chore: import upstream snapshot with attribution

samples/cpp/videocapture_audio.cpp

@@ -0,0 +1,59 @@
+#include <opencv2/core.hpp>
+#include <opencv2/videoio.hpp>
+#include <opencv2/highgui.hpp>
+#include <iostream>
+
+using namespace cv;
+using namespace std;
+
+int main(int argc, char** argv)
+{
+    CommandLineParser parser(argc, argv, "{@audio||}");
+    string file = parser.get<string>("@audio");
+
+    if (file.empty())
+    {
+        return 1;
+    }
+
+    Mat frame;
+    vector<vector<Mat>> audioData;
+    VideoCapture cap;
+    vector<int> params {    CAP_PROP_AUDIO_STREAM, 0,
+                            CAP_PROP_VIDEO_STREAM, -1,
+                            CAP_PROP_AUDIO_DATA_DEPTH, CV_16S   };
+
+    cap.open(file, CAP_MSMF, params);
+    if (!cap.isOpened())
+    {
+        cerr << "ERROR! Can't to open file: " + file << endl;
+        return -1;
+    }
+
+    const int audioBaseIndex = (int)cap.get(CAP_PROP_AUDIO_BASE_INDEX);
+    const int numberOfChannels = (int)cap.get(CAP_PROP_AUDIO_TOTAL_CHANNELS);
+    cout << "CAP_PROP_AUDIO_DATA_DEPTH: " << depthToString((int)cap.get(CAP_PROP_AUDIO_DATA_DEPTH)) << endl;
+    cout << "CAP_PROP_AUDIO_SAMPLES_PER_SECOND: " << cap.get(CAP_PROP_AUDIO_SAMPLES_PER_SECOND) << endl;
+    cout << "CAP_PROP_AUDIO_TOTAL_CHANNELS: " << numberOfChannels << endl;
+    cout << "CAP_PROP_AUDIO_TOTAL_STREAMS: " << cap.get(CAP_PROP_AUDIO_TOTAL_STREAMS) << endl;
+
+    int numberOfSamples = 0;
+    audioData.resize(numberOfChannels);
+    for (;;)
+    {
+        if (cap.grab())
+        {
+            for (int nCh = 0; nCh < numberOfChannels; nCh++)
+            {
+                cap.retrieve(frame, audioBaseIndex+nCh);
+                audioData[nCh].push_back(frame);
+                numberOfSamples+=frame.cols;
+            }
+        }
+        else { break; }
+    }
+
+    cout << "Number of samples: " << numberOfSamples << endl;
+
+    return 0;
+}