public void Initialize(Stream stream, AudioInfo audioInfo, MetadataDictionary metadata, SettingsDictionary settings)
{
Contract.Ensures(_encoder != null);
// 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);
// Call the external ID3 encoder:
ExportFactory <IMetadataEncoder> metadataEncoderFactory =
ExtensionProvider.GetFactories <IMetadataEncoder>("Extension", EncoderInfo.FileExtension).Single();
if (metadataEncoderFactory == null)
{
throw new ExtensionInitializationException(string.Format(CultureInfo.CurrentCulture,
Resources.SampleEncoderMetadataEncoderError, EncoderInfo.FileExtension));
}
using (ExportLifetimeContext <IMetadataEncoder> metadataEncoderLifetime = metadataEncoderFactory.CreateExport())
metadataEncoderLifetime.Value.WriteMetadata(stream, metadata, settings);
_encoder = InitializeEncoder(audioInfo, stream);
ConfigureEncoder(settings, _encoder);
if (_encoder.InitializeParams() != 0)
{
throw new IOException(Resources.SampleEncoderFailedToInitialize);
}
}
static void ConfigureEncoderForQuality(SettingsDictionary settings, NativeEncoder encoder)
{
Contract.Requires(settings != null);
Contract.Requires(encoder != null);
encoder.SetVbr(VbrMode.Mtrh);
if (!string.IsNullOrEmpty(settings["ForceCBR"]))
{
throw new InvalidSettingException(Resources.SampleEncoderUnexpectedForceCBR);
}
float vbrQuality;
if (string.IsNullOrEmpty(settings["VBRQuality"]))
{
vbrQuality = 2;
}
else if (!float.TryParse(settings["VBRQuality"], out vbrQuality) || vbrQuality < 0 || vbrQuality >= 10)
{
throw new InvalidSettingException(string.Format(CultureInfo.CurrentCulture,
Resources.SampleEncoderBadVBRQuality, settings["VBRQuality"]));
}
encoder.SetVbrQuality(vbrQuality);
}
static void ConfigureEncoder(SettingsDictionary settings, NativeEncoder encoder)
{
Contract.Requires(settings != null);
Contract.Requires(encoder != null);
// Set the quality if specified, otherwise select "3":
uint quality;
if (string.IsNullOrEmpty(settings["Quality"]))
{
quality = 3;
}
else if (!uint.TryParse(settings["Quality"], out quality) || quality > 9)
{
throw new InvalidSettingException(string.Format(CultureInfo.CurrentCulture,
Resources.SampleEncoderBadQuality, settings["Quality"]));
}
encoder.SetQuality((int)quality);
// Set a bitrate only if specified. Otherwise, default to a variable bitrate:
if (!string.IsNullOrEmpty(settings["BitRate"]))
{
ConfigureEncoderForBitRate(settings, encoder);
}
else
{
ConfigureEncoderForQuality(settings, encoder);
}
}
static void ConfigureEncoderForBitRate(SettingsDictionary settings, NativeEncoder encoder)
{
Contract.Requires(settings != null);
Contract.Requires(encoder != null);
uint bitRate;
if (!uint.TryParse(settings["BitRate"], out bitRate) || bitRate < 8 || bitRate > 320)
{
throw new InvalidSettingException(string.Format(CultureInfo.CurrentCulture,
Resources.SampleEncoderBadBitRate, settings["BitRate"]));
}
// Default to an average bitrate, unless a constant bitrate is specified:
if (string.IsNullOrEmpty(settings["ForceCBR"]) ||
string.Compare(settings["ForceCBR"], bool.FalseString, StringComparison.OrdinalIgnoreCase) == 0)
{
encoder.SetVbr(VbrMode.Abr);
encoder.SetMeanBitRate((int)bitRate);
}
else if (string.Compare(settings["ForceCBR"], bool.TrueString, StringComparison.OrdinalIgnoreCase) == 0)
{
encoder.SetBitRate((int)bitRate);
}
else
{
throw new InvalidSettingException(string.Format(CultureInfo.CurrentCulture,
Resources.SampleEncoderBadForceCBR, settings["ForceCBR"]));
}
}
static NativeEncoder InitializeEncoder(AudioInfo audioInfo, Stream output)
{
Contract.Requires(audioInfo != null);
Contract.Requires(output != null);
Contract.Requires(output.CanWrite);
Contract.Requires(output.CanSeek);
Contract.Ensures(Contract.Result <NativeEncoder>() != null);
var result = new NativeEncoder(output);
result.SetSampleCount((uint)audioInfo.SampleCount);
result.SetSampleRate(audioInfo.SampleRate);
result.SetChannels(audioInfo.Channels);
return(result);
}
