libavcodec/thread.h

   1 /*
   2  * Copyright (c) 2008 Alexander Strange <astrange@ithinksw.com>
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg 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 GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 /**
  22  * @file
  23  * Multithreading API for decoders
  24  * @author Alexander Strange <astrange@ithinksw.com>
  25  */
  26
  27 #ifndef AVCODEC_THREAD_H
  28 #define AVCODEC_THREAD_H
  29
  30 #include "libavutil/buffer.h"
  31
  32 #include "avcodec.h"
  33
  34 int ff_thread_can_start_frame(AVCodecContext *avctx);
  35
  36 /**
  37  * If the codec defines update_thread_context(), call this
  38  * when they are ready for the next thread to start decoding
  39  * the next frame. After calling it, do not change any variables
  40  * read by the update_thread_context() method, or call ff_thread_get_buffer().
  41  *
  42  * @param avctx The context.
  43  */
  44 void ff_thread_finish_setup(AVCodecContext *avctx);
  45
  46 /**
  47  * Wrapper around get_buffer() for frame-multithreaded codecs.
  48  * Call this function instead of ff_get_buffer(f).
  49  * Cannot be called after the codec has called ff_thread_finish_setup().
  50  *
  51  * @param avctx The current context.
  52  * @param f The frame to write into.
  53  */
  54 int ff_thread_get_buffer(AVCodecContext *avctx, AVFrame *f, int flags);
  55
  56 int ff_slice_thread_execute_with_mainfunc(AVCodecContext *avctx,
  57         int (*action_func2)(AVCodecContext *c, void *arg, int jobnr, int threadnr),
  58         int (*main_func)(AVCodecContext *c), void *arg, int *ret, int job_count);
  59
  60 enum ThreadingStatus {
  61     FF_THREAD_IS_COPY,
  62     FF_THREAD_IS_FIRST_THREAD,
  63     FF_THREAD_NO_FRAME_THREADING,
  64 };
  65
  66 /**
  67  * Allows to synchronize objects whose lifetime is the whole decoding
  68  * process among all frame threads.
  69  *
  70  * When called from a non-copy thread, do nothing.
  71  * When called from another thread, place a new RefStruct reference
  72  * at the given offset in the calling thread's private data from
  73  * the RefStruct reference in the private data of the first decoding thread.
  74  * The first thread must have a valid RefStruct reference at the given
  75  * offset in its private data; the calling thread must not have
  76  * a reference at this offset in its private data (must be NULL).
  77  *
  78  * @param avctx  an AVCodecContext
  79  * @param offset offset of the RefStruct reference in avctx's private data
  80  *
  81  * @retval FF_THREAD_IS_COPY if frame-threading is in use and the
  82  *         calling thread is a copy; in this case, the RefStruct reference
  83  *         will be set.
  84  * @retval FF_THREAD_IS_MAIN_THREAD if frame-threading is in use
  85  *         and the calling thread is the main thread.
  86  * @retval FF_THREAD_NO_FRAME_THREADING if frame-threading is not in use.
  87  */
  88 enum ThreadingStatus ff_thread_sync_ref(AVCodecContext *avctx, size_t offset);
  89
  90 #endif /* AVCODEC_THREAD_H */