FFmpeg: libavcodec/frame_thread_encoder.c Source File
Go to the documentation of this file. 1 /*
2 * Copyright (c) 2012 Michael Niedermayer <michaelni@gmx.at>
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 #include <stdatomic.h>
22
24
34
35 #define MAX_THREADS 64
36 /* There can be as many as MAX_THREADS + 1 outstanding tasks.
37 * An additional + 1 is needed so that one can distinguish
38 * the case of zero and MAX_THREADS + 1 outstanding tasks modulo
39 * the number of buffers. */
40 #define BUFFER_SIZE (MAX_THREADS + 2)
41
49
52
55
61
65
69
70 #define OFF(member) offsetof(ThreadContext, member)
72 (
OFF(task_fifo_mutex),
OFF(finished_task_mutex)),
73 (
OFF(task_fifo_cond),
OFF(finished_task_cond)));
74 #undef OFF
75
79
85 unsigned task_index;
86
88 while (
c->next_task_index ==
c->task_index ||
atomic_load(&
c->exit)) {
91 goto end;
92 }
94 }
95 task_index =
c->next_task_index;
96 c->next_task_index = (
c->next_task_index + 1) %
c->max_tasks;
98 /* The main thread ensures that any two outstanding tasks have
99 * different indices, ergo each worker thread owns its element
100 * of c->tasks with the exception of finished, which is shared
101 * with the main thread and guarded by finished_task_mutex. */
102 task = &
c->tasks[task_index];
105
112 }
113 end:
117 }
118
120 {
125
128 return 0;
129
134 "Forcing thread count to 1 for MJPEG encoding, use -thread_type slice "
135 "or a constant quantizer if you want to use multiple cpu cores\n");
137 }
142 "MJPEG CBR encoding works badly with frame multi-threading, consider "
143 "using -threads 1, -thread_type slice or a constant quantizer.\n");
144
147 int warn = 0;
149
151 warn = 1;
156 }
157 // huffyuv does not support these with multiple frame threads currently
158 if (warn) {
160 "Forcing thread count to 1 for huffyuv encoding with first pass or context 1\n");
162 }
163 }
164
168 }
169
171 return 0;
172
175
180
181 c->parent_avctx = avctx;
182
187
189 for (
unsigned j = 0; j <
c->max_tasks; j++) {
194 }
195 }
196
198 void *tmpv;
200 if (!thread_avctx) {
203 }
205 *thread_avctx = *avctx;
216 }
219
227 }
228 }
229
231
232 return 0;
240 }
241
243 {
245
246 /* In case initializing the mutexes/condition variables failed,
247 * they must not be used. In this case the thread_count is zero
248 * as no thread has been initialized yet. */
254
257 }
258
259 for (
unsigned i = 0;
i <
c->max_tasks;
i++) {
262 }
263
266 }
267
270 {
273
275
278
280 c->task_index = (
c->task_index + 1) %
c->max_tasks;
283 }
284
285 outtask = &
c->tasks[
c->finished_task_index];
287 /* The access to task_index in the following code is ok,
288 * because it is only ever changed by the main thread. */
289 if (
c->task_index ==
c->finished_task_index ||
291 (
c->task_index -
c->finished_task_index +
c->max_tasks) %
c->max_tasks <= avctx->
thread_count)) {
293 return 0;
294 }
297 }
299 /* We now own outtask completely: No worker thread touches it any more,
300 * because there is no outstanding task with this index. */
304 c->finished_task_index = (
c->finished_task_index + 1) %
c->max_tasks;
305
307 }
static av_always_inline int pthread_join(pthread_t thread, void **value_ptr)
#define AV_LOG_WARNING
Something somehow does not look correct.
#define atomic_store(object, desired)
Filter the word "frame" indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
const AVClass * priv_class
AVClass for the private context.
#define AV_CODEC_FLAG_QSCALE
Use fixed qscale.
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
This structure describes decoded (raw) audio or video data.
int capabilities
Codec capabilities.
void * frame_thread_encoder
int ff_encode_encode_cb(AVCodecContext *avctx, AVPacket *avpkt, AVFrame *frame, int *got_packet)
av_cold void ff_pthread_free(void *obj, const unsigned offsets[])
void av_packet_free(AVPacket **pkt)
Free the packet, if the packet is reference counted, it will be unreferenced first.
const struct AVCodec * codec
int thread_count
thread count is used to decide how many independent tasks should be passed to execute()
AVCodecContext * parent_avctx
int flags
AV_CODEC_FLAG_*.
unsigned finished_task_index
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
av_cold int ff_frame_thread_encoder_init(AVCodecContext *avctx)
Initialize frame thread encoder.
AVCodecContext * avcodec_alloc_context3(const AVCodec *codec)
Allocate an AVCodecContext and set its fields to default values.
#define av_assert0(cond)
assert() equivalent, that is always enabled.
int thread_type
Which multithreading methods to use.
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
#define atomic_load(object)
static av_always_inline int pthread_cond_broadcast(pthread_cond_t *cond)
DEFINE_OFFSET_ARRAY(ThreadContext, thread_ctx, pthread_init_cnt,(OFF(task_fifo_mutex), OFF(finished_task_mutex)),(OFF(task_fifo_cond), OFF(finished_task_cond)))
static av_always_inline int pthread_create(pthread_t *thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
int ff_thread_video_encode_frame(AVCodecContext *avctx, AVPacket *pkt, AVFrame *frame, int *got_packet_ptr)
#define AV_CODEC_CAP_FRAME_THREADS
Codec supports frame-level multithreading.
pthread_mutex_t task_fifo_mutex
struct AVCodecInternal * internal
Private context used for internal data.
int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options)
Initialize the AVCodecContext to use the given AVCodec.
int av_opt_get_int(void *obj, const char *name, int search_flags, int64_t *out_val)
void av_packet_move_ref(AVPacket *dst, AVPacket *src)
Move every field in src to dst and reset src.
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
#define pthread_mutex_unlock(a)
int av_opt_copy(void *dst, const void *src)
Copy options from src object into dest object.
#define attribute_align_arg
AVPacket * av_packet_alloc(void)
Allocate an AVPacket and set its fields to default values.
#define FF_THREAD_FRAME
Decode more than one frame at once.
pthread_cond_t finished_task_cond
#define i(width, name, range_min, range_max)
#define av_assert1(cond)
assert() equivalent, that does not lie in speed critical code.
void av_frame_move_ref(AVFrame *dst, AVFrame *src)
Move everything contained in src to dst and reset src.
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
static void *attribute_align_arg worker(void *v)
AVBufferRef * hw_frames_ctx
A reference to the AVHWFramesContext describing the input (for encoding) or output (decoding) frames.
pthread_mutex_t finished_task_mutex
static av_always_inline int pthread_cond_signal(pthread_cond_t *cond)
main external API structure.
int active_thread_type
Which multithreading methods are in use by the codec.
unsigned pthread_init_cnt
av_cold void ff_frame_thread_encoder_free(AVCodecContext *avctx)
av_cold int ff_pthread_init(void *obj, const unsigned offsets[])
Initialize/destroy a list of mutexes/conditions contained in a structure.
static av_always_inline int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
av_cold void ff_codec_close(AVCodecContext *avctx)
This structure stores compressed data.
#define atomic_init(obj, value)
pthread_cond_t task_fifo_cond
#define AV_CODEC_FLAG_PASS1
Use internal 2pass ratecontrol in first pass mode.
#define pthread_mutex_lock(a)
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