Misc

README.md

@@ -147,6 +147,16 @@ Default: `false`
 
 Default: `false`
 
+#### disable_ebu_style
+
+`"disable_ebu_style" : true | false`
+
+`true` means that the STL reader does not try to map EBU style as described in EBU Tech 3360
+
+Implies `disable_line_padding`
+
+Default: `false`
+
 #### program_start_tc
 
 `"program_start_tc" : "TCP" | "HH:MM:SS:FF"`
@@ -163,14 +173,22 @@ Overrides the font stack
 
 Default: `"Verdana, Arial, Tiresias, sansSerif"`
 
-#### ax_row_count
+#### max_row_count
 
 `"max_row_count" : "MNR" | integer`
 
 Specifies a maximum number of rows for open subtitles, either the MNR field of the GSI block or a user-specified value
 
 Default: `23`
 
+#### force_bottom
+
+`"force_bottom" : true | false`
+
+Overrides line positions, force to bottom
+
+Default: `false`
+
 ### SRT Writer configuration
 
 #### text_formatting
@@ -191,6 +209,14 @@ Default: `true`
 
 Default: `false`
 
+#### text_position
+
+`"text_position" : true | false`
+
+`true` means that the VTT writer outputs text alignment cue settings
+
+Default: `false`
+
 #### cue_id
 
 `"cue_id" : true | false`
@@ -271,9 +297,11 @@ Unit test code coverage is provided by the script at `scripts/coverage.sh`
 
 Automated testing is provided by the script at `scripts/ci.sh`
 
+Before first use, run `git submodule update --init` to get some required TTML samples from the W3C
+
 #### Local
 
-Run `./scripts/ci.sh`
+Run `PYTHONPATH=src/main/python scripts/ci.sh`
 
 #### GitHub actions
 

src/main/python/ttconv/stl/config.py

@@ -75,9 +75,13 @@ class STLReaderConfiguration(ModuleConfiguration):
   disable_fill_line_gap: bool = field(default=False, metadata={"decoder": bool})
   program_start_tc: typing.Optional[str] = field(default=None, metadata={"decoder": _decode_start_tc})
   disable_line_padding: bool = field(default=False, metadata={"decoder": bool})
+  disable_ebu_style: bool = field(default=False, metadata={"decoder": bool})
+  if disable_ebu_style:
+    disable_line_padding=True
   font_stack: typing.Optional[typing.Tuple[typing.Union[str, styles.GenericFontFamilyType]]] = \
                   field(default=None, metadata={"decoder": _decode_font_stack})
   max_row_count: typing.Optional[typing.Union[int, str]] = field(default=None, metadata={"decoder": _decode_max_row_count})
+  force_bottom: bool = field(default=False, metadata={"decoder": bool})
 
   @classmethod
   def name(cls):

src/main/python/ttconv/stl/datafile.py

@@ -247,9 +247,11 @@ def __init__(
     gsi_block: bytes,
     disable_fill_line_gap: bool = False,
     disable_line_padding: bool = False,
+    disable_ebu_style: bool = False,
     start_tc: typing.Optional[str] = None,
     font_stack: typing.Tuple[typing.Union[str, styles.GenericFontFamilyType]] = None,
-    max_row_count: typing.Optional[typing.Union[int, str]] = None
+    max_row_count: typing.Optional[typing.Union[int, str]] = None,
+    force_bottom: bool = False,
     ):
 
     self.gsi = _GSIBlock._make(
@@ -260,12 +262,13 @@ def __init__(
 
     self.doc = model.ContentDocument()
 
-    self.doc.set_cell_resolution(
-      model.CellResolutionType(
-        columns=round(100 * DEFAULT_TELETEXT_COLS / (100 - 2 * DEFAULT_HORIZONTAL_SAFE_MARGIN_PCT)),
-        rows=round(100 * DEFAULT_TELETEXT_ROWS / (100 - 2 * DEFAULT_VERTICAL_SAFE_MARGIN_PCT))
+    if not disable_ebu_style:
+      self.doc.set_cell_resolution(
+        model.CellResolutionType(
+          columns=round(100 * DEFAULT_TELETEXT_COLS / (100 - 2 * DEFAULT_HORIZONTAL_SAFE_MARGIN_PCT)),
+          rows=round(100 * DEFAULT_TELETEXT_ROWS / (100 - 2 * DEFAULT_VERTICAL_SAFE_MARGIN_PCT))
+        )
       )
-    )
 
     self.doc.set_active_area(
       model.ActiveAreaType(
@@ -374,6 +377,9 @@ def __init__(
     else:
       self.max_row_count = max_row_count
 
