Fix limited value ranges in properties.

[dcpomatic.git] / src / lib / ffmpeg_content.cc

diff --git a/src/lib/ffmpeg_content.cc b/src/lib/ffmpeg_content.cc
index 1fb95535f0e74af738f262f481fc22e380d300e6..03763fc289b0135e91cb764ff736cb9591e2853f 100644 (file)
--- a/src/lib/ffmpeg_content.cc
+++ b/src/lib/ffmpeg_content.cc
@@ -540,8 +540,10 @@ FFmpegContent::add_properties (shared_ptr<const Film> film, list<UserProperty>&
                video->add_properties (p);
 
                if (_bits_per_pixel) {
-                       int const sub = 219 * pow (2, _bits_per_pixel.get() - 8);
-                       int const total = pow (2, _bits_per_pixel.get());
+                       /* Assuming there's three components, so bits per pixel component is _bits_per_pixel / 3 */
+                       int const lim_start = pow(2, _bits_per_pixel.get() / 3 - 4);
+                       int const lim_end = 235 * pow(2, _bits_per_pixel.get() / 3 - 8);
+                       int const total = pow(2, _bits_per_pixel.get() / 3);
 
                        switch (_color_range.get_value_or(AVCOL_RANGE_UNSPECIFIED)) {
                        case AVCOL_RANGE_UNSPECIFIED:
@@ -554,7 +556,7 @@ FFmpegContent::add_properties (shared_ptr<const Film> film, list<UserProperty>&
                                /// file is limited, so that not all possible values are valid.
                                p.push_back (
                                        UserProperty (
-                                               UserProperty::VIDEO, _("Colour range"), String::compose (_("Limited (%1-%2)"), (total - sub) / 2, (total + sub) / 2)
+                                               UserProperty::VIDEO, _("Colour range"), String::compose(_("Limited (%1-%2)"), lim_start, lim_end)
                                                )
                                        );
                                break;