Tune QP thresholds for HW H.264 encoder.

webrtc/api/java/jni/androidmediaencoder_jni.cc

Index: webrtc/api/java/jni/androidmediaencoder_jni.cc
diff --git a/webrtc/api/java/jni/androidmediaencoder_jni.cc b/webrtc/api/java/jni/androidmediaencoder_jni.cc
index 71e297c948ddbc29839e973961f5d92b5ca13895..937aef8349063d70e3e8d57c61c6e30de20fdf1d 100644
--- a/webrtc/api/java/jni/androidmediaencoder_jni.cc
+++ b/webrtc/api/java/jni/androidmediaencoder_jni.cc
@@ -387,8 +387,8 @@ int32_t MediaCodecVideoEncoder::InitEncode(
           codec_settings->width, codec_settings->height);
     } else if (codecType_ == kVideoCodecH264) {
       // H264 QP is in the range [0, 51].
-      const int kLowQpThreshold = 17;
-      const int kBadQpThreshold = 40;
+      const int kLowQpThreshold = 21;
+      const int kBadQpThreshold = 36;
       quality_scaler_.Init(kLowQpThreshold, kBadQpThreshold, false,
           codec_settings->startBitrate,
           codec_settings->width, codec_settings->height);