Change default to three threads for video decoding and add command line --video-threads.

BUG=44128
TEST=player_wtl.exe --video-threads=6 d:\mediatests\crowd\crowd2.mp4

Review URL: http://codereview.chromium.org/2080008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@47723 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 34 insertions, 15 deletions

diff --git a/media/base/media_switches.cc b/media/base/media_switches.cc
index 7fa286e..3b684ce 100644
--- a/media/base/media_switches.cc
+++ b/media/base/media_switches.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -11,6 +11,11 @@ namespace switches {
 const char kAlsaDevice[] = "alsa-device";
 #endif
 
+// Enable hardware decoding using OpenMax API.
+// In practice this is for ChromeOS ARM.
 const char kEnableOpenMax[] = "enable-openmax";
 
+// Set number of threads to use for video decoding.
+const char kVideoThreads[] = "video-threads";
+
 }  // namespace switches
diff --git a/media/base/media_switches.h b/media/base/media_switches.h
index 28e3bb6..6e0e0d3 100644
--- a/media/base/media_switches.h
+++ b/media/base/media_switches.h
@@ -1,11 +1,11 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Defines all the "media" command-line switches.
 
-#ifndef MEDIA_BASE_SWITCHES_H_
-#define MEDIA_BASE_SWITCHES_H_
+#ifndef MEDIA_BASE_MEDIA_SWITCHES_H_
+#define MEDIA_BASE_MEDIA_SWITCHES_H_
 
 #include "build/build_config.h"
 
@@ -16,7 +16,9 @@ extern const char kAlsaDevice[];
 #endif
 
 extern const char kEnableOpenMax[];
+extern const char kVideoThreads[];
+
 
 }  // namespace switches
 
-#endif  // MEDIA_BASE_SWITCHES_H_
+#endif  // MEDIA_BASE_MEDIA_SWITCHES_H_
diff --git a/media/filters/ffmpeg_video_decode_engine.cc b/media/filters/ffmpeg_video_decode_engine.cc
index bf6089a..3313c27 100644
--- a/media/filters/ffmpeg_video_decode_engine.cc
+++ b/media/filters/ffmpeg_video_decode_engine.cc
@@ -4,10 +4,12 @@
 
 #include "media/filters/ffmpeg_video_decode_engine.h"
 
+#include "base/command_line.h"
 #include "base/task.h"
 #include "media/base/buffers.h"
 #include "media/base/callback.h"
 #include "media/base/limits.h"
+#include "media/base/media_switches.h"
 #include "media/ffmpeg/ffmpeg_common.h"
 #include "media/ffmpeg/ffmpeg_util.h"
 #include "media/filters/ffmpeg_demuxer.h"
@@ -24,8 +26,9 @@ FFmpegVideoDecodeEngine::~FFmpegVideoDecodeEngine() {
 
 void FFmpegVideoDecodeEngine::Initialize(AVStream* stream, Task* done_cb) {
   AutoTaskRunner done_runner(done_cb);
+  CHECK(state_ == kCreated);
 
-  // Always try to use two threads for video decoding.  There is little reason
+  // Always try to use three threads for video decoding.  There is little reason
   // not to since current day CPUs tend to be multi-core and we measured
   // performance benefits on older machines such as P4s with hyperthreading.
   //
@@ -33,10 +36,10 @@ void FFmpegVideoDecodeEngine::Initialize(AVStream* stream, Task* done_cb) {
   // continue processing. Although it'd be nice to have the option of a single
   // decoding thread, FFmpeg treats having one thread the same as having zero
   // threads (i.e., avcodec_decode_video() will execute on the calling thread).
-  // Yet another reason for having two threads :)
-  static const int kDecodeThreads = 2;
+  // Yet another reason for having three threads :)
+  static const int kDecodeThreads = 3;
+  static const int kMaxDecodeThreads = 16;
 
-  CHECK(state_ == kCreated);
 
   codec_context_ = stream->codec;
   codec_context_->flags2 |= CODEC_FLAG2_FAST;  // Enable faster H264 decode.
@@ -47,10 +50,18 @@ void FFmpegVideoDecodeEngine::Initialize(AVStream* stream, Task* done_cb) {
 
   AVCodec* codec = avcodec_find_decoder(codec_context_->codec_id);
 
-  // TODO(fbarchard): On next ffmpeg roll, retest Theora multi-threading.
+  // TODO(fbarchard): Improve thread logic based on size / codec.
   int decode_threads = (codec_context_->codec_id == CODEC_ID_THEORA)
       ? 1 : kDecodeThreads;
 
