videoio: add missing CAP_PROP_SAR_NUM/DEN propepties into .hpp file

reuse av_guess_sample_aspect_ratio() if available in ffmpeg

modules/videoio/include/opencv2/videoio.hpp

@@ -164,7 +164,12 @@ enum VideoCaptureProperties {
        CAP_PROP_IRIS          =36,
        CAP_PROP_SETTINGS      =37, //!< Pop up video/camera filter dialog (note: only supported by DSHOW backend currently. The property value is ignored)
        CAP_PROP_BUFFERSIZE    =38,
-       CAP_PROP_AUTOFOCUS     =39
+       CAP_PROP_AUTOFOCUS     =39,
+       CAP_PROP_SAR_NUM       =40, //!< Sample aspect ratio: num/den (num)
+       CAP_PROP_SAR_DEN       =41, //!< Sample aspect ratio: num/den (den)
+#ifndef CV_DOXYGEN
+       CV__CAP_PROP_LATEST
+#endif
      };
 
 

modules/videoio/src/cap_ffmpeg_impl.hpp

@@ -406,6 +406,29 @@ inline int _opencv_ffmpeg_av_image_get_buffer_size(enum AVPixelFormat pix_fmt, i
 #endif
 };
 
+static AVRational _opencv_ffmpeg_get_sample_aspect_ratio(AVStream *stream)
+{
+#if LIBAVUTIL_VERSION_MICRO >= 100 && LIBAVUTIL_BUILD >= CALC_FFMPEG_VERSION(54, 5, 100)
+    return av_guess_sample_aspect_ratio(NULL, stream, NULL);
+#else
+    AVRational undef = {0, 1};
+
+    // stream
+    AVRational ratio = stream ? stream->sample_aspect_ratio : undef;
+    av_reduce(&ratio.num, &ratio.den, ratio.num, ratio.den, INT_MAX);
+    if (ratio.num > 0 && ratio.den > 0)
+        return ratio;
+
+    // codec
+    ratio  = stream && stream->codec ? stream->codec->sample_aspect_ratio : undef;
+    av_reduce(&ratio.num, &ratio.den, ratio.num, ratio.den, INT_MAX);
+    if (ratio.num > 0 && ratio.den > 0)
+        return ratio;
+
+    return undef;
+#endif
+}
+
 
 struct CvCapture_FFMPEG
 {
@@ -427,7 +450,6 @@ struct CvCapture_FFMPEG
     double  get_duration_sec() const;
     double  get_fps() const;
     int     get_bitrate() const;
-    AVRational get_sample_aspect_ratio(AVStream *stream) const;
 
     double  r2d(AVRational r) const;
     int64_t dts_to_frame_number(int64_t dts);
@@ -1089,9 +1111,9 @@ double CvCapture_FFMPEG::getProperty( int property_id ) const
         return (double)video_st->codec.codec_tag;
 #endif
     case CV_FFMPEG_CAP_PROP_SAR_NUM:
-        return get_sample_aspect_ratio(ic->streams[video_stream]).num;
+        return _opencv_ffmpeg_get_sample_aspect_ratio(ic->streams[video_stream]).num;
     case CV_FFMPEG_CAP_PROP_SAR_DEN:
-        return get_sample_aspect_ratio(ic->streams[video_stream]).den;
+        return _opencv_ffmpeg_get_sample_aspect_ratio(ic->streams[video_stream]).den;
     default:
         break;
     }
@@ -1164,28 +1186,6 @@ int64_t CvCapture_FFMPEG::dts_to_frame_number(int64_t dts)
     return (int64_t)(get_fps() * sec + 0.5);
 }
 
-AVRational CvCapture_FFMPEG::get_sample_aspect_ratio(AVStream *stream) const
-{
-    AVRational undef = {0, 1};
-    AVRational stream_sample_aspect_ratio = stream ? stream->sample_aspect_ratio : undef;
-    AVRational frame_sample_aspect_ratio  = stream && stream->codec ? stream->codec->sample_aspect_ratio : undef;
-
-    av_reduce(&stream_sample_aspect_ratio.num, &stream_sample_aspect_ratio.den,
-        stream_sample_aspect_ratio.num,  stream_sample_aspect_ratio.den, INT_MAX);
-    if (stream_sample_aspect_ratio.num <= 0 || stream_sample_aspect_ratio.den <= 0)
-        stream_sample_aspect_ratio = undef;
-
-    av_reduce(&frame_sample_aspect_ratio.num, &frame_sample_aspect_ratio.den,
-        frame_sample_aspect_ratio.num,  frame_sample_aspect_ratio.den, INT_MAX);
-    if (frame_sample_aspect_ratio.num <= 0 || frame_sample_aspect_ratio.den <= 0)
-        frame_sample_aspect_ratio = undef;
-
-    if (stream_sample_aspect_ratio.num)
-        return stream_sample_aspect_ratio;
-    else
-        return frame_sample_aspect_ratio;
-}
-
 double CvCapture_FFMPEG::dts_to_sec(int64_t dts)
 {
     return (double)(dts - ic->streams[video_stream]->start_time) *