public void Initialize(Stream stream, AudioInfo audioInfo, MetadataDictionary metadata, SettingsDictionary settings)
{
_encoder = new NativeVorbisEncoder();
_output = stream;
// Load the external gain filter:
ExportFactory <ISampleFilter> sampleFilterFactory =
ExtensionProvider.GetFactories <ISampleFilter>("Name", "ReplayGain").SingleOrDefault();
if (sampleFilterFactory == null)
{
throw new ExtensionInitializationException(Resources.SampleEncoderReplayGainFilterError);
}
_replayGainFilterLifetime = sampleFilterFactory.CreateExport();
_replayGainFilterLifetime.Value.Initialize(metadata, settings);
_oggStream = IntializeOggStream(settings);
_buffer = new byte[4096];
if (!string.IsNullOrEmpty(settings["BitRate"]))
{
ConfigureEncoderForBitRate(settings, audioInfo, _encoder);
}
else
{
ConfigureEncoderForQuality(settings, audioInfo, _encoder);
}
WriteHeader(metadata, stream);
}
static void ConfigureEncoderForQuality(SettingsDictionary settings, AudioInfo audioInfo, NativeVorbisEncoder encoder)
{
Contract.Requires(settings != null);
Contract.Requires(audioInfo != null);
Contract.Requires(encoder != null);
if (!string.IsNullOrEmpty(settings["ControlMode"]) &&
string.Compare(settings["ControlMode"], "Variable", StringComparison.OrdinalIgnoreCase) != 0)
{
throw new InvalidSettingException(string.Format(CultureInfo.CurrentCulture,
Resources.SampleEncoderBadQualityControlMode, settings["ControlMode"]));
}
// Set the quality if specified, otherwise select "5":
float quality;
if (string.IsNullOrEmpty(settings["VBRQuality"]))
{
quality = 5;
}
else if (!float.TryParse(settings["VBRQuality"], out quality) || quality < -1 || quality > 10)
{
throw new InvalidSettingException(string.Format(CultureInfo.CurrentCulture,
Resources.SampleEncoderBadVbrQuality, settings["VBRQuality"]));
}
encoder.Initialize(audioInfo.Channels, audioInfo.SampleRate, quality / 10);
}
static void ConfigureEncoderForBitRate(SettingsDictionary settings, AudioInfo audioInfo, NativeVorbisEncoder encoder)
{
Contract.Requires(settings != null);
Contract.Requires(audioInfo != null);
Contract.Requires(encoder != null);
int bitRate;
if (!int.TryParse(settings["BitRate"], out bitRate) || bitRate < 32 || bitRate > 500)
{
throw new InvalidSettingException(string.Format(CultureInfo.CurrentCulture,
Resources.SampleEncoderBadBitRate, settings["BitRate"]));
}
if (string.IsNullOrEmpty(settings["ControlMode"]) ||
string.Compare(settings["ControlMode"], "Variable", StringComparison.OrdinalIgnoreCase) == 0)
{
// Configure the nominal bitrate, but then disable bitrate management:
encoder.SetupManaged(audioInfo.Channels, audioInfo.SampleRate, -1, bitRate * 1000, -1);
encoder.Control(0x15, IntPtr.Zero); // OV_ECTL_RATEMANAGE2_SET
encoder.SetupInitialize();
}
else if (string.Compare(settings["ControlMode"], "Average", StringComparison.OrdinalIgnoreCase) == 0)
{
encoder.Initialize(audioInfo.Channels, audioInfo.SampleRate, -1, bitRate * 1000, -1);
}
else if (string.Compare(settings["ControlMode"], "Constant", StringComparison.OrdinalIgnoreCase) == 0)
{
encoder.Initialize(audioInfo.Channels, audioInfo.SampleRate, bitRate, bitRate * 1000, bitRate);
}
else
{
throw new InvalidSettingException(string.Format(CultureInfo.CurrentCulture,
Resources.SampleEncoderBadBitRateControlMode, settings["ControlMode"]));
}
}