every.c

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/*
 * Copyright (c) 2013-2019 CESNET, z. s. p. o.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, is permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of CESNET nor the names of its contributors may be
 *    used to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
 * EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#include "config_unix.h"
#include "config_win32.h"
#endif /* HAVE_CONFIG_H */
 
#include "capture_filter.h"
 
#include "debug.h"
#include "lib_common.h"
#include "utils/color_out.h"
#include "video.h"
#include "video_codec.h"
 
struct module;
 
static int init(struct module *parent, const char *cfg, void **state);
static void done(void *state);
static struct video_frame *filter(void *state, struct video_frame *in);
 
struct state_every {
        int num;
        int denom;
        int current;
};
 
static void usage() {
        color_printf("Passes only every n-th frame.\n"
                     "See also capture filter " TBOLD("ratelimit") ".\n\n");
        color_printf(TBOLD("every") " usage:\n");
        printf("\tevery:numerator[/denominator]\n\n");
        printf("Example: every:2 - every second frame will be dropped\n");
        printf("The special case every:0 can be used to discard all frames\n");
}
 
static int init(struct module *parent, const char *cfg, void **state)
{
        UNUSED(parent);
 
        int n;
        int denom = 1;;
        if (strlen(cfg) == 0) {
                usage();
                return -1;
        }
        if(strcasecmp(cfg, "help") == 0) {
                usage();
                return 1;
        }
        n = atoi(cfg);
        if(strchr(cfg, '/')) {
                denom = atoi(strchr(cfg, '/') + 1);
        }
        if (denom > n && n != 0) {
                log_msg(LOG_LEVEL_ERROR, "Currently, numerator has to be greater "
                       "(or equal, which, however, has a little use) than denominator.\n");
                return -1;
        }
 
        struct state_every *s = calloc(1, sizeof(struct state_every));
        s->num = n;
        s->denom = denom;
 
        s->current = -1;
 
        *state = s;
        return 0;
}
 
static void done(void *state)
{
        free(state);
}
 
static void dispose_frame(struct video_frame *f) {
        VIDEO_FRAME_DISPOSE((struct video_frame *) f->callbacks.dispose_udata);
        vf_free(f);
}
 
static struct video_frame *filter(void *state, struct video_frame *in)
{
        struct state_every *s = state;
 
        if (s->num == 0) {
                VIDEO_FRAME_DISPOSE(in);
                return NULL;
        }
 
        s->current = (s->current + 1) % s->num;
 
        if (s->current >= s->denom) {
                VIDEO_FRAME_DISPOSE(in);
                return NULL;
        }
 
        struct video_frame *frame = vf_alloc_desc(video_desc_from_frame(in));
        memcpy(frame->tiles, in->tiles, in->tile_count * sizeof(struct tile));
        frame->fps /= (double) s->num / s->denom;
 
        frame->callbacks.dispose = dispose_frame;
        frame->callbacks.dispose_udata = in;
 
        return frame;
}
 
static const struct capture_filter_info capture_filter_every = {
        .init = init,
        .done = done,
        .filter = filter,
};
 
REGISTER_MODULE(every, &capture_filter_every, LIBRARY_CLASS_CAPTURE_FILTER, CAPTURE_FILTER_ABI_VERSION);