Fix line numbers in binary STL files.

[libsub.git] / src / stl_binary_reader.cc

diff --git a/src/stl_binary_reader.cc b/src/stl_binary_reader.cc
index 7c5386b84789dc0f28f717e9adb74b8bc78cac9d..35091f083cfbcddebcbdcb12af77595a7289d35f 100644 (file)
--- a/src/stl_binary_reader.cc
+++ b/src/stl_binary_reader.cc
@@ -36,7 +36,7 @@ using boost::lexical_cast;
 using boost::algorithm::replace_all;
 using boost::is_any_of;
 using boost::locale::conv::utf_to_utf;
-using boost::shared_ptr;
+using std::shared_ptr;
 using namespace sub;
 
 namespace sub {
@@ -166,6 +166,17 @@ void STLBinaryReader::read (shared_ptr<InputReader> reader)
        subtitle_groups = atoi (reader->get_string(248, 3).c_str());
        maximum_characters = atoi (reader->get_string(251, 2).c_str());
        maximum_rows = atoi (reader->get_string(253, 2).c_str());
+
+       if (maximum_rows == 99) {
+               /* https://tech.ebu.ch/docs/tech/tech3360.pdf says
+                  "It is recommended that for files with a large MNR value (e.g. '99') the
+                  font size (height) should be defined as ~ 1/15 of the 'Subtitle Safe Area'
+                  and a lineHeight of 120% is used to achieve a row height of ~ 1/12 of the height
+                  of the 'Subtitle Safe Area'.
+               */
+               maximum_rows = 12;
+       }
+
        timecode_status = _tables.timecode_status_file_to_enum (reader->get_string(255, 1));
        start_of_programme = reader->get_string(256, 8);
        first_in_cue = reader->get_string(264, 8);
@@ -176,6 +187,7 @@ void STLBinaryReader::read (shared_ptr<InputReader> reader)
        editor_name = reader->get_string(309, 32);
        editor_contact_details = reader->get_string(341, 32);
 
+       int highest_line = 0;
        for (int i = 0; i < tti_blocks; ++i) {
 
                reader->read (128, "TTI");
@@ -196,11 +208,15 @@ void STLBinaryReader::read (shared_ptr<InputReader> reader)
                bool italic = false;
                bool underline = false;
 
-               for (size_t i = 0; i < lines.size(); ++i) {
+               for (size_t j = 0; j < lines.size(); ++j) {
                        RawSubtitle sub;
                        sub.from = reader->get_timecode(5, frame_rate);
                        sub.to = reader->get_timecode(9, frame_rate);
-                       sub.vertical_position.line = reader->get_int(13, 1) + i;
+                       /* XXX: vertical position of TTI extension blocks should be ignored (spec page 10) so this
+                        * is wrong if the EBN of this TTI block is not 255 (I think).
+                        */
+                       sub.vertical_position.line = reader->get_int(13, 1) + j;
+                       highest_line = std::max(highest_line, *sub.vertical_position.line);
                        sub.vertical_position.lines = maximum_rows;
                        sub.vertical_position.reference = TOP_OF_SCREEN;
                        sub.italic = italic;
@@ -223,9 +239,9 @@ void STLBinaryReader::read (shared_ptr<InputReader> reader)
 
                        /* Loop over characters */
                        string text;
-                       for (size_t j = 0; j < lines[i].size(); ++j) {
+                       for (size_t k = 0; k < lines[j].size(); ++k) {
 
-                               unsigned char const c = static_cast<unsigned char> (lines[i][j]);
+                               unsigned char const c = static_cast<unsigned char> (lines[j][k]);
 
                                if (c == 0x8f) {
                                        /* Unused space i.e. end of line */
@@ -253,7 +269,7 @@ void STLBinaryReader::read (shared_ptr<InputReader> reader)
                                        underline = false;
                                        break;
                                default:
-                                       text += lines[i][j];
+                                       text += lines[j][k];
                                        break;
                                }
 
@@ -269,6 +285,14 @@ void STLBinaryReader::read (shared_ptr<InputReader> reader)
                        /* XXX: justification */
                }
        }
+
+       /* Fix line numbers so they don't go off the bottom of the screen */
+       if (highest_line > maximum_rows) {
+               int correction = highest_line - maximum_rows;
+               for (auto& i: _subs) {
+                       *i.vertical_position.line -= correction;
+               }
+       }
 }
 
 map<string, string>