Render inband text tracks in the media pipeline

media/base/decoder_buffer.h

 // Copyright (c) 2012 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 MEDIA_BASE_DECODER_BUFFER_H_
 #define MEDIA_BASE_DECODER_BUFFER_H_
 
 #include <string>
+#include <vector>
 
 #include "base/logging.h"
 #include "base/memory/aligned_memory.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "media/base/decrypt_config.h"
 #include "media/base/media_export.h"
 
@@ skipping 107 matching lines @@
   }
 
   // If there's no data in this buffer, it represents end of stream.
   bool end_of_stream() const {
     return data_ == NULL;
   }
 
   // Returns a human-readable string describing |*this|.
   std::string AsHumanReadableString();
 
+  // Utility function to create side data item for decoder buffer.
+  template<typename T>
+  static void MakeSideData(T id_begin, T id_end,

[acolwell GONE FROM CHROMIUM, 2013/10/24 18:57:51]

This doesn't belong here. This class is format independent and this logic is
WebVTT specific. I think placing this in something like
media/filters/webvtt_util.h would be a better solution.

[Matthew Heaney (Chromium), 2013/10/25 03:05:38]

Done.

+                           T settings_begin, T settings_end,
+                           std::vector<uint8>* side_data);
+
  protected:
   friend class base::RefCountedThreadSafe<DecoderBuffer>;
 
   // Allocates a buffer of size |size| >= 0 and copies |data| into it.  Buffer
   // will be padded and aligned as necessary.  If |data| is NULL then |data_| is
   // set to NULL and |buffer_size_| to 0.
   DecoderBuffer(const uint8* data, int size,
                 const uint8* side_data, int side_data_size);
   virtual ~DecoderBuffer();
 
  private:
   base::TimeDelta timestamp_;
   base::TimeDelta duration_;
 
   int size_;
   scoped_ptr<uint8, base::ScopedPtrAlignedFree> data_;
   int side_data_size_;
   scoped_ptr<uint8, base::ScopedPtrAlignedFree> side_data_;
   scoped_ptr<DecryptConfig> decrypt_config_;
   base::TimeDelta discard_padding_;
 
   // Constructor helper method for memory allocations.
   void Initialize();
 
   DISALLOW_COPY_AND_ASSIGN(DecoderBuffer);
 };
 
 }  // namespace media
 
+template<typename T>
+inline void media::DecoderBuffer::MakeSideData(
+    T id_begin, T id_end,
+    T settings_begin, T settings_end,
+    std::vector<uint8>* side_data) {
+  // The DecoderBuffer only supports a single side data item. In the case of
+  // a WebVTT cue, we can have potentially two side data items. In order to
+  // avoid disrupting DecoderBuffer any more than we need to, we copy both
+  // side data items onto a single one, and terminate each with a NUL marker.
+  side_data->clear();
+  side_data->insert(side_data->end(), id_begin, id_end);
+  side_data->push_back(0);
+  side_data->insert(side_data->end(), settings_begin, settings_end);
+  side_data->push_back(0);
+}
+
 #endif  // MEDIA_BASE_DECODER_BUFFER_H_