FFmpeg
frame_thread_encoder.c
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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 
23 #include "frame_thread_encoder.h"
24 
25 #include "libavutil/avassert.h"
26 #include "libavutil/cpu.h"
27 #include "libavutil/opt.h"
28 #include "libavutil/thread.h"
29 #include "avcodec.h"
30 #include "avcodec_internal.h"
31 #include "encode.h"
32 #include "internal.h"
33 #include "pthread_internal.h"
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 
42 typedef struct{
46  int finished;
48 } Task;
49 
50 typedef struct{
52 
53  pthread_mutex_t task_fifo_mutex; /* Used to guard (next_)task_index */
55 
56  unsigned pthread_init_cnt;
57  unsigned max_tasks;
58  Task tasks[BUFFER_SIZE];
59  pthread_mutex_t finished_task_mutex; /* Guards tasks[i].finished */
61 
62  unsigned next_task_index;
63  unsigned task_index;
65 
69 
70 #define OFF(member) offsetof(ThreadContext, member)
71 DEFINE_OFFSET_ARRAY(ThreadContext, thread_ctx, pthread_init_cnt,
72  (OFF(task_fifo_mutex), OFF(finished_task_mutex)),
73  (OFF(task_fifo_cond), OFF(finished_task_cond)));
74 #undef OFF
75 
76 static void * attribute_align_arg worker(void *v){
77  AVCodecContext *avctx = v;
79 
80  while (!atomic_load(&c->exit)) {
81  int ret;
82  AVPacket *pkt;
83  AVFrame *frame;
84  Task *task;
85  unsigned task_index;
86 
87  pthread_mutex_lock(&c->task_fifo_mutex);
88  while (c->next_task_index == c->task_index || atomic_load(&c->exit)) {
89  if (atomic_load(&c->exit)) {
90  pthread_mutex_unlock(&c->task_fifo_mutex);
91  goto end;
92  }
93  pthread_cond_wait(&c->task_fifo_cond, &c->task_fifo_mutex);
94  }
95  task_index = c->next_task_index;
96  c->next_task_index = (c->next_task_index + 1) % c->max_tasks;
97  pthread_mutex_unlock(&c->task_fifo_mutex);
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];
103  frame = task->indata;
104  pkt = task->outdata;
105 
106  ret = ff_encode_encode_cb(avctx, pkt, frame, &task->got_packet);
107  pthread_mutex_lock(&c->finished_task_mutex);
108  task->return_code = ret;
109  task->finished = 1;
110  pthread_cond_signal(&c->finished_task_cond);
111  pthread_mutex_unlock(&c->finished_task_mutex);
112  }
113 end:
114  ff_codec_close(avctx);
115  av_freep(&avctx);
116  return NULL;
117 }
118 
120 {
121  int i=0;
122  ThreadContext *c;
123  AVCodecContext *thread_avctx = NULL;
124  int ret;
125 
126  if( !(avctx->thread_type & FF_THREAD_FRAME)
128  return 0;
129 
130  if( !avctx->thread_count
131  && avctx->codec_id == AV_CODEC_ID_MJPEG
132  && !(avctx->flags & AV_CODEC_FLAG_QSCALE)) {
133  av_log(avctx, AV_LOG_DEBUG,
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");
136  avctx->thread_count = 1;
137  }
138  if( avctx->thread_count > 1
139  && avctx->codec_id == AV_CODEC_ID_MJPEG
140  && !(avctx->flags & AV_CODEC_FLAG_QSCALE))
141  av_log(avctx, AV_LOG_WARNING,
142  "MJPEG CBR encoding works badly with frame multi-threading, consider "
143  "using -threads 1, -thread_type slice or a constant quantizer.\n");
144 
145  if (avctx->codec_id == AV_CODEC_ID_HUFFYUV ||
146  avctx->codec_id == AV_CODEC_ID_FFVHUFF) {
147  int warn = 0;
148  int64_t tmp;
149 
150  if (avctx->flags & AV_CODEC_FLAG_PASS1)
151  warn = 1;
152  else if (av_opt_get_int(avctx->priv_data, "context", 0, &tmp) >= 0 &&
153  tmp > 0) {
154  warn = av_opt_get_int(avctx->priv_data, "non_deterministic", 0, &tmp) < 0
155  || !tmp;
156  }
157  // huffyuv does not support these with multiple frame threads currently
158  if (warn) {
159  av_log(avctx, AV_LOG_WARNING,
160  "Forcing thread count to 1 for huffyuv encoding with first pass or context 1\n");
161  avctx->thread_count = 1;
162  }
163  }
164 
165  if(!avctx->thread_count) {
166  avctx->thread_count = av_cpu_count();
167  avctx->thread_count = FFMIN(avctx->thread_count, MAX_THREADS);
168  }
169 
170  if(avctx->thread_count <= 1)
171  return 0;
172 
173  if(avctx->thread_count > MAX_THREADS)
174  return AVERROR(EINVAL);
175 
178  if(!c)
179  return AVERROR(ENOMEM);
180 
181  c->parent_avctx = avctx;
182 
183  ret = ff_pthread_init(c, thread_ctx_offsets);
184  if (ret < 0)
