From 753848865dfda270c4adaf3095b2ea7117271749 Mon Sep 17 00:00:00 2001
From: oparviai <oparviai@f3a24b6a-cf45-0410-b55a-8c22e2698227>
Date: Sat, 15 Oct 2016 19:34:59 +0000
Subject: [PATCH] Added function to get duration ratio between the original
 input and processed output tracks.

---
 include/SoundTouch.h                 | 18 ++++++++++++++++++
 source/SoundTouch/RateTransposer.cpp |  2 +-
 source/SoundTouch/RateTransposer.h   |  3 +++
 source/SoundTouch/SoundTouch.cpp     | 11 ++++++++++-
 4 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/include/SoundTouch.h b/include/SoundTouch.h
index 482d312..edbee84 100644
--- a/include/SoundTouch.h
+++ b/include/SoundTouch.h
@@ -259,6 +259,24 @@ public:
     /// Sets sample rate.
     void setSampleRate(uint srate);
 
+    /// Get ratio between input and output audio durations, useful for calculating
+    /// processed output duration: if you'll process a stream of N samples, then 
+    /// you can expect to get out N * getInputOutputSampleRatio() samples.
+    ///
+    /// This ratio will give accurate target duration ratio for a full audio track, 
+    /// given that the the whole track is processed with same processing parameters.
+    /// 
+    /// If this ratio is applied to calculate intermediate offsets inside a processing
+    /// stream, then this ratio is approximate and can deviate +- some tens of milliseconds 
+    /// from ideal offset, yet by end of the audio stream the duration ratio will become
+    /// exact.
+    ///
+    /// Example: if processing with parameters "-tempo=15 -pitch=-3", the function
+    /// will return value 0.8695652... Now, if processing an audio stream whose duration
+    /// is exactly one million audio samples, then you can expect the processed 
+    /// output duration  be 0.869565 * 1000000 = 869565 samples.
+    double getInputOutputSampleRatio();
+
     /// Flushes the last samples from the processing pipeline to the output.
     /// Clears also the internal processing buffers.
     //
diff --git a/source/SoundTouch/RateTransposer.cpp b/source/SoundTouch/RateTransposer.cpp
index 1b61eae..926adc6 100644
--- a/source/SoundTouch/RateTransposer.cpp
+++ b/source/SoundTouch/RateTransposer.cpp
@@ -211,7 +211,7 @@ int RateTransposer::isEmpty() const
 /// Return approximate initial input-output latency
 int RateTransposer::getLatency() const
 {
-	return (bUseAAFilter) ? pAAFilter->getLength() : 0;
+    return (bUseAAFilter) ? pAAFilter->getLength() : 0;
 }
 
 
diff --git a/source/SoundTouch/RateTransposer.h b/source/SoundTouch/RateTransposer.h
index b122d4f..87f1dff 100644
--- a/source/SoundTouch/RateTransposer.h
+++ b/source/SoundTouch/RateTransposer.h
@@ -172,6 +172,9 @@ public:
 
     /// Returns nonzero if there aren't any samples available for outputting.
     int isEmpty() const;
+
+    /// Return approximate initial input-output latency
+    int getLatency() const;
 };
 
 }
diff --git a/source/SoundTouch/SoundTouch.cpp b/source/SoundTouch/SoundTouch.cpp
index b942b80..7617f97 100644
--- a/source/SoundTouch/SoundTouch.cpp
+++ b/source/SoundTouch/SoundTouch.cpp
@@ -475,7 +475,6 @@ int SoundTouch::getSetting(int settingId) const
             return size;
         }
 
-
         case SETTING_NOMINAL_OUTPUT_SEQUENCE :
         {
             int size = pTDStretch->getOutputBatchSize();
@@ -514,6 +513,7 @@ int SoundTouch::getSetting(int settingId) const
 }
 
 
+
 // Clears all the samples in the object's output and internal processing
 // buffers.
 void SoundTouch::clear()
@@ -567,3 +567,12 @@ uint SoundTouch::receiveSamples(uint maxSamples)
     samplesOutput += (long)ret;
     return ret;
 }
+
+
+/// Get ratio between input and output audio durations, useful for calculating
+/// processed output duration: if you'll process a stream of N samples, then 
+/// you can expect to get out N * getInputOutputSampleRatio() samples.
+double SoundTouch::getInputOutputSampleRatio()
+{
+    return 1.0 / (tempo * rate);
+}