source/common/wavefront.h

   1 /*****************************************************************************
   2  * Copyright (C) 2013 x265 project
   3  *
   4  * Authors: Steve Borho <steve@borho.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02111, USA.
  19  *
  20  * This program is also available under a commercial proprietary license.
  21  * For more information, contact us at license @ x265.com
  22  *****************************************************************************/
  23
  24 #ifndef X265_WAVEFRONT_H
  25 #define X265_WAVEFRONT_H
  26
  27 #include "common.h"
  28 #include "threadpool.h"
  29
  30 namespace x265 {
  31 // x265 private namespace
  32
  33 // Generic wave-front scheduler, manages busy-state of CU rows as a priority
  34 // queue (higher CU rows have priority over lower rows)
  35 //
  36 // Derived classes must implement ProcessRow().
  37 class WaveFront : public JobProvider
  38 {
  39 private:
  40
  41     // bitmaps of rows queued for processing, uses atomic intrinsics
  42
  43     // Dependencies are categorized as internal and external. Internal dependencies
  44     // are caused by neighbor block availability.  External dependencies are generally
  45     // reference frame reconstructed pixels being available.
  46     uint32_t volatile *m_internalDependencyBitmap;
  47     uint32_t volatile *m_externalDependencyBitmap;
  48
  49     // number of words in the bitmap
  50     int m_numWords;
  51
  52     int m_numRows;
  53
  54 public:
  55
  56     WaveFront(ThreadPool *pool)
  57         : JobProvider(pool)
  58         , m_internalDependencyBitmap(0)
  59         , m_externalDependencyBitmap(0)
  60     {}
  61
  62     virtual ~WaveFront();
  63
  64     // If returns false, the frame must be encoded in series.
  65     bool init(int numRows);
  66
  67     // Enqueue a row to be processed (mark its internal dependencies as resolved).
  68     // A worker thread will later call processRow(row).
  69     // This provider must be enqueued in the pool before enqueuing a row
  70     void enqueueRow(int row);
  71
  72     // Mark a row as no longer having internal dependencies resolved. Returns
  73     // true if bit clear was successful, false otherwise.
  74     bool dequeueRow(int row);
  75
  76     // Mark the row's external dependencies as being resolved
  77     void enableRow(int row);
  78
  79     // Mark all row external dependencies as being resolved. Some wavefront
  80     // implementations (lookahead, for instance) have no recon pixel dependencies.
  81     void enableAllRows();
  82
  83     // Mark all rows as having external dependencies which must be
  84     // resolved before each row may proceed.
  85     void clearEnabledRowMask();
  86
  87     // WaveFront's implementation of JobProvider::findJob. Consults
  88     // m_queuedBitmap and calls ProcessRow(row) for lowest numbered queued row
  89     // or returns false
  90     bool findJob(int threadId);
  91
  92     // Start or resume encode processing of this row, must be implemented by
  93     // derived classes.
  94     virtual void processRow(int row, int threadId) = 0;
  95 };
  96 } // end namespace x265
  97
  98 #endif // ifndef X265_WAVEFRONT_H