Switch VP9 lossy to CBR encoding.

remoting/codec/video_encoder_vpx.cc

 // Copyright 2013 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.
 
 #include "remoting/codec/video_encoder_vpx.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/sys_info.h"
@@ skipping 27 matching lines @@
 // Magic encoder profile numbers for I420 and I444 input formats.
 const int kVp9I420ProfileNumber = 0;
 const int kVp9I444ProfileNumber = 1;
 
 void SetCommonCodecParameters(vpx_codec_enc_cfg_t* config,
                               const webrtc::DesktopSize& size) {
   // Use millisecond granularity time base.
   config->g_timebase.num = 1;
   config->g_timebase.den = 1000;
 
-  // Adjust default target bit-rate to account for actual desktop size.
-  config->rc_target_bitrate = size.width() * size.height() *
-      config->rc_target_bitrate / config->g_w / config->g_h;
-
   config->g_w = size.width();
   config->g_h = size.height();
   config->g_pass = VPX_RC_ONE_PASS;
 
   // Start emitting packets immediately.
   config->g_lag_in_frames = 0;
 
   // Since the transport layer is reliable, keyframes should not be necessary.
   // However, due to crbug.com/440223, decoding fails after 30,000 non-key
   // frames, so take the hit of an "unnecessary" key-frame every 10,000 frames.
   config->kf_min_dist = 10000;
   config->kf_max_dist = 10000;
 
   // Using 2 threads gives a great boost in performance for most systems with
   // adequate processing power. NB: Going to multiple threads on low end
   // windows systems can really hurt performance.
   // http://crbug.com/99179
   config->g_threads = (base::SysInfo::NumberOfProcessors() > 2) ? 2 : 1;
 }
 
 void SetVp8CodecParameters(vpx_codec_enc_cfg_t* config,
                            const webrtc::DesktopSize& size) {
+  // Adjust default target bit-rate to account for actual desktop size.
+  config->rc_target_bitrate = size.width() * size.height() *
+      config->rc_target_bitrate / config->g_w / config->g_h;
+
   SetCommonCodecParameters(config, size);
 
   // Value of 2 means using the real time profile. This is basically a
   // redundant option since we explicitly select real time mode when doing
   // encoding.
   config->g_profile = 2;
 
   // Clamping the quantizer constrains the worst-case quality and CPU usage.
   config->rc_min_quantizer = 20;
   config->rc_max_quantizer = 30;
 }
 
 void SetVp9CodecParameters(vpx_codec_enc_cfg_t* config,
                            const webrtc::DesktopSize& size,
                            bool lossless_color,
                            bool lossless_encode) {
   SetCommonCodecParameters(config, size);
 
   // Configure VP9 for I420 or I444 source frames.
   config->g_profile =
       lossless_color ? kVp9I444ProfileNumber : kVp9I420ProfileNumber;
 
   if (lossless_encode) {
     // Disable quantization entirely, putting the encoder in "lossless" mode.
     config->rc_min_quantizer = 0;
     config->rc_max_quantizer = 0;
   } else {
-    // Lossy encode using the same settings as for VP8.
-    config->rc_min_quantizer = 20;
+    config->rc_min_quantizer = 4;
     config->rc_max_quantizer = 30;
+    config->rc_end_usage = VPX_CBR;
+    config->rc_target_bitrate = 500;

[Wez, 2015/04/18 00:00:23]

nit: Please add a comment to indicate that we are hard-coding to 500Kbps in the
absence of access to a good bandwidth estimator.

Suggest also setting the rc_end_usage explicitly to variable bit-rate in the
lossless case, for clarity.

[aconverse, 2015/04/20 17:12:26]

Done.

   }
 }
 
 void SetVp8CodecOptions(vpx_codec_ctx_t* codec) {
   // CPUUSED of 16 will have the smallest CPU load. This turns off sub-pixel
   // motion search.
   vpx_codec_err_t ret = vpx_codec_control(codec, VP8E_SET_CPUUSED, 16);
   DCHECK_EQ(VPX_CODEC_OK, ret) << "Failed to set CPUUSED";
 
   // Use the lowest level of noise sensitivity so as to spend less time
@@ skipping 386 matching lines @@
     uint8* map = active_map_.get() + top * active_map_width_;
     for (int y = top; y <= bottom; ++y) {
       for (int x = left; x <= right; ++x)
         map[x] = 1;
       map += active_map_width_;
     }
   }
 }
 
 }  // namespace remoting