PeerStreamer

/*

 * 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

 * video crop filter

 */

#include "avfilter.h"

#include "libavcore/imgutils.h"

typedef struct {

    int  x;             ///< x offset of the non-cropped area with respect to the input area

    int  y;             ///< y offset of the non-cropped area with respect to the input area

    int  w;             ///< width of the cropped area

    int  h;             ///< height of the cropped area

    int max_step[4];    ///< max pixel step for each plane, expressed as a number of bytes

    int hsub, vsub;     ///< chroma subsampling

} CropContext;

static int query_formats(AVFilterContext *ctx)

{

    static const enum PixelFormat pix_fmts[] = {

        PIX_FMT_RGB48BE,      PIX_FMT_RGB48LE,

        PIX_FMT_ARGB,         PIX_FMT_RGBA,

        PIX_FMT_ABGR,         PIX_FMT_BGRA,

        PIX_FMT_RGB24,        PIX_FMT_BGR24,

        PIX_FMT_RGB565BE,     PIX_FMT_RGB565LE,

        PIX_FMT_RGB555BE,     PIX_FMT_RGB555LE,

        PIX_FMT_BGR565BE,     PIX_FMT_BGR565LE,

        PIX_FMT_BGR555BE,     PIX_FMT_BGR555LE,

        PIX_FMT_GRAY16BE,     PIX_FMT_GRAY16LE,

        PIX_FMT_YUV420P16LE,  PIX_FMT_YUV420P16BE,

        PIX_FMT_YUV422P16LE,  PIX_FMT_YUV422P16BE,

        PIX_FMT_YUV444P16LE,  PIX_FMT_YUV444P16BE,

        PIX_FMT_YUV444P,      PIX_FMT_YUV422P,

        PIX_FMT_YUV420P,      PIX_FMT_YUV411P,

        PIX_FMT_YUV410P,      PIX_FMT_YUV440P,

        PIX_FMT_YUVJ444P,     PIX_FMT_YUVJ422P,

        PIX_FMT_YUVJ420P,     PIX_FMT_YUVJ440P,

        PIX_FMT_YUVA420P,

        PIX_FMT_RGB8,         PIX_FMT_BGR8,

        PIX_FMT_RGB4_BYTE,    PIX_FMT_BGR4_BYTE,

        PIX_FMT_PAL8,         PIX_FMT_GRAY8,

        PIX_FMT_NONE

    };

    avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));

    return 0;

}

static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)

{

    CropContext *crop = ctx->priv;

    if (args)

        sscanf(args, "%d:%d:%d:%d", &crop->x, &crop->y, &crop->w, &crop->h);

    return 0;

}

static int config_input(AVFilterLink *link)

{

    AVFilterContext *ctx = link->dst;

    CropContext *crop = ctx->priv;

    const AVPixFmtDescriptor *pix_desc = &av_pix_fmt_descriptors[link->format];

    av_fill_image_max_pixstep(crop->max_step, NULL, pix_desc);

    crop->hsub = av_pix_fmt_descriptors[link->format].log2_chroma_w;

    crop->vsub = av_pix_fmt_descriptors[link->format].log2_chroma_h;

    if (crop->w == 0)

        crop->w = link->w - crop->x;

    if (crop->h == 0)

        crop->h = link->h - crop->y;

    crop->x &= ~((1 << crop->hsub) - 1);

    crop->y &= ~((1 << crop->vsub) - 1);

    av_log(link->dst, AV_LOG_INFO, "x:%d y:%d w:%d h:%d\n",

           crop->x, crop->y, crop->w, crop->h);

    if (crop->x <  0 || crop->y <  0                    ||

        crop->w <= 0 || crop->h <= 0                    ||

        (unsigned)crop->x + (unsigned)crop->w > link->w ||

        (unsigned)crop->y + (unsigned)crop->h > link->h) {

        av_log(ctx, AV_LOG_ERROR,

               "Output area %d:%d:%d:%d not within the input area 0:0:%d:%d or zero-sized\n",

               crop->x, crop->y, crop->w, crop->h, link->w, link->h);

        return AVERROR(EINVAL);

    }

    return 0;

}

static int config_output(AVFilterLink *link)

{

    CropContext *crop = link->src->priv;

    link->w = crop->w;

    link->h = crop->h;

    return 0;

}

static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref)

{

    CropContext *crop = link->dst->priv;

    AVFilterBufferRef *ref2 = avfilter_ref_buffer(picref, ~0);

    int i;

    picref->video->w = crop->w;

    picref->video->h = crop->h;

    ref2->data[0] += crop->y * ref2->linesize[0];

    ref2->data[0] += (crop->x * crop->max_step[0]);

    if (!(av_pix_fmt_descriptors[link->format].flags & PIX_FMT_PAL)) {

        for (i = 1; i < 3; i ++) {

            if (ref2->data[i]) {

                ref2->data[i] += (crop->y >> crop->vsub) * ref2->linesize[i];

                ref2->data[i] += (crop->x * crop->max_step[i]) >> crop->hsub;

            }

        }

    }

    /* alpha plane */

    if (ref2->data[3]) {

        ref2->data[3] += crop->y * ref2->linesize[3];

        ref2->data[3] += (crop->x * crop->max_step[3]);

    }

    avfilter_start_frame(link->dst->outputs[0], ref2);

}

static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir)

{

    AVFilterContext *ctx = link->dst;

    CropContext *crop = ctx->priv;

    if (y >= crop->y + crop->h || y + h <= crop->y)

        return;

    if (y < crop->y) {

        h -= crop->y - y;

        y  = crop->y;

    }

    if (y + h > crop->y + crop->h)

        h = crop->y + crop->h - y;

    avfilter_draw_slice(ctx->outputs[0], y - crop->y, h, slice_dir);

}

AVFilter avfilter_vf_crop = {

    .name      = "crop",

    .description = NULL_IF_CONFIG_SMALL("Crop the input video to x:y:width:height."),

    .priv_size = sizeof(CropContext),

    .query_formats = query_formats,

    .init          = init,

    .inputs    = (AVFilterPad[]) {{ .name             = "default",

                                    .type             = AVMEDIA_TYPE_VIDEO,

                                    .start_frame      = start_frame,

                                    .draw_slice       = draw_slice,

                                    .get_video_buffer = avfilter_null_get_video_buffer,

                                    .config_props     = config_input, },

                                  { .name = NULL}},

    .outputs   = (AVFilterPad[]) {{ .name             = "default",

                                    .type             = AVMEDIA_TYPE_VIDEO,

                                    .config_props     = config_output, },

                                  { .name = NULL}},

};