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pthread.c
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1 /*
2  * Copyright (c) 2004 Roman Shaposhnik
3  * Copyright (c) 2008 Alexander Strange (astrange@ithinksw.com)
4  *
5  * Many thanks to Steven M. Schultz for providing clever ideas and
6  * to Michael Niedermayer <michaelni@gmx.at> for writing initial
7  * implementation.
8  *
9  * This file is part of FFmpeg.
10  *
11  * FFmpeg is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU Lesser General Public
13  * License as published by the Free Software Foundation; either
14  * version 2.1 of the License, or (at your option) any later version.
15  *
16  * FFmpeg is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19  * Lesser General Public License for more details.
20  *
21  * You should have received a copy of the GNU Lesser General Public
22  * License along with FFmpeg; if not, write to the Free Software
23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24  */
25 
26 /**
27  * @file
28  * Multithreading support functions
29  * @see doc/multithreading.txt
30  */
31 
32 #include "avcodec.h"
33 #include "internal.h"
34 #include "pthread_internal.h"
35 #include "thread.h"
36 
37 /**
38  * Set the threading algorithms used.
39  *
40  * Threading requires more than one thread.
41  * Frame threading requires entire frames to be passed to the codec,
42  * and introduces extra decoding delay, so is incompatible with low_delay.
43  *
44  * @param avctx The context.
45  */
47 {
48  int frame_threading_supported = (avctx->codec->capabilities & CODEC_CAP_FRAME_THREADS)
49  && !(avctx->flags & CODEC_FLAG_TRUNCATED)
50  && !(avctx->flags & CODEC_FLAG_LOW_DELAY)
51  && !(avctx->flags2 & CODEC_FLAG2_CHUNKS);
52  if (avctx->thread_count == 1) {
53  avctx->active_thread_type = 0;
54  } else if (frame_threading_supported && (avctx->thread_type & FF_THREAD_FRAME)) {
56  } else if (avctx->codec->capabilities & CODEC_CAP_SLICE_THREADS &&
57  avctx->thread_type & FF_THREAD_SLICE) {
59  } else if (!(avctx->codec->capabilities & CODEC_CAP_AUTO_THREADS)) {
60  avctx->thread_count = 1;
61  avctx->active_thread_type = 0;
62  }
63 
64  if (avctx->thread_count > MAX_AUTO_THREADS)
65  av_log(avctx, AV_LOG_WARNING,
66  "Application has requested %d threads. Using a thread count greater than %d is not recommended.\n",
68 }
69 
71 {
73 
75  return ff_slice_thread_init(avctx);
76  else if (avctx->active_thread_type&FF_THREAD_FRAME)
77  return ff_frame_thread_init(avctx);
78 
79  return 0;
80 }
81 
83 {
85  ff_frame_thread_free(avctx, avctx->thread_count);
86  else
87  ff_slice_thread_free(avctx);
88 }