/* * Copyright (c) 2007 Bobby Bingham * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * scale video filter */ #include "avfilter.h" #include "libavutil/avstring.h" #include "libavutil/eval.h" #include "libavutil/mathematics.h" #include "libavutil/opt.h" #include "libavutil/pixdesc.h" #include "libswscale/swscale.h" static const char *const var_names[] = { "PI", "PHI", "E", "in_w", "iw", "in_h", "ih", "out_w", "ow", "out_h", "oh", "a", "dar", "sar", "hsub", "vsub", NULL }; enum var_name { VAR_PI, VAR_PHI, VAR_E, VAR_IN_W, VAR_IW, VAR_IN_H, VAR_IH, VAR_OUT_W, VAR_OW, VAR_OUT_H, VAR_OH, VAR_A, VAR_DAR, VAR_SAR, VAR_HSUB, VAR_VSUB, VARS_NB }; typedef struct { struct SwsContext *sws; ///< software scaler context /** * New dimensions. Special values are: * 0 = original width/height * -1 = keep original aspect */ int w, h; unsigned int flags; ///sws flags int hsub, vsub; ///< chroma subsampling int slice_y; ///< top of current output slice int input_is_pal; ///< set to 1 if the input format is paletted char w_expr[256]; ///< width expression string char h_expr[256]; ///< height expression string } ScaleContext; static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque) { ScaleContext *scale = ctx->priv; const char *p; av_strlcpy(scale->w_expr, "iw", sizeof(scale->w_expr)); av_strlcpy(scale->h_expr, "ih", sizeof(scale->h_expr)); scale->flags = SWS_BILINEAR; if (args) { sscanf(args, "%255[^:]:%255[^:]", scale->w_expr, scale->h_expr); p = strstr(args,"flags="); if (p) { const AVClass *class = sws_get_class(); const AVOption *o = av_opt_find(&class, "sws_flags", NULL, 0, AV_OPT_SEARCH_FAKE_OBJ); int ret = av_opt_eval_flags(&class, o, p + 6, &scale->flags); if (ret < 0) return ret; } } return 0; } static av_cold void uninit(AVFilterContext *ctx) { ScaleContext *scale = ctx->priv; sws_freeContext(scale->sws); scale->sws = NULL; } static int query_formats(AVFilterContext *ctx) { AVFilterFormats *formats; enum PixelFormat pix_fmt; int ret; if (ctx->inputs[0]) { formats = NULL; for (pix_fmt = 0; pix_fmt < PIX_FMT_NB; pix_fmt++) if ( sws_isSupportedInput(pix_fmt) && (ret = avfilter_add_format(&formats, pix_fmt)) < 0) { avfilter_formats_unref(&formats); return ret; } avfilter_formats_ref(formats, &ctx->inputs[0]->out_formats); } if (ctx->outputs[0]) { formats = NULL; for (pix_fmt = 0; pix_fmt < PIX_FMT_NB; pix_fmt++) if ( sws_isSupportedOutput(pix_fmt) && (ret = avfilter_add_format(&formats, pix_fmt)) < 0) { avfilter_formats_unref(&formats); return ret; } avfilter_formats_ref(formats, &ctx->outputs[0]->in_formats); } return 0; } static int config_props(AVFilterLink *outlink) { AVFilterContext *ctx = outlink->src; AVFilterLink *inlink = outlink->src->inputs[0]; ScaleContext *scale = ctx->priv; int64_t w, h; double var_values[VARS_NB], res; char *expr; int ret; var_values[VAR_PI] = M_PI; var_values[VAR_PHI] = M_PHI; var_values[VAR_E] = M_E; var_values[VAR_IN_W] = var_values[VAR_IW] = inlink->w; var_values[VAR_IN_H] = var_values[VAR_IH] = inlink->h; var_values[VAR_OUT_W] = var_values[VAR_OW] = NAN; var_values[VAR_OUT_H] = var_values[VAR_OH] = NAN; var_values[VAR_DAR] = var_values[VAR_A] = (float) inlink->w / inlink->h; var_values[VAR_SAR] = inlink->sample_aspect_ratio.num ? (float) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1; var_values[VAR_HSUB] = 1<<av_pix_fmt_descriptors[inlink->format].log2_chroma_w; var_values[VAR_VSUB] = 1<<av_pix_fmt_descriptors[inlink->format].log2_chroma_h; /* evaluate width and height */ av_expr_parse_and_eval(&res, (expr = scale->w_expr), var_names, var_values, NULL, NULL, NULL, NULL, NULL, 0, ctx); scale->w = var_values[VAR_OUT_W] = var_values[VAR_OW] = res; if ((ret = av_expr_parse_and_eval(&res, (expr = scale->h_expr), var_names, var_values, NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail; scale->h = var_values[VAR_OUT_H] = var_values[VAR_OH] = res; /* evaluate again the width, as it may depend on the output height */ if ((ret = av_expr_parse_and_eval(&res, (expr = scale->w_expr), var_names, var_values, NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) goto fail; scale->w = res; w = scale->w; h = scale->h; /* sanity check params */ if (w < -1 || h < -1) { av_log(ctx, AV_LOG_ERROR, "Size values less than -1 are not acceptable.