Mojo interfaces needed for switching audio rendering stream creation and closing from IPC to Mojo

media/mojo/interfaces/audio_output.mojom

+// Copyright 2015 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.
+
+module content.mojom;
+
+struct AudioOutputStreamParameters {
+
+  enum Format {
+    AUDIO_PCM_LINEAR = 0,            // PCM is 'raw' amplitude samples.
+    AUDIO_PCM_LOW_LATENCY,           // Linear PCM, low latency requested.
+    AUDIO_FAKE,                      // Creates a fake AudioOutputStream object.
+    AUDIO_FORMAT_LAST = AUDIO_FAKE,  // Only used for validation of format.
+  };
+
+  // Enumerates the various representations of the ordering of audio channels.
+  // Logged to UMA, so never reuse a value, always add new/greater ones!
+  enum ChannelLayout {
+    CHANNEL_LAYOUT_NONE = 0,
+    CHANNEL_LAYOUT_UNSUPPORTED = 1,
+
+    // Front C
+    CHANNEL_LAYOUT_MONO = 2,
+
+    // Front L, Front R
+    CHANNEL_LAYOUT_STEREO = 3,
+
+    // Front L, Front R, Back C
+    CHANNEL_LAYOUT_2_1 = 4,
+
+    // Front L, Front R, Front C
+    CHANNEL_LAYOUT_SURROUND = 5,
+
+    // Front L, Front R, Front C, Back C
+    CHANNEL_LAYOUT_4_0 = 6,
+
+    // Front L, Front R, Side L, Side R
+    CHANNEL_LAYOUT_2_2 = 7,
+
+    // Front L, Front R, Back L, Back R
+    CHANNEL_LAYOUT_QUAD = 8,
+
+    // Front L, Front R, Front C, Side L, Side R
+    CHANNEL_LAYOUT_5_0 = 9,
+
+    // Front L, Front R, Front C, LFE, Side L, Side R
+    CHANNEL_LAYOUT_5_1 = 10,
+
+    // Front L, Front R, Front C, Back L, Back R
+    CHANNEL_LAYOUT_5_0_BACK = 11,
+
+    // Front L, Front R, Front C, LFE, Back L, Back R
+    CHANNEL_LAYOUT_5_1_BACK = 12,
+
+    // Front L, Front R, Front C, Side L, Side R, Back L, Back R
+    CHANNEL_LAYOUT_7_0 = 13,
+
+    // Front L, Front R, Front C, LFE, Side L, Side R, Back L, Back R
+    CHANNEL_LAYOUT_7_1 = 14,
+
+    // Front L, Front R, Front C, LFE, Side L, Side R, Front LofC, Front RofC
+    CHANNEL_LAYOUT_7_1_WIDE = 15,
+
+    // Stereo L, Stereo R
+    CHANNEL_LAYOUT_STEREO_DOWNMIX = 16,
+
+    // Stereo L, Stereo R, LFE
+    CHANNEL_LAYOUT_2POINT1 = 17,
+
+    // Stereo L, Stereo R, Front C, LFE
+    CHANNEL_LAYOUT_3_1 = 18,
+
+    // Stereo L, Stereo R, Front C, Rear C, LFE
+    CHANNEL_LAYOUT_4_1 = 19,
+
+    // Stereo L, Stereo R, Front C, Side L, Side R, Back C
+    CHANNEL_LAYOUT_6_0 = 20,
+
+    // Stereo L, Stereo R, Side L, Side R, Front LofC, Front RofC
+    CHANNEL_LAYOUT_6_0_FRONT = 21,
+
+    // Stereo L, Stereo R, Front C, Rear L, Rear R, Rear C
+    CHANNEL_LAYOUT_HEXAGONAL = 22,
+
+    // Stereo L, Stereo R, Front C, LFE, Side L, Side R, Rear Center
+    CHANNEL_LAYOUT_6_1 = 23,
+
+    // Stereo L, Stereo R, Front C, LFE, Back L, Back R, Rear Center
+    CHANNEL_LAYOUT_6_1_BACK = 24,
+
+    // Stereo L, Stereo R, Side L, Side R, Front LofC, Front RofC, LFE
+    CHANNEL_LAYOUT_6_1_FRONT = 25,
+
+    // Front L, Front R, Front C, Side L, Side R, Front LofC, Front RofC
+    CHANNEL_LAYOUT_7_0_FRONT = 26,
+
+    // Front L, Front R, Front C, LFE, Back L, Back R, Front LofC, Front RofC
+    CHANNEL_LAYOUT_7_1_WIDE_BACK = 27,
+
+    // Front L, Front R, Front C, Side L, Side R, Rear L, Back R, Back C.
+    CHANNEL_LAYOUT_OCTAGONAL = 28,
+
+    // Channels are not explicitly mapped to speakers.
+    CHANNEL_LAYOUT_DISCRETE = 29,
+
+    // Front L, Front R, Front C. Front C contains the keyboard mic audio. This
+    // layout is only intended for input for WebRTC. The Front C channel
+    // is stripped away in the WebRTC audio input pipeline and never seen outside
+    // of that.
+    CHANNEL_LAYOUT_STEREO_AND_KEYBOARD_MIC = 30,
+
+    // Front L, Front R, Side L, Side R, LFE
+    CHANNEL_LAYOUT_4_1_QUAD_SIDE = 31,
+
+    // Max value, must always equal the largest entry ever logged.
+    CHANNEL_LAYOUT_MAX = CHANNEL_LAYOUT_4_1_QUAD_SIDE
+  };
+
+
+  Format format_;                 // Format of the stream.
+  ChannelLayout channel_layout_;  // Order of surround sound channels.
+  int32 channels_;                  // Number of channels. Value set based on
+                                  // |channel_layout|.
+  int32 sample_rate_;               // Sampling frequency/rate.
+  int32 bits_per_sample_;           // Number of bits per sample.
+  int32 frames_per_buffer_;         // Number of frames in a buffer.
+  int32 effects_;                   // Bitmask using PlatformEffectsMask.
+
+};
+
+// Used on the renderer side.
+interface AudioOutputStream {
+  Close();
+};
+
+// Used on the renderer side.
+interface AudioOutput {
+  CreateStream(
+      int32 stream_id_,
+      int32 render_frame_id_,
+      AudioOutputStreamParameters params) =>
+      (AudioOutputStream? stream,
+       int32 stream_id,
+       handle<shared_buffer>? shared_buffer,
+       handle? socket_descriptor);
+};