From f70f266ca0ccbc19189a2d8dca19ace39f5e6967 Mon Sep 17 00:00:00 2001
From: itsmattkc <itsmattkc@gmail.com>
Date: Tue, 16 Jun 2020 03:49:12 +1000
Subject: [PATCH] render: queue audio alongside video

Previously, audio was all queued first and would therefore all have to
finish before any video frames could start caching. No longer! Now they're
queued side by side so users won't have to wait for audio to finish before
their cached frames come in.
---
 app/render/backend/renderbackend.cpp |  9 +++++----
 app/render/backend/renderbackend.h   |  2 +-
 app/task/render/render.cpp           | 14 +++++++++-----
 3 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/app/render/backend/renderbackend.cpp b/app/render/backend/renderbackend.cpp
index 636b5808c..5a1c8d3bd 100644
--- a/app/render/backend/renderbackend.cpp
+++ b/app/render/backend/renderbackend.cpp
@@ -175,18 +175,19 @@ void RenderBackend::SetVideoDownloadMatrix(const QMatrix4x4 &mat)
   video_download_matrix_ = mat;
 }
 
-QList<TimeRange> RenderBackend::SplitRangeIntoChunks(const TimeRange &r)
+std::list<TimeRange> RenderBackend::SplitRangeIntoChunks(const TimeRange &r)
 {
+  // FIXME: Magic number
   const int chunk_size = 2;
 
-  QList<TimeRange> split_ranges;
+  std::list<TimeRange> split_ranges;
 
   int start_time = qFloor(r.in().toDouble() / static_cast<double>(chunk_size)) * chunk_size;
   int end_time = qCeil(r.out().toDouble() / static_cast<double>(chunk_size)) * chunk_size;
 
   for (int i=start_time; i<end_time; i+=chunk_size) {
-    split_ranges.append(TimeRange(qMax(r.in(), rational(i)),
-                                  qMin(r.out(), rational(i + chunk_size))));
+    split_ranges.push_back(TimeRange(qMax(r.in(), rational(i)),
+                                     qMin(r.out(), rational(i + chunk_size))));
   }
 
   return split_ranges;
diff --git a/app/render/backend/renderbackend.h b/app/render/backend/renderbackend.h
index 90c7d3ca9..8f9339691 100644
--- a/app/render/backend/renderbackend.h
+++ b/app/render/backend/renderbackend.h
@@ -87,7 +87,7 @@ public:
 
   void SetVideoDownloadMatrix(const QMatrix4x4& mat);
 
-  static QList<TimeRange> SplitRangeIntoChunks(const TimeRange& r);
+  static std::list<TimeRange> SplitRangeIntoChunks(const TimeRange& r);
 
 public slots:
   void NodeGraphChanged(NodeInput *source);
diff --git a/app/task/render/render.cpp b/app/task/render/render.cpp
index 175e3144d..133a6bf1d 100644
--- a/app/task/render/render.cpp
+++ b/app/task/render/render.cpp
@@ -74,16 +74,14 @@ void RenderTask::Render(const TimeRangeList& video_range,
   double total_length = 0;
   double video_frame_sz = video_params_.time_base().toDouble();
 
+  std::list<TimeRange> audio_queue;
   std::list<RangeSampleFuturePair> audio_lookup_table;
   if (!audio_range.isEmpty()) {
     foreach (const TimeRange& r, audio_range) {
       total_length += r.length().toDouble();
 
-      QList<TimeRange> ranges = RenderBackend::SplitRangeIntoChunks(r);
-
-      foreach (const TimeRange& split, ranges) {
-        audio_lookup_table.push_back({split, backend_.RenderAudio(split)});
-      }
+      std::list<TimeRange> ranges = RenderBackend::SplitRangeIntoChunks(r);
+      audio_queue.insert(audio_queue.end(), ranges.begin(), ranges.end());
     }
   }
 
@@ -123,6 +121,7 @@ void RenderTask::Render(const TimeRangeList& video_range,
   while (!IsCancelled()
          && (!render_lookup_table.empty()
              || !frame_queue.empty()
+             || !audio_queue.empty()
              || !download_futures.empty()
              || !audio_lookup_table.empty())) {
 
@@ -168,6 +167,11 @@ void RenderTask::Render(const TimeRangeList& video_range,
       frame_queue.pop_front();
     }
 
+    if (!audio_queue.empty()) {
+      audio_lookup_table.push_back({audio_queue.front(), backend_.RenderAudio(audio_queue.front())});
+      audio_queue.pop_front();
+    }
+
     i = render_lookup_table.begin();
 
     while (!IsCancelled() && i != render_lookup_table.end()) {