WebRtcVoiceEngine: Use AudioDecoderFactory to generate recv codecs.

webrtc/media/engine/payload_type_mapper.cc

Index: webrtc/media/engine/payload_type_mapper.cc
diff --git a/webrtc/media/engine/payload_type_mapper.cc b/webrtc/media/engine/payload_type_mapper.cc
new file mode 100644
index 0000000000000000000000000000000000000000..87b54be33b51f530e0aac15da859d614bba7eedd
--- /dev/null
+++ b/webrtc/media/engine/payload_type_mapper.cc
@@ -0,0 +1,159 @@
+/*
+ *  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/media/engine/payload_type_mapper.h"
+
+#include "webrtc/common_types.h"
+#include "webrtc/media/base/mediaconstants.h"
+
+namespace cricket {
+
+PayloadTypeMapper::PayloadTypeMapper()
+    // RFC 3551 reserves payload type numbers in the range 96-127 exclusively
+    // for dynamic assignment. Once those are used up, it is recommended that
+    // payload types unassigned by the RFC are used for dynamic payload type
+    // mapping, before any static payload ids. At this point, we only support
+    // mapping within the exclusive range.
+    : next_unused_payload_type_(96),
+      max_payload_type_(127),
+      mappings_({
+          // Static payload type assignments according to RFC 3551.
+          {{"PCMU",   8000, 1}, 0},
+          {{"GSM",    8000, 1}, 3},
+          {{"G723",   8000, 1}, 4},
+          {{"DVI4",   8000, 1}, 5},
+          {{"DVI4",  16000, 1}, 6},
+          {{"LPC",    8000, 1}, 7},
+          {{"PCMA",   8000, 1}, 8},
+          {{"G722",   8000, 1}, 9},
+          {{"L16",   44100, 2}, 10},
+          {{"L16",   44100, 1}, 11},
+          {{"QCELP",  8000, 1}, 12},
+          {{"CN",     8000, 1}, 13},
+          // RFC 4566 is a bit ambiguous on the contents of the "encoding
+          // parameters" field, which, for audio, encodes the number of
+          // channels. It is "optional and may be omitted if the number of
+          // channels is one". Does that necessarily imply that an omitted
+          // encoding parameter means one channel?  Since RFC 3551 doesn't
+          // specify a value for this parameter for MPA, I've included both 0
+          // and 1 here, to increase the chances it will be correctly used if
+          // someone implements an MPEG audio encoder/decoder.
+          {{"MPA",   90000, 0}, 14},
+          {{"MPA",   90000, 1}, 14},
+          {{"G728",   8000, 1}, 15},
+          {{"DVI4",  11025, 1}, 16},
+          {{"DVI4",  22050, 1}, 17},
+          {{"G729",   8000, 1}, 18},
+
+          // Payload type assignments currently used by WebRTC.
+          // Includes video, to reduce collisions (and thus reassignments)
+          // RTX codecs mapping to specific video payload types
+          {{kRtxCodecName,    90000, 0,
+              {{kCodecParamAssociatedPayloadType,
+                      std::to_string(kDefaultVp8PlType)}}},
+                kDefaultRtxVp8PlType},
+          {{kRtxCodecName,    90000, 0,
+              {{kCodecParamAssociatedPayloadType,
+                      std::to_string(kDefaultVp9PlType)}}},
+                kDefaultRtxVp9PlType},
+          {{kRtxCodecName,    90000, 0,
+              {{kCodecParamAssociatedPayloadType,
+                      std::to_string(kDefaultRedPlType)}}},
+                kDefaultRtxRedPlType},
+          {{kRtxCodecName,    90000, 0,
+              {{kCodecParamAssociatedPayloadType,
+                      std::to_string(kDefaultH264PlType)}}},
+                kDefaultRtxH264PlType},
+          // Other codecs
+          {{kVp8CodecName,    90000, 0}, kDefaultVp8PlType},
+          {{kVp9CodecName,    90000, 0}, kDefaultVp9PlType},
+          {{kIlbcCodecName,    8000, 1}, 102},
+          {{kIsacCodecName,   16000, 1}, 103},
+          {{kIsacCodecName,   32000, 1}, 104},
+          {{kCnCodecName,     16000, 1}, 105},
+          {{kCnCodecName,     32000, 1}, 106},
+          {{kH264CodecName,   90000, 0}, kDefaultH264PlType},
+          {{kOpusCodecName,   48000, 2,
+              {{"minptime", "10"}, {"useinbandfec", "1"}}}, 111},
+          {{kRedCodecName,    90000, 0}, kDefaultRedPlType},
+          {{kUlpfecCodecName, 90000, 0}, kDefaultUlpfecType},
+          {{kDtmfCodecName,    8000, 1}, 126}}) {
+  // TODO(ossu): Try to keep this as change-proof as possible until we're able
+  // to remove the payload type constants from everywhere in the code.
+  for (const auto& mapping : mappings_) {
+    used_payload_types_.insert(mapping.second);
+  }
+}
+
+PayloadTypeMapper::~PayloadTypeMapper() = default;
+
+rtc::Optional<int> PayloadTypeMapper::GetMappingFor(
+    const webrtc::SdpAudioFormat& format) {
+  auto iter = mappings_.find(format);
+  if (iter != mappings_.end())
+    return rtc::Optional<int>(iter->second);
+
+  for (; next_unused_payload_type_ <= max_payload_type_;
+       ++next_unused_payload_type_) {
+    int payload_type = next_unused_payload_type_;
+    if (used_payload_types_.find(payload_type) == used_payload_types_.end()) {
+      used_payload_types_.insert(payload_type);
+      mappings_[format] = payload_type;
+      ++next_unused_payload_type_;
+      return rtc::Optional<int>(payload_type);
+    }
+  }
+
+  return rtc::Optional<int>();
+}
+
+rtc::Optional<int> PayloadTypeMapper::FindMappingFor(
+    const webrtc::SdpAudioFormat& format) const {
+  auto iter = mappings_.find(format);
+  if (iter != mappings_.end())
+    return rtc::Optional<int>(iter->second);
+
+  return rtc::Optional<int>();
+}
+
+rtc::Optional<AudioCodec> PayloadTypeMapper::ToAudioCodec(
+    const webrtc::SdpAudioFormat& format) {
+  // TODO(ossu): We can safely set bitrate to zero here, since that field is
+  // not presented in the SDP. It is used to ferry around some target bitrate
+  // values for certain codecs (ISAC and Opus) and in ways it really
+  // shouldn't. It should be removed once we no longer use CodecInsts in the
+  // ACM or NetEq.
+  auto opt_payload_type = GetMappingFor(format);
+  if (opt_payload_type) {
+    AudioCodec codec(*opt_payload_type, format.name, format.clockrate_hz, 0,
+                     format.num_channels);
+    codec.params = format.parameters;
+    return rtc::Optional<AudioCodec>(std::move(codec));
+  }
+
+  return rtc::Optional<AudioCodec>();
+}
+
+bool PayloadTypeMapper::SdpAudioFormatOrdering::operator()(
+    const webrtc::SdpAudioFormat& a,
+    const webrtc::SdpAudioFormat& b) const {
+  if (a.clockrate_hz == b.clockrate_hz) {
+    if (a.num_channels == b.num_channels) {
+      int name_cmp = STR_CASE_CMP(a.name.c_str(), b.name.c_str());
+      if (name_cmp == 0)
+        return a.parameters < b.parameters;
+      return name_cmp < 0;
+    }
+    return a.num_channels < b.num_channels;
+  }
+  return a.clockrate_hz < b.clockrate_hz;
+}
+
+}  // namespace cricket