =				\
 	$(BOOST_LDFLAGS)		\
-	$(BOOST_PROGRAM_OPTIONS_LIB)
+	$(BOOST_PROGRAM_OPTIONS_LIB) \
+	-ltbb \
+	$(DEPS_CFLAGS) \
+	$(DEPS_LIBS)

configure.ac

@@ -42,6 +42,11 @@ m4_include([m4/ax_boost_program_options.m4])
 AX_BOOST_BASE([1.33.1])
 AX_BOOST_PROGRAM_OPTIONS
 
+#
+# Check for OpenCV
+#
+PKG_CHECK_MODULES([DEPS], [opencv])
+
 #
 # Check for TBB
 #

src/encoder/Makefile.am

@@ -6,4 +6,4 @@ AM_CXXFLAGS = 			\
 	$(BOOST_CPPFLAGS)	\
 	$(DEBUG_CXXFLAGS)
 
-______lib_libencoder_a_SOURCES =
+______lib_libencoder_a_SOURCES = video.cc video_writer.cc video_reader.cc

src/encoder/video.cc

@@ -0,0 +1,7 @@
+#include "video.hh"
+
+void Video::copy(Video& v)
+{
+  for (auto it = v.images_.begin(); it != v.images_.end(); ++it)
+    this->images_.push_back(new cv::Mat(**it));
+}

src/encoder/video.hh

@@ -0,0 +1,17 @@
+#ifndef VIDEO_HH_
+# define VIDEO_HH_
+
+# include <string>
+# include "tbb/concurrent_vector.h"
+# include "opencv2/opencv.hpp"
+
+class Video
+{
+  public:
+    void close();
+    void copy(Video& v);
+  protected:
+    tbb::concurrent_vector<cv::Mat*> images_;
+};
+
+#endif /* !VIDEO_HH_ */

src/encoder/video_reader.cc

@@ -0,0 +1,42 @@
+#include "video_reader.hh"
+
+VideoReader::VideoReader(std::string filename)
+	: capture_(filename)
+{
+  if (this->capture_.isOpened())
+  {
+    while (this->capture_.grab())
+    {
+      cv::Mat retrieved;
+      cv::Mat* mat = new cv::Mat();
+      this->capture_.retrieve(retrieved);
+      *mat = retrieved.clone();
+      this->images_.push_back(mat);
+    }
+  }
+}
+
+int VideoReader::fps_get()
+{
+  if (this->capture_.isOpened())
+    return (int)this->capture_.get(CV_CAP_PROP_FPS);
+  else
+    return -1;
+}
+
+int VideoReader::width_get()
+{
+  if (this->capture_.isOpened())
+    return (int)this->capture_.get(CV_CAP_PROP_FRAME_WIDTH);
+  else
+    return -1;
+}
+
+int VideoReader::height_get()
+{
+  if (this->capture_.isOpened())
+    return (int)this->capture_.get(CV_CAP_PROP_FRAME_HEIGHT);
+  else
+    return -1;
+}
+

src/encoder/video_reader.hh

@@ -0,0 +1,18 @@
+#ifndef VIDEO_READER_HH_
+# define VIDEO_READER_HH_
+
+# include <string>
+# include "video.hh"
+
+class VideoReader: public Video
+{
+  public:
+    VideoReader(std::string filename);
+    int fps_get();
+    int width_get();
+    int height_get();
+  private:
+    cv::VideoCapture capture_;
+};
+
+#endif /* !VIDEO_READER_HH_ */

src/encoder/video_writer.cc

@@ -0,0 +1,20 @@
+#include "video_writer.hh"
+
+bool VideoWriter::open(std::string filename, std::string enc,
+                        int fps, int width, int height)
+{
+  if (enc.length() != 4)
+    return false;
+
+  return this->writer_.open(filename,
+    CV_FOURCC(enc[0], enc[1], enc[2], enc[3]), fps, { width, height } );
+}
+
+void VideoWriter::write()
+{
+  if (this->writer_.isOpened())
+  {
+    for (auto it = this->images_.begin(); it != this->images_.end(); ++it)
+      this->writer_.write(**it);
+  }
+}

src/encoder/video_writer.hh

@@ -0,0 +1,17 @@
+#ifndef VIDEO_WRITER_HH_
+# define VIDEO_WRITER_HH_
+
+# include <string>
+# include "video.hh"
+
+class VideoWriter: public Video
+{
+  public:
+    void write();
+    bool open(std::string filename, std::string enc,
+              int fps, int width, int height);
+  private:
+    cv::VideoWriter writer_;
+};
+
+#endif /* !VIDEO_WRITER_HH_ */

src/main.cc

@@ -1,6 +1,10 @@
 #include <iostream>
 #include <boost/program_options.hpp>
 
+#include "encoder/video.hh"
+#include "encoder/video_reader.hh"
+#include "encoder/video_writer.hh"
+
 int
 main (int argc, char** argv)
 {
@@ -12,6 +16,8 @@ main (int argc, char** argv)
     ("help,h", "produce help message")
     ("filter,f", po::value<std::vector<std::string> > (), "apply a filter")
     ("input-file,i", po::value<std::vector<std::string> > (), "file to treat")
+    ("output,o", po::value<std::vector<std::string> > (), "output file")
+    ("codec,c", po::value<std::vector<std::string> > (), "output codec")
     ;
 
   // Handle ./prpa file.avi instead of ./prpa --input-file=file.avi
@@ -54,5 +60,13 @@ main (int argc, char** argv)
   else
     std::cout << 0 << std::endl;
 
+  VideoReader vr(vm["input-file"].as<std::vector<std::string> >()[0]);
+  VideoWriter vw = VideoWriter();
+  vw.open(vm["output"].as<std::vector<std::string> >()[0],
+    vm["codec"].as<std::vector<std::string> >()[0],
+    vr.fps_get(), vr.width_get(), vr.height_get());
+  vw.copy(vr);
+  vw.write();
+
   return 0;
 }