VAVDA: Redesign stage 1.

content/common/gpu/media/vaapi_delegate.h

+// Copyright (c) 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 an implementation of VaapiDelegate, used by
+// VaapiVideoDecodeAccelerator and VaapiH264Decoder to interface
+// with libva (VA-API library for hardware video decode).
+
+#ifndef CONTENT_COMMON_GPU_MEDIA_VAAPI_DELEGATE_H_
+#define CONTENT_COMMON_GPU_MEDIA_VAAPI_DELEGATE_H_
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/synchronization/lock.h"
+#include "media/base/video_decoder_config.h"
+#include "third_party/libva/va/va.h"
+#include "third_party/libva/va/va_x11.h"
+#include "ui/gfx/size.h"
+
+namespace content {
+
+// This class handles VA-API calls and ensures proper locking of VA-API calls
+// to libva, the userspace shim to the HW decoder driver. libva is not
+// thread-safe, so we have to perform locking ourselves. This class is fully
+// synchronous and its methods can be called from any thread and may wait on
+// the va_lock_ while other, concurrent calls run.
+//
+// This class is responsible for managing VAAPI connection, contexts and state.
+// It is also responsible for managing and freeing VABuffers (not VASurfaces),
+// which are used to queue decode parameters and slice data to the HW decoder,
+// as well as underlying memory for VASurfaces themselves.
+class VaapiDelegate : public base::RefCountedThreadSafe<VaapiDelegate> {

[Ami GONE FROM CHROMIUM, 2013/05/22 23:59:47]

please rename to wrapper.  Delegate means a different thing to wrapper (if
anything, FooDelegate would be the thing that a FooWrapper wraps, as it is the
thing that is dispatched to, not the thing doing the dispatching).

[Pawel Osciak, 2013/05/24 01:46:39]

Done. Lunch topic next time I visit KIR? ;)

+ public:
+  // |report_error_to_uma_cb| will be used to report errors for UMA purposes,

[Ami GONE FROM CHROMIUM, 2013/05/22 23:59:47]

nit: with the gloriously informative new name, this comment is less necessary.

[Pawel Osciak, 2013/05/24 01:46:39]

Done.

+  // independently from reporting errors to clients.
+  static scoped_refptr<VaapiDelegate> Create(
+      media::VideoCodecProfile profile,
+      Display* x_display,
+      const base::Closure& report_error_to_uma_cb);
+
+  // Create |num_surfaces| backing surfaces in driver for VASurfaces, each
+  // of size |size|. Returns true when successful, with the created IDs in
+  // |va_surfaces| to be managed and later wrapped in VASurfaces.
+  // The client must DestroySurfaces() each time before calling this method
+  // again to free the allocated surfaces first, but is not required to do so
+  // at destruction time, as this will be done automatically from
+  // the destructor.
+  bool CreateSurfaces(gfx::Size size,
+                      size_t num_surfaces,
+                      std::vector<VASurfaceID>* va_surfaces);
+
+  // Free all memory allocated in CreateSurfaces.
+  void DestroySurfaces();
+
+  // Submit parameters or slice data of |va_buffer_type|, copying them from
+  // |buffer| of size |size|, into HW decoder. The data in |buffer| is no
+  // longer needed and can be freed after this method returns.
+  // Data submitted via this method awaits in the HW decoder until
+  // DecodeAndDestroyPendingBuffers is called to execute or
+  // DestroyPendingBuffers is used to cancel a pending decode.
+  bool SubmitBuffer(VABufferType va_buffer_type, size_t size, void* buffer);
+
+  // Cancel and destroy all buffers queued to the HW decoder via SubmitBuffer.
+  // Useful when a pending decode is to be cancelled (on reset or error).
+  void DestroyPendingBuffers();
+
+  // Execute decode in hardware and destroy pending buffers.

[Ami GONE FROM CHROMIUM, 2013/05/22 23:59:47]

what does a false return value mean?  more data necessary?  stream error?  etc.

[Pawel Osciak, 2013/05/24 01:46:39]

Done.

+  bool DecodeAndDestroyPendingBuffers(VASurfaceID va_surface_id);
+
+
+  // Put data from |va_surface_id| into |x_pixmap| of size |size|,
+  // converting/scaling to it.
+  bool PutSurfaceIntoPixmap(VASurfaceID va_surface_id,
+                            Pixmap x_pixmap,
+                            gfx::Size dest_size);

[Ami GONE FROM CHROMIUM, 2013/05/22 23:59:47]

Is it ever the case that the pixmap & the surface have different sizes?

[Pawel Osciak, 2013/05/24 01:46:39]

Not for us, but it's allowed, it'd be scaled then.

+
+  // Do any necessary initialization before the sandbox is enabled.
+  static void PreSandboxInitialization();
+
+ private:
+  friend class base::RefCountedThreadSafe<VaapiDelegate>;
+  VaapiDelegate();
+  ~VaapiDelegate();
+
+  bool Initialize(media::VideoCodecProfile profile,
+                  Display* x_display,
+                  const base::Closure& report_error__to_uma_cb);
+  void Deinitialize();
+
+  bool SubmitDecode(VASurfaceID va_surface_id);

[Ami GONE FROM CHROMIUM, 2013/05/22 23:59:47]

ditto q about meaning of return false.

[Pawel Osciak, 2013/05/24 01:46:39]

Done.

+
+  // Lazily initialize static data after sandbox is enabled.  Return false on
+  // init failure.
+  static bool PostSandboxInitialization();
+
+  // Libva is not thread safe, so we have to do locking for it ourselves.
+  // This lock is to be taken for the duration of all VA-API calls and for
+  // the entire decode execution sequence in DecodeAndDestroyPendingBuffers().
+  base::Lock va_lock_;
+
+  // Allocated ids for VASurfaces.
+  std::vector<VASurfaceID> va_surface_ids_;
+
+  // VA handles.
+  // Both valid after successful Initialize() and until Deinitialize().
+  VADisplay va_display_;
+  VAConfigID va_config_id_;
+  // Created for the current set of va_surface_ids_ in CreateSurfaces() and
+  // valid until DestroySurfaces().
+  VAContextID va_context_id_;
+
+  // Data queued up for HW decoder, to be committed on next HW decode.
+  std::vector<VABufferID> pending_slice_bufs_;
+  std::vector<VABufferID> pending_va_bufs_;
+
+  // Called to report decoding errors to UMA. Errors to clients are reported via
+  // return values from public methods.
+  base::Closure report_error_to_uma_cb_;
+
+  // Has static initialization of pre-sandbox components completed successfully?
+  static bool pre_sandbox_init_done_;
+
+  DISALLOW_COPY_AND_ASSIGN(VaapiDelegate);
+};
+

[Ami GONE FROM CHROMIUM, 2013/05/22 23:59:47]

nit: add an extra \n I think.

[Pawel Osciak, 2013/05/24 01:46:39]

Moved out.

+// 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 VaapiDelegate.
+//        |
+// +----->|
+// |      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
+//                       VaapiDelegate frees VASurfaceID.
+//
+class 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_VAAPI_DELEGATE_H_