185  goto fail;
186  atomic_init(&c->exit, 0);
187 
188  c->max_tasks = avctx->thread_count + 2;
189  for (unsigned j = 0; j < c->max_tasks; j++) {
190  if (!(c->tasks[j].indata = av_frame_alloc()) ||
191  !(c->tasks[j].outdata = av_packet_alloc())) {
192  ret = AVERROR(ENOMEM);
193  goto fail;
194  }
195  }
196 
197  for(i=0; i<avctx->thread_count ; i++){
198  void *tmpv;
199  thread_avctx = avcodec_alloc_context3(avctx->codec);
200  if (!thread_avctx) {
201  ret = AVERROR(ENOMEM);
202  goto fail;
203  }
204  tmpv = thread_avctx->priv_data;
205  *thread_avctx = *avctx;
206  thread_avctx->priv_data = tmpv;
207  thread_avctx->internal = NULL;
208  thread_avctx->hw_frames_ctx = NULL;
209  ret = av_opt_copy(thread_avctx, avctx);
210  if (ret < 0)
211  goto fail;
212  if (avctx->codec->priv_class) {
213  ret = av_opt_copy(thread_avctx->priv_data, avctx->priv_data);
214  if (ret < 0)
215  goto fail;
216  }
217  thread_avctx->thread_count = 1;
218  thread_avctx->active_thread_type &= ~FF_THREAD_FRAME;
219 
220  if ((ret = avcodec_open2(thread_avctx, avctx->codec, NULL)) < 0)
221  goto fail;
222  av_assert0(!thread_avctx->internal->frame_thread_encoder);
223  thread_avctx->internal->frame_thread_encoder = c;
224  if ((ret = pthread_create(&c->worker[i], NULL, worker, thread_avctx))) {
225  ret = AVERROR(ret);
226  goto fail;
227  }
228  }
229 
231 
232  return 0;
233 fail:
234  ff_codec_close(thread_avctx);
235  av_freep(&thread_avctx);
236  avctx->thread_count = i;
237  av_log(avctx, AV_LOG_ERROR, "ff_frame_thread_encoder_init failed\n");
239  return ret;
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. */
249  if (avctx->thread_count > 0) {
250  pthread_mutex_lock(&c->task_fifo_mutex);
251  atomic_store(&c->exit, 1);
252  pthread_cond_broadcast(&c->task_fifo_cond);
253  pthread_mutex_unlock(&c->task_fifo_mutex);
254 
255  for (int i = 0; i < avctx->thread_count; i++)
256  pthread_join(c->worker[i], NULL);
257  }
258 
259  for (unsigned i = 0; i < c->max_tasks; i++) {
260  av_frame_free(&c->tasks[i].indata);
261  av_packet_free(&c->tasks[i].outdata);
262  }
263 
264  ff_pthread_free(c, thread_ctx_offsets);
266 }
267 
269  AVFrame *frame, int *got_packet_ptr)
270 {
272  Task *outtask;
273 
274  av_assert1(!*got_packet_ptr);
275 
276  if(frame){
277  av_frame_move_ref(c->tasks[c->task_index].indata, frame);
278 
279  pthread_mutex_lock(&c->task_fifo_mutex);
280  c->task_index = (c->task_index + 1) % c->max_tasks;
281  pthread_cond_signal(&c->task_fifo_cond);
282  pthread_mutex_unlock(&c->task_fifo_mutex);
283  }
284 
285  outtask = &c->tasks[c->finished_task_index];
286  pthread_mutex_lock(&c->finished_task_mutex);
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 ||
290  (frame && !outtask->finished &&
291  (c->task_index - c->finished_task_index + c->max_tasks) % c->max_tasks <= avctx->thread_count)) {
292  pthread_mutex_unlock(&c->finished_task_mutex);
293  return 0;
294  }
295  while (!outtask->finished) {
296  pthread_cond_wait(&c->finished_task_cond, &c->finished_task_mutex);
297  }
298  pthread_mutex_unlock(&c->finished_task_mutex);
299  /* We now own outtask completely: No worker thread touches it any more,
300  * because there is no outstanding task with this index. */
301  outtask->finished = 0;
302  av_packet_move_ref(pkt, outtask->outdata);
303  *got_packet_ptr = outtask->got_packet;
304  c->finished_task_index = (c->finished_task_index + 1) % c->max_tasks;
305 
306  return outtask->return_code;
307 }
pthread_mutex_t
_fmutex pthread_mutex_t
Definition: os2threads.h:53
pthread_join
static av_always_inline int pthread_join(pthread_t thread, void **value_ptr)
Definition: os2threads.h:94
AV_LOG_WARNING
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:186
atomic_store
#define atomic_store(object, desired)
Definition: stdatomic.h:85
AVERROR
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
opt.h
AV_CODEC_ID_HUFFYUV
@ AV_CODEC_ID_HUFFYUV
Definition: codec_id.h:77
Task::finished
int finished
Definition: frame_thread_encoder.c:46
AVCodec::priv_class
const AVClass * priv_class
AVClass for the private context.
Definition: codec.h:212
thread.h
AV_CODEC_FLAG_QSCALE
#define AV_CODEC_FLAG_QSCALE
Use fixed qscale.
Definition: avcodec.h:224
BUFFER_SIZE
#define BUFFER_SIZE
Definition: frame_thread_encoder.c:40
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:88
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:340
tmp
static uint8_t tmp[11]
Definition: aes_ctr.c:28
AVCodec::capabilities
int capabilities
Codec capabilities.
Definition: codec.h:206
internal.h
AVCodecInternal::frame_thread_encoder
void * frame_thread_encoder
Definition: internal.h:89
encode.h
atomic_int
intptr_t atomic_int
Definition: stdatomic.h:55
ff_encode_encode_cb
int ff_encode_encode_cb(AVCodecContext *avctx, AVPacket *avpkt, AVFrame *frame, int *got_packet)
Definition: encode.c:247
ff_pthread_free
av_cold void ff_pthread_free(void *obj, const unsigned offsets[])
Definition: pthread.c:91
av_packet_free
void av_packet_free(AVPacket **pkt)
Free the packet, if the packet is reference counted, it will be unreferenced first.
Definition: avpacket.c:74
AVCodecContext::codec
const struct AVCodec * codec
Definition: avcodec.h:454
fail
#define fail()
Definition: checkasm.h:179
AVCodecContext::thread_count
int thread_count
thread count is used to decide how many independent tasks should be passed to execute()
Definition: avcodec.h:1582
ThreadContext::parent_avctx
AVCodecContext * parent_avctx
Definition: frame_thread_encoder.c:51
AVCodecContext::flags
int flags
AV_CODEC_FLAG_*.
Definition: avcodec.h:502
MAX_THREADS
#define MAX_THREADS
Definition: frame_thread_encoder.c:35
Task::outdata
AVPacket * outdata
Definition: frame_thread_encoder.c:44
ThreadContext::finished_task_index
unsigned finished_task_index
Definition: frame_thread_encoder.c:64
av_frame_alloc
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:76
avassert.h
pkt
AVPacket * pkt
Definition: movenc.c:59
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
frame_thread_encoder.h
av_cold
#define av_cold
Definition: attributes.h:90
ff_frame_thread_encoder_init
av_cold int ff_frame_thread_encoder_init(AVCodecContext *avctx)
Initialize frame thread encoder.
Definition: frame_thread_encoder.c:119
avcodec_alloc_context3
AVCodecContext * avcodec_alloc_context3(const AVCodec *codec)
Allocate an AVCodecContext and set its fields to default values.
Definition: options.c:149
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:40
AVCodecContext::thread_type
int thread_type
Which multithreading methods to use.
Definition: avcodec.h:1592
ThreadContext::exit
atomic_int exit
Definition: frame_thread_encoder.c:67
AV_LOG_DEBUG
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:201
AV_CODEC_ID_FFVHUFF
@ AV_CODEC_ID_FFVHUFF
Definition: codec_id.h:119
atomic_load
#define atomic_load(object)
Definition: stdatomic.h:93
pthread_cond_broadcast
static av_always_inline int pthread_cond_broadcast(pthread_cond_t *cond)
Definition: os2threads.h:162
DEFINE_OFFSET_ARRAY
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)))
frame
static AVFrame * frame
Definition: demux_decode.c:54
AVCodecContext::codec_id
enum AVCodecID codec_id
Definition: avcodec.h:455
pthread_create
static av_always_inline int pthread_create(pthread_t *thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
Definition: os2threads.h:80
ff_thread_video_encode_frame
int ff_thread_video_encode_frame(AVCodecContext *avctx, AVPacket *pkt, AVFrame *frame, int *got_packet_ptr)
Definition: frame_thread_encoder.c:268
AV_CODEC_CAP_FRAME_THREADS
#define AV_CODEC_CAP_FRAME_THREADS
Codec supports frame-level multithreading.
Definition: codec.h:110
ThreadContext::task_fifo_mutex
pthread_mutex_t task_fifo_mutex
Definition: frame_thread_encoder.c:53
NULL
#define NULL
Definition: coverity.c:32
AVCodecContext::internal
struct AVCodecInternal * internal
Private context used for internal data.
Definition: avcodec.h:480
pthread_internal.h
avcodec_open2
int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *codec, AVDictionary **options)
Initialize the AVCodecContext to use the given AVCodec.
Definition: avcodec.c:128
av_opt_get_int
int av_opt_get_int(void *obj, const char *name, int search_flags, int64_t *out_val)
Definition: opt.c:1203
av_packet_move_ref
void av_packet_move_ref(AVPacket *dst, AVPacket *src)
Move every field in src to dst and reset src.
Definition: avpacket.c:484
c
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
Definition: undefined.txt:32
pthread_mutex_unlock
#define pthread_mutex_unlock(a)
Definition: ffprobe.c:81
av_opt_copy
int av_opt_copy(void *dst, const void *src)
Copy options from src object into dest object.
Definition: opt.c:2105
av_cpu_count
int av_cpu_count(void)
Definition: cpu.c:209
attribute_align_arg
#define attribute_align_arg
Definition: internal.h:50
Task::indata
AVFrame * indata
Definition: frame_thread_encoder.c:43
cpu.h
ThreadContext::next_task_index
unsigned next_task_index
Definition: frame_thread_encoder.c:62
ThreadContext::task_index
unsigned task_index
Definition: frame_thread_encoder.c:63
av_packet_alloc
AVPacket * av_packet_alloc(void)
Allocate an AVPacket and set its fields to default values.
Definition: avpacket.c:63
pthread_t
Definition: os2threads.h:44
FF_THREAD_FRAME
#define FF_THREAD_FRAME
Decode more than one frame at once.
Definition: avcodec.h:1593
AV_CODEC_ID_MJPEG
@ AV_CODEC_ID_MJPEG
Definition: codec_id.h:59
ThreadContext::finished_task_cond
pthread_cond_t finished_task_cond
Definition: frame_thread_encoder.c:60
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:255
av_assert1
#define av_assert1(cond)
assert() equivalent, that does not lie in speed critical code.
Definition: avassert.h:56
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
av_frame_move_ref
void av_frame_move_ref(AVFrame *dst, AVFrame *src)
Move everything contained in src to dst and reset src.
Definition: frame.c:561
av_mallocz
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:254
pthread_cond_t
Definition: os2threads.h:58
worker
static void *attribute_align_arg worker(void *v)
Definition: frame_thread_encoder.c:76
OFF
#define OFF(member)
Definition: frame_thread_encoder.c:70
AVCodecContext::hw_frames_ctx
AVBufferRef * hw_frames_ctx
A reference to the AVHWFramesContext describing the input (for encoding) or output (decoding) frames.
Definition: avcodec.h:1475
avcodec.h
ThreadContext::finished_task_mutex
pthread_mutex_t finished_task_mutex
Definition: frame_thread_encoder.c:59
ret
ret
Definition: filter_design.txt:187
pthread_cond_signal
static av_always_inline int pthread_cond_signal(pthread_cond_t *cond)
Definition: os2threads.h:152
AVCodecContext
main external API structure.
Definition: avcodec.h:445
AVCodecContext::active_thread_type
int active_thread_type
Which multithreading methods are in use by the codec.
Definition: avcodec.h:1601
ThreadContext
Definition: frame_thread_encoder.c:50
avcodec_internal.h
ThreadContext::pthread_init_cnt
unsigned pthread_init_cnt
Definition: frame_thread_encoder.c:56
ff_frame_thread_encoder_free
av_cold void ff_frame_thread_encoder_free(AVCodecContext *avctx)
Definition: frame_thread_encoder.c:242
ff_pthread_init
av_cold int ff_pthread_init(void *obj, const unsigned offsets[])
Initialize/destroy a list of mutexes/conditions contained in a structure.
Definition: pthread.c:104
pthread_cond_wait
static av_always_inline int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
Definition: os2threads.h:192
ThreadContext::max_tasks
unsigned max_tasks
Definition: frame_thread_encoder.c:57
ff_codec_close
av_cold void ff_codec_close(AVCodecContext *avctx)
Definition: avcodec.c:401
Task::got_packet
int got_packet
Definition: frame_thread_encoder.c:47
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:472
AVPacket
This structure stores compressed data.
Definition: packet.h:499
Task::return_code
int return_code
Definition: frame_thread_encoder.c:45
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:34
Task
Definition: frame_thread_encoder.c:42
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
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#define atomic_init(obj, value)
Definition: stdatomic.h:33
ThreadContext::task_fifo_cond
pthread_cond_t task_fifo_cond
Definition: frame_thread_encoder.c:54
AV_CODEC_FLAG_PASS1
#define AV_CODEC_FLAG_PASS1
Use internal 2pass ratecontrol in first pass mode.
Definition: avcodec.h:310
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#define pthread_mutex_lock(a)
Definition: ffprobe.c:77