Fix bug where min transmit bitrate wasn't working

webrtc/video/end_to_end_tests.cc

Index: webrtc/video/end_to_end_tests.cc
diff --git a/webrtc/video/end_to_end_tests.cc b/webrtc/video/end_to_end_tests.cc
index e5b12ce0b1e96027dfac849543c2965303307bca..ac2af53c38e26c34469a83c0ba84ac917d9b2982 100644
--- a/webrtc/video/end_to_end_tests.cc
+++ b/webrtc/video/end_to_end_tests.cc
@@ -25,6 +25,7 @@
 #include "webrtc/modules/include/module_common_types.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp.h"
 #include "webrtc/modules/rtp_rtcp/source/byte_io.h"
+#include "webrtc/modules/rtp_rtcp/source/rtp_utility.h"
 #include "webrtc/modules/rtp_rtcp/source/rtcp_utility.h"
 #include "webrtc/modules/video_coding/codecs/h264/include/h264.h"
 #include "webrtc/modules/video_coding/codecs/vp8/include/vp8.h"
@@ -2498,6 +2499,119 @@ TEST_F(EndToEndTest, ReportsSetEncoderRates) {
   RunBaseTest(&test);
 }
 
+class MinTransmitBitrateTest : public test::EndToEndTest,

[perkj_webrtc, 2016/07/04 07:24:49]

Why is this not a VideoSendStream test? What is the difference with EndToEnd
tests?

[perkj_webrtc, 2016/07/04 07:24:49]

How about testing padding instead?  There are tests that tests padding I think,
so why not change one of those tests to check that padding is sent if we start
with no padding and switch content type that needs padding? 

[sprang_webrtc, 2016/07/04 09:08:47]

I did that at first, it turned out to flake way too easily, so I abandoned it.

[sprang_webrtc, 2016/07/04 09:08:47]

I initially had planned to check received padding, but I ended up begin way too
flaky. Now it doesn't make sense anymore so have moved it to send stream test.

+                               public test::FakeEncoder {
+ public:
+  static const uint32_t kMinTransmitBitrateBps = 400000;
+  static const uint32_t kActualEncodeBitrateBps = 40000;
+  static const uint32_t kMinFramesToSend = 10;
+
+  explicit MinTransmitBitrateTest(bool run_init_phase_without_mtb)

[perkj_webrtc, 2016/07/04 07:24:49]

bool test_switch_content_type ? 

[sprang_webrtc, 2016/07/04 09:08:47]

Done.

+      : EndToEndTest(test::CallTest::kDefaultTimeoutMs),
+        FakeEncoder(Clock::GetRealTimeClock()),
+        call_(nullptr),
+        send_stream_(nullptr),
+        frames_sent_(0),
+        in_init_phase_(run_init_phase_without_mtb) {}
+
+  void OnVideoStreamsCreated(
+      VideoSendStream* send_stream,
+      const std::vector<VideoReceiveStream*>& receive_streams) override {
+    send_stream_ = send_stream;
+  }
+
+  void ModifyVideoConfigs(
+      VideoSendStream::Config* send_config,
+      std::vector<VideoReceiveStream::Config>* receive_configs,
+      VideoEncoderConfig* encoder_config) override {
+    send_config->encoder_settings.encoder = this;
+    RTC_DCHECK_EQ(1u, encoder_config->streams.size());
+    encoder_config->streams[0].target_bitrate_bps = kMinTransmitBitrateBps * 2;
+    encoder_config->streams[0].max_bitrate_bps = kMinTransmitBitrateBps * 4;
+    if (in_init_phase_) {
+      encoder_config->min_transmit_bitrate_bps = 0;
+      encoder_config->content_type =
+          VideoEncoderConfig::ContentType::kRealtimeVideo;
+    } else {
+      encoder_config->min_transmit_bitrate_bps = kMinTransmitBitrateBps;
+      encoder_config->content_type = VideoEncoderConfig::ContentType::kScreen;
+    }
+    encoder_config_ = *encoder_config;
+  }
+
+  int32_t SetRates(uint32_t new_target_bitrate, uint32_t framerate) override {
+    // Make sure not to trigger on any default zero bitrates.
+    if (new_target_bitrate == 0)
+      return 0;
+    rtc::CritScope lock(&crit_);
+    return FakeEncoder::SetRates(
+        std::min<uint32_t>(new_target_bitrate, kActualEncodeBitrateBps / 1000),
+        framerate);
+  }
+
+  int32_t Encode(const VideoFrame& input_image,
+                 const CodecSpecificInfo* codec_specific_info,
+                 const std::vector<FrameType>* frame_types) override {
+    int32_t res =
+        FakeEncoder::Encode(input_image, codec_specific_info, frame_types);
+    CheckDoneState();
+    return res;
+  }
+
+  void OnCallsCreated(Call* sender_call, Call* receiver_call) override {
+    call_ = sender_call;
+  }
+
+  void CheckDoneState() {
+    rtc::CritScope lock(&crit_);
+
+    if (in_init_phase_)
+      EXPECT_EQ(0, call_->GetStats().min_transmit_bitrate_bps);
+
+    // Wait until at least kMinFramesToSend frames have been encoded, so that
+    // we have reliable data.
+    if (++frames_sent_ < kMinFramesToSend)
+      return;
+
+    if (in_init_phase_) {
+      // We've sent kMinFramesToSend frames with default configuration, switch
+      // to enabling screen content and setting min transmit bitrate.
+      frames_sent_ = 0;
+      encoder_config_.min_transmit_bitrate_bps = kMinTransmitBitrateBps;
+      encoder_config_.content_type = VideoEncoderConfig::ContentType::kScreen;
+      send_stream_->ReconfigureVideoEncoder(encoder_config_);
+      in_init_phase_ = false;
+      return;
+    }
+
+    // Make sure the pacer has been configured with a min transmit bitrate.
+    if (call_->GetStats().min_transmit_bitrate_bps > 0)
+      observation_complete_.Set();
+  }
+
+  void PerformTest() override {
+    ASSERT_TRUE(Wait()) << "Timed out waiting for a valid padding bitrate.";
+  }
+
+ private:
+  rtc::CriticalSection crit_;
+  Call* call_;
+  VideoSendStream* send_stream_;
+  VideoEncoderConfig encoder_config_;
+  uint32_t frames_sent_ GUARDED_BY(crit_);
+  bool in_init_phase_;
+};
+
+TEST_F(EndToEndTest, RespectsMinTransmitBitrate) {
+  MinTransmitBitrateTest test(false);
+  RunBaseTest(&test);
+}
+
+TEST_F(EndToEndTest, RespectsMinTransmitBitrateAfterContentSwitch) {
+  MinTransmitBitrateTest test(true);
+  RunBaseTest(&test);
+}
+
 TEST_F(EndToEndTest, GetStats) {
   static const int kStartBitrateBps = 3000000;
   static const int kExpectedRenderDelayMs = 20;