/// <inheritdoc />
public async Task <ClosedCaptionTrack> GetClosedCaptionTrackAsync(ClosedCaptionTrackInfo info)
{
info.EnsureNotNull(nameof(info));
// Get manifest
var raw = await _httpClient.GetStringAsync(info.Url).ConfigureAwait(false);
var trackXml = XElement.Parse(raw).StripNamespaces();
// Parse captions
var captions = new List <ClosedCaption>();
foreach (var captionXml in trackXml.Descendants("p"))
{
var text = (string)captionXml;
if (text.IsBlank())
{
continue; // some autogenerated captions are blank
}
var offset = TimeSpan.FromMilliseconds((double)captionXml.Attribute("t"));
var duration = TimeSpan.FromMilliseconds((double)captionXml.Attribute("d"));
var caption = new ClosedCaption(text, offset, duration);
captions.Add(caption);
}
return(new ClosedCaptionTrack(info, captions));
}
/// <inheritdoc />
public async Task DownloadClosedCaptionTrackAsync(ClosedCaptionTrackInfo info, Stream output,
IProgress <double> progress = null, CancellationToken cancellationToken = default(CancellationToken))
{
info.EnsureNotNull(nameof(info));
output.EnsureNotNull(nameof(output));
// Get the track
var track = await GetClosedCaptionTrackAsync(info).ConfigureAwait(false);
// 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()).ConfigureAwait(false);
// Report progress
progress?.Report((i + 1.0) / track.Captions.Count);
}
}
}