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