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;
+
+// CastDecoderBuffer provides an interface for passing a single frame of audio
+// or video data to the pipeline backend.  End-of-stream is indicated by passing
+// a frame where end_of_stream() returns true.
+// Buffer ownership passes to backend when they are pushed (see
+// MediaComponentDevice::PushFrame).
+class CastDecoderBuffer {
+ public:
+  virtual ~CastDecoderBuffer() {}

[byungchul, 2015/07/29 20:32:23]

If it won't be destroyed by shlib, it should be a protected dtor.

[gunsch-google, 2015/07/29 20:48:26]

This will be owned and destroyed by shlib.

[halliwell, 2015/07/29 22:39:27]

Correct.  This definitely needs to be public.

+
+  // Returns the stream id of this decoder buffer.
+  virtual StreamId stream_id() const = 0;

[byungchul, 2015/07/29 20:32:23]

Still don't understand why these names are lower-case, and then why not a simple
struct. What's the meaning of lower-case function names here?

[gunsch-google, 2015/07/29 20:48:26]

I'm in favor of getters. For example, data() and decrypt_config() might not be
owned by this class, but this class might just indirectly point to the
references elsewhere (which it does). So to avoid copying and keep lifetime
management reasonable, they need getters. At that point, simple struct is not a
good choice.

[halliwell, 2015/07/29 22:39:27]

After offline discussion, prefer to leave these as-is.  We definitely need
getter functions here to avoid copying data.  Whether to CamelCase their names
seems debatable and I'd rather spend remaining time on converting other backend
implementations, let me know if you strongly object though :)

[byungchul, 2015/07/29 23:12:29]

A TODO would be appreciated to not forget re-address naming later :)

[halliwell, 2015/07/30 00:19:57]

Ok, TODO added :)

+
+  // 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 and only if the buffer is unencrypted.
+  virtual const CastDecryptConfig* decrypt_config() const = 0;
+
+  // Indicates 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_