Motown in-proc streaming framework used to implement media services.

services/media/framework/lpcm_util.h

+// Copyright 2016 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.
+
+#ifndef SERVICES_MEDIA_FRAMEWORK_LPCM_UTIL_H_
+#define SERVICES_MEDIA_FRAMEWORK_LPCM_UTIL_H_
+
+#include <memory>
+
+#include "services/media/framework/stream_type.h"
+
+namespace mojo {
+namespace media {
+
+// Helper class that performs various LPCM processing functions.
+class LpcmUtil {

[jeffbrown, 2016/02/02 05:35:46]

Avoid "Util" or "Helper" types.  Perhaps call this LpcmFormat or something.

+ public:
+  static std::unique_ptr<LpcmUtil> Create(const LpcmStreamType& stream_type);

[jeffbrown, 2016/02/02 05:35:46]

Can instances be shared?  Consider GetInstance perhaps if the number of types is
finite.

+
+  virtual ~LpcmUtil() {}
+
+  // Fills the buffer with silence.
+  virtual void Silence(void* buffer, uint64_t frame_count) const = 0;
+
+  // Copies samples.
+  virtual void Copy(const void* in, void* out, uint64_t frame_count) const = 0;
+
+  // Mixes samples.

[jeffbrown, 2016/02/02 05:35:46]

The description is a bit unclear.  Is this summing?  What's the gain factor?

+  virtual void Mix(const void* in, void* out, uint64_t frame_count) const = 0;
+
+  // Interleaves non-interleaved samples. This assumes ffmpeg non-interleaved
+  // ("planar") layout, in which the buffer (in) is divided evenly into a
+  // channel buffer per channel. The samples for each channel are contiguous
+  // in the respective channel buffer with possible empty space at the end
+  // (hence the in_type_count and the frame_count).
+  virtual void Interleave(
+      const void* in,
+      uint64_t in_byte_count,

[jeffbrown, 2016/02/02 05:35:46]

Mixing bytes and frames could be error prone.

+      void* out,
+      uint64_t frame_count) const = 0;
+};
+
+}  // namespace media
+}  // namespace mojo
+
+#endif // SERVICES_MEDIA_FRAMEWORK_LPCM_UTIL_H_