| /* |
| * 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 slicing filter |
| */ |
| |
| #include "avfilter.h" |
| #include "video.h" |
| #include "libavutil/pixdesc.h" |
| |
| typedef struct { |
| int h; ///< output slice height |
| int vshift; ///< vertical chroma subsampling shift |
| uint32_t lcg_state; ///< LCG state used to compute random slice height |
| int use_random_h; ///< enable the use of random slice height values |
| } SliceContext; |
| |
| static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque) |
| { |
| SliceContext *slice = ctx->priv; |
| |
| slice->h = 16; |
| if (args) { |
| if (!strcmp(args, "random")) { |
| slice->use_random_h = 1; |
| } else { |
| sscanf(args, "%d", &slice->h); |
| } |
| } |
| return 0; |
| } |
| |
| static int config_props(AVFilterLink *link) |
| { |
| SliceContext *slice = link->dst->priv; |
| |
| slice->vshift = av_pix_fmt_descriptors[link->format].log2_chroma_h; |
| |
| return 0; |
| } |
| |
| static void start_frame(AVFilterLink *link, AVFilterBufferRef *picref) |
| { |
| SliceContext *slice = link->dst->priv; |
| |
| if (slice->use_random_h) { |
| slice->lcg_state = slice->lcg_state * 1664525 + 1013904223; |
| slice->h = 8 + (uint64_t)slice->lcg_state * 25 / UINT32_MAX; |
| } |
| |
| /* ensure that slices play nice with chroma subsampling, and enforce |
| * a reasonable minimum size for the slices */ |
| slice->h = FFMAX(8, slice->h & (-1 << slice->vshift)); |
| |
| av_log(link->dst, AV_LOG_DEBUG, "h:%d\n", slice->h); |
| |
| avfilter_start_frame(link->dst->outputs[0], picref); |
| } |
| |
| static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir) |
| { |
| SliceContext *slice = link->dst->priv; |
| int y2; |
| |
| if (slice_dir == 1) { |
| for (y2 = y; y2 + slice->h <= y + h; y2 += slice->h) |
| avfilter_draw_slice(link->dst->outputs[0], y2, slice->h, slice_dir); |
| |
| if (y2 < y + h) |
| avfilter_draw_slice(link->dst->outputs[0], y2, y + h - y2, slice_dir); |
| } else if (slice_dir == -1) { |
| for (y2 = y + h; y2 - slice->h >= y; y2 -= slice->h) |
| avfilter_draw_slice(link->dst->outputs[0], y2 - slice->h, slice->h, slice_dir); |
| |
| if (y2 > y) |
| avfilter_draw_slice(link->dst->outputs[0], y, y2 - y, slice_dir); |
| } |
| } |
| |
| AVFilter avfilter_vf_slicify = { |
| .name = "slicify", |
| .description = NULL_IF_CONFIG_SMALL("Pass the images of input video on to next video filter as multiple slices."), |
| |
| .init = init, |
| |
| .priv_size = sizeof(SliceContext), |
| |
| .inputs = (const AVFilterPad[]) {{ .name = "default", |
| .type = AVMEDIA_TYPE_VIDEO, |
| .get_video_buffer = ff_null_get_video_buffer, |
| .start_frame = start_frame, |
| .draw_slice = draw_slice, |
| .config_props = config_props, |
| .end_frame = ff_null_end_frame, }, |
| { .name = NULL}}, |
| .outputs = (const AVFilterPad[]) {{ .name = "default", |
| .type = AVMEDIA_TYPE_VIDEO, }, |
| { .name = NULL}}, |
| }; |