FFmpeg
framequeue.h
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1 /*
2  * Generic frame queue
3  * Copyright (c) 2016 Nicolas George
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public License
9  * as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15  * GNU Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public License
18  * along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #ifndef AVFILTER_FRAMEQUEUE_H
23 #define AVFILTER_FRAMEQUEUE_H
24 
25 /**
26  * FFFrameQueue: simple AVFrame queue API
27  *
28  * Note: this API is not thread-safe. Concurrent access to the same queue
29  * must be protected by a mutex or any synchronization mechanism.
30  */
31 
32 #include "libavutil/frame.h"
33 
34 typedef struct FFFrameBucket {
37 
38 /**
39  * Structure to hold global options and statistics for frame queues.
40  *
41  * This structure is intended to allow implementing global control of the
42  * frame queues, including memory consumption caps.
43  *
44  * It is currently empty.
45  */
46 typedef struct FFFrameQueueGlobal {
47  char dummy; /* C does not allow empty structs */
49 
50 /**
51  * Queue of AVFrame pointers.
52  */
53 typedef struct FFFrameQueue {
54 
55  /**
56  * Array of allocated buckets, used as a circular buffer.
57  */
59 
60  /**
61  * Size of the array of buckets.
62  */
63  size_t allocated;
64 
65  /**
66  * Tail of the queue.
67  * It is the index in the array of the next frame to take.
68  */
69  size_t tail;
70 
71  /**
72  * Number of currently queued frames.
73  */
74  size_t queued;
75 
76  /**
77  * Pre-allocated bucket for queues of size 1.
78  */
80 
81  /**
82  * Total number of frames entered in the queue.
83  */
85 
86  /**
87  * Total number of frames dequeued from the queue.
88  * queued = total_frames_head - total_frames_tail
89  */
91 
92  /**
93  * Total number of samples entered in the queue.
94  */
96 
97  /**
98  * Total number of samples dequeued from the queue.
99  * queued_samples = total_samples_head - total_samples_tail
100  */
102 
103  /**
104  * Indicate that samples are skipped
105  */
107 
108 } FFFrameQueue;
109 
110 /**
111  * Init a global structure.
112  */
114 
115 /**
116  * Init a frame queue and attach it to a global structure.
117  */
119 
120 /**
121  * Free the queue and all queued frames.
122  */
124 
125 /**
126  * Add a frame.
127  * @return >=0 or an AVERROR code.
128  */
130 
131 /**
132  * Take the first frame in the queue.
133  * Must not be used with empty queues.
134  */
136 
137 /**
138  * Access a frame in the queue, without removing it.
139  * The first frame is numbered 0; the designated frame must exist.
140  */
141 AVFrame *ff_framequeue_peek(FFFrameQueue *fq, size_t idx);
142 
143 /**
144  * Get the number of queued frames.
145  */
146 static inline size_t ff_framequeue_queued_frames(const FFFrameQueue *fq)
147 {
148  return fq->queued;
149 }
150 
151 /**
152  * Get the number of queued samples.
153  */
154 static inline uint64_t ff_framequeue_queued_samples(const FFFrameQueue *fq)
155 {
156  return fq->total_samples_head - fq->total_samples_tail;
157 }
158 
159 /**
160  * Update the statistics after a frame accessed using ff_framequeue_peek()
161  * was modified.
162  * Currently used only as a marker.
163  */
164 static inline void ff_framequeue_update_peeked(FFFrameQueue *fq, size_t idx)
165 {
166 }
167 
168 /**
169  * Skip samples from the first frame in the queue.
170  *
171  * This function must be used when the first frame was accessed using
172  * ff_framequeue_peek() and samples were consumed from it.
173  * It adapts the data pointers and timestamps of the head frame to account
174  * for the skipped samples.
175  */
176 void ff_framequeue_skip_samples(FFFrameQueue *fq, size_t samples, AVRational time_base);
177 
178 #endif /* AVFILTER_FRAMEQUEUE_H */
This structure describes decoded (raw) audio or video data.
Definition: frame.h:295
uint64_t total_frames_head
Total number of frames entered in the queue.
Definition: framequeue.h:84
Queue of AVFrame pointers.
Definition: framequeue.h:53
size_t allocated
Size of the array of buckets.
Definition: framequeue.h:63
uint64_t total_samples_head
Total number of samples entered in the queue.
Definition: framequeue.h:95
void ff_framequeue_skip_samples(FFFrameQueue *fq, size_t samples, AVRational time_base)
Skip samples from the first frame in the queue.
Definition: framequeue.c:126
uint64_t total_frames_tail
Total number of frames dequeued from the queue.
Definition: framequeue.h:90
reference-counted frame API
size_t tail
Tail of the queue.
Definition: framequeue.h:69
void ff_framequeue_global_init(FFFrameQueueGlobal *fqg)
Init a global structure.
Definition: framequeue.c:30
AVFrame * ff_framequeue_peek(FFFrameQueue *fq, size_t idx)
Access a frame in the queue, without removing it.
Definition: framequeue.c:115
void ff_framequeue_init(FFFrameQueue *fq, FFFrameQueueGlobal *fqg)
Init a frame queue and attach it to a global structure.
Definition: framequeue.c:47
uint64_t total_samples_tail
Total number of samples dequeued from the queue.
Definition: framequeue.h:101
size_t queued
Number of currently queued frames.
Definition: framequeue.h:74
Rational number (pair of numerator and denominator).
Definition: rational.h:58
int samples_skipped
Indicate that samples are skipped.
Definition: framequeue.h:106
static uint64_t ff_framequeue_queued_samples(const FFFrameQueue *fq)
Get the number of queued samples.
Definition: framequeue.h:154
FFFrameBucket * queue
Array of allocated buckets, used as a circular buffer.
Definition: framequeue.h:58
static size_t ff_framequeue_queued_frames(const FFFrameQueue *fq)
Get the number of queued frames.
Definition: framequeue.h:146
void ff_framequeue_free(FFFrameQueue *fq)
Free the queue and all queued frames.
Definition: framequeue.c:53
static void ff_framequeue_update_peeked(FFFrameQueue *fq, size_t idx)
Update the statistics after a frame accessed using ff_framequeue_peek() was modified.
Definition: framequeue.h:164
FFFrameBucket first_bucket
Pre-allocated bucket for queues of size 1.
Definition: framequeue.h:79
Filter the word “frame” indicates either a video frame or a group of audio samples
int ff_framequeue_add(FFFrameQueue *fq, AVFrame *frame)
Add a frame.
Definition: framequeue.c:63
AVFrame * ff_framequeue_take(FFFrameQueue *fq)
Take the first frame in the queue.
Definition: framequeue.c:98
Structure to hold global options and statistics for frame queues.
Definition: framequeue.h:46
AVFrame * frame
Definition: framequeue.h:35
FFFrameQueue: simple AVFrame queue API.
Definition: framequeue.h:34