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Fix WebVTT cue setting preservation #12340

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Fix WebVTT cue setting preservation #12340

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10 changes: 8 additions & 2 deletions src/libse/ContainerFormats/Mp4/Mp4Parser.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -706,11 +706,17 @@ private void ReadVttWithSize(Mdat mdat, List<TimeSegment> trunSamples, ref doubl
private void AddVttParagraph(double timeTotalMs, string payload, double before, string style)
{
var p = new Paragraph(payload, before, timeTotalMs);
var positionInfo = WebVTT.GetPositionInfo(style);
var positionInfo = WebVTT.GetAssAlignmentTagFromCueSettings(style);
if (!string.IsNullOrEmpty(positionInfo))
{
p.Text = positionInfo + p.Text;
p.Extra = style;
}

p.Style = string.IsNullOrEmpty(positionInfo)
? WebVTT.GetPositionInfoRaw(style)
: string.Empty;
if (!string.IsNullOrEmpty(p.Style) || !string.IsNullOrEmpty(positionInfo))
{
VttcSubtitle.Header = "WEBVTT";
}
VttcSubtitle.Paragraphs.Add(p);
Expand Down
128 changes: 48 additions & 80 deletions src/libse/SubtitleFormats/WebVTT.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,6 @@
using SkiaSharp;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
Expand Down Expand Up @@ -97,7 +96,7 @@ public override string ToText(Subtitle subtitle, string title)
return sb.ToString().Trim();
}

internal static string GetPositionInfoFromAssTag(Paragraph p)
internal static string GetPositionInfoFromAssTag(Paragraph p, string cueSettings = null)
{
string positionInfo;
if (p.Text.StartsWith("{\\an1", StringComparison.Ordinal))
Expand Down Expand Up @@ -134,7 +133,12 @@ internal static string GetPositionInfoFromAssTag(Paragraph p)
}
else
{
positionInfo = Configuration.Settings.SubtitleSettings.WebVttCueAn2;
// Treat \an2 as the default alignment and preserve any raw cue settings.
positionInfo = !string.IsNullOrEmpty(cueSettings)
? cueSettings
: string.IsNullOrEmpty(p.Style)
? Configuration.Settings.SubtitleSettings.WebVttCueAn2
: p.Style;
}

return (" " + positionInfo).TrimEnd();
Expand Down Expand Up @@ -292,8 +296,10 @@ public override void LoadSubtitle(Subtitle subtitle, List<string> lines, string
p.StartTime.TotalMilliseconds += addSeconds * 1000;
p.EndTime.TotalMilliseconds += addSeconds * 1000;

positionInfo = GetPositionInfo(s);
p.Style = GetPositionInfoRaw(s);
positionInfo = GetAssAlignmentTagFromCueSettings(s);
p.Style = string.IsNullOrEmpty(positionInfo)
? GetPositionInfoRaw(s)
: string.Empty;
p.Region = GetRegion(s);
}
catch (Exception exception)
Expand Down Expand Up @@ -475,110 +481,72 @@ private static double GetXTimeStampSeconds(string input)
return 0;
}

internal static string GetPositionInfo(string s)
internal static string GetAssAlignmentTagFromCueSettings(string s)
{
//position: x --- 0% = left, 100% = right (horizontal)
//line: x --- 0 or -16 or 0% = top, 16 or -1 or 100% = bottom (vertical)
var pos = GetTag(s, "position:");
var line = GetTag(s, "line:");
var positionInfo = string.Empty;
var hAlignLeft = false;
var hAlignRight = false;
var vAlignTop = false;
var vAlignMiddle = false;
double number;

if (!string.IsNullOrEmpty(pos) && pos.EndsWith('%') && double.TryParse(pos.TrimEnd('%'), NumberStyles.AllowDecimalPoint, CultureInfo.InvariantCulture, out number))
var cueSettings = GetPositionInfoRaw(s).Trim();
if (string.IsNullOrEmpty(cueSettings))
{
if (number < 25)
{
hAlignLeft = true;
}
else if (number > 75)
{
hAlignRight = true;
}
return string.Empty;
}

if (!string.IsNullOrEmpty(line))
var subtitleSettings = Configuration.Settings.SubtitleSettings;

