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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 & AV_CODEC_CAP_FRAME_THREADS)
49  && !(avctx->flags & AV_CODEC_FLAG_TRUNCATED)
50  && !(avctx->flags & AV_CODEC_FLAG_LOW_DELAY)
51  && !(avctx->flags2 & AV_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 & AV_CODEC_CAP_SLICE_THREADS &&
57  avctx->thread_type & FF_THREAD_SLICE) {
59  } else if (!(avctx->codec->capabilities & AV_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 }
const struct AVCodec * codec
Definition: avcodec.h:1497
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
void ff_slice_thread_free(AVCodecContext *avctx)
Definition: pthread_slice.c:77
#define AV_CODEC_FLAG2_CHUNKS
Input bitstream might be truncated at a packet boundaries instead of only at frame boundaries...
Definition: avcodec.h:917
#define AV_CODEC_CAP_AUTO_THREADS
Codec supports avctx->thread_count == 0 (auto).
Definition: avcodec.h:1024
static void validate_thread_parameters(AVCodecContext *avctx)
Set the threading algorithms used.
Definition: pthread.c:46
Multithreading support functions.
#define AV_CODEC_FLAG_LOW_DELAY
Force low delay.
Definition: avcodec.h:875
int ff_thread_init(AVCodecContext *avctx)
Definition: pthread.c:70
#define av_log(a,...)
AVCodecContext * avctx
Definition: psymodel.c:94
void ff_frame_thread_free(AVCodecContext *avctx, int thread_count)
int active_thread_type
Which multithreading methods are in use by the codec.
Definition: avcodec.h:2758
int capabilities
Codec capabilities.
Definition: avcodec.h:3370
int flags
AV_CODEC_FLAG_*.
Definition: avcodec.h:1568
void ff_thread_free(AVCodecContext *avctx)
Definition: pthread.c:82
#define AV_CODEC_CAP_FRAME_THREADS
Codec supports frame-level multithreading.
Definition: avcodec.h:1012
#define FF_THREAD_FRAME
Decode more than one frame at once.
Definition: avcodec.h:2750
#define FF_THREAD_SLICE
Decode more than one part of a single frame at once.
Definition: avcodec.h:2751
int thread_count
thread count is used to decide how many independent tasks should be passed to execute() ...
Definition: avcodec.h:2739
#define AV_CODEC_CAP_SLICE_THREADS
Codec supports slice-based (or partition-based) multithreading.
Definition: avcodec.h:1016
Libavcodec external API header.
main external API structure.
Definition: avcodec.h:1488
int ff_slice_thread_init(AVCodecContext *avctx)
#define MAX_AUTO_THREADS
common internal api header.
int flags2
AV_CODEC_FLAG2_*.
Definition: avcodec.h:1575
#define AV_CODEC_FLAG_TRUNCATED
Input bitstream might be truncated at a random location instead of only at frame boundaries.
Definition: avcodec.h:867
int ff_frame_thread_init(AVCodecContext *avctx)
int thread_type
Which multithreading methods to use.
Definition: avcodec.h:2749