/// <summary>
/// Writes the actual closed caption track which is identified by the specified metadata to the specified writer.
/// Closed captions are written in the SRT file format.
/// </summary>
public async Task WriteToAsync(ClosedCaptionTrackInfo trackInfo, TextWriter writer,
IProgress <double>?progress = null, CancellationToken cancellationToken = default)
{
var track = await GetAsync(trackInfo);
var buffer = new StringBuilder();
for (var i = 0; i < track.Captions.Count; i++)
{
var caption = track.Captions[i];
buffer.Clear();
cancellationToken.ThrowIfCancellationRequested();
// Line number
buffer.AppendLine((i + 1).ToString());
// Time start --> time end
buffer.Append(caption.Offset.ToString(@"hh\:mm\:ss\,fff"));
buffer.Append(" --> ");
buffer.Append((caption.Offset + caption.Duration).ToString(@"hh\:mm\:ss\,fff"));
buffer.AppendLine();
// Actual text
buffer.AppendLine(caption.Text);
await writer.WriteLineAsync(buffer.ToString());
progress?.Report((i + 1.0) / track.Captions.Count);
}
}
/// <summary>
/// Downloads the closed caption track identified by the specified metadata to the specified file.
/// </summary>
/// <remarks>
/// Closed captions are written in the SRT file format.
/// </remarks>
public async ValueTask DownloadAsync(
ClosedCaptionTrackInfo trackInfo,
string filePath,
IProgress <double>?progress = null,
CancellationToken cancellationToken = default)
{
using var writer = File.CreateText(filePath);
await WriteToAsync(trackInfo, writer, progress, cancellationToken);
}
/// <summary>
/// Gets the closed caption track identified by the specified metadata.
/// </summary>
public async ValueTask <ClosedCaptionTrack> GetAsync(
ClosedCaptionTrackInfo trackInfo,
CancellationToken cancellationToken = default)
{
var trackExtractor = await _controller.GetClosedCaptionTrackAsync(trackInfo.Url, cancellationToken);
var captions = trackExtractor
.GetClosedCaptions()
.Select(c =>
{
var text = c.TryGetText();
if (string.IsNullOrWhiteSpace(text))
{
return(null);
}
var offset =
c.TryGetOffset() ??
throw new YoutubeExplodeException("Could not extract caption offset.");
var duration =
c.TryGetDuration() ??
throw new YoutubeExplodeException("Could not extract caption duration.");
var parts = c
.GetParts()
.Select(p =>
{
var partText = p.TryGetText();
if (string.IsNullOrWhiteSpace(partText))
{
return(null);
}
var partOffset =
p.TryGetOffset() ??
throw new YoutubeExplodeException("Could not extract caption part offset.");
return(new ClosedCaptionPart(partText, partOffset));
})
.WhereNotNull()
.ToArray();
return(new ClosedCaption(text, offset, duration, parts));
})
.WhereNotNull()
.ToArray();
return(new ClosedCaptionTrack(captions));
}
/// <summary>
/// Gets the actual closed caption track which is identified by the specified metadata.
/// </summary>
public async Task <ClosedCaptionTrack> GetAsync(ClosedCaptionTrackInfo trackInfo)
{
var response = await ClosedCaptionTrackResponse.GetAsync(_httpClient, trackInfo.Url);
var captions = response.GetClosedCaptions()
.Where(t => !string.IsNullOrWhiteSpace(t.GetText()))
.Select(t => new ClosedCaption(
t.GetText(),
t.GetOffset(),
t.GetDuration()
)).ToArray();
return(new ClosedCaptionTrack(captions));
}
