fifo.c 3.62 KB
Newer Older
Stefano Sabatini's avatar
Stefano Sabatini committed
1
/*
2
 * Copyright (c) 2007 Bobby Bingham
Stefano Sabatini's avatar
Stefano Sabatini committed
3
 *
4
 * This file is part of Libav.
Stefano Sabatini's avatar
Stefano Sabatini committed
5
 *
6
 * Libav is free software; you can redistribute it and/or
Stefano Sabatini's avatar
Stefano Sabatini committed
7 8 9 10
 * 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.
 *
11
 * Libav is distributed in the hope that it will be useful,
Stefano Sabatini's avatar
Stefano Sabatini committed
12 13 14 15 16
 * 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
17
 * License along with Libav; if not, write to the Free Software
Stefano Sabatini's avatar
Stefano Sabatini committed
18 19 20 21 22 23 24 25 26
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * FIFO buffering video filter
 */

#include "avfilter.h"
27
#include "internal.h"
28
#include "video.h"
Stefano Sabatini's avatar
Stefano Sabatini committed
29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80

typedef struct BufPic {
    AVFilterBufferRef *picref;
    struct BufPic     *next;
} BufPic;

typedef struct {
    BufPic  root;
    BufPic *last;   ///< last buffered picture
} FifoContext;

static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
{
    FifoContext *fifo = ctx->priv;
    fifo->last = &fifo->root;

    av_log(ctx, AV_LOG_INFO, "\n");
    return 0;
}

static av_cold void uninit(AVFilterContext *ctx)
{
    FifoContext *fifo = ctx->priv;
    BufPic *pic, *tmp;

    for (pic = fifo->root.next; pic; pic = tmp) {
        tmp = pic->next;
        avfilter_unref_buffer(pic->picref);
        av_free(pic);
    }
}

static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
{
    FifoContext *fifo = inlink->dst->priv;

    fifo->last->next = av_mallocz(sizeof(BufPic));
    fifo->last = fifo->last->next;
    fifo->last->picref = picref;
}

static void end_frame(AVFilterLink *inlink) { }

static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir) { }

static int request_frame(AVFilterLink *outlink)
{
    FifoContext *fifo = outlink->src->priv;
    BufPic *tmp;
    int ret;

    if (!fifo->root.next) {
81
        if ((ret = ff_request_frame(outlink->src->inputs[0])) < 0)
Stefano Sabatini's avatar
Stefano Sabatini committed
82 83 84 85 86
            return ret;
    }

    /* by doing this, we give ownership of the reference to the next filter,
     * so we don't have to worry about dereferencing it ourselves. */
87 88 89
    ff_start_frame(outlink, fifo->root.next->picref);
    ff_draw_slice (outlink, 0, outlink->h, 1);
    ff_end_frame  (outlink);
Stefano Sabatini's avatar
Stefano Sabatini committed
90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110

    if (fifo->last == fifo->root.next)
        fifo->last = &fifo->root;
    tmp = fifo->root.next->next;
    av_free(fifo->root.next);
    fifo->root.next = tmp;

    return 0;
}

AVFilter avfilter_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),

    .inputs    = (AVFilterPad[]) {{ .name            = "default",
                                    .type            = AVMEDIA_TYPE_VIDEO,
111
                                    .get_video_buffer= ff_null_get_video_buffer,
Stefano Sabatini's avatar
Stefano Sabatini committed
112 113 114 115 116 117 118 119 120 121
                                    .start_frame     = start_frame,
                                    .draw_slice      = draw_slice,
                                    .end_frame       = end_frame,
                                    .rej_perms       = AV_PERM_REUSE2, },
                                  { .name = NULL}},
    .outputs   = (AVFilterPad[]) {{ .name            = "default",
                                    .type            = AVMEDIA_TYPE_VIDEO,
                                    .request_frame   = request_frame, },
                                  { .name = NULL}},
};