VP9 wrapper: Adjust speed setting.

webrtc/modules/video_coding/codecs/vp9/vp9_impl.cc

 /*
  *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  *
  */
@@ skipping 24 matching lines @@
 // VP9DecoderImpl::ReturnFrame helper function used with WrappedI420Buffer.
 static void WrappedI420BufferNoLongerUsedCb(
     webrtc::Vp9FrameBufferPool::Vp9FrameBuffer* img_buffer) {
   img_buffer->Release();
 }
 
 }  // anonymous namespace
 
 namespace webrtc {
 
+// Only positive speeds, range for real-time coding currently is: 5 - 8.
+// Lower means slower/better quality, higher means fastest/lower quality.
+int GetCpuSpeed(int width, int height) {

[tommi, 2015/07/08 09:13:39]

Can this be in an anonymous namespace?
Also, I find the function name and parameters to be confusing. :-/
The return value doesn't tell you anything about the speed of the cpu...  where
is the range defined (aside from the comment)?  Would it make sense to call this
GetCompressionQuality or GetEncodingQuality?

+  // For smaller resolutions, use lower speed setting (get some coding gain at
+  // the cost of increased encoding complexity).
+  if (width * height <= 352 * 288)
+    return 5;
+  else
+    return 7;
+}
+
 VP9Encoder* VP9Encoder::Create() {
   return new VP9EncoderImpl();
 }
 
 VP9EncoderImpl::VP9EncoderImpl()
     : encoded_image_(),
       encoded_complete_callback_(NULL),
       inited_(false),
       timestamp_(0),
       picture_id_(0),
@@ skipping 132 matching lines @@
   config_->rc_buf_optimal_sz = 600;
   config_->rc_buf_sz = 1000;
   // Set the maximum target size of any key-frame.
   rc_max_intra_target_ = MaxIntraTarget(config_->rc_buf_optimal_sz);
   if (inst->codecSpecific.VP9.keyFrameInterval  > 0) {
     config_->kf_mode = VPX_KF_AUTO;
     config_->kf_max_dist = inst->codecSpecific.VP9.keyFrameInterval;
   } else {
     config_->kf_mode = VPX_KF_DISABLED;
   }
-
   // Determine number of threads based on the image size and #cores.
   config_->g_threads = NumberOfThreads(config_->g_w,
                                        config_->g_h,
                                        number_of_cores);
+  cpu_speed_ = GetCpuSpeed(config_->g_w, config_->g_h);
   return InitAndSetControlSettings(inst);
 }
 
 int VP9EncoderImpl::NumberOfThreads(int width,
                                     int height,
                                     int number_of_cores) {
   // Keep the number of encoder threads equal to the possible number of column
   // tiles, which is (1, 2, 4, 8). See comments below for VP9E_SET_TILE_COLUMNS.
   if (width * height >= 1280 * 720 && number_of_cores > 4) {
     return 4;
   } else if (width * height >= 640 * 480 && number_of_cores > 2) {
     return 2;
   } else {
     // 1 thread less than VGA.
     return 1;
   }
 }
 
 int VP9EncoderImpl::InitAndSetControlSettings(const VideoCodec* inst) {
   if (vpx_codec_enc_init(encoder_, vpx_codec_vp9_cx(), config_, 0)) {
     return WEBRTC_VIDEO_CODEC_UNINITIALIZED;
   }
-  // Only positive speeds, currently: 0 - 8.
-  // O means slowest/best quality, 8 means fastest/lower quality.
-  cpu_speed_ = 7;

[tommi, 2015/07/08 09:13:39]

cpu_speed_ is in my opinion not a great variable name. For something that
determines quality of the encoding, I would have liked to use something like
encoding_quality_ and define the range in constants (min/max).  As is, cpu_used_
would at least be better since it matches with the vpx settings constant.

-  // Note: some of these codec controls still use "VP8" in the control name.
-  // TODO(marpan): Update this in the next/future libvpx version.
   vpx_codec_control(encoder_, VP8E_SET_CPUUSED, cpu_speed_);
   vpx_codec_control(encoder_, VP8E_SET_MAX_INTRA_BITRATE_PCT,
                     rc_max_intra_target_);
   vpx_codec_control(encoder_, VP9E_SET_AQ_MODE,
                     inst->codecSpecific.VP9.adaptiveQpMode ? 3 : 0);
   // Control function to set the number of column tiles in encoding a frame, in
   // log2 unit: e.g., 0 = 1 tile column, 1 = 2 tile columns, 2 = 4 tile columns.
   // The number tile columns will be capped by the encoder based on image size
   // (minimum width of tile column is 256 pixels, maximum is 4096).
   vpx_codec_control(encoder_, VP9E_SET_TILE_COLUMNS, (config_->g_threads >> 1));
@@ skipping 314 matching lines @@
     decoder_ = NULL;
   }
   // Releases buffers from the pool. Any buffers not in use are deleted. Buffers
   // still referenced externally are deleted once fully released, not returning
   // to the pool.
   frame_buffer_pool_.ClearPool();
   inited_ = false;
   return WEBRTC_VIDEO_CODEC_OK;
 }
 }  // namespace webrtc