Add FlexfecReceiveStream.

webrtc/call/flexfec_receive_stream_unittest.cc

+/*
+ *  Copyright (c) 2016 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.
+ */
+
+#include "webrtc/base/basictypes.h"
+#include "webrtc/call/flexfec_receive_stream.h"
+#include "webrtc/modules/rtp_rtcp/include/flexfec_receiver.h"
+#include "webrtc/modules/rtp_rtcp/source/byte_io.h"
+#include "webrtc/modules/rtp_rtcp/mocks/mock_recovered_packet_receiver.h"
+#include "webrtc/test/gmock.h"
+#include "webrtc/test/gtest.h"
+
+namespace webrtc {
+
+TEST(FlexfecReceiveStreamTest, ConfigToString) {
+  FlexfecReceiveStream::Config config;
+  config.flexfec_payload_type = 118;
+  config.flexfec_ssrc = 12545412;
+  config.protected_media_ssrc = 89372;
+
+  EXPECT_EQ(
+      "{flexfec_payload_type: 118, "
+      "flexfec_ssrc: 12545412, "
+      "protected_media_ssrc: 89372}",
+      config.ToString());

[philipel, 2016/10/18 10:43:34]

Is the format of the string representation of the config important? Is it part
of some bigger JSON object or something like that?

It feel strange to test something that should produce some arbitrary result (in
this case, a human readable representation).

[brandtr, 2016/10/18 14:31:18]

Nope, this is purely for human consumption.

Since a similar test exists here:
https://cs.chromium.org/chromium/src/third_party/webrtc/audio/audio_receive_s...,
I added this unit test here. I agree that it's not super useful though, so I
wouldn't mind removing it, if you think that is better than keeping it? (I guess
the maintenance burden of keeping it shouldn't be very big.)

[philipel, 2016/10/19 09:10:50]

I think you should remove this test, or if you want to keep it add a comment
that explains that the output does not follow a strict format.

The reason for this is that we have tests that use the log output, and adding a
test like this makes it look like that might be the case here.

[brandtr, 2016/10/19 09:31:24]

Ok, thanks for the explanation. Removing the test.

+}
+
+TEST(FlexfecReceiveStreamTest, ConstructDestruct) {
+  FlexfecReceiveStream::Config config;
+  config.flexfec_payload_type = 118;
+  config.flexfec_ssrc = 424223;
+  config.protected_media_ssrc = 912512;
+  MockRecoveredPacketReceiver callback;
+
+  internal::FlexfecReceiveStream receive_stream(config, &callback);
+}
+
+TEST(FlexfecReceiveStreamTest, StartStop) {
+  FlexfecReceiveStream::Config config;
+  config.flexfec_payload_type = 118;
+  config.flexfec_ssrc = 1652392;
+  config.protected_media_ssrc = 23300443;
+  MockRecoveredPacketReceiver callback;
+  internal::FlexfecReceiveStream receive_stream(config, &callback);
+
+  receive_stream.Start();
+  receive_stream.Stop();
+}
+
+// Create a FlexFEC packet that protects a single media packet and ensure
+// that the callback is called. Correctness of recovery is checked in the
+// FlexfecReceiver unit tests.
+TEST(FlexfecReceiveStreamTest, RecoversPacketWhenStarted) {

[stefan-webrtc, 2016/10/17 17:56:04]

Useful test!

+  constexpr uint8_t kFlexfecPlType = 118;
+  constexpr uint8_t kFlexfecSeqNum[] = {0x00, 0x01};
+  constexpr uint8_t kFlexfecTs[] = {0x00, 0x11, 0x22, 0x33};
+  constexpr uint8_t kFlexfecSsrc[] = {0x00, 0x00, 0x00, 0x01};
+  constexpr uint8_t kMediaPlType = 107;
+  constexpr uint8_t kMediaSeqNum[] = {0x00, 0x02};
+  constexpr uint8_t kMediaTs[] = {0xaa, 0xbb, 0xcc, 0xdd};
+  constexpr uint8_t kMediaSsrc[] = {0x00, 0x00, 0x00, 0x02};
+
+  // This packet mask protects a single media packet, i.e., the FlexFEC payload
+  // is a copy of that media packet. When inserted in the FlexFEC pipeline,
+  // it will thus trivially recover the lost media packet.
+  constexpr uint8_t kKBit0 = 1 << 7;
+  constexpr uint8_t kFlexfecPktMask[] = {kKBit0 | 0x00, 0x01};
+  constexpr uint8_t kPayloadLength[] = {0x00, 0x04};
+  constexpr uint8_t kSsrcCount = 1;
+  constexpr uint8_t kReservedBits = 0x00;
+  constexpr uint8_t kPayloadBits = 0x00;
+  // clang-format off
+  constexpr uint8_t kFlexfecPacket[] = {
+      // RTP header.
+      0x80,            kFlexfecPlType,  kFlexfecSeqNum[0],  kFlexfecSeqNum[1],
+      kFlexfecTs[0],   kFlexfecTs[1],   kFlexfecTs[2],      kFlexfecTs[3],
+      kFlexfecSsrc[0], kFlexfecSsrc[1], kFlexfecSsrc[2],    kFlexfecSsrc[3],
+      // FlexFEC header.
+      0x00,            kMediaPlType,    kPayloadLength[0],  kPayloadLength[1],
+      kMediaTs[0],     kMediaTs[1],     kMediaTs[2],        kMediaTs[3],
+      kSsrcCount,      kReservedBits,   kReservedBits,      kReservedBits,
+      kMediaSsrc[0],   kMediaSsrc[1],   kMediaSsrc[2],      kMediaSsrc[3],
+      kMediaSeqNum[0], kMediaSeqNum[1], kFlexfecPktMask[0], kFlexfecPktMask[1],
+      // FEC payload.
+      kPayloadBits,    kPayloadBits,    kPayloadBits,       kPayloadBits};
+  // clang-format on
+  constexpr size_t kFlexfecPacketLength = sizeof(kFlexfecPacket);
+
+  FlexfecReceiveStream::Config config;
+  config.flexfec_payload_type = kFlexfecPlType;
+  config.flexfec_ssrc = ByteReader<uint32_t>::ReadBigEndian(kFlexfecSsrc);
+  config.protected_media_ssrc = ByteReader<uint32_t>::ReadBigEndian(kMediaSsrc);
+  testing::StrictMock<MockRecoveredPacketReceiver> recovered_packet_receiver;
+  internal::FlexfecReceiveStream receive_stream(config,
+                                                &recovered_packet_receiver);
+
+  // Do not call back before being started.
+  receive_stream.AddAndProcessReceivedPacket(kFlexfecPacket,
+                                             kFlexfecPacketLength);
+
+  // Call back after being started.
+  receive_stream.Start();
+  EXPECT_CALL(
+      recovered_packet_receiver,
+      OnRecoveredPacket(::testing::_, kRtpHeaderSize + kPayloadLength[1]));
+  receive_stream.AddAndProcessReceivedPacket(kFlexfecPacket,
+                                             kFlexfecPacketLength);
+}
+
+}  // namespace webrtc