Injectable audio encoders: BuiltinAudioEncoderFactory

webrtc/modules/audio_coding/codecs/builtin_audio_encoder_factory.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/modules/audio_coding/codecs/builtin_audio_encoder_factory.h"
+
+#include <vector>
+
+#include "webrtc/base/checks.h"
+#include "webrtc/base/logging.h"
+#include "webrtc/base/optional.h"
+#include "webrtc/common_types.h"
+#include "webrtc/modules/audio_coding/codecs/g711/audio_encoder_pcm.h"
+#ifdef WEBRTC_CODEC_G722
+#include "webrtc/modules/audio_coding/codecs/g722/audio_encoder_g722.h"
+#endif
+#ifdef WEBRTC_CODEC_ILBC
+#include "webrtc/modules/audio_coding/codecs/ilbc/audio_encoder_ilbc.h"
+#endif
+#ifdef WEBRTC_CODEC_ISACFX
+#include "webrtc/modules/audio_coding/codecs/isac/fix/include/audio_encoder_isacfix.h"
+#endif
+#ifdef WEBRTC_CODEC_ISAC
+#include "webrtc/modules/audio_coding/codecs/isac/main/include/audio_encoder_isac.h"
+#endif
+#ifdef WEBRTC_CODEC_OPUS
+#include "webrtc/modules/audio_coding/codecs/opus/audio_encoder_opus.h"
+#endif
+#include "webrtc/modules/audio_coding/codecs/pcm16b/audio_encoder_pcm16b.h"
+
+namespace webrtc {
+
+namespace {
+
+template <typename T>
+std::unique_ptr<AudioEncoder> AudioEncoderConstructor(
+    int payload_type,
+    const SdpAudioFormat& format) {
+  auto opt_info = T::QueryAudioFormat(format);
+  if (opt_info) {
+    return std::unique_ptr<AudioEncoder>(new T(payload_type, format));
+  }
+  return nullptr;
+}

[kwiberg-webrtc, 2017/02/19 21:41:10]

To reduce the scope, this could be a private member of NamedEncoderFactory. Or
even better, a lambda in ForEncoder.

[ossu, 2017/02/20 12:20:26]

True. Will do.

+
+struct NamedEncoderFactory {
+  const char *name;
+  rtc::Optional<AudioFormatInfo> (*QueryAudioFormat)(
+      const SdpAudioFormat& format);
+  std::unique_ptr<AudioEncoder> (*MakeAudioEncoder)(
+      int payload_type,
+      const SdpAudioFormat& format);
+
+  template <typename T>
+  static NamedEncoderFactory ForEncoder() {
+    return {T::GetPayloadName(),
+            T::QueryAudioFormat,
+            AudioEncoderConstructor<T>};
+  }
+};
+
+NamedEncoderFactory encoder_factories[] = {
+#ifdef WEBRTC_CODEC_G722
+  NamedEncoderFactory::ForEncoder<AudioEncoderG722>(),
+#endif
+#ifdef WEBRTC_CODEC_ILBC
+  NamedEncoderFactory::ForEncoder<AudioEncoderIlbc>(),
+#endif
+#if defined(WEBRTC_CODEC_ISACFX)
+  NamedEncoderFactory::ForEncoder<AudioEncoderIsacFix>(),
+#elif defined(WEBRTC_CODEC_ISAC)
+  NamedEncoderFactory::ForEncoder<AudioEncoderIsac>(),
+#endif
+
+#ifdef WEBRTC_CODEC_OPUS
+  NamedEncoderFactory::ForEncoder<AudioEncoderOpus>(),
+#endif
+  NamedEncoderFactory::ForEncoder<AudioEncoderPcm16B>(),
+  NamedEncoderFactory::ForEncoder<AudioEncoderPcmA>(),
+  NamedEncoderFactory::ForEncoder<AudioEncoderPcmU>(),
+};
+
+}  // namespace
+
+class BuiltinAudioEncoderFactory : public AudioEncoderFactory {
+ public:
+  BuiltinAudioEncoderFactory() {
+    // TODO(ossu): Make this a one-time initialization, preferable static.

[kwiberg-webrtc, 2017/02/19 21:41:10]

Yes.

+    auto add_if_supported =
+        [this] (const SdpAudioFormat& format) {
+          for (const auto& ef : encoder_factories) {
+            if (STR_CASE_CMP(format.name.c_str(), ef.name) == 0) {
+              auto opt_info = ef.QueryAudioFormat(format);
+              if (opt_info) {
+                supported_encoders_.push_back({format, *opt_info});
+              }
+            }
+          }
+        };
+
+    add_if_supported({"opus", 48000, 2, {{"minptime", "10"},
+                                         {"useinbandfec", "1"}}});
+    add_if_supported({"isac", 16000, 1});
+    add_if_supported({"isac", 32000, 1});
+    add_if_supported({"G722", 8000, 1});
+    add_if_supported({"iLBC", 8000, 1});
+    add_if_supported({"PCMU", 8000, 1});
+    add_if_supported({"PCMA", 8000, 1});
+  }
+
+  std::vector<AudioCodecSpec> GetSupportedEncoders() override {
+    return supported_encoders_;
+  }
+
+  bool IsSupportedEncoder(const SdpAudioFormat& format) override {
+    for (const auto& ef : encoder_factories) {
+      if (STR_CASE_CMP(format.name.c_str(), ef.name) == 0) {
+        return !!ef.QueryAudioFormat(format);
+      }
+    }
+    return false;
+  }
+
+  rtc::Optional<AudioFormatInfo> QueryAudioFormat(
+      const SdpAudioFormat& format) override {
+    LOG(LS_INFO) << "Querying for format " << format;
+    for (const auto& ef : encoder_factories) {
+      if (STR_CASE_CMP(format.name.c_str(), ef.name) == 0) {
+        return ef.QueryAudioFormat(format);
+      }
+    }
+    for (const auto& spec : supported_encoders_) {
+      if (STR_CASE_CMP(format.name.c_str(), spec.format.name.c_str()) == 0 &&
+          format.clockrate_hz == spec.format.clockrate_hz &&
+          format.num_channels == spec.format.num_channels) {
+        return rtc::Optional<AudioFormatInfo>(spec.info);
+      }
+    }

[kwiberg-webrtc, 2017/02/19 21:41:10]

Maybe I'm just confused, but why are you looking in encoder_factories AND
supported_encoders_?

[ossu, 2017/02/20 12:20:25]

Hmm... either I forgot to remove my temporary implementation (the second block),
or I made a mistake while pulling out just these changes using git. Either way,
the second block should go.

+    return rtc::Optional<AudioFormatInfo>();
+  }
+
+  std::unique_ptr<AudioEncoder> MakeAudioEncoder(
+      int payload_type,
+      const SdpAudioFormat& format) override {
+    for (const auto& ef : encoder_factories) {
+      if (STR_CASE_CMP(format.name.c_str(), ef.name) == 0) {
+        return ef.MakeAudioEncoder(payload_type, format);
+      }
+    }
+    return nullptr;
+  }
+
+ private:
+  std::vector<AudioCodecSpec> supported_encoders_;
+};
+
+rtc::scoped_refptr<AudioEncoderFactory> CreateBuiltinAudioEncoderFactory() {
+  return rtc::scoped_refptr<AudioEncoderFactory>(
+      new rtc::RefCountedObject<BuiltinAudioEncoderFactory>());
+}
+
+}  // namespace webrtc