G711 implementation of the Audio{En,De}coderFactoryTemplate APIs

webrtc/api/audio_codecs/g711/audio_encoder_g711.cc

+/*
+ *  Copyright (c) 2017 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/api/audio_codecs/g711/audio_encoder_g711.h"
+
+#include <memory>
+#include <vector>
+
+#include "webrtc/common_types.h"
+#include "webrtc/modules/audio_coding/codecs/g711/audio_encoder_pcm.h"
+#include "webrtc/rtc_base/ptr_util.h"
+#include "webrtc/rtc_base/safe_conversions.h"
+#include "webrtc/rtc_base/safe_minmax.h"
+#include "webrtc/rtc_base/string_to_number.h"
+
+namespace webrtc {
+
+rtc::Optional<AudioEncoderG711::Config> AudioEncoderG711::SdpToConfig(
+    const SdpAudioFormat& format) {
+  const bool is_pcmu = STR_CASE_CMP(format.name.c_str(), "PCMU") == 0;
+  const bool is_pcma = STR_CASE_CMP(format.name.c_str(), "PCMA") == 0;
+  if (format.clockrate_hz == 8000 && format.num_channels >= 1 &&
+      (is_pcmu || is_pcma)) {
+    Config config;
+    config.type = is_pcmu ? Config::Type::kPcmU : Config::Type::kPcmA;
+    config.num_channels = rtc::dchecked_cast<int>(format.num_channels);
+    config.frame_size_ms = 20;
+    auto ptime_iter = format.parameters.find("ptime");
+    if (ptime_iter != format.parameters.end()) {
+      const auto ptime = rtc::StringToNumber<int>(ptime_iter->second);
+      if (ptime && *ptime > 0) {
+        config.frame_size_ms = rtc::SafeClamp(10 * (*ptime / 10), 10, 60);
+      }
+    }
+    RTC_DCHECK(config.IsOk());
+    return rtc::Optional<Config>(config);
+  } else {
+    return rtc::Optional<Config>();
+  }
+}
+
+void AudioEncoderG711::AppendSupportedEncoders(
+    std::vector<AudioCodecSpec>* specs) {
+  for (const char* type : {"PCMU", "PCMA"}) {
+    specs->push_back({{type, 8000, 1}, {8000, 1, 64000}});
+  }
+}
+
+AudioCodecInfo AudioEncoderG711::QueryAudioEncoder(const Config& config) {
+  RTC_DCHECK(config.IsOk());
+  return {8000, rtc::dchecked_cast<size_t>(config.num_channels),
+          64000 * config.num_channels};
+}
+
+std::unique_ptr<AudioEncoder> AudioEncoderG711::MakeAudioEncoder(
+    const Config& config,
+    int payload_type) {
+  RTC_DCHECK(config.IsOk());
+  switch (config.type) {
+    case Config::Type::kPcmU: {
+      AudioEncoderPcmU::Config impl_config;
+      impl_config.num_channels = config.num_channels;
+      impl_config.frame_size_ms = config.frame_size_ms;
+      impl_config.payload_type = payload_type;
+      return rtc::MakeUnique<AudioEncoderPcmU>(impl_config);
+    }
+    case Config::Type::kPcmA: {
+      AudioEncoderPcmA::Config impl_config;
+      impl_config.num_channels = config.num_channels;
+      impl_config.frame_size_ms = config.frame_size_ms;
+      impl_config.payload_type = payload_type;
+      return rtc::MakeUnique<AudioEncoderPcmA>(impl_config);
+    }
+    default: { return nullptr; }
+  }
+}
+
+}  // namespace webrtc