\n"); return AVERROR(EINVAL); } if (w == -1 && h == -1) scale->w = scale->h = 0; if (!(w = scale->w)) w = inlink->w; if (!(h = scale->h)) h = inlink->h; if (w == -1) w = av_rescale(h, inlink->w, inlink->h); if (h == -1) h = av_rescale(w, inlink->h, inlink->w); if (w > INT_MAX || h > INT_MAX || (h * inlink->w) > INT_MAX || (w * inlink->h) > INT_MAX) av_log(ctx, AV_LOG_ERROR, "Rescaled value for width or height is too big.\n"); outlink->w = w; outlink->h = h; /* TODO: make algorithm configurable */ av_log(ctx, AV_LOG_INFO, "w:%d h:%d fmt:%s -> w:%d h:%d fmt:%s flags:0x%0x\n", inlink ->w, inlink ->h, av_pix_fmt_descriptors[ inlink->format].name, outlink->w, outlink->h, av_pix_fmt_descriptors[outlink->format].name, scale->flags); scale->input_is_pal = av_pix_fmt_descriptors[inlink->format].flags & PIX_FMT_PAL || av_pix_fmt_descriptors[inlink->format].flags & PIX_FMT_PSEUDOPAL; if (scale->sws) sws_freeContext(scale->sws); if (inlink->w == outlink->w && inlink->h == outlink->h && inlink->format == outlink->format) scale->sws = NULL; else { scale->sws = sws_getContext(inlink ->w, inlink ->h, inlink ->format, outlink->w, outlink->h, outlink->format, scale->flags, NULL, NULL, NULL); if (!scale->sws) return AVERROR(EINVAL); } if (inlink->sample_aspect_ratio.num) outlink->sample_aspect_ratio = av_mul_q((AVRational){outlink->h*inlink->w, outlink->w*inlink->h}, inlink->sample_aspect_ratio); else outlink->sample_aspect_ratio = inlink->sample_aspect_ratio; return 0; fail: av_log(NULL, AV_LOG_ERROR, "Error when evaluating the expression '%s'\n", expr); return ret; } static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref) { ScaleContext *scale = link->dst->priv; AVFilterLink *outlink = link->dst->outputs[0]; AVFilterBufferRef *outpicref; if (!scale->sws) { avfilter_start_frame(outlink, avfilter_ref_buffer(picref, ~0)); return; } scale->hsub = av_pix_fmt_descriptors[link->format].log2_chroma_w; scale->vsub = av_pix_fmt_descriptors[link->format].log2_chroma_h; outpicref = avfilter_get_video_buffer(outlink, AV_PERM_WRITE, outlink->w, outlink->h); avfilter_copy_buffer_ref_props(outpicref, picref); outpicref->video->w = outlink->w; outpicref->video->h = outlink->h; outlink->out_buf = outpicref; av_reduce(&outpicref->video->pixel_aspect.num, &outpicref->video->pixel_aspect.den, (int64_t)picref->video->pixel_aspect.num * outlink->h * link->w, (int64_t)picref->video->pixel_aspect.den * outlink->w * link->h, INT_MAX); scale->slice_y = 0; avfilter_start_frame(outlink, avfilter_ref_buffer(outpicref, ~0)); } static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir) { ScaleContext *scale = link->dst->priv; int out_h; AVFilterBufferRef *cur_pic = link->cur_buf; const uint8_t *data[4]; if (!scale->sws) { avfilter_draw_slice(link->dst->outputs[0], y, h, slice_dir); return; } if (scale->slice_y == 0 && slice_dir == -1) scale->slice_y = link->dst->outputs[0]->h; data[0] = cur_pic->data[0] + y * cur_pic->linesize[0]; data[1] = scale->input_is_pal ? cur_pic->data[1] : cur_pic->data[1] + (y>>scale->vsub) * cur_pic->linesize[1]; data[2] = cur_pic->data[2] + (y>>scale->vsub) * cur_pic->linesize[2]; data[3] = cur_pic->data[3] + y * cur_pic->linesize[3]; out_h = sws_scale(scale->sws, data, cur_pic->linesize, y, h, link->dst->outputs[0]->out_buf->data, link->dst->outputs[0]->out_buf->linesize); if (slice_dir == -1) scale->slice_y -= out_h; avfilter_draw_slice(link->dst->outputs[0], scale->slice_y, out_h, slice_dir); if (slice_dir == 1) scale->slice_y += out_h; } AVFilter avfilter_vf_scale = { .name = "scale", .description = NULL_IF_CONFIG_SMALL("Scale the input video to width:height size and/or convert the image format."), .init = init, .uninit = uninit, .query_formats = query_formats, .priv_size = sizeof(ScaleContext), .inputs = (AVFilterPad[]) {{ .name = "default", .type = AVMEDIA_TYPE_VIDEO, .start_frame = start_frame, .draw_slice = draw_slice, .min_perms = AV_PERM_READ, }, { .name = NULL}}, .outputs = (AVFilterPad[]) {{ .name = "default", .type = AVMEDIA_TYPE_VIDEO, .config_props = config_props, }, { .name = NULL}}, };