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/buffers.h"
  18 #include "media/base/decrypt_config.h"
  19 #include "media/base/media_export.h"
  20
  21 namespace media {
  22
  23 // A specialized buffer for interfacing with audio / video decoders.
  24 //
  25 // Specifically ensures that data is aligned and padded as necessary by the
  26 // underlying decoding framework.  On desktop platforms this means memory is
  27 // allocated using FFmpeg with particular alignment and padding requirements.
  28 //
  29 // Also includes decoder specific functionality for decryption.
  30 //
  31 // NOTE: It is illegal to call any method when end_of_stream() is true.
  32 class MEDIA_EXPORT DecoderBuffer
  33     : public base::RefCountedThreadSafe<DecoderBuffer> {
  34  public:
  35   enum {
  36     kPaddingSize = 32,
  37 #if defined(ARCH_CPU_ARM_FAMILY)
  38     kAlignmentSize = 16
  39 #else
  40     kAlignmentSize = 32
  41 #endif
  42   };
  43
  44   // Allocates buffer with |size| >= 0.  Buffer will be padded and aligned
  45   // as necessary.
  46   explicit DecoderBuffer(int size);
  47
  48   // Create a DecoderBuffer whose |data_| is copied from |data|.  Buffer will be
  49   // padded and aligned as necessary.  |data| must not be NULL and |size| >= 0.
  50   static scoped_refptr<DecoderBuffer> CopyFrom(const uint8* data, int size);
  51
  52   // Create a DecoderBuffer whose |data_| is copied from |data| and |side_data_|
  53   // is copied from |side_data|. Buffers will be padded and aligned as necessary
  54   // Data pointers must not be NULL and sizes must be >= 0.
  55   static scoped_refptr<DecoderBuffer> CopyFrom(const uint8* data, int size,
  56                                                const uint8* side_data,
  57                                                int side_data_size);
  58
  59   // Create a DecoderBuffer indicating we've reached end of stream.
  60   //
  61   // Calling any method other than end_of_stream() on the resulting buffer
  62   // is disallowed.
  63   static scoped_refptr<DecoderBuffer> CreateEOSBuffer();
  64
  65   base::TimeDelta timestamp() const {
  66     DCHECK(!end_of_stream());
  67     return timestamp_;
  68   }
  69
  70   // TODO(dalecurtis): This should be renamed at some point, but to avoid a yak
  71   // shave keep as a virtual with hacker_style() for now.
  72   virtual void set_timestamp(base::TimeDelta timestamp);
  73
  74   base::TimeDelta duration() const {
  75     DCHECK(!end_of_stream());
  76     return duration_;
  77   }
  78
  79   void set_duration(base::TimeDelta duration) {
  80     DCHECK(!end_of_stream());
  81     DCHECK(duration == kNoTimestamp() ||
  82            (duration >= base::TimeDelta() && duration != kInfiniteDuration()))
  83         << duration.InSecondsF();
  84     duration_ = duration;
  85   }
  86
  87   const uint8* data() const {
  88     DCHECK(!end_of_stream());
  89     return data_.get();
  90   }
  91
  92   uint8* writable_data() const {
  93     DCHECK(!end_of_stream());
  94     return data_.get();
  95   }
  96
  97   int data_size() const {
  98     DCHECK(!end_of_stream());
  99     return size_;
 100   }
 101
 102   const uint8* side_data() const {
 103     DCHECK(!end_of_stream());
 104     return side_data_.get();
 105   }
 106
 107   int side_data_size() const {
 108     DCHECK(!end_of_stream());
 109     return side_data_size_;
 110   }
 111
 112   // A discard window indicates the amount of data which should be discard from
 113   // this buffer after decoding.  The first value is the amount of the front and
 114   // the second the amount off the back.  A value of kInfiniteDuration() for the
 115   // first value indicates the entire buffer should be discarded; the second
 116   // value must be base::TimeDelta() in this case.
 117   typedef std::pair<base::TimeDelta, base::TimeDelta> DiscardPadding;
 118   const DiscardPadding& discard_padding() const {
 119     DCHECK(!end_of_stream());
 120     return discard_padding_;
 121   }
 122
 123   void set_discard_padding(const DiscardPadding& discard_padding) {
 124     DCHECK(!end_of_stream());
 125     discard_padding_ = discard_padding;
 126   }
 127
 128   const DecryptConfig* decrypt_config() const {
 129     DCHECK(!end_of_stream());
 130     return decrypt_config_.get();
 131   }
 132
 133   void set_decrypt_config(scoped_ptr<DecryptConfig> decrypt_config) {
 134     DCHECK(!end_of_stream());
 135     decrypt_config_ = decrypt_config.Pass();
 136   }
 137
 138   // If there's no data in this buffer, it represents end of stream.
 139   bool end_of_stream() const {
 140     return data_ == NULL;
 141   }
 142
 143   // Indicates this buffer is part of a splice around |splice_timestamp_|.
 144   // Returns kNoTimestamp() if the buffer is not part of a splice.
 145   base::TimeDelta splice_timestamp() const {
 146     DCHECK(!end_of_stream());
 147     return splice_timestamp_;
 148   }
 149
 150   // When set to anything but kNoTimestamp() indicates this buffer is part of a
 151   // splice around |splice_timestamp|.
 152   void set_splice_timestamp(base::TimeDelta splice_timestamp) {
 153     DCHECK(!end_of_stream());
 154     splice_timestamp_ = splice_timestamp;
 155   }
 156
 157   // Returns a human-readable string describing |*this|.
 158   std::string AsHumanReadableString();
 159
 160  protected:
 161   friend class base::RefCountedThreadSafe<DecoderBuffer>;
 162
 163   // Allocates a buffer of size |size| >= 0 and copies |data| into it.  Buffer
 164   // will be padded and aligned as necessary.  If |data| is NULL then |data_| is
 165   // set to NULL and |buffer_size_| to 0.
 166   DecoderBuffer(const uint8* data, int size,
 167                 const uint8* side_data, int side_data_size);
 168   virtual ~DecoderBuffer();
 169
 170  private:
 171   base::TimeDelta timestamp_;
 172   base::TimeDelta duration_;
 173
 174   int size_;
 175   scoped_ptr<uint8, base::AlignedFreeDeleter> data_;
 176   int side_data_size_;
 177   scoped_ptr<uint8, base::AlignedFreeDeleter> side_data_;
 178   scoped_ptr<DecryptConfig> decrypt_config_;
 179   DiscardPadding discard_padding_;
 180   base::TimeDelta splice_timestamp_;
 181
 182   // Constructor helper method for memory allocations.
 183   void Initialize();
 184
 185   DISALLOW_COPY_AND_ASSIGN(DecoderBuffer);
 186 };
 187
 188 }  // namespace media
 189
 190 #endif  // MEDIA_BASE_DECODER_BUFFER_H_