if (cueSettings == subtitleSettings.WebVttCueAn1)
{
line = line.Trim();
if (line.EndsWith('%'))
{
if (double.TryParse(line.TrimEnd('%'), NumberStyles.AllowDecimalPoint, CultureInfo.InvariantCulture, out number))
{
if (number < 25)
{
vAlignTop = true;
}
else if (number < 75)
{
vAlignMiddle = true;
}
}
}
else
{
if (double.TryParse(line, NumberStyles.AllowDecimalPoint, CultureInfo.InvariantCulture, out number))
{
if (number >= 0 && number <= 7)
{
vAlignTop = true; // Positive numbers indicate top down
}
else if (number > 7 && number < 11)
{
vAlignMiddle = true;
}
}
}
return "{\\an1}";
}

if (hAlignLeft)
if (cueSettings == subtitleSettings.WebVttCueAn2)
{
if (vAlignTop)
{
return "{\\an7}";
}
return "{\\an2}";
}

if (vAlignMiddle)
{
return "{\\an4}";
}
if (cueSettings == subtitleSettings.WebVttCueAn3)
{
return "{\\an3}";
}

return "{\\an1}";
if (cueSettings == subtitleSettings.WebVttCueAn4)
{
return "{\\an4}";
}

if (hAlignRight)
if (cueSettings == subtitleSettings.WebVttCueAn5)
{
if (vAlignTop)
{
return "{\\an9}";
}
return "{\\an5}";
}

if (vAlignMiddle)
{
return "{\\an6}";
}
if (cueSettings == subtitleSettings.WebVttCueAn6)
{
return "{\\an6}";
}

return "{\\an3}";
if (cueSettings == subtitleSettings.WebVttCueAn7)
{
return "{\\an7}";
}

if (vAlignTop)
if (cueSettings == subtitleSettings.WebVttCueAn8)
{
return "{\\an8}";
}

if (vAlignMiddle)
if (cueSettings == subtitleSettings.WebVttCueAn9)
{
return "{\\an5}";
return "{\\an9}";
}

return positionInfo;
return string.Empty;
}

internal static string GetPositionInfoRaw(string s)
{
//line: 72.69 % align:left position:44.90 % size:10.21 %
if (string.IsNullOrEmpty(s))
{
return string.Empty;
}

var list = new List<int>();

var idx = s.IndexOf("line:", StringComparison.Ordinal);
Expand Down
18 changes: 7 additions & 11 deletions src/libse/SubtitleFormats/WebVTTFileWithLineNumber.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,7 @@ public override string ToText(Subtitle subtitle, string title)
{
const string timeCodeFormatNoHours = "{0:00}:{1:00}.{2:000}"; // mm:ss.cc
const string timeCodeFormatHours = "{0:00}:{1:00}:{2:00}.{3:000}"; // hh:mm:ss.cc
const string paragraphWriteFormat = "{0} --> {1}{2}{5}{3}{4}{5}";
const string paragraphWriteFormat = "{0} --> {1}{2}{4}{3}{4}";

var sb = new StringBuilder();
sb.AppendLine("WEBVTT FILE");
Expand All @@ -34,23 +34,17 @@ public override string ToText(Subtitle subtitle, string title)
{
var start = string.Format(timeCodeFormatNoHours, p.StartTime.Minutes, p.StartTime.Seconds, p.StartTime.Milliseconds);
var end = string.Format(timeCodeFormatNoHours, p.EndTime.Minutes, p.EndTime.Seconds, p.EndTime.Milliseconds);
var positionInfo = WebVTT.GetPositionInfoFromAssTag(p);
var positionInfo = WebVTT.GetPositionInfoFromAssTag(p, p.Extra);

if (p.StartTime.Hours > 0 || p.EndTime.Hours > 0)
{
start = string.Format(timeCodeFormatHours, p.StartTime.Hours, p.StartTime.Minutes, p.StartTime.Seconds, p.StartTime.Milliseconds);
end = string.Format(timeCodeFormatHours, p.EndTime.Hours, p.EndTime.Minutes, p.EndTime.Seconds, p.EndTime.Milliseconds);
}

var style = string.Empty;
if (!string.IsNullOrEmpty(p.Extra) && subtitle.Header == "WEBVTT FILE")
{
style = p.Extra;
}

sb.Append(count);
sb.AppendLine();
sb.AppendLine(string.Format(paragraphWriteFormat, start, end, positionInfo, WebVTT.FormatText(p), style, Environment.NewLine));
sb.AppendLine(string.Format(paragraphWriteFormat, start, end, positionInfo, WebVTT.FormatText(p), Environment.NewLine));
count++;
}

