Fix missing subtitles in some cases.

We were passing subtitles back from decoders to SubtitleDecoder
using dcp::SubtitleStrings and relying on their storage of time
to know when the subtitles were.  These times are quantised (by
the use of dcp::SubtitleString) and then compared with unquantised
times (kept as ContentTime) in the main checking loop in
SubtitleDecoder::get().

Fix this by storing periods as ContentTimePeriod as well as
in the dcp::SubtitleStrings.

1 files changed, 19 insertions, 14 deletions

diff --git a/src/lib/content_subtitle.h b/src/lib/content_subtitle.h
index ef904a980..3c0ce523e 100644
--- a/src/lib/content_subtitle.h
+++ b/src/lib/content_subtitle.h
@@ -31,37 +31,42 @@ class Image;
 class ContentSubtitle
 {
 public:
-	virtual ContentTimePeriod period () const = 0;
+	ContentSubtitle (ContentTimePeriod p)
+		: _period (p)
+	{}
+
+	ContentTimePeriod period () const {
+		return _period;
+	}
+
+private:
+	ContentTimePeriod _period;
 };
 
 class ContentImageSubtitle : public ContentSubtitle
 {
 public:
 	ContentImageSubtitle (ContentTimePeriod p, boost::shared_ptr<Image> im, dcpomatic::Rect<double> r)
-		: sub (im, r)
-		, _period (p)
+		: ContentSubtitle (p)
+		, sub (im, r)
 	{}
 
-	ContentTimePeriod period () const {
-		return _period;
-	}
-
 	/* Our subtitle, with its rectangle unmodified by any offsets or scales that the content specifies */
 	ImageSubtitle sub;
-
-private:
-	ContentTimePeriod _period;
 };
 
+/** A text subtitle.  We store the time period separately (as well as in the dcp::SubtitleStrings)
+ *  as the dcp::SubtitleString timings are sometimes quite heavily quantised and this causes problems
+ *  when we want to compare the quantised periods to the unquantised ones.
+ */
 class ContentTextSubtitle : public ContentSubtitle
 {
 public:
-	ContentTextSubtitle (std::list<dcp::SubtitleString> s)
-		: subs (s)
+	ContentTextSubtitle (ContentTimePeriod p, std::list<dcp::SubtitleString> s)
+		: ContentSubtitle (p)
+		, subs (s)
 	{}
 
-	ContentTimePeriod period () const;
-
 	std::list<dcp::SubtitleString> subs;
 };