chromecast/media/audio/mixer_service/mixer_service.proto

// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

syntax = "proto2";

option optimize_for = LITE_RUNTIME;

package chromecast.media.mixer_service;

enum ContentType {
  CONTENT_TYPE_MEDIA = 0;
  CONTENT_TYPE_ALARM = 1;
  CONTENT_TYPE_COMMUNICATION = 2;
  CONTENT_TYPE_OTHER = 3;
}

enum SampleFormat {
  // Interleaved formats:
  SAMPLE_FORMAT_INT16_I = 0;
  SAMPLE_FORMAT_INT32_I = 1;
  SAMPLE_FORMAT_FLOAT_I = 2;
  // Planar formats:
  SAMPLE_FORMAT_INT16_P = 3;
  SAMPLE_FORMAT_INT32_P = 4;
  SAMPLE_FORMAT_FLOAT_P = 5;
}

message OutputStreamParams {
  enum StreamType {
    STREAM_TYPE_DEFAULT = 0;
    STREAM_TYPE_SFX = 1;
  }
  optional StreamType stream_type = 1;

  optional ContentType content_type = 2;
  optional SampleFormat sample_format = 3;

  optional string device_id = 4;

  optional int32 sample_rate = 5;
  optional int32 num_channels = 6;
  optional sint32 channel_selection = 7 [default = -1];

  optional int32 fill_size_frames = 8;
  optional int32 start_threshold_frames = 9;
  optional int32 max_buffered_frames = 10;

  optional bool use_fader = 11;
  optional int32 fade_frames = 12;

  // If |true|, playback will not start until a start timestamp has been
  // provided via a SetStartTimestamp message.
  optional bool use_start_timestamp = 13;
}

// Indicates that we want to start playing the sample with PTS |start_pts|
// at audio clock timestamp |start_timestamp| in microseconds. May be sent
// multiple times to restart playback at a new timestamp (ie for hard
// corrections).
message SetStartTimestamp {
  optional int64 start_timestamp = 1;
  optional int64 start_pts = 2;
}

// Informs the mixer how fast the PTS increases per frame. For example if the
// playback rate is 2.0, then each frame increases the PTS by 2.0 / sample_rate
// seconds.
message SetPlaybackRate {
  optional float playback_rate = 1;
}

// Changes the volume multiplier for an audio output stream.
message StreamVolume {
  optional float volume = 1;
}

// Immediately pauses/resumes playback for an audio output stream.
message SetPaused {
  optional bool paused = 1;
}

// Indicates that previously pushed audio data has been queued for playback,
// and the next audio data that is pushed to the mixer will start playing at
// |next_playback_timestamp|.
message BufferPushResult {
  optional fixed64 next_playback_timestamp = 1;
}

// Indicates that EOS for an audio output stream has been played out.
message EosPlayedOut {}

// Indicates that an audio output stream is ready for playback (ie, has enough
// audio data to exceed the start threshold, and has output delay information).
message ReadyForPlayback {
  optional fixed64 delay_microseconds = 1;
}

// Indicates current stream config for a loopback / redirected audio stream.
// Sent whenever the config changes; will be sent at least once before any audio
// data is sent.
message StreamConfig {
  optional SampleFormat sample_format = 1;
  optional int32 sample_rate = 2;
  optional int32 num_channels = 3;
}

// Sent to indicate that the mixer should stream loopback audio data back over
// this connection.
message LoopbackDataRequest {}

// Sent to indicate that the mixer should redirect specific audio output
// stream data back over this connection.
message RedirectionRequest {
  optional int32 order = 1;
  optional int32 num_channels = 2;
  optional bool apply_volume = 4;
  optional int64 extra_delay_microseconds = 5;
}

// Sets the patterns to determine which audio output streams should be
// redirected.
message RedirectedStreamPatterns {
  message Pattern {
    optional ContentType content_type = 1;
    optional string device_id_pattern = 2;
  }
  repeated Pattern patterns = 1;
}

// Sets volume multiplier for all streams of a given content type.
message SetDeviceVolume {
  optional ContentType content_type = 1;
  optional float volume_multiplier = 2;
}

// Sets mute state all streams of a given content type.
message SetDeviceMuted {
  optional ContentType content_type = 1;
  optional bool muted = 2;
}

// Sets the maximum effective volume multiplier for a given content type.
message SetVolumeLimit {
  optional ContentType content_type = 1;
  optional float max_volume_multiplier = 2;
}

// Sends arbitrary config data to a specific postprocessor.
message ConfigurePostprocessor {
  optional string name = 1;
  optional bytes config = 2;
}

// Instructs the mixer to reload postprocessors based on the config file.
message ReloadPostprocessors {}

// Asks the mixer to send / stop sending stream count updates.
message RequestStreamCount {
  optional bool subscribe = 1;
}

// Indicates how many output streams are currently being handled by the mixer.
message StreamCount {
  optional int32 primary = 1;
  optional int32 sfx = 2;
}

// Indicates an error on an audio stream.
message Error {
  enum Type {
    INVALID_STREAM_ERROR = 0;
    XRUN_ERROR = 1;  // Underrun or overrun.
  }
  optional Type type = 1;
  optional string message = 2;
}

message Generic {
  optional OutputStreamParams output_stream_params = 1;
  optional SetStartTimestamp set_start_timestamp = 2;
  optional SetPlaybackRate set_playback_rate = 3;
  optional StreamVolume set_stream_volume = 4;
  optional SetPaused set_paused = 5;
  optional BufferPushResult push_result = 6;
  optional EosPlayedOut eos_played_out = 7;
  optional ReadyForPlayback ready_for_playback = 8;
  optional StreamConfig stream_config = 9;
  optional LoopbackDataRequest loopback_request = 10;
  optional RedirectionRequest redirection_request = 11;
  optional RedirectedStreamPatterns redirected_stream_patterns = 12;
  optional SetDeviceVolume set_device_volume = 13;
  optional SetDeviceMuted set_device_muted = 14;
  optional SetVolumeLimit set_volume_limit = 15;
  optional ConfigurePostprocessor configure_postprocessor = 16;
  optional ReloadPostprocessors reload_postprocessors = 17;
  optional RequestStreamCount request_stream_count = 18;
  optional StreamCount stream_count = 19;
  optional Error error = 20;
}