Expand Down Expand Up @@ -112,8 +106,10 @@ public override void LoadSubtitle(Subtitle subtitle, List<string> lines, string
StartTime = WebVTT.GetTimeCodeFromString(parts[0]),
EndTime = WebVTT.GetTimeCodeFromString(parts[1])
};
positionInfo = WebVTT.GetPositionInfo(s);
p.Extra = WebVTT.GetPositionInfoRaw(s);
positionInfo = WebVTT.GetAssAlignmentTagFromCueSettings(s);
p.Extra = string.IsNullOrEmpty(positionInfo)
? WebVTT.GetPositionInfoRaw(s)
: string.Empty;
p.Region = WebVTT.GetRegion(s);
}
catch (Exception exception)
Expand Down
68 changes: 68 additions & 0 deletions tests/libse/SubtitleFormats/WebVttTest.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -61,6 +61,74 @@ public void LoadSubtitleDoesNotMergeCuesWithSameTimeCodesButDifferentRegions()
Assert.Equal("World", subtitle.Paragraphs[1].Text);
}

[Fact]
public void LoadAndSave_PreservesCueSettingsThatDoNotMatchAnPreset()
{
var vtt = "WEBVTT\r\n\r\n00:00:21.731 --> 00:00:23.356 position:3% line:5% align:left\r\nHello";
var subtitle = LoadWebVttSubtitle(vtt);

Assert.Equal("position:3% line:5% align:left", subtitle.Paragraphs[0].Style);
Assert.Equal("Hello", subtitle.Paragraphs[0].Text);

var saved = new WebVTT().ToText(subtitle, null);

Assert.Contains("00:00:21.731 --> 00:00:23.356 position:3% line:5% align:left", saved);
}

[Fact]
public void LoadSubtitle_ConvertsCueSettingsMatchingAnPresetToAssTag()
{
var vtt = "WEBVTT\r\n\r\n00:00:21.731 --> 00:00:23.356 position:20% line:20%\r\nHello";
var subtitle = LoadWebVttSubtitle(vtt);

Assert.Equal("{\\an7}Hello", subtitle.Paragraphs[0].Text);
Assert.Equal(string.Empty, subtitle.Paragraphs[0].Style);
}

[Fact]
public void Save_RemovingLoadedAnTagDoesNotKeepItsOriginalCueSettings()
{
var vtt = "WEBVTT\r\n\r\n00:00:21.731 --> 00:00:23.356 position:20% line:20%\r\nHello";
var subtitle = LoadWebVttSubtitle(vtt);
subtitle.Paragraphs[0].Text = "Hello";

var saved = new WebVTT().ToText(subtitle, null);

Assert.DoesNotContain("position:20% line:20%", saved);
}

[Fact]
public void FileWithLineNumber_LoadAndSave_PreservesCueSettingsThatDoNotMatchAnPreset()
{
var vtt = "WEBVTT FILE\r\n\r\n1\r\n00:00.000 --> 00:02.000 position:3% line:5% align:left\r\nHello";
var subtitle = new Subtitle();
var format = new WebVTTFileWithLineNumber();
format.LoadSubtitle(subtitle, new List<string>(vtt.Split(new[] { "\r\n" }, StringSplitOptions.None)), null);

Assert.Equal("position:3% line:5% align:left", subtitle.Paragraphs[0].Extra);

var saved = format.ToText(subtitle, null);

Assert.Contains("00:00.000 --> 00:02.000 position:3% line:5% align:left", saved);
}

[Fact]
public void Save_AnTagOverridesExistingCueSettings()
{
var subtitle = new Subtitle();
subtitle.Paragraphs.Add(new Paragraph
{
StartTime = new TimeCode(0, 0, 21, 731),
EndTime = new TimeCode(0, 0, 23, 356),
Style = "position:10% line:3%",
Text = "{\\an7}Hello"
});

var saved = new WebVTT().ToText(subtitle, null);

Assert.Contains("00:00:21.731 --> 00:00:23.356 position:20% line:20%", saved);
}

// Regression coverage for https://github.com/SubtitleEdit/subtitleedit/issues/10676
// Apple TV WebVTT files carry `X-TIMESTAMP-MAP=MPEGTS:900000,LOCAL:00:00:00.000` (HLS segment metadata)
// and a STYLE block using class selectors like `.styledotAB9216dotitalic` for italic/bold/color.
Expand Down