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, 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   int data_size() const {
 100     DCHECK(!end_of_stream());
 101     return size_;
 102   }
 103
 104   const uint8* side_data() const {
 105     DCHECK(!end_of_stream());
 106     return side_data_.get();
 107   }
 108
 109   int side_data_size() const {
 110     DCHECK(!end_of_stream());
 111     return side_data_size_;
 112   }
 113
 114   // A discard window indicates the amount of data which should be discard from
 115   // this buffer after decoding.  The first value is the amount of the front and
 116   // the second the amount off the back.  A value of kInfiniteDuration() for the
 117   // first value indicates the entire buffer should be discarded; the second
 118   // value must be base::TimeDelta() in this case.
 119   typedef std::pair<base::TimeDelta, base::TimeDelta> DiscardPadding;
 120   const DiscardPadding& discard_padding() const {
 121     DCHECK(!end_of_stream());
 122     return discard_padding_;
 123   }
 124
 125   void set_discard_padding(const DiscardPadding& discard_padding) {
 126     DCHECK(!end_of_stream());
 127     discard_padding_ = discard_padding;
 128   }
 129
 130   const DecryptConfig* decrypt_config() const {
 131     DCHECK(!end_of_stream());
 132     return decrypt_config_.get();
 133   }
 134
 135   void set_decrypt_config(scoped_ptr<DecryptConfig> decrypt_config) {
 136     DCHECK(!end_of_stream());
 137     decrypt_config_ = decrypt_config.Pass();
 138   }
 139
 140   // If there's no data in this buffer, it represents end of stream.
 141   bool end_of_stream() const {
 142     return data_ == NULL;
 143   }
 144
 145   // Indicates this buffer is part of a splice around |splice_timestamp_|.
 146   // Returns kNoTimestamp() if the buffer is not part of a splice.
 147   base::TimeDelta splice_timestamp() const {
 148     DCHECK(!end_of_stream());
 149     return splice_timestamp_;
 150   }
 151
 152   // When set to anything but kNoTimestamp() indicates this buffer is part of a
 153   // splice around |splice_timestamp|.
 154   void set_splice_timestamp(base::TimeDelta splice_timestamp) {
 155     DCHECK(!end_of_stream());
 156     splice_timestamp_ = splice_timestamp;
 157   }
 158
 159   bool is_key_frame() const {
 160     DCHECK(!end_of_stream());
 161     return is_key_frame_;
 162   }
 163
 164   void set_is_key_frame(bool is_key_frame) {
 165     DCHECK(!end_of_stream());
 166     is_key_frame_ = is_key_frame;
 167   }
 168
 169   // Returns a human-readable string describing |*this|.
 170   std::string AsHumanReadableString();
 171
 172  protected:
 173   friend class base::RefCountedThreadSafe<DecoderBuffer>;
 174
 175   // Allocates a buffer of size |size| >= 0 and copies |data| into it.  Buffer
 176   // will be padded and aligned as necessary.  If |data| is NULL then |data_| is
 177   // set to NULL and |buffer_size_| to 0.  |is_key_frame_| will default to
 178   // false.
 179   DecoderBuffer(const uint8* data, int size,
 180                 const uint8* side_data, int side_data_size);
 181   virtual ~DecoderBuffer();
 182
 183  private:
 184   base::TimeDelta timestamp_;
 185   base::TimeDelta duration_;
 186
 187   int size_;
 188   scoped_ptr<uint8, base::AlignedFreeDeleter> data_;
 189   int side_data_size_;
 190   scoped_ptr<uint8, base::AlignedFreeDeleter> side_data_;
 191   scoped_ptr<DecryptConfig> decrypt_config_;
 192   DiscardPadding discard_padding_;
 193   base::TimeDelta splice_timestamp_;
 194   bool is_key_frame_;
 195
 196   // Constructor helper method for memory allocations.
 197   void Initialize();
 198
 199   DISALLOW_COPY_AND_ASSIGN(DecoderBuffer);
 200 };
 201
 202 }  // namespace media
 203
 204 #endif  // MEDIA_BASE_DECODER_BUFFER_H_