From 5c66861bdfd8ca60728f9ecede21284452fc6491 Mon Sep 17 00:00:00 2001
From: Paul Adenot <paul@paul.cx>
Date: Mon, 2 Sep 2013 15:15:24 +0200
Subject: [PATCH] Bug 881959 - Clamp the DelayNode.delayTime to
 128/AudioContext.sampleRate when in a cycle. r=ehsan

--HG--
extra : rebase_source : 7cf8945371bb6ff169ad61a8ccdda0ece36b5e83
---
 content/media/MediaStreamGraph.h     |  3 +++
 content/media/webaudio/DelayNode.cpp | 18 ++++++++++++++----
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/content/media/MediaStreamGraph.h b/content/media/MediaStreamGraph.h
index a2efa053485..82598370336 100644
--- a/content/media/MediaStreamGraph.h
+++ b/content/media/MediaStreamGraph.h
@@ -943,6 +943,9 @@ public:
    */
   virtual void ForwardTrackEnabled(TrackID aOutputID, bool aEnabled) {};
 
+  bool InCycle() const { return mInCycle; }
+
+
 protected:
   // This state is all accessed only on the media graph thread.
 
diff --git a/content/media/webaudio/DelayNode.cpp b/content/media/webaudio/DelayNode.cpp
index ddf93101deb..6fed03c9f37 100644
--- a/content/media/webaudio/DelayNode.cpp
+++ b/content/media/webaudio/DelayNode.cpp
@@ -128,18 +128,28 @@ public:
     float* const* outputChannels = reinterpret_cast<float* const*>
       (const_cast<void* const*>(aOutput->mChannelData.Elements()));
 
+
+    bool inCycle = aStream->AsProcessedStream()->InCycle();
     double sampleRate = aStream->SampleRate();
     if (mDelay.HasSimpleValue()) {
-      double delayFrames = mDelay.GetValue() * sampleRate;
-      mProcessor.Process(delayFrames, inputChannels, outputChannels,
+      // If this DelayNode is in a cycle, make sure the delay value is at least
+      // one block.
+      float delayFrames = mDelay.GetValue() * sampleRate;
+      float delayFramesClamped = inCycle ? std::max(static_cast<float>(WEBAUDIO_BLOCK_SIZE), delayFrames) :
+                                           delayFrames;
+      mProcessor.Process(delayFramesClamped, inputChannels, outputChannels,
                          numChannels, WEBAUDIO_BLOCK_SIZE);
     } else {
       // Compute the delay values for the duration of the input AudioChunk
+      // If this DelayNode is in a cycle, make sure the delay value is at least
+      // one block.
       double computedDelay[WEBAUDIO_BLOCK_SIZE];
       TrackTicks tick = aStream->GetCurrentPosition();
       for (size_t counter = 0; counter < WEBAUDIO_BLOCK_SIZE; ++counter) {
-        computedDelay[counter] =
-          mDelay.GetValueAtTime(tick, counter) * sampleRate;
+        float delayAtTick = mDelay.GetValueAtTime(tick, counter) * sampleRate;
+        float delayAtTickClamped = inCycle ? std::max(static_cast<float>(WEBAUDIO_BLOCK_SIZE), delayAtTick) :
+                                             delayAtTick;
+        computedDelay[counter] = delayAtTickClamped;
       }
       mProcessor.Process(computedDelay, inputChannels, outputChannels,
                          numChannels, WEBAUDIO_BLOCK_SIZE);