media/base/decoder_buffer.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef MEDIA_BASE_DECODER_BUFFER_H_
   6 #define MEDIA_BASE_DECODER_BUFFER_H_
   7
   8 #include <string>
   9 #include <utility>
  10
  11 #include "base/logging.h"
  12 #include "base/memory/aligned_memory.h"
  13 #include "base/memory/ref_counted.h"
  14 #include "base/memory/scoped_ptr.h"
  15 #include "base/time/time.h"
  16 #include "build/build_config.h"
  17 #include "media/base/decrypt_config.h"
  18 #include "media/base/media_export.h"
  19
  20 namespace media {
  21
  22 // A specialized buffer for interfacing with audio / video decoders.
  23 //
  24 // Specifically ensures that data is aligned and padded as necessary by the
  25 // underlying decoding framework.  On desktop platforms this means memory is
  26 // allocated using FFmpeg with particular alignment and padding requirements.
  27 //
  28 // Also includes decoder specific functionality for decryption.
  29 //
  30 // NOTE: It is illegal to call any method when end_of_stream() is true.
  31 class MEDIA_EXPORT DecoderBuffer
  32     : public base::RefCountedThreadSafe<DecoderBuffer> {
  33  public:
  34   enum {
  35     kPaddingSize = 16,
  36 #if defined(ARCH_CPU_ARM_FAMILY)
  37     kAlignmentSize = 16
  38 #else
  39     kAlignmentSize = 32
  40 #endif
  41   };
  42
  43   // Allocates buffer with |size| >= 0.  Buffer will be padded and aligned
  44   // as necessary.
  45   explicit DecoderBuffer(int size);
  46
  47   // Create a DecoderBuffer whose |data_| is copied from |data|.  Buffer will be
  48   // padded and aligned as necessary.  |data| must not be NULL and |size| >= 0.
  49   static scoped_refptr<DecoderBuffer> CopyFrom(const uint8* data, int size);
  50
  51   // Create a DecoderBuffer whose |data_| is copied from |data| and |side_data_|
  52   // is copied from |side_data|. Buffers will be padded and aligned as necessary
  53   // Data pointers must not be NULL and sizes must be >= 0.
  54   static scoped_refptr<DecoderBuffer> CopyFrom(const uint8* data, int size,
  55                                                const uint8* side_data,
  56                                                int side_data_size);
  57
  58   // Create a DecoderBuffer indicating we've reached end of stream.
  59   //
  60   // Calling any method other than end_of_stream() on the resulting buffer
  61   // is disallowed.
  62   static scoped_refptr<DecoderBuffer> CreateEOSBuffer();
  63
  64   base::TimeDelta timestamp() const {
  65     DCHECK(!end_of_stream());
  66     return timestamp_;
  67   }
  68
  69   // TODO(dalecurtis): This should be renamed at some point, but to avoid a yak
  70   // shave keep as a virtual with hacker_style() for now.
  71   virtual void set_timestamp(base::TimeDelta timestamp);
  72
  73   base::TimeDelta duration() const {
  74     DCHECK(!end_of_stream());
  75     return duration_;
  76   }
  77
  78   void set_duration(base::TimeDelta duration) {
  79     DCHECK(!end_of_stream());
  80     duration_ = duration;
  81   }
  82
  83   const uint8* data() const {
  84     DCHECK(!end_of_stream());
  85     return data_.get();
  86   }
  87
  88   uint8* writable_data() const {
  89     DCHECK(!end_of_stream());
  90     return data_.get();
  91   }
  92
  93   int data_size() const {
  94     DCHECK(!end_of_stream());
  95     return size_;
  96   }
  97
  98   const uint8* side_data() const {
  99     DCHECK(!end_of_stream());
 100     return side_data_.get();
 101   }
 102
 103   int side_data_size() const {
 104     DCHECK(!end_of_stream());
 105     return side_data_size_;
 106   }
 107
 108   // A discard window indicates the amount of data which should be discard from
 109   // this buffer after decoding.  The first value is the amount of the front and
 110   // the second the amount off the back.  A value of kInfiniteDuration() for the
 111   // first value indicates the entire buffer should be discarded; the second
 112   // value must be base::TimeDelta() in this case.
 113   typedef std::pair<base::TimeDelta, base::TimeDelta> DiscardPadding;
 114   const DiscardPadding& discard_padding() const {
 115     DCHECK(!end_of_stream());
 116     return discard_padding_;
 117   }
 118
 119   void set_discard_padding(const DiscardPadding& discard_padding) {
 120     DCHECK(!end_of_stream());
 121     discard_padding_ = discard_padding;
 122   }
 123
 124   const DecryptConfig* decrypt_config() const {
 125     DCHECK(!end_of_stream());
 126     return decrypt_config_.get();
 127   }
 128
 129   void set_decrypt_config(scoped_ptr<DecryptConfig> decrypt_config) {
 130     DCHECK(!end_of_stream());
 131     decrypt_config_ = decrypt_config.Pass();
 132   }
 133
 134   // If there's no data in this buffer, it represents end of stream.
 135   bool end_of_stream() const {
 136     return data_ == NULL;
 137   }
 138
 139   // Indicates this buffer is part of a splice around |splice_timestamp_|.
 140   // Returns kNoTimestamp() if the buffer is not part of a splice.
 141   base::TimeDelta splice_timestamp() const {
 142     DCHECK(!end_of_stream());
 143     return splice_timestamp_;
 144   }
 145
 146   // When set to anything but kNoTimestamp() indicates this buffer is part of a
 147   // splice around |splice_timestamp|.
 148   void set_splice_timestamp(base::TimeDelta splice_timestamp) {
 149     DCHECK(!end_of_stream());
 150     splice_timestamp_ = splice_timestamp;
 151   }
 152
 153   // Returns a human-readable string describing |*this|.
 154   std::string AsHumanReadableString();
 155
 156  protected:
 157   friend class base::RefCountedThreadSafe<DecoderBuffer>;
 158
 159   // Allocates a buffer of size |size| >= 0 and copies |data| into it.  Buffer
 160   // will be padded and aligned as necessary.  If |data| is NULL then |data_| is
 161   // set to NULL and |buffer_size_| to 0.
 162   DecoderBuffer(const uint8* data, int size,
 163                 const uint8* side_data, int side_data_size);
 164   virtual ~DecoderBuffer();
 165
 166  private:
 167   base::TimeDelta timestamp_;
 168   base::TimeDelta duration_;
 169
 170   int size_;
 171   scoped_ptr<uint8, base::AlignedFreeDeleter> data_;
 172   int side_data_size_;
 173   scoped_ptr<uint8, base::AlignedFreeDeleter> side_data_;
 174   scoped_ptr<DecryptConfig> decrypt_config_;
 175   DiscardPadding discard_padding_;
 176   base::TimeDelta splice_timestamp_;
 177
 178   // Constructor helper method for memory allocations.
 179   void Initialize();
 180
 181   DISALLOW_COPY_AND_ASSIGN(DecoderBuffer);
 182 };
 183
 184 }  // namespace media
 185
 186 #endif  // MEDIA_BASE_DECODER_BUFFER_H_