From a3c28798a13f45070308fc131898b090c004f83b Mon Sep 17 00:00:00 2001
From: Jean-Yves Avenard <jyavenard@mozilla.com>
Date: Wed, 24 Dec 2014 23:11:35 +1100
Subject: [PATCH] Bug 1111319: Reorder video frames with respect to decoding
 sliding window. r=rillian

---
 dom/media/fmp4/apple/AppleVDADecoder.cpp | 18 +++++++++---------
 dom/media/fmp4/apple/AppleVDADecoder.h   |  1 +
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/dom/media/fmp4/apple/AppleVDADecoder.cpp b/dom/media/fmp4/apple/AppleVDADecoder.cpp
index 899c5a75f868..cd5e3bfee9a8 100644
--- a/dom/media/fmp4/apple/AppleVDADecoder.cpp
+++ b/dom/media/fmp4/apple/AppleVDADecoder.cpp
@@ -48,11 +48,19 @@ AppleVDADecoder::AppleVDADecoder(const mp4_demuxer::VideoDecoderConfig& aConfig,
   // Retrieve video dimensions from H264 SPS NAL.
   mPictureWidth = mConfig.image_width;
   mPictureHeight = mConfig.image_height;
+  mMaxRefFrames = 4;
   mp4_demuxer::SPSData spsdata;
   if (mp4_demuxer::H264::DecodeSPSFromExtraData(mConfig.extra_data, spsdata) &&
       spsdata.pic_width && spsdata.pic_height) {
     mPictureWidth = spsdata.pic_width;
     mPictureHeight = spsdata.pic_height;
+    // max_num_ref_frames determines the size of the sliding window
+    // we need to queue that many frames in order to guarantee proper
+    // pts frames ordering. Use a minimum of 4 to ensure proper playback of
+    // non compliant videos.
+    mMaxRefFrames =
+      (spsdata.max_num_ref_frames + 1) > mMaxRefFrames ?
+        spsdata.max_num_ref_frames + 1 : mMaxRefFrames;
   }
 
   LOG("Creating AppleVDADecoder for %dx%d h.264 video",
@@ -282,17 +290,9 @@ AppleVDADecoder::OutputFrame(CVPixelBufferRef aImage,
   // in composition order.
   mReorderQueue.Push(data);
   // Assume a frame with a PTS <= current DTS is ready.
-  while (mReorderQueue.Length() > 0) {
+  while (mReorderQueue.Length() > mMaxRefFrames) {
     nsRefPtr<VideoData> readyData = mReorderQueue.Pop();
-    if (readyData->mTime <= aFrameRef->decode_timestamp) {
-      LOG("returning queued frame with pts %lld", readyData->mTime);
       mCallback->Output(readyData);
-    } else {
-      LOG("requeued frame with pts %lld > %lld",
-          readyData->mTime, aFrameRef->decode_timestamp);
-      mReorderQueue.Push(readyData);
-      break;
-    }
   }
   LOG("%llu decoded frames queued",
       static_cast<unsigned long long>(mReorderQueue.Length()));
diff --git a/dom/media/fmp4/apple/AppleVDADecoder.h b/dom/media/fmp4/apple/AppleVDADecoder.h
index 82084a609ba3..785721bbf90c 100644
--- a/dom/media/fmp4/apple/AppleVDADecoder.h
+++ b/dom/media/fmp4/apple/AppleVDADecoder.h
@@ -92,6 +92,7 @@ public:
   ReorderQueue mReorderQueue;
   uint32_t mPictureWidth;
   uint32_t mPictureHeight;
+  uint32_t mMaxRefFrames;
 
 private:
   VDADecoder mDecoder;