content/common/gpu/media/va_surface.h

   1 // Copyright 2013 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 // This file contains the definition of VASurface class, used for decoding by
   6 // VaapiVideoDecodeAccelerator and VaapiH264Decoder.
   7
   8 #ifndef CONTENT_COMMON_GPU_MEDIA_VA_SURFACE_H_
   9 #define CONTENT_COMMON_GPU_MEDIA_VA_SURFACE_H_
  10
  11 #include "base/callback.h"
  12 #include "base/memory/ref_counted.h"
  13 #include "content/common/content_export.h"
  14 #include "third_party/libva/va/va.h"
  15 #include "ui/gfx/geometry/size.h"
  16
  17 namespace content {
  18
  19 // A VA-API-specific decode surface used by VaapiH264Decoder to decode into
  20 // and use as reference for decoding other surfaces. It is also handed by the
  21 // decoder to VaapiVideoDecodeAccelerator when the contents of the surface are
  22 // ready and should be displayed. VAVDA converts the surface contents into an
  23 // X/Drm Pixmap bound to a texture for display and releases its reference to it.
  24 // Decoder releases its references to the surface when it's done decoding and
  25 // using it as reference. Note that a surface may still be used for reference
  26 // after it's been sent to output and also after it is no longer used by VAVDA.
  27 // Thus, the surface can be in use by both VAVDA and the Decoder at the same
  28 // time, or by either of them, with the restriction that VAVDA will never get
  29 // the surface until the contents are ready, and it is guaranteed that the
  30 // contents will not change after that.
  31 // When both the decoder and VAVDA release their references to the surface,
  32 // it is freed and the release callback is executed to put the surface back
  33 // into available surfaces pool, which is managed externally.
  34 //
  35 //   VASurfaceID is allocated in VaapiWrapper.
  36 //        |
  37 // +----->|
  38 // |      v
  39 // | VASurfaceID is put onto VaapiVideoDecodeAccelerator::available_va_surfaces_
  40 // |      |      list.
  41 // |      v
  42 // | VASurfaceID is taken off of the VVDA:available_va_surfaces_ when
  43 // |      |      VaapiH264Decoder requests more output surfaces, is wrapped into
  44 // |      |      a VASurface and passed to VaapiH264Decoder.
  45 // |      v
  46 // | VASurface is put onto VaapiH264Decoder::available_va_surfaces_, keeping
  47 // |      |      the only reference to it until it's needed for decoding.
  48 // |      v
  49 // | VaapiH264Decoder starts decoding a new frame. It takes a VASurface off of
  50 // |      |      VHD::available_va_surfaces_ and assigns it to a DecodeSurface,
  51 // |      |      which now keeps the only reference.
  52 // |      v
  53 // | DecodeSurface is used for decoding, putting data into associated VASurface.
  54 // |      |
  55 // |      |--------------------------------------------------+
  56 // |      |                                                  |
  57 // |      v                                                  v
  58 // | DecodeSurface is to be output.              VaapiH264Decoder uses the
  59 // | VaapiH264Decoder passes the associated      DecodeSurface and associated
  60 // | VASurface to VaapiVideoDecodeAccelerator,   VASurface as reference for
  61 // | which stores it (taking a ref) on           decoding more frames.
  62 // | pending_output_cbs_ queue until an output               |
  63 // | VaapiPicture becomes available.                         v
  64 // |                 |                           Once the DecodeSurface is not
  65 // |                 |                           needed as reference anymore,
  66 // |                 v                           it is released, releasing the
  67 // | A VaapiPicture becomes available after      associated VASurface reference.
  68 // | the client of VVDA returns                              |
  69 // | a PictureBuffer associated with it. VVDA                |
  70 // | puts the contents of the VASurface into                 |
  71 // | it and releases the reference to VASurface.             |
  72 // |                 |                                       |
  73 // |                 '---------------------------------------'
  74 // |                                     |
  75 // |                                     v
  76 // | Neither VVDA nor VHD hold a reference to VASurface. VASurface is released,
  77 // | ReleaseCB gets called in its destructor, which puts the associated
  78 // | VASurfaceID back onto VVDA::available_va_surfaces_.
  79 // |                                     |
  80 // '-------------------------------------|
  81 //                                       |
  82 //                                       v
  83 //                       VaapiWrapper frees VASurfaceID.
  84 //
  85 class CONTENT_EXPORT VASurface : public base::RefCountedThreadSafe<VASurface> {
  86  public:
  87   // Provided by user, will be called when all references to the surface
  88   // are released.
  89   typedef base::Callback<void(VASurfaceID)> ReleaseCB;
  90
  91   VASurface(VASurfaceID va_surface_id,
  92             const gfx::Size& size,
  93             const ReleaseCB& release_cb);
  94
  95   VASurfaceID id() {
  96     return va_surface_id_;
  97   }
  98
  99   const gfx::Size& size() const { return size_; }
 100
 101  private:
 102   friend class base::RefCountedThreadSafe<VASurface>;
 103   ~VASurface();
 104
 105   const VASurfaceID va_surface_id_;
 106   gfx::Size size_;
 107   ReleaseCB release_cb_;
 108
 109   DISALLOW_COPY_AND_ASSIGN(VASurface);
 110 };
 111
 112 }  // namespace content
 113
 114 #endif  // CONTENT_COMMON_GPU_MEDIA_VA_SURFACE_H_