/* * 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; } 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 */