/// <summary>
/// Gets the stream identified by the specified metadata.
/// </summary>
public async ValueTask <Stream> GetAsync(
IStreamInfo streamInfo,
CancellationToken cancellationToken = default)
{
// For most streams, YouTube limits transfer speed to match the video playback rate.
// This helps them avoid unnecessary bandwidth, but for us it's a hindrance because
// we want to download the stream as fast as possible.
// To solve this, we divide the logical stream up into multiple segments and download
// them all separately.
var isThrottled = !Regex.IsMatch(streamInfo.Url, "ratebypass[=/]yes");
var segmentSize = isThrottled
? 9_898_989 // breakpoint after which the throttling kicks in
: (long?)null; // no segmentation for non-throttled streams
var stream = new SegmentedHttpStream(
_httpClient,
streamInfo.Url,
streamInfo.Size.Bytes,
segmentSize
);
// Pre-resolve inner stream eagerly
await stream.PreloadAsync(cancellationToken);
return(stream);
}
private async Task <YoutubeMediaPacket> _fillGab(YoutubeRequestURL packetRequestURL, Range lostRange, YoutubeMediaPacketType type)
{
packetRequestURL.RequestPath.QueryString.SetValue("range", $"{lostRange.Start}-{lostRange.End}");
var requestableURL = packetRequestURL.ToRequestableURL();
// debugging
YTrackLogger.Log("\nfilling broken range for type " + type + " : " + lostRange.ToString() + " from : " + requestableURL);
long httpSegmentSize = packetRequestURL.RequestPath.QueryString.HasValue("ratebypass") && packetRequestURL.RequestPath.QueryString.GetValue("ratebypass") == "yes"
? (long)lostRange.Length
: 9_898_989;
YoutubeMediaPacket packet;
using (SegmentedHttpStream segmentedHttpStream = new SegmentedHttpStream(_client, requestableURL, (long)lostRange.Length, httpSegmentSize))
{
try
{
string tmpFileName = Path.GetTempFileName();
using (Stream outputStream = new FileStream(tmpFileName, FileMode.Append))
{
IProgress <double> progressPercentage = new Progress <double>(b => packetDownloadProgressChanged(b));
await segmentedHttpStream.CopyToStreamAsync(outputStream, progressPercentage);
}
// no need to check whether the packetRequestURL is a valid requist URL
// because we requested it anyway
packet = new YoutubeMediaPacket(type, packetRequestURL, tmpFileName);
OnPacketDownloadCompleted?.Invoke(this, packet);
}
catch (Exception e)
{
// two exception may be thrown
// WebException if something went wrong when fetch the new packets
// IOException if something went wrong when writing the packet file to disk
// I'll raise PacketDownloadExceptionThrown and re-throw exception
if (e is WebException)
{
_onGabPacketDownloadExceptionThrown?.Invoke(this, new PacketDownloadExceptionEventArgumanets()
{
Exception = e as WebException,
FailedPacketRequestURL = packetRequestURL,
Range = lostRange
});
}
// re-throw the error to the caller
Helpers.YTrackLogger.Log("Failed to download Packet : " + e.Message + "\n\n" + e.StackTrace);
throw;
}
}
return(packet);
}