+    self.disable_ebu_style = disable_ebu_style
+    self.force_bottom = force_bottom
+
     # p_element for use across cumulative subtitles 
     self.cur_p_element = None
 
@@ -499,32 +505,46 @@ def process_tti_block(self, tti_block: bytes):
       else:
         self.cur_p_element.set_style(styles.StyleProperties.TextAlign, styles.TextAlignType.center)
 
-      self.cur_p_element.set_style(
-        styles.StyleProperties.LineHeight,
-        styles.LengthType(DEFAULT_LINE_HEIGHT_PCT,
-        styles.LengthType.Units.pct)
-      )
-
       if self.is_teletext() and not is_double_height_characters:
         font_size = DEFAULT_SINGLE_HEIGHT_FONT_SIZE_PCT
       else:
         font_size = DEFAULT_DOUBLE_HEIGHT_FONT_SIZE_PCT
 
-      self.cur_p_element.set_style(
-        styles.StyleProperties.FontSize,
-        styles.LengthType(
-          font_size,
-          styles.LengthType.Units.pct
+      if not self.disable_ebu_style:
+        self.cur_p_element.set_style(
+          styles.StyleProperties.FontSize,
+          styles.LengthType(
+            font_size,
+            styles.LengthType.Units.pct
+          )
+        )
+        self.cur_p_element.set_style(
+          styles.StyleProperties.LineHeight,
+          styles.LengthType(DEFAULT_LINE_HEIGHT_PCT,
+          styles.LengthType.Units.pct)
         )
-      )
 
       safe_area_height =  round(100 - DEFAULT_VERTICAL_SAFE_MARGIN_PCT * 2)
       safe_area_width =  round(100 - DEFAULT_HORIZONTAL_SAFE_MARGIN_PCT * 2)
 
+      if self.force_bottom:
+        # single region of the full safe area
+        r_y = DEFAULT_VERTICAL_SAFE_MARGIN_PCT
+        r_height = 100 - r_y
+
+        region = _get_region_from_model(
+          self.doc,
+          round(DEFAULT_HORIZONTAL_SAFE_MARGIN_PCT),
+          r_y,
+          safe_area_width,
+          r_height,
+          styles.DisplayAlignType.after
+        )
+
       # assume that VP < max number of rows/2 means bottom-aligned and otherwise top-aligned
       # probably should offer an option to override this
 
-      if tti.VP < self.get_max_row_count() // 2:
+      elif tti.VP < self.get_max_row_count() // 2:
         # top-aligned large region
 
         r_y = DEFAULT_VERTICAL_SAFE_MARGIN_PCT + ((tti.VP - 1) / self.get_max_row_count()) * safe_area_height

src/main/python/ttconv/stl/reader.py

@@ -47,9 +47,11 @@ def to_model(data_file: typing.IO, config: typing.Optional[STLReaderConfiguratio
     data_file.read(1024),
     disable_fill_line_gap=False if config is None else config.disable_fill_line_gap,
     disable_line_padding=False if config is None else config.disable_line_padding,
+    disable_ebu_style=False if config is None else config.disable_ebu_style,
     start_tc=None if config is None else config.program_start_tc,
     font_stack=None if config is None else config.font_stack,
-    max_row_count=None if config is None else config.max_row_count
+    max_row_count=None if config is None else config.max_row_count,
+    force_bottom=False if config is None else config.force_bottom
     )
 
   for i in itertools.count():

src/main/python/ttconv/tt.py

@@ -376,7 +376,7 @@ def convert(args):
     #
     # Write out the converted file
     #
-    tree_from_model.write(outputfile, encoding="utf-8")
+    tree_from_model.write(outputfile, encoding="utf-8", xml_declaration=True)
 
   elif writer_type is FileTypes.SRT:
     #

src/main/python/ttconv/vtt/config.py

@@ -41,5 +41,8 @@ def name(cls):
   # outputs `line` and `line alignment` cue settings
   line_position: bool = field(default=False, metadata={"decoder": bool})
 
