mythccextractor: Fix teletext subtitle duration

Previously ProcessTeletext() didn't leave one subtitle behind.  This caused the
length calculation in IngestSubtitle() to never be performed, which meant that
the length was always set to the default value 750 ms.

Fixes #11081.

mythtv/libs/libmythtv/mythccextractorplayer.cpp

@@ -84,7 +84,7 @@ void MythCCExtractorPlayer::OnGotNewFrame(void)
 
     Ingest608Captions();  Process608Captions(kProcessNormal);
     Ingest708Captions();  Process708Captions(kProcessNormal);
-    IngestTeletext();     ProcessTeletext();
+    IngestTeletext();     ProcessTeletext(kProcessNormal);
     IngestDVBSubtitles(); ProcessDVBSubtitles(kProcessNormal);
 }
 
@@ -190,6 +190,7 @@ bool MythCCExtractorPlayer::run(void)
 
     Process608Captions(kProcessFinalize);
     Process708Captions(kProcessFinalize);
+    ProcessTeletext(kProcessFinalize);
     ProcessDVBSubtitles(kProcessFinalize);
 
     SetPlaying(false);
@@ -563,7 +564,7 @@ void MythCCExtractorPlayer::IngestTeletext(void)
     }
 }
 
-void MythCCExtractorPlayer::ProcessTeletext(void)
+void MythCCExtractorPlayer::ProcessTeletext(uint flags)
 {
     int i = 0;
     TeletextInfo::iterator ttxit = m_ttx_info.begin();
@@ -578,6 +579,8 @@ void MythCCExtractorPlayer::ProcessTeletext(void)
         {
             if ((*it).empty())
                 continue; // Skip empty subtitle streams.
+            if (((kProcessFinalize & flags) == 0) && ((*it).size() <= 1))
+                continue; // Leave one caption behind so it can be amended
 
             uint page = it.key();
 
@@ -607,7 +610,7 @@ void MythCCExtractorPlayer::ProcessTeletext(void)
                 continue;
             }
 
-            while (!(*it).empty())
+            while ((*it).size() > ((kProcessFinalize & flags) ? 0 : 1))
             {
                 if ((*it).front().length <= 0)
                     (*it).front().length = OneSubtitle::kDefaultLength;