Load CMA backend from shared library

chromecast/public/media/cast_decoder_buffer.h

+// 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.
+
+#ifndef CHROMECAST_PUBLIC_MEDIA_CAST_DECODER_BUFFER_H_
+#define CHROMECAST_PUBLIC_MEDIA_CAST_DECODER_BUFFER_H_
+
+#include <stdint.h>
+
+#include <cstddef>
+
+#include "stream_id.h"
+
+namespace chromecast {
+namespace media {
+
+class CastDecryptConfig;
+
+// DecoderBuffer exposes only the properties of an audio/video buffer.

[gunsch, 2015/07/29 17:04:20]

Can we rewrite this description to be more a description for the OEM of what
this class is and how it's meant to be used, rather than implementation details?

[halliwell, 2015/07/29 19:58:20]

Done.  I took a swing at updating a number of other comments too, several were
phrased from the POV of API clients, not implementers.

+// The way a DecoderBuffer is created and organized in memory
+// is left as a detail of the implementation of derived classes.
+class CastDecoderBuffer {
+ public:
+  virtual ~CastDecoderBuffer() {}
+
+  // Returns the stream id of this decoder buffer belonging to. it's optional
+  // and default value is kPrimary.

[gunsch, 2015/07/29 17:04:20]

Can we make this not optional, and simply return kPrimary in the "default" case,
instead of putting that on the OEM?

[halliwell, 2015/07/29 19:58:20]

I'm not quite sure what the intent of the "it's optional" comment was ... was it
just trying to say that in a single-stream case, the stream id is always
kPrimary?  Simplified now ... let me know if I missed something :)

+  virtual StreamId stream_id() const = 0;
+
+  // Returns the PTS of the frame in microseconds.
+  virtual int64_t timestamp() const = 0;
+
+  // Gets the frame data.
+  virtual const uint8_t* data() const = 0;
+
+  // Returns the size of the frame in bytes.
+  virtual size_t data_size() const = 0;
+
+  // Returns the decrypt configuration.
+  // Returns NULL if the buffer has no decrypt info.

[gunsch, 2015/07/29 17:04:20]

Can we strengthen this statement to "Returns NULL iff the buffer is not
encrypted" ?

[halliwell, 2015/07/29 19:58:20]

We can, comment updated.

+  virtual const CastDecryptConfig* decrypt_config() const = 0;
+
+  // Indicate if this is a special frame that indicates the end of the stream.
+  // If true, functions to access the frame content cannot be called.
+  virtual bool end_of_stream() const = 0;
+};
+
+}  // namespace media
+}  // namespace chromecast
+
+#endif  // CHROMECAST_PUBLIC_MEDIA_CAST_DECODER_BUFFER_H_