New interface (AudioDecoderFactory), with an implementation

webrtc/modules/audio_coding/codecs/builtin_audio_decoder_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_decoder_factory.h"
+
+#include <vector>
+
+#include "webrtc/base/checks.h"
+#include "webrtc/common_types.h"
+#include "webrtc/modules/audio_coding/codecs/cng/webrtc_cng.h"
+#include "webrtc/modules/audio_coding/codecs/g711/audio_decoder_pcm.h"
+#ifdef WEBRTC_CODEC_G722
+#include "webrtc/modules/audio_coding/codecs/g722/audio_decoder_g722.h"
+#endif
+#ifdef WEBRTC_CODEC_ILBC
+#include "webrtc/modules/audio_coding/codecs/ilbc/audio_decoder_ilbc.h"
+#endif
+#ifdef WEBRTC_CODEC_ISACFX
+#include "webrtc/modules/audio_coding/codecs/isac/fix/include/audio_decoder_isacfix.h"
+#endif
+#ifdef WEBRTC_CODEC_ISAC
+#include "webrtc/modules/audio_coding/codecs/isac/main/include/audio_decoder_isac.h"
+#endif
+#ifdef WEBRTC_CODEC_OPUS
+#include "webrtc/modules/audio_coding/codecs/opus/audio_decoder_opus.h"
+#endif
+#include "webrtc/modules/audio_coding/codecs/pcm16b/audio_decoder_pcm16b.h"
+
+namespace webrtc {
+
+namespace {
+
+struct NamedDecoderConstructor {
+  const char* name;
+  std::unique_ptr<AudioDecoder> (*constructor)(int clockrate_hz,
+                                               int num_channels);
+};
+
+std::unique_ptr<AudioDecoder> Unique(AudioDecoder* d) {
+  return std::unique_ptr<AudioDecoder>(d);
+}
+
+// TODO(kwiberg): These factory functions should probably be moved to each
+// decoder.
+NamedDecoderConstructor decoder_constructors[] = {
+    {"pcmu",
+     [](int clockrate_hz, int num_channels) {
+       return clockrate_hz == 8000 && num_channels >= 1
+                  ? Unique(new AudioDecoderPcmU(num_channels))
+                  : nullptr;
+     }},
+    {"pcma",
+     [](int clockrate_hz, int num_channels) {
+       return clockrate_hz == 8000 && num_channels >= 1
+                  ? Unique(new AudioDecoderPcmA(num_channels))
+                  : nullptr;
+     }},
+#ifdef WEBRTC_CODEC_ILBC
+    {"ilbc",
+     [](int clockrate_hz, int num_channels) {
+       return clockrate_hz == 8000 && num_channels == 1
+                  ? Unique(new AudioDecoderIlbc)
+                  : nullptr;
+     }},
+#endif
+#if defined(WEBRTC_CODEC_ISACFX)
+    {"isac",
+     [](int clockrate_hz, int num_channels) {
+       return clockrate_hz == 16000 && num_channels == 1
+                  ? Unique(new AudioDecoderIsacFix)
+                  : nullptr;
+     }},
+#elif defined(WEBRTC_CODEC_ISAC)
+    {"isac",
+     [](int clockrate_hz, int num_channels) {
+       return (clockrate_hz == 16000 || clockrate_hz == 32000) &&
+                      num_channels == 1
+                  ? Unique(new AudioDecoderIsac)
+                  : nullptr;
+     }},
+#endif
+    {"l16",
+     [](int clockrate_hz, int num_channels) {
+       return num_channels >= 1 ? Unique(new AudioDecoderPcm16B(num_channels))
+                                : nullptr;
+     }},
+#ifdef WEBRTC_CODEC_G722
+    {"g722",
+     [](int clockrate_hz, int num_channels) {
+       if (clockrate_hz == 8000) {
+         if (num_channels == 1)
+           return Unique(new AudioDecoderG722);
+         if (num_channels == 2)
+           return Unique(new AudioDecoderG722Stereo);
+       }
+       return Unique(nullptr);
+     }},
+#endif
+#ifdef WEBRTC_CODEC_OPUS
+    {"opus",
+     [](int clockrate_hz, int num_channels) {
+       return clockrate_hz == 48000 && (num_channels == 1 || num_channels == 2)
+                  ? Unique(new AudioDecoderOpus(num_channels))
+                  : nullptr;
+     }},
+#endif
+};
+
+class BuiltinAudioDecoderFactory : public AudioDecoderFactory {
+ public:
+  std::vector<SdpAudioFormat> GetSupportedFormats() override {
+    FATAL() << "Not implemented yet!";
+  }
+
+  std::unique_ptr<AudioDecoder> MakeAudioDecoder(
+      const SdpAudioFormat& format) override {
+    for (const auto& dc : decoder_constructors) {
+      if (STR_CASE_CMP(format.name.c_str(), dc.name) == 0) {
+        return std::unique_ptr<AudioDecoder>(
+            dc.constructor(format.clockrate_hz, format.num_channels));
+      }
+    }
+    return nullptr;
+  }
+};
+
+}  // namespace
+
+std::unique_ptr<AudioDecoderFactory> CreateBuiltinAudioDecoderFactory() {
+  return std::unique_ptr<AudioDecoderFactory>(new BuiltinAudioDecoderFactory);
+}
+
+}  // namespace webrtc