// Copyright 2018 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

syntax = "proto3";

package google.cloud.dialogflow.v2beta1;

import "google/api/annotations.proto";

option cc_enable_arenas = true;
option csharp_namespace = "Google.Cloud.Dialogflow.V2beta1";
option go_package = "google.golang.org/genproto/googleapis/cloud/dialogflow/v2beta1;dialogflow";
option java_multiple_files = true;
option java_outer_classname = "AudioConfigProto";
option java_package = "com.google.cloud.dialogflow.v2beta1";
option objc_class_prefix = "DF";

// Description of which voice to use for speech synthesis.
message VoiceSelectionParams {
  // Optional. The name of the voice. If not set, the service will choose a
  // voice based on the other parameters such as language_code and gender.
  string name = 1;

  // Optional. The preferred gender of the voice. If not set, the service will
  // choose a voice based on the other parameters such as language_code and
  // name. Note that this is only a preference, not requirement. If a
  // voice of the appropriate gender is not available, the synthesizer should
  // substitute a voice with a different gender rather than failing the request.
  SsmlVoiceGender ssml_gender = 2;
}

// Configuration of how speech should be synthesized.
message SynthesizeSpeechConfig {
  // Optional. Speaking rate/speed, in the range [0.25, 4.0]. 1.0 is the normal
  // native speed supported by the specific voice. 2.0 is twice as fast, and
  // 0.5 is half as fast. If unset(0.0), defaults to the native 1.0 speed. Any
  // other values < 0.25 or > 4.0 will return an error.
  double speaking_rate = 1;

  // Optional. Speaking pitch, in the range [-20.0, 20.0]. 20 means increase 20
  // semitones from the original pitch. -20 means decrease 20 semitones from the
  // original pitch.
  double pitch = 2;

  // Optional. Volume gain (in dB) of the normal native volume supported by the
  // specific voice, in the range [-96.0, 16.0]. If unset, or set to a value of
  // 0.0 (dB), will play at normal native signal amplitude. A value of -6.0 (dB)
  // will play at approximately half the amplitude of the normal native signal
  // amplitude. A value of +6.0 (dB) will play at approximately twice the
  // amplitude of the normal native signal amplitude. We strongly recommend not
  // to exceed +10 (dB) as there's usually no effective increase in loudness for
  // any value greater than that.
  double volume_gain_db = 3;

  // Optional. An identifier which selects 'audio effects' profiles that are
  // applied on (post synthesized) text to speech. Effects are applied on top of
  // each other in the order they are given.
  repeated string effects_profile_id = 5;

  // Optional. The desired voice of the synthesized audio.
  VoiceSelectionParams voice = 4;
}

// Instructs the speech synthesizer how to generate the output audio content.
message OutputAudioConfig {
  // Required. Audio encoding of the synthesized audio content.
  OutputAudioEncoding audio_encoding = 1;

  // Optional. The synthesis sample rate (in hertz) for this audio. If not
  // provided, then the synthesizer will use the default sample rate based on
  // the audio encoding. If this is different from the voice's natural sample
  // rate, then the synthesizer will honor this request by converting to the
  // desired sample rate (which might result in worse audio quality).
  int32 sample_rate_hertz = 2;

  // Optional. Configuration of how speech should be synthesized.
  SynthesizeSpeechConfig synthesize_speech_config = 3;
}

// Gender of the voice as described in
// [SSML voice element](https://www.w3.org/TR/speech-synthesis11/#edef_voice).
enum SsmlVoiceGender {
  // An unspecified gender, which means that the client doesn't care which
  // gender the selected voice will have.
  SSML_VOICE_GENDER_UNSPECIFIED = 0;

  // A male voice.
  SSML_VOICE_GENDER_MALE = 1;

  // A female voice.
  SSML_VOICE_GENDER_FEMALE = 2;

  // A gender-neutral voice.
  SSML_VOICE_GENDER_NEUTRAL = 3;
}

// Audio encoding of the output audio format in Text-To-Speech.
enum OutputAudioEncoding {
  // Not specified.
  OUTPUT_AUDIO_ENCODING_UNSPECIFIED = 0;

  // Uncompressed 16-bit signed little-endian samples (Linear PCM).
  // Audio content returned as LINEAR16 also contains a WAV header.
  OUTPUT_AUDIO_ENCODING_LINEAR_16 = 1;

  // MP3 audio.
  OUTPUT_AUDIO_ENCODING_MP3 = 2;

  // Opus encoded audio wrapped in an ogg container. The result will be a
  // file which can be played natively on Android, and in browsers (at least
  // Chrome and Firefox). The quality of the encoding is considerably higher
  // than MP3 while using approximately the same bitrate.
  OUTPUT_AUDIO_ENCODING_OGG_OPUS = 3;
}