Avisynth audio provider: add option to allow no downmix

Author: wangqr

src/audio_provider_avs.cpp

@@ -110,12 +110,14 @@ void AvisynthAudioProvider::LoadFromClip(AVSValue clip) {
 	if (!vi.HasAudio()) throw agi::AudioDataNotFound("No audio found.");
 
 	IScriptEnvironment *env = avs_wrapper.GetEnv();
+	AVSValue script;
 
 	// Convert to one channel
-	AVSValue script = env->Invoke(OPT_GET("Audio/Downmixer")->GetString().c_str(), clip);
+	if (OPT_GET("Audio/Downmixer")->GetString() != "None")
+		script = env->Invoke(OPT_GET("Audio/Downmixer")->GetString().c_str(), clip);
+	else
+		script = clip;
 
-	// Convert to 16 bits per sample
-	script = env->Invoke("ConvertAudioTo16bit", script);
 	vi = script.AsClip()->GetVideoInfo();
 
 	// Convert sample rate
@@ -135,8 +137,8 @@ void AvisynthAudioProvider::LoadFromClip(AVSValue clip) {
 	channels = vi.AudioChannels();
 	decoded_samples = num_samples = vi.num_audio_samples;
 	sample_rate = vi.SamplesPerSecond();
-	bytes_per_sample = vi.BytesPerAudioSample();
-	float_samples = false;
+	bytes_per_sample = vi.BytesPerChannelSample();
+	float_samples = vi.IsSampleType(SAMPLE_FLOAT);
 
 	this->clip = tempclip;
 }

src/preferences.cpp

@@ -387,8 +387,8 @@ void Advanced_Audio(wxTreebook *book, Preferences *parent) {
 
 #ifdef WITH_AVISYNTH
 	auto avisynth = p->PageSizer("Avisynth");
-	const wxString adm_arr[3] = { "ConvertToMono", "GetLeftChannel", "GetRightChannel" };
-	wxArrayString adm_choice(3, adm_arr);
+	const wxString adm_arr[4] = { "None", "ConvertToMono", "GetLeftChannel", "GetRightChannel" };
+	wxArrayString adm_choice(4, adm_arr);
 	p->OptionChoice(avisynth, _("Avisynth down-mixer"), adm_choice, "Audio/Downmixer");
 	p->OptionAdd(avisynth, _("Force sample rate"), "Provider/Audio/AVS/Sample Rate");
 #endif