/// <summary>
/// Initializes a new instance of the <see cref="TranscodingThrottler"/> class.
/// </summary>
/// <param name="job">Transcoding job dto.</param>
/// <param name="logger">Instance of the <see cref="ILogger{TranscodingThrottler}"/> interface.</param>
/// <param name="config">Instance of the <see cref="IConfigurationManager"/> interface.</param>
/// <param name="fileSystem">Instance of the <see cref="IFileSystem"/> interface.</param>
public TranscodingThrottler(TranscodingJobDto job, ILogger <TranscodingThrottler> logger, IConfigurationManager config, IFileSystem fileSystem)
{
_job = job;
_logger = logger;
_config = config;
_fileSystem = fileSystem;
}
private bool IsThrottleAllowed(TranscodingJobDto job, int thresholdSeconds)
{
var bytesDownloaded = job.BytesDownloaded ?? 0;
var transcodingPositionTicks = job.TranscodingPositionTicks ?? 0;
var downloadPositionTicks = job.DownloadPositionTicks ?? 0;
var path = job.Path;
var gapLengthInTicks = TimeSpan.FromSeconds(thresholdSeconds).Ticks;
if (downloadPositionTicks > 0 && transcodingPositionTicks > 0)
{
// HLS - time-based consideration
var targetGap = gapLengthInTicks;
var gap = transcodingPositionTicks - downloadPositionTicks;
if (gap < targetGap)
{
_logger.LogDebug("Not throttling transcoder gap {0} target gap {1}", gap, targetGap);
return(false);
}
_logger.LogDebug("Throttling transcoder gap {0} target gap {1}", gap, targetGap);
return(true);
}
if (bytesDownloaded > 0 && transcodingPositionTicks > 0)
{
// Progressive Streaming - byte-based consideration
try
{
var bytesTranscoded = job.BytesTranscoded ?? _fileSystem.GetFileInfo(path).Length;
// Estimate the bytes the transcoder should be ahead
double gapFactor = gapLengthInTicks;
gapFactor /= transcodingPositionTicks;
var targetGap = bytesTranscoded * gapFactor;
var gap = bytesTranscoded - bytesDownloaded;
if (gap < targetGap)
{
_logger.LogDebug("Not throttling transcoder gap {0} target gap {1} bytes downloaded {2}", gap, targetGap, bytesDownloaded);
return(false);
}
_logger.LogDebug("Throttling transcoder gap {0} target gap {1} bytes downloaded {2}", gap, targetGap, bytesDownloaded);
return(true);
}
catch (Exception ex)
{
_logger.LogError(ex, "Error getting output size");
return(false);
}
}
_logger.LogDebug("No throttle data for " + path);
return(false);
}