// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// This file contains the definition of VASurface class, used for decoding by
// VaapiVideoDecodeAccelerator and VaapiH264Decoder.
#ifndef CONTENT_COMMON_GPU_MEDIA_VA_SURFACE_H_
#define CONTENT_COMMON_GPU_MEDIA_VA_SURFACE_H_
#include "third_party/libva/va/va.h"
namespace content {
// A VA-API-specific decode surface used by VaapiH264Decoder to decode into
// and use as reference for decoding other surfaces. It is also handed by the
// decoder to VaapiVideoDecodeAccelerator when the contents of the surface are
// ready and should be displayed. VAVDA converts the surface contents into an
// X Pixmap bound to a texture for display and releases its reference to it.
// Decoder releases its references to the surface when it's done decoding and
// using it as reference. Note that a surface may still be used for reference
// after it's been sent to output and also after it is no longer used by VAVDA.
// Thus, the surface can be in use by both VAVDA and the Decoder at the same
// time, or by either of them, with the restriction that VAVDA will never get
// the surface until the contents are ready, and it is guaranteed that the
// contents will not change after that.
// When both the decoder and VAVDA release their references to the surface,
// it is freed and the release callback is executed to put the surface back
// into available surfaces pool, which is managed externally.
//
// VASurfaceID is allocated in VaapiWrapper.
// |
// +----->|
// | v
// | VASurfaceID is put onto VaapiVideoDecodeAccelerator::available_va_surfaces_
// | | list.
// | v
// | VASurfaceID is taken off of the VVDA:available_va_surfaces_ when
// | | VaapiH264Decoder requests more output surfaces, is wrapped into
// | | a VASurface and passed to VaapiH264Decoder.
// | v
// | VASurface is put onto VaapiH264Decoder::available_va_surfaces_, keeping
// | | the only reference to it until it's needed for decoding.
// | v
// | VaapiH264Decoder starts decoding a new frame. It takes a VASurface off of
// | | VHD::available_va_surfaces_ and assigns it to a DecodeSurface,
// | | which now keeps the only reference.
// | v
// | DecodeSurface is used for decoding, putting data into associated VASurface.
// | |
// | |--------------------------------------------------+
// | | |
// | v v
// | DecodeSurface is to be output. VaapiH264Decoder uses the
// | VaapiH264Decoder passes the associated DecodeSurface and associated
// | VASurface to VaapiVideoDecodeAccelerator, VASurface as reference for
// | which stores it (taking a ref) on decoding more frames.
// | pending_output_cbs_ queue until an output |
// | TFPPicture becomes available. v
// | | Once the DecodeSurface is not
// | | needed as reference anymore,
// | v it is released, releasing the
// | A TFPPicture becomes available after associated VASurface reference.
// | the client of VVDA returns |
// | a PictureBuffer associated with it. VVDA |
// | puts the contents of the VASurface into |
// | it and releases the reference to VASurface. |
// | | |
// | '---------------------------------------'
// | |
// | v
// | Neither VVDA nor VHD hold a reference to VASurface. VASurface is released,
// | ReleaseCB gets called in its destructor, which puts the associated
// | VASurfaceID back onto VVDA::available_va_surfaces_.
// | |
// '-------------------------------------|
// |
// v
// VaapiWrapper frees VASurfaceID.
//
class CONTENT_EXPORT VASurface : public base::RefCountedThreadSafe<VASurface> {
public:
// Provided by user, will be called when all references to the surface
// are released.
typedef base::Callback<void(VASurfaceID)> ReleaseCB;
VASurface(VASurfaceID va_surface_id, const ReleaseCB& release_cb);
VASurfaceID id() {
return va_surface_id_;
}
private:
friend class base::RefCountedThreadSafe<VASurface>;
~VASurface();
const VASurfaceID va_surface_id_;
ReleaseCB release_cb_;
DISALLOW_COPY_AND_ASSIGN(VASurface);
};
} // namespace content
#endif // CONTENT_COMMON_GPU_MEDIA_VA_SURFACE_H_