+  const CommandLine* cmd_line = CommandLine::ForCurrentProcess();
+  std::string threads(cmd_line->GetSwitchValueASCII(switches::kVideoThreads));
+  if ((!threads.empty() &&
+      !StringToInt(threads, &decode_threads)) ||
+      decode_threads < 0 || decode_threads > kMaxDecodeThreads) {
+    decode_threads = kDecodeThreads;
+  }
+
   // We don't allocate AVFrame on the stack since different versions of FFmpeg
   // may change the size of AVFrame, causing stack corruption.  The solution is
   // to let FFmpeg allocate the structure via avcodec_alloc_frame().
@@ -66,10 +77,11 @@ void FFmpegVideoDecodeEngine::Initialize(AVStream* stream, Task* done_cb) {
   }
 }
 
+// TODO(fbarchard): Find way to remove this memcpy of the entire image.
 static void CopyPlane(size_t plane,
                       scoped_refptr<VideoFrame> video_frame,
                       const AVFrame* frame) {
-  DCHECK(video_frame->width() % 2 == 0);
+  DCHECK_EQ(video_frame->width() % 2, 0u);
   const uint8* source = frame->data[plane];
   const size_t source_stride = frame->linesize[plane];
   uint8* dest = video_frame->data(plane);
diff --git a/media/filters/ffmpeg_video_decode_engine_unittest.cc b/media/filters/ffmpeg_video_decode_engine_unittest.cc
index f1d1680..4d16a7e 100644
--- a/media/filters/ffmpeg_video_decode_engine_unittest.cc
+++ b/media/filters/ffmpeg_video_decode_engine_unittest.cc
@@ -65,7 +65,7 @@ class FFmpegVideoDecodeEngineTest : public testing::Test {
         .WillOnce(Return(&codec_));
     EXPECT_CALL(*MockFFmpeg::get(), AVCodecAllocFrame())
         .WillOnce(Return(&yuv_frame_));
-    EXPECT_CALL(*MockFFmpeg::get(), AVCodecThreadInit(&codec_context_, 2))
+    EXPECT_CALL(*MockFFmpeg::get(), AVCodecThreadInit(&codec_context_, 3))
         .WillOnce(Return(0));
     EXPECT_CALL(*MockFFmpeg::get(), AVCodecOpen(&codec_context_, &codec_))
         .WillOnce(Return(0));
@@ -121,7 +121,7 @@ TEST_F(FFmpegVideoDecodeEngineTest, Initialize_InitThreadFails) {
       .WillOnce(Return(&codec_));
   EXPECT_CALL(*MockFFmpeg::get(), AVCodecAllocFrame())
       .WillOnce(Return(&yuv_frame_));
-  EXPECT_CALL(*MockFFmpeg::get(), AVCodecThreadInit(&codec_context_, 2))
+  EXPECT_CALL(*MockFFmpeg::get(), AVCodecThreadInit(&codec_context_, 3))
       .WillOnce(Return(-1));
   EXPECT_CALL(*MockFFmpeg::get(), AVFree(&yuv_frame_))
       .Times(1);
@@ -139,7 +139,7 @@ TEST_F(FFmpegVideoDecodeEngineTest, Initialize_OpenDecoderFails) {
       .WillOnce(Return(&codec_));
   EXPECT_CALL(*MockFFmpeg::get(), AVCodecAllocFrame())
       .WillOnce(Return(&yuv_frame_));
-  EXPECT_CALL(*MockFFmpeg::get(), AVCodecThreadInit(&codec_context_, 2))
+  EXPECT_CALL(*MockFFmpeg::get(), AVCodecThreadInit(&codec_context_, 3))
       .WillOnce(Return(0));
   EXPECT_CALL(*MockFFmpeg::get(), AVCodecOpen(&codec_context_, &codec_))
       .WillOnce(Return(-1));
diff --git a/media/test/ffmpeg_tests/ffmpeg_tests.cc b/media/test/ffmpeg_tests/ffmpeg_tests.cc
index abfbeff..73dd46d 100644
--- a/media/test/ffmpeg_tests/ffmpeg_tests.cc
+++ b/media/test/ffmpeg_tests/ffmpeg_tests.cc
@@ -87,7 +87,7 @@ int main(int argc, const char** argv) {
   }
 
   // Default flags that match Chrome defaults.
-  int video_threads = 2;
+  int video_threads = 3;
   int verbose_level = AV_LOG_FATAL;
   int max_frames = 0;
   int max_loops = 0;