+  # outputs `text alignment` cue settings
+  text_position: bool = field(default=False, metadata={"decoder": bool})
+
   # outputs cue identifier
   cue_id: bool = field(default=True, metadata={"decoder": bool})

src/main/python/ttconv/vtt/cue.py

@@ -42,6 +42,12 @@ class LineAlignment(Enum):
     center = "center"
     end = "end"
 
+  class TextAlignment(Enum):
+    """WebVTT text alignment cue setting"""
+    left = "left"
+    middle = "middle"
+    right = "right"
+
   _EOL_SEQ_RE = re.compile(r"\n{2,}")
 
   def __init__(self, identifier: Optional[int] = None):
@@ -51,6 +57,7 @@ def __init__(self, identifier: Optional[int] = None):
     self._text: str = ""
     self._line: int = None
     self._align: VttCue.LineAlignment = None
+    self._textalign: VttCue.TextAlignment = None
 
   def set_begin(self, offset: Fraction):
     """Sets the paragraph begin time code"""
@@ -89,6 +96,10 @@ def get_align(self) -> Optional[LineAlignment]:
     """Return the WebVTT line alignment cue setting"""
     return self._align
 
+  def set_textalign(self, textalign: TextAlignment):
+    """Sets the WebVTT text alignment cue setting"""
+    self._textalign = textalign
+
   def is_only_whitespace_or_empty(self):
     """Returns whether the paragraph text contains only whitespace or is empty"""
     return len(self._text) == 0 or self._text.isspace()
@@ -123,6 +134,10 @@ def __str__(self) -> str:
     # cue timing
     t += f"{self._begin} --> {self._end}"
 
+    # cue text position
+    if self._textalign is not None:
+      t += f" align:{self._textalign.value}"
+
     # cue line position
     if self._line is not None:
       t += f" line:{self._line}%"

src/main/python/ttconv/vtt/writer.py

@@ -39,7 +39,7 @@
 from ttconv.isd import ISD
 from ttconv.vtt.cue import VttCue
 from ttconv.vtt.css_class import CssClass
-from ttconv.style_properties import ExtentType, PositionType, StyleProperties, FontStyleType, NamedColors, FontWeightType, TextDecorationType, DisplayAlignType
+from ttconv.style_properties import ExtentType, PositionType, StyleProperties, FontStyleType, NamedColors, FontWeightType, TextDecorationType, DisplayAlignType, TextAlignType
 
 LOGGER = logging.getLogger(__name__)
 
@@ -84,7 +84,12 @@ def __init__(self, config: VTTWriterConfiguration):
         StyleProperties.DisplayAlign: [],
         StyleProperties.Extent: [],
       })
-
+
+    if self._config.text_position:
+      supported_styles.update({
+        StyleProperties.TextAlign: [],
+      })
+
     self._filters.append(SupportedStylePropertiesFilter(supported_styles))
 
     self._filters.append(
@@ -175,6 +180,15 @@ def process_p(self, region: ISD.Region, element: model.P, begin: Fraction, end:
         cue.set_line(round(position.v_offset.value + extent.height.value / 2))
         cue.set_align(VttCue.LineAlignment.center)
 
+    if self._config.text_position:
+      text_align = element.get_style(StyleProperties.TextAlign)
+      if text_align == TextAlignType.center:
+        cue.set_textalign(VttCue.TextAlignment.middle)
+      elif text_align == TextAlignType.start:
+        cue.set_textalign(VttCue.TextAlignment.left)
+      elif text_align == TextAlignType.end:
+        cue.set_textalign(VttCue.TextAlignment.right)
+
     self._paragraphs.append(cue)
 
     for elem in list(element):

src/test/python/test_vtt_writer.py

@@ -114,21 +114,25 @@ def test_position(self):
   <head>
     <styling>
       <style xml:id="style.center" tts:fontFamily="Arial" tts:fontSize="100%" tts:fontStyle="normal" tts:fontWeight="normal" tts:backgroundColor="transparent" tts:color="white" tts:textAlign="center"/>
+      <style xml:id="style.left" tts:fontFamily="Arial" tts:fontSize="100%" tts:fontStyle="normal" tts:fontWeight="normal" tts:backgroundColor="transparent" tts:color="white" tts:textAlign="left"/>
+      <style xml:id="style.right" tts:fontFamily="Arial" tts:fontSize="100%" tts:fontStyle="normal" tts:fontWeight="normal" tts:backgroundColor="transparent" tts:color="white" tts:textAlign="right"/>
     </styling>
     <layout>
       <region xml:id="region.after" tts:displayAlign="after" tts:backgroundColor="transparent" tts:origin="10% 10%" tts:extent="80% 80%"/>
       <region xml:id="region.before" tts:displayAlign="before" tts:backgroundColor="transparent" tts:origin="10% 10%" tts:extent="80% 80%"/>
+      <region xml:id="region.center" tts:displayAlign="center" tts:backgroundColor="transparent" tts:origin="10% 10%" tts:extent="80% 80%"/>
     </layout>
   </head>
   <body>
     <div>
       <p style="style.center" region="region.after" begin="00:00:03:12" end="00:00:12:00">Only one or two short samples are needed<br/>to make sure the conversion basically works</p>
-      <p style="style.center" region="region.before" begin="00:00:14:09" end="00:00:25:17">Cool, got it, will do it by end of next week.</p>
+      <p style="style.left" region="region.before" begin="00:00:14:09" end="00:00:25:17">Cool, got it, will do it by end of next week.</p>
+      <p style="style.right" region="region.center" begin="00:00:26:00" end="00:00:28:00">Yes.</p>
     </div>
   </body>
 </tt>"""
 
-    expected_vtt="""WEBVTT
+    expected_vtt_line="""WEBVTT
 
 1
 00:00:03.501 --> 00:00:12.000 line:90%,end
@@ -138,17 +142,57 @@ def test_position(self):
 2
 00:00:14.375 --> 00:00:25.709 line:10%,start
 Cool, got it, will do it by end of next week.
+
+3
+00:00:26.000 --> 00:00:28.000 line:50%,center
+Yes.
+"""
+    expected_vtt_align="""WEBVTT
+
+1
+00:00:03.501 --> 00:00:12.000 align:middle
+Only one or two short samples are needed
+to make sure the conversion basically works
+
+2
+00:00:14.375 --> 00:00:25.709 align:left
+Cool, got it, will do it by end of next week.
+
+3
+00:00:26.000 --> 00:00:28.000 align:right
+Yes.
+"""
+    expected_vtt_line_and_align="""WEBVTT
+
+1
+00:00:03.501 --> 00:00:12.000 align:middle line:90%,end
+Only one or two short samples are needed
+to make sure the conversion basically works
+
+2
+00:00:14.375 --> 00:00:25.709 align:left line:10%,start
+Cool, got it, will do it by end of next week.
+
+3
+00:00:26.000 --> 00:00:28.000 align:right line:50%,center
+Yes.
 """
 
     model = imsc_reader.to_model(et.ElementTree(et.fromstring(ttml_doc_str)))
     config = VTTWriterConfiguration()
     config.line_position = True
     vtt_from_model = vtt_writer.from_model(model, config)
-    self.assertEqual(expected_vtt, vtt_from_model)
+    self.assertEqual(expected_vtt_line, vtt_from_model)
+    config.text_position = True
+    vtt_from_model = vtt_writer.from_model(model, config)
+    self.assertEqual(expected_vtt_line_and_align, vtt_from_model)
+    config.line_position = False
+    vtt_from_model = vtt_writer.from_model(model, config)
+    self.assertEqual(expected_vtt_align, vtt_from_model)
 
-    config = VTTWriterConfiguration.parse(json.loads('{"line_position":true}'))
+    config = VTTWriterConfiguration.parse(json.loads('{"line_position":true, "text_position":true}'))
     vtt_from_model = vtt_writer.from_model(model, config)
-    self.assertEqual(expected_vtt, vtt_from_model)
+    self.assertEqual(expected_vtt_line_and_align, vtt_from_model)
 
   def test_cue_id(self):
     ttml_doc_str = """<?xml version="1.0" encoding="UTF-8"?>