On Wed, Mar 31, 2010 at 5:25 PM, Brandon Mintern <[email protected]> wrote: > On Wed, Mar 31, 2010 at 5:19 PM, Michael Niedermayer <[email protected]> wrote: >> On Wed, Mar 31, 2010 at 01:23:29AM -0400, Brandon Mintern wrote: >>> On Wed, Mar 31, 2010 at 12:43 AM, Brandon Mintern <[email protected]> >>> wrote: >>> > I am happy to present my first-ever open source code contribution, a >>> > "fade" filter for libavfilter! >>> [snip] >> [...] >> >>> +static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir) >>> +{ >>> + FadeContext *fade = link->dst->priv; >>> + AVFilterPicRef *in = link->cur_pic; >>> + AVFilterPicRef *out = link->dst->outputs[0]->outpic; >>> + uint8_t *inrow, *outrow; >>> + int i, j, plane; >>> + >>> + /* luma plane */ >>> + inrow = in-> data[0] + y * in-> linesize[0]; >>> + outrow = out->data[0] + y * out->linesize[0]; >>> + for(i = 0; i < h; i ++) { >>> + for(j = 0; j < link->w; j ++) >>> + outrow[j] = (uint8_t) ((float) inrow[j] * fade->fade_factor + >>> 0.5); >> >> please avoid floats, it makes regression testing unneccesarily hard >> Its probably ok to use floats/doubles in init, but it feels wrong >> at the pixel level [snip] > > Thanks for the feedback. The line you indicated is actually just an > explicit cast that I can remove if you'd like. However, the > floating-point arithmetic is being used to calculate the new pixel > values and round them to the nearest uint8_t. I can instead stick to > integer arithmetic, but then the numbers will be truncated instead of > rounded. Do you have another suggestion? Is AVRational (I think that's > what it called) something I should be using instead? > > Brandon
OK, here's a new patch which starts frame counting from 0 (that seems to be the early consensus, it simplifies the code a little bit, and I think vsrc_movie.c uses that convention), and it also removes the explicit cast to float from the above code. Again, my latest patch is also available at http://bmintern.homeunix.com/~brandon/vf_fade.patch, assuming my Internet connection isn't down (it's usually not). Brandon Index: allfilters.c =================================================================== --- allfilters.c (revision 5726) +++ allfilters.c (working copy) @@ -37,6 +37,7 @@ REGISTER_FILTER (ASPECT, aspect, vf); REGISTER_FILTER (CROP, crop, vf); REGISTER_FILTER (DRAWBOX, drawbox, vf); + REGISTER_FILTER (FADE, fade, vf); REGISTER_FILTER (FIFO, fifo, vf); REGISTER_FILTER (FORMAT, format, vf); REGISTER_FILTER (FPS, fps, vf); Index: vf_fade.c =================================================================== --- vf_fade.c (revision 0) +++ vf_fade.c (revision 0) @@ -0,0 +1,165 @@ +/* + * video fade filter + * copyright (c) 2010 Brandon Mintern + * based heavily on vf_negate.c which is 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 + */ + +/* + # A few usage examples follow, usable too as test scenarios. + + # Fade in first 30 frames of video + ffmpeg -i input.avi -vfilters fade=in:0:30 output.avi + + # Fade out last 45 frames of a 200-frame video + ffmpeg -i input.avi -vfilters fade=out:155:45 output.avi + + # Fade in first 25 frames and fade out last 25 frames of a 1000-frame video + ffmpeg -i input.avi -vfilters "fade=in:0:25, fade=out:975:25" output.avi + + # Make first 5 frames black, then fade in from frame 5-24 + ffmpeg -i input.avi -vfilters "fade=in:5:20" output.avi +*/ + +#include "avfilter.h" + +typedef struct +{ + float fade_factor, fade_per_frame; + unsigned int frame_index, start_frame, stop_frame; + int hsub, vsub; +} FadeContext; + +static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque) +{ + FadeContext *fade = ctx->priv; + unsigned int frames; + char in_out[4]; + + if(args && sscanf(args, " %3[^:]:%u:%u", in_out, + &fade->start_frame, &frames) == 3) { + frames = frames ? frames : 1; + fade->fade_per_frame = 1.0 / frames; + if (!strcmp(in_out, "in")) + fade->fade_factor = 0.0; + else if (!strcmp(in_out, "out")) { + fade->fade_per_frame = -fade->fade_per_frame; + fade->fade_factor = 1.0; + } + else { + av_log(ctx, AV_LOG_ERROR, + "init() 1st arg must be 'in' or 'out':'%s'\n", in_out); + return -1; + } + fade->stop_frame = fade->start_frame + frames; + return 0; + } + av_log(ctx, AV_LOG_ERROR, + "init() expected 3 arguments '(in|out):#:#':'%s'\n", args); + return -1; +} + +static int query_formats(AVFilterContext *ctx) +{ + enum PixelFormat pix_fmts[] = { + PIX_FMT_YUV444P, PIX_FMT_YUV422P, PIX_FMT_YUV420P, + PIX_FMT_YUV411P, PIX_FMT_YUV410P, + PIX_FMT_YUVJ444P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ420P, + PIX_FMT_YUV440P, PIX_FMT_YUVJ440P, + PIX_FMT_NONE + }; + + avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts)); + return 0; +} + +static int config_props(AVFilterLink *link) +{ + FadeContext *fade = link->dst->priv; + avcodec_get_chroma_sub_sample(link->format, &fade->hsub, &fade->vsub); + return 0; +} + + +static void start_frame(AVFilterLink *link, AVFilterPicRef *picref) +{ + FadeContext *fade = link->dst->priv; + if(fade->frame_index >= fade->start_frame && + fade->frame_index < fade->stop_frame) { + fade->fade_factor += fade->fade_per_frame; + } + fade->frame_index++; + avfilter_default_start_frame(link, picref); +} + +static void draw_slice(AVFilterLink *link, int y, int h, int slice_dir) +{ + FadeContext *fade = link->dst->priv; + AVFilterPicRef *in = link->cur_pic; + AVFilterPicRef *out = link->dst->outputs[0]->outpic; + uint8_t *inrow, *outrow; + int i, j, plane; + + /* luma plane */ + inrow = in-> data[0] + y * in-> linesize[0]; + outrow = out->data[0] + y * out->linesize[0]; + for(i = 0; i < h; i ++) { + for(j = 0; j < link->w; j ++) + outrow[j] = (uint8_t) (inrow[j] * fade->fade_factor + 0.5); + inrow += in-> linesize[0]; + outrow += out->linesize[0]; + } + + /* chroma planes */ + for(plane = 1; plane < 3; plane ++) { + inrow = in-> data[plane] + (y >> fade->vsub) * in-> linesize[plane]; + outrow = out->data[plane] + (y >> fade->vsub) * out->linesize[plane]; + + for(i = 0; i < h >> fade->vsub; i ++) { + for(j = 0; j < link->w >> fade->hsub; j ++) + outrow[j] = (uint8_t) (128.5+(inrow[j]-128)*fade->fade_factor); + inrow += in-> linesize[plane]; + outrow += out->linesize[plane]; + } + } + + avfilter_draw_slice(link->dst->outputs[0], y, h, slice_dir); +} + +AVFilter avfilter_vf_fade = +{ + .name = "fade", + + .init = init, + + .priv_size = sizeof(FadeContext), + + .query_formats = query_formats, + + .inputs = (AVFilterPad[]) {{ .name = "default", + .type = CODEC_TYPE_VIDEO, + .start_frame = start_frame, + .draw_slice = draw_slice, + .config_props = config_props, + .min_perms = AV_PERM_READ, }, + { .name = NULL}}, + .outputs = (AVFilterPad[]) {{ .name = "default", + .type = CODEC_TYPE_VIDEO, }, + { .name = NULL}}, +}; + Index: Makefile =================================================================== --- Makefile (revision 5726) +++ Makefile (working copy) @@ -18,6 +18,7 @@ OBJS-$(CONFIG_ASPECT_FILTER) += vf_aspect.o OBJS-$(CONFIG_CROP_FILTER) += vf_crop.o OBJS-$(CONFIG_DRAWBOX_FILTER) += vf_drawbox