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 #include "media/base/timestamp_constants.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, and |is_key_frame_| will default to false.
  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   // The buffer's |is_key_frame_| will default to false.
  51   static scoped_refptr<DecoderBuffer> CopyFrom(const uint8* data, int size);
  52
  53   // Create a DecoderBuffer whose |data_| is copied from |data| and |side_data_|
  54   // is copied from |side_data|. Buffers will be padded and aligned as necessary
  55   // Data pointers must not be NULL and sizes must be >= 0. The buffer's
  56   // |is_key_frame_| will default to false.
  57   static scoped_refptr<DecoderBuffer> CopyFrom(const uint8* data, int size,
  58                                                const uint8* side_data,
  59                                                int side_data_size);
  60
  61   // Create a DecoderBuffer indicating we've reached end of stream.
  62   //
  63   // Calling any method other than end_of_stream() on the resulting buffer
  64   // is disallowed.
  65   static scoped_refptr<DecoderBuffer> CreateEOSBuffer();
  66
  67   base::TimeDelta timestamp() const {
  68     DCHECK(!end_of_stream());
  69     return timestamp_;
  70   }
  71
  72   // TODO(dalecurtis): This should be renamed at some point, but to avoid a yak
  73   // shave keep as a virtual with hacker_style() for now.
  74   virtual void set_timestamp(base::TimeDelta timestamp);
  75
  76   base::TimeDelta duration() const {
  77     DCHECK(!end_of_stream());
  78     return duration_;
  79   }
  80
  81   void set_duration(base::TimeDelta duration) {
  82     DCHECK(!end_of_stream());
  83     DCHECK(duration == kNoTimestamp() ||
  84            (duration >= base::TimeDelta() && duration != kInfiniteDuration()))
  85         << duration.InSecondsF();
  86     duration_ = duration;
  87   }
  88
  89   const uint8* data() const {
  90     DCHECK(!end_of_stream());
  91     return data_.get();
  92   }
  93
  94   uint8* writable_data() const {
  95     DCHECK(!end_of_stream());
  96     return data_.get();
  97   }
  98
  99   // TODO(servolk): data_size should return size_t instead of int
 100   int data_size() const {
 101     DCHECK(!end_of_stream());
 102     return size_;
 103   }
 104
 105   const uint8* side_data() const {
 106     DCHECK(!end_of_stream());
 107     return side_data_.get();
 108   }
 109
 110   // TODO(servolk): side_data_size should return size_t instead of int
 111   int side_data_size() const {
 112     DCHECK(!end_of_stream());
 113     return side_data_size_;
 114   }
 115
 116   // A discard window indicates the amount of data which should be discard from
 117   // this buffer after decoding.  The first value is the amount of the front and
 118   // the second the amount off the back.  A value of kInfiniteDuration() for the
 119   // first value indicates the entire buffer should be discarded; the second
 120   // value must be base::TimeDelta() in this case.
 121   typedef std::pair<base::TimeDelta, base::TimeDelta> DiscardPadding;
 122   const DiscardPadding& discard_padding() const {
 123     DCHECK(!end_of_stream());
 124     return discard_padding_;
 125   }
 126
 127   void set_discard_padding(const DiscardPadding& discard_padding) {
 128     DCHECK(!end_of_stream());
 129     discard_padding_ = discard_padding;
 130   }
 131
 132   const DecryptConfig* decrypt_config() const {
 133     DCHECK(!end_of_stream());
 134     return decrypt_config_.get();
 135   }
 136
 137   void set_decrypt_config(scoped_ptr<DecryptConfig> decrypt_config) {
 138     DCHECK(!end_of_stream());
 139     decrypt_config_ = decrypt_config.Pass();
 140   }
 141
 142   // If there's no data in this buffer, it represents end of stream.
 143   bool end_of_stream() const {
 144     return data_ == NULL;
 145   }
 146
 147   // Indicates this buffer is part of a splice around |splice_timestamp_|.
 148   // Returns kNoTimestamp() if the buffer is not part of a splice.
 149   base::TimeDelta splice_timestamp() const {
 150     DCHECK(!end_of_stream());
 151     return splice_timestamp_;
 152   }
 153
 154   // When set to anything but kNoTimestamp() indicates this buffer is part of a
 155   // splice around |splice_timestamp|.
 156   void set_splice_timestamp(base::TimeDelta splice_timestamp) {
 157     DCHECK(!end_of_stream());
 158     splice_timestamp_ = splice_timestamp;
 159   }
 160
 161   bool is_key_frame() const {
 162     DCHECK(!end_of_stream());
 163     return is_key_frame_;
 164   }
 165
 166   void set_is_key_frame(bool is_key_frame) {
 167     DCHECK(!end_of_stream());
 168     is_key_frame_ = is_key_frame;
 169   }
 170
 171   // Returns a human-readable string describing |*this|.
 172   std::string AsHumanReadableString();
 173
 174   // Replaces any existing side data with data copied from |side_data|.
 175   void CopySideDataFrom(const uint8* side_data, int side_data_size);
 176
 177  protected:
 178   friend class base::RefCountedThreadSafe<DecoderBuffer>;
 179
 180   // Allocates a buffer of size |size| >= 0 and copies |data| into it.  Buffer
 181   // will be padded and aligned as necessary.  If |data| is NULL then |data_| is
 182   // set to NULL and |buffer_size_| to 0.  |is_key_frame_| will default to
 183   // false.
 184   DecoderBuffer(const uint8* data, int size,
 185                 const uint8* side_data, int side_data_size);
 186   virtual ~DecoderBuffer();
 187
 188  private:
 189   base::TimeDelta timestamp_;
 190   base::TimeDelta duration_;
 191
 192   // TODO(servolk): Consider changing size_/side_data_size_ types to size_t.
 193   int size_;
 194   scoped_ptr<uint8, base::AlignedFreeDeleter> data_;
 195   int side_data_size_;
 196   scoped_ptr<uint8, base::AlignedFreeDeleter> side_data_;
 197   scoped_ptr<DecryptConfig> decrypt_config_;
 198   DiscardPadding discard_padding_;
 199   base::TimeDelta splice_timestamp_;
 200   bool is_key_frame_;
 201
 202   // Constructor helper method for memory allocations.
 203   void Initialize();
 204
 205   DISALLOW_COPY_AND_ASSIGN(DecoderBuffer);
 206 };
 207
 208 }  // namespace media
 209
 210 #endif  // MEDIA_BASE_DECODER_BUFFER_H_