Use high QP threshold for HW VP8 encoder frame downscaling.

talk/app/webrtc/java/jni/androidmediaencoder_jni.cc

Index: talk/app/webrtc/java/jni/androidmediaencoder_jni.cc
diff --git a/talk/app/webrtc/java/jni/androidmediaencoder_jni.cc b/talk/app/webrtc/java/jni/androidmediaencoder_jni.cc
index 7f558c0551b07e657d2163df58167a4734ecf06d..d63b7d1d60212b56a08efae43ae7bcbee0268290 100644
--- a/talk/app/webrtc/java/jni/androidmediaencoder_jni.cc
+++ b/talk/app/webrtc/java/jni/androidmediaencoder_jni.cc
@@ -77,7 +77,9 @@ namespace webrtc_jni {
 #define MAX_ENCODER_Q_SIZE 2
 // Maximum allowed latency in ms.
 #define MAX_ENCODER_LATENCY_MS 70
-
+// Maximum amount of dropped frames caused by full encoder queue - exceeding
+// this threshold means that encoder probably got stuck and need to be reset.
+#define MAX_DROPPED_FRAMES 60

[pbos-webrtc, 2016/01/18 10:33:07]

ENCODER_STALL_FRAMEDROP_THRESHOLD maybe, something indicating that it's
detecting stalls.

[jackychen_, 2016/01/19 02:21:01]

In the comment, "reset the encoder when it drops more than 70 frames in a raw",
but 60 here? Maybe remove concrete number in the comment.

[AlexG, 2016/01/19 22:13:41]

Done.

[AlexG, 2016/01/19 22:13:41]

Done.

 
 // Logging macros.
 #define TAG_ENCODER "MediaCodecVideoEncoder"
@@ -221,6 +223,7 @@ class MediaCodecVideoEncoder : public webrtc::VideoEncoder,
   int frames_received_;  // Number of frames received by encoder.
   int frames_encoded_;  // Number of frames encoded by encoder.
   int frames_dropped_;  // Number of frames dropped by encoder.
+  int frames_dropped_q_full_;  // Number of dropped frames caused by full queue.

[pbos-webrtc, 2016/01/18 10:33:07]

consecutive_full_queue_frame_drops_

[AlexG, 2016/01/19 22:13:41]

Done.

   int frames_in_queue_;  // Number of frames in encoder queue.
   int64_t start_time_ms_;  // Start time for statistics.
   int current_frames_;  // Number of frames in the current statistics interval.
@@ -370,18 +373,15 @@ int32_t MediaCodecVideoEncoder::InitEncode(
       // always = 127. Note that in SW, QP is that of the user-level range [0,
       // 63].
       const int kMaxQp = 127;
-      // TODO(pbos): Investigate whether high-QP thresholds make sense for VP8.
-      // This effectively disables high QP as VP8 QP can't go above this
-      // threshold.
-      const int kDisabledBadQpThreshold = kMaxQp + 1;
-      quality_scaler_.Init(kMaxQp / kLowQpThresholdDenominator,
-                           kDisabledBadQpThreshold, true);
+      const int kBadQpThreshold = kMaxQp  - kMaxQp / 4;

[pbos-webrtc, 2016/01/18 10:33:07]

I think this should just be hard-coded as another value, max_qp / 4 doesn't
really mean anything quantifyable, right?

[AlexG, 2016/01/19 22:13:41]

Done.

+      quality_scaler_.Init(
+          kMaxQp / kLowQpThresholdDenominator, kBadQpThreshold, false);
     } else if (codecType_ == kVideoCodecH264) {
       // H264 QP is in the range [0, 51].
       const int kMaxQp = 51;
       const int kBadQpThreshold = 40;
-      quality_scaler_.Init(kMaxQp / kLowQpThresholdDenominator, kBadQpThreshold,
-                           false);
+      quality_scaler_.Init(
+          kMaxQp / kLowQpThresholdDenominator, kBadQpThreshold, false);
     } else {
       // When adding codec support to additional hardware codecs, also configure
       // their QP thresholds for scaling.
@@ -429,9 +429,6 @@ int32_t MediaCodecVideoEncoder::SetChannelParameters(uint32_t /* packet_loss */,
 
 int32_t MediaCodecVideoEncoder::SetRates(uint32_t new_bit_rate,
                                          uint32_t frame_rate) {
-  if (scale_)
-    quality_scaler_.ReportFramerate(frame_rate);
-
   return codec_thread_->Invoke<int32_t>(
       Bind(&MediaCodecVideoEncoder::SetRatesOnCodecThread,
            this,
@@ -498,6 +495,7 @@ int32_t MediaCodecVideoEncoder::InitEncodeOnCodecThread(
   frames_received_ = 0;
   frames_encoded_ = 0;
   frames_dropped_ = 0;
+  frames_dropped_q_full_ = 0;
   frames_in_queue_ = 0;
   current_timestamp_us_ = 0;
   start_time_ms_ = GetCurrentTimeMs();
@@ -614,12 +612,20 @@ int32_t MediaCodecVideoEncoder::EncodeOnCodecThread(
     if (frames_in_queue_ > MAX_ENCODER_Q_SIZE ||
         encoder_latency_ms > MAX_ENCODER_LATENCY_MS) {
       ALOGD << "Drop frame - encoder is behind by " << encoder_latency_ms <<
-          " ms. Q size: " << frames_in_queue_;
+          " ms. Q size: " << frames_in_queue_ << ". Consecutive drops: " <<
+          frames_dropped_q_full_;
       current_timestamp_us_ += rtc::kNumMicrosecsPerSec / last_set_fps_;
+      frames_dropped_q_full_++;
+      if (frames_dropped_q_full_ >= MAX_DROPPED_FRAMES) {
+        ALOGE << "Encoder got stuck. Reset.";
+        ResetCodecOnCodecThread();
+        return WEBRTC_VIDEO_CODEC_ERROR;
+      }
       OnDroppedFrame();
       return WEBRTC_VIDEO_CODEC_OK;
     }
   }
+  frames_dropped_q_full_ = 0;
 
   VideoFrame input_frame = frame;
   if (scale_) {
@@ -662,6 +668,7 @@ int32_t MediaCodecVideoEncoder::EncodeOnCodecThread(
       ALOGW << "Encoder drop frame - no input buffers available";
       current_timestamp_us_ += rtc::kNumMicrosecsPerSec / last_set_fps_;
       frame_rtc_times_ms_.erase(frame_rtc_times_ms_.begin());
+      OnDroppedFrame();
       return WEBRTC_VIDEO_CODEC_OK;  // TODO(fischman): see webrtc bug 2887.
     }
     if (j_input_buffer_index == -2) {
@@ -815,6 +822,9 @@ int32_t MediaCodecVideoEncoder::SetRatesOnCodecThread(uint32_t new_bit_rate,
       last_set_fps_ == frame_rate) {
     return WEBRTC_VIDEO_CODEC_OK;
   }
+  if (scale_) {
+    quality_scaler_.ReportFramerate(frame_rate);
+  }
   JNIEnv* jni = AttachCurrentThreadIfNeeded();
   ScopedLocalRefFrame local_ref_frame(jni);
   if (new_bit_rate > 0) {