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ffmpeg / libavfilter / vf_fade.c @ master

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/*
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 * Copyright (c) 2010 Brandon Mintern
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 * Copyright (c) 2007 Bobby Bingham
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file
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 * video fade filter
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 * based heavily on vf_negate.c by Bobby Bingham
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 */
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#include "libavutil/pixdesc.h"
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#include "avfilter.h"
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typedef struct {
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    int factor, fade_per_frame;
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    unsigned int frame_index, start_frame, stop_frame;
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    int hsub, vsub, bpp;
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} FadeContext;
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static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
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{
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    FadeContext *fade = ctx->priv;
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    unsigned int nb_frames;
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    char in_out[4];
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    if (!args ||
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        sscanf(args, " %3[^:]:%u:%u", in_out, &fade->start_frame, &nb_frames) != 3) {
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        av_log(ctx, AV_LOG_ERROR,
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               "Expected 3 arguments '(in|out):#:#':'%s'\n", args);
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        return AVERROR(EINVAL);
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    }
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    nb_frames = nb_frames ? nb_frames : 1;
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    fade->fade_per_frame = (1 << 16) / nb_frames;
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    if (!strcmp(in_out, "in"))
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        fade->factor = 0;
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    else if (!strcmp(in_out, "out")) {
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        fade->fade_per_frame = -fade->fade_per_frame;
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        fade->factor = (1 << 16);
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    } else {
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        av_log(ctx, AV_LOG_ERROR,
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               "first argument must be 'in' or 'out':'%s'\n", in_out);
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        return AVERROR(EINVAL);
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    }
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    fade->stop_frame = fade->start_frame + nb_frames;
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    av_log(ctx, AV_LOG_INFO,
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           "type:%s start_frame:%d nb_frames:%d\n",
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           in_out, fade->start_frame, nb_frames);
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    return 0;
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}
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static int query_formats(AVFilterContext *ctx)
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{
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    const static enum PixelFormat pix_fmts[] = {
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        PIX_FMT_YUV444P,  PIX_FMT_YUV422P,  PIX_FMT_YUV420P,
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        PIX_FMT_YUV411P,  PIX_FMT_YUV410P,
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        PIX_FMT_YUVJ444P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ420P,
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        PIX_FMT_YUV440P,  PIX_FMT_YUVJ440P,
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        PIX_FMT_RGB24,    PIX_FMT_BGR24,
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        PIX_FMT_NONE
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    };
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    avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));
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    return 0;
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}
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static int config_props(AVFilterLink *inlink)
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{
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    FadeContext *fade = inlink->dst->priv;
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    const AVPixFmtDescriptor *pixdesc = &av_pix_fmt_descriptors[inlink->format];
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    fade->hsub = pixdesc->log2_chroma_w;
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    fade->vsub = pixdesc->log2_chroma_h;
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    fade->bpp = av_get_bits_per_pixel(pixdesc) >> 3;
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    return 0;
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}
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static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
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{
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    FadeContext *fade = inlink->dst->priv;
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    AVFilterBufferRef *outpic = inlink->cur_buf;
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    uint8_t *p;
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    int i, j, plane;
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    if (fade->factor < UINT16_MAX) {
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        /* luma or rgb plane */
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        for (i = 0; i < h; i++) {
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            p = outpic->data[0] + (y+i) * outpic->linesize[0];
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            for (j = 0; j < inlink->w * fade->bpp; j++) {
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                /* fade->factor is using 16 lower-order bits for decimal
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                 * places. 32768 = 1 << 15, it is an integer representation
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                 * of 0.5 and is for rounding. */
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                *p = (*p * fade->factor + 32768) >> 16;
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                p++;
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            }
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        }
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        if (outpic->data[1] && outpic->data[2]) {
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            /* chroma planes */
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            for (plane = 1; plane < 3; plane++) {
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                for (i = 0; i < h; i++) {
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                    p = outpic->data[plane] + ((y+i) >> fade->vsub) * outpic->linesize[plane];
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                    for (j = 0; j < inlink->w >> fade->hsub; j++) {
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                        /* 8421367 = ((128 << 1) + 1) << 15. It is an integer
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                         * representation of 128.5. The .5 is for rounding
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                         * purposes. */
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                        *p = ((*p - 128) * fade->factor + 8421367) >> 16;
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                        p++;
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                    }
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                }
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            }
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        }
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    }
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    avfilter_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
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}
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static void end_frame(AVFilterLink *inlink)
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{
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    FadeContext *fade = inlink->dst->priv;
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    avfilter_end_frame(inlink->dst->outputs[0]);
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    if (fade->frame_index >= fade->start_frame &&
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        fade->frame_index <= fade->stop_frame)
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        fade->factor += fade->fade_per_frame;
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    fade->factor = av_clip_uint16(fade->factor);
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    fade->frame_index++;
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}
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AVFilter avfilter_vf_fade = {
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    .name          = "fade",
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    .description   = NULL_IF_CONFIG_SMALL("Fade in/out input video"),
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    .init          = init,
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    .priv_size     = sizeof(FadeContext),
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    .query_formats = query_formats,
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    .inputs    = (AVFilterPad[]) {{ .name            = "default",
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                                    .type            = AVMEDIA_TYPE_VIDEO,
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                                    .config_props    = config_props,
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                                    .get_video_buffer = avfilter_null_get_video_buffer,
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                                    .start_frame      = avfilter_null_start_frame,
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                                    .draw_slice      = draw_slice,
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                                    .end_frame       = end_frame,
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                                    .min_perms       = AV_PERM_READ | AV_PERM_WRITE,
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                                    .rej_perms       = AV_PERM_PRESERVE, },
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                                  { .name = NULL}},
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    .outputs   = (AVFilterPad[]) {{ .name            = "default",
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                                    .type            = AVMEDIA_TYPE_VIDEO, },
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                                  { .name = NULL}},
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};