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 "libavutil/thread.h"
33
34 #include "avcodec.h"
35 #include "codec_internal.h"
36 #include "pthread_internal.h"
37 #include "thread.h"
38
39 /**
40 * Set the threading algorithms used.
41 *
42 * Threading requires more than one thread.
43 * Frame threading requires entire frames to be passed to the codec,
44 * and introduces extra decoding delay, so is incompatible with low_delay.
45 *
46 * @param avctx The context.
47 */
validate_thread_parameters(AVCodecContext *avctx)48 static void validate_thread_parameters(AVCodecContext *avctx)
49 {
50 int frame_threading_supported = (avctx->codec->capabilities & AV_CODEC_CAP_FRAME_THREADS)
51 #if FF_API_FLAG_TRUNCATED
52 && !(avctx->flags & AV_CODEC_FLAG_TRUNCATED)
53 #endif
54 && !(avctx->flags & AV_CODEC_FLAG_LOW_DELAY)
55 && !(avctx->flags2 & AV_CODEC_FLAG2_CHUNKS);
56 if (avctx->thread_count == 1) {
57 avctx->active_thread_type = 0;
58 } else if (frame_threading_supported && (avctx->thread_type & FF_THREAD_FRAME)) {
59 avctx->active_thread_type = FF_THREAD_FRAME;
60 } else if (avctx->codec->capabilities & AV_CODEC_CAP_SLICE_THREADS &&
61 avctx->thread_type & FF_THREAD_SLICE) {
62 avctx->active_thread_type = FF_THREAD_SLICE;
63 } else if (!(ffcodec(avctx->codec)->caps_internal & FF_CODEC_CAP_AUTO_THREADS)) {
64 avctx->thread_count = 1;
65 avctx->active_thread_type = 0;
66 }
67
68 if (avctx->thread_count > MAX_AUTO_THREADS)
69 av_log(avctx, AV_LOG_WARNING,
70 "Application has requested %d threads. Using a thread count greater than %d is not recommended.\n",
71 avctx->thread_count, MAX_AUTO_THREADS);
72 }
73
ff_thread_init(AVCodecContext *avctx)74 int ff_thread_init(AVCodecContext *avctx)
75 {
76 validate_thread_parameters(avctx);
77
78 if (avctx->active_thread_type&FF_THREAD_SLICE)
79 return ff_slice_thread_init(avctx);
80 else if (avctx->active_thread_type&FF_THREAD_FRAME)
81 return ff_frame_thread_init(avctx);
82
83 return 0;
84 }
85
ff_thread_free(AVCodecContext *avctx)86 void ff_thread_free(AVCodecContext *avctx)
87 {
88 if (avctx->active_thread_type&FF_THREAD_FRAME)
89 ff_frame_thread_free(avctx, avctx->thread_count);
90 else
91 ff_slice_thread_free(avctx);
92 }
93
ff_pthread_free(void *obj, const unsigned offsets[])94 av_cold void ff_pthread_free(void *obj, const unsigned offsets[])
95 {
96 unsigned cnt = *(unsigned*)((char*)obj + offsets[0]);
97 const unsigned *cur_offset = offsets;
98
99 *(unsigned*)((char*)obj + offsets[0]) = 0;
100
101 for (; *(++cur_offset) != THREAD_SENTINEL && cnt; cnt--)
102 pthread_mutex_destroy((pthread_mutex_t*)((char*)obj + *cur_offset));
103 for (; *(++cur_offset) != THREAD_SENTINEL && cnt; cnt--)
104 pthread_cond_destroy ((pthread_cond_t *)((char*)obj + *cur_offset));
105 }
106
ff_pthread_init(void *obj, const unsigned offsets[])107 av_cold int ff_pthread_init(void *obj, const unsigned offsets[])
108 {
109 const unsigned *cur_offset = offsets;
110 unsigned cnt = 0;
111 int err;
112
113 #define PTHREAD_INIT_LOOP(type) \
114 for (; *(++cur_offset) != THREAD_SENTINEL; cnt++) { \
115 pthread_ ## type ## _t *dst = (void*)((char*)obj + *cur_offset); \
116 err = pthread_ ## type ## _init(dst, NULL); \
117 if (err) { \
118 err = AVERROR(err); \
119 goto fail; \
120 } \
121 }
122 PTHREAD_INIT_LOOP(mutex)
123 PTHREAD_INIT_LOOP(cond)
124
125 fail:
126 *(unsigned*)((char*)obj + offsets[0]) = cnt;
127 return err;
128 }
129