/*
* Generic frame queue
* Copyright (c) 2016 Nicolas George
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVFILTER_FRAMEQUEUE_H
#define AVFILTER_FRAMEQUEUE_H
/**
* FFFrameQueue: simple AVFrame queue API
*
* Note: this API is not thread-safe. Concurrent access to the same queue
* must be protected by a mutex or any synchronization mechanism.
*/
#include "libavutil/frame.h"
typedef struct FFFrameBucket {
AVFrame *frame;
} FFFrameBucket;
/**
* Structure to hold global options and statistics for frame queues.
*
* This structure is intended to allow implementing global control of the
* frame queues, including memory consumption caps.
*
* It is currently empty.
*/
typedef struct FFFrameQueueGlobal {
char dummy; /* C does not allow empty structs */
} FFFrameQueueGlobal;
/**
* Queue of AVFrame pointers.
*/
typedef struct FFFrameQueue {
/**
* Array of allocated buckets, used as a circular buffer.
*/
FFFrameBucket *queue;
/**
* Size of the array of buckets.
*/
size_t allocated;
/**
* Tail of the queue.
* It is the index in the array of the next frame to take.
*/
size_t tail;
/**
* Number of currently queued frames.
*/
size_t queued;
/**
* Pre-allocated bucket for queues of size 1.
*/
FFFrameBucket first_bucket;
/**
* Total number of frames entered in the queue.
*/
uint64_t total_frames_head;
/**
* Total number of frames dequeued from the queue.
* queued = total_frames_head - total_frames_tail
*/
uint64_t total_frames_tail;
/**
* Total number of samples entered in the queue.
*/
uint64_t total_samples_head;
/**
* Total number of samples dequeued from the queue.
* queued_samples = total_samples_head - total_samples_tail
*/
uint64_t total_samples_tail;
/**
* Indicate that samples are skipped
*/
int samples_skipped;
} FFFrameQueue;
/**
* Init a global structure.
*/
void ff_framequeue_global_init(FFFrameQueueGlobal *fqg);
/**
* Init a frame queue and attach it to a global structure.
*/
void ff_framequeue_init(FFFrameQueue *fq, FFFrameQueueGlobal *fqg);
/**
* Free the queue and all queued frames.
*/
void ff_framequeue_free(FFFrameQueue *fq);
/**
* Add a frame.
* @return >=0 or an AVERROR code.
*/
int ff_framequeue_add(FFFrameQueue *fq, AVFrame *frame);
/**
* Take the first frame in the queue.
* Must not be used with empty queues.
*/
AVFrame *ff_framequeue_take(FFFrameQueue *fq);
/**
* Access a frame in the queue, without removing it.
* The first frame is numbered 0; the designated frame must exist.
*/
AVFrame *ff_framequeue_peek(FFFrameQueue *fq, size_t idx);
/**
* Get the number of queued frames.
*/
static inline size_t ff_framequeue_queued_frames(const FFFrameQueue *fq)
{
return fq->queued;
}
/**
* Get the number of queued samples.
*/
static inline uint64_t ff_framequeue_queued_samples(const FFFrameQueue *fq)
{
return fq->total_samples_head - fq->total_samples_tail;
}
/**
* Update the statistics after a frame accessed using ff_framequeue_peek()
* was modified.
* Currently used only as a marker.
*/
static inline void ff_framequeue_update_peeked(FFFrameQueue *fq, size_t idx)
{
}
/**
* Skip samples from the first frame in the queue.
*
* This function must be used when the first frame was accessed using
* ff_framequeue_peek() and samples were consumed from it.
* It adapts the data pointers and timestamps of the head frame to account
* for the skipped samples.
*/
void ff_framequeue_skip_samples(FFFrameQueue *fq, size_t samples, AVRational time_base);
#endif /* AVFILTER_FRAMEQUEUE_H */