/// <summary>
/// Gets the actual closed caption track associated with given metadata
/// and downloads it as SRT file.
/// </summary>
public async Task DownloadClosedCaptionTrackAsync(ClosedCaptionTrackInfo info, string filePath,
IProgress <double> progress, CancellationToken cancellationToken)
{
info.GuardNotNull(nameof(info));
filePath.GuardNotNull(nameof(filePath));
// Get the track
var track = await GetClosedCaptionTrackAsync(info).ConfigureAwait(false);
// Save to file as SRT
using (var writer = File.CreateText(filePath))
{
for (var i = 0; i < track.Captions.Count; i++)
{
// Make sure cancellation was not requested
cancellationToken.ThrowIfCancellationRequested();
var caption = track.Captions[i];
var buffer = new StringBuilder();
// 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);
// Write to stream
await writer.WriteLineAsync(buffer.ToString()).ConfigureAwait(false);
// Report progress
progress?.Report((i + 1.0) / track.Captions.Count);
}
}
}
/// <inheritdoc />
public async Task DownloadClosedCaptionTrackAsync(ClosedCaptionTrackInfo info, Stream output,
IProgress <double> progress = null, CancellationToken cancellationToken = default)
{
info.GuardNotNull(nameof(info));
output.GuardNotNull(nameof(output));
// Get the track
var track = await GetClosedCaptionTrackAsync(info);
// Save to file as SRT
using (var writer = new StreamWriter(output, Encoding.UTF8, 1024, true))
{
for (var i = 0; i < track.Captions.Count; i++)
{
// Make sure cancellation was not requested
cancellationToken.ThrowIfCancellationRequested();
var caption = track.Captions[i];
var buffer = new StringBuilder();
// 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);
// Write to stream
await writer.WriteLineAsync(buffer.ToString());
// Report progress
progress?.Report((i + 1.0) / track.Captions.Count);
}
}
}
/// <summary>
/// Gets the actual closed caption track represented by given metadata
/// </summary>
public async Task <ClosedCaptionTrack> GetClosedCaptionTrackAsync(ClosedCaptionTrackInfo info)
{
info.GuardNotNull(nameof(info));
// Get manifest
var response = await _httpService.GetStringAsync(info.Url).ConfigureAwait(false);
var trackXml = XElement.Parse(response).StripNamespaces();
// Parse captions
var captions = new List <ClosedCaption>();
foreach (var captionXml in trackXml.Descendants("text"))
{
var text = captionXml.Value;
var offset = TimeSpan.FromSeconds((double)captionXml.AttributeStrict("start"));
var duration = TimeSpan.FromSeconds((double)captionXml.AttributeStrict("dur"));
var caption = new ClosedCaption(text, offset, duration);
captions.Add(caption);
}
return(new ClosedCaptionTrack(info, captions));
}