/* * Copyright (c) 2007 Bobby Bingham * * 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 */ /** * @file * FIFO buffering filter */ #include "libavutil/common.h"#include "libavutil/mathematics.h" #include "audio.h"#include "avfilter.h"#include "internal.h" typedef struct Buf {    AVFrame *frame;    struct Buf *next;} Buf; typedef struct FifoContext {    Buf  root;    Buf *last;   ///< last buffered frame     /**     * When a specific number of output samples is requested, the partial     * buffer is stored here     */    AVFrame *out;    int allocated_samples;      ///< number of samples out was allocated for} FifoContext; static av_cold int init(AVFilterContext *ctx){    FifoContext *s = ctx->priv;    s->last = &s->root;     return 0;} static av_cold void uninit(AVFilterContext *ctx){    FifoContext *s = ctx->priv;    Buf *buf, *tmp;     for (buf = s->root.next; buf; buf = tmp) {        tmp = buf->next;        av_frame_free(&buf->frame);        av_free(buf);    }     av_frame_free(&s->out);} static int add_to_queue(AVFilterLink *inlink, AVFrame *frame){    FifoContext *s = inlink->dst->priv;     s->last->next = av_mallocz(sizeof(Buf));    if (!s->last->next) {        av_frame_free(&frame);        return AVERROR(ENOMEM);    }     s->last = s->last->next;    s->last->frame = frame;     return 0;} static void queue_pop(FifoContext *s){    Buf *tmp = s->root.next->next;    if (s->last == s->root.next)        s->last = &s->root;    av_freep(&s->root.next);    s->root.next = tmp;} static int request_frame(AVFilterLink *outlink){    FifoContext *s = outlink->src->priv;    int ret = 0;     if (!s->root.next) {        if ((ret = ff_request_frame(outlink->src->inputs[0])) < 0)            return ret;        if (!s->root.next)            return 0;    }    ret = ff_filter_frame(outlink, s->root.next->frame);    queue_pop(s);    return ret;} static const AVFilterPad avfilter_vf_fifo_inputs[] = {    {        .name         = "default",        .type         = AVMEDIA_TYPE_VIDEO,        .filter_frame = add_to_queue,    },}; static const AVFilterPad avfilter_vf_fifo_outputs[] = {    {        .name          = "default",        .type          = AVMEDIA_TYPE_VIDEO,        .request_frame = request_frame,    },}; const AVFilter ff_vf_fifo = {    .name        = "fifo",    .description = NULL_IF_CONFIG_SMALL("Buffer input images and send them when they are requested."),    .init        = init,    .uninit      = uninit,    .priv_size   = sizeof(FifoContext),    FILTER_INPUTS(avfilter_vf_fifo_inputs),    FILTER_OUTPUTS(avfilter_vf_fifo_outputs),}; static const AVFilterPad avfilter_af_afifo_inputs[] = {    {        .name         = "default",        .type         = AVMEDIA_TYPE_AUDIO,        .filter_frame = add_to_queue,    },}; static const AVFilterPad avfilter_af_afifo_outputs[] = {    {        .name          = "default",        .type          = AVMEDIA_TYPE_AUDIO,        .request_frame = request_frame,    },}; const AVFilter ff_af_afifo = {    .name        = "afifo",    .description = NULL_IF_CONFIG_SMALL("Buffer input frames and send them when they are requested."),    .init        = init,    .uninit      = uninit,    .priv_size   = sizeof(FifoContext),    FILTER_INPUTS(avfilter_af_afifo_inputs),    FILTER_OUTPUTS(avfilter_af_afifo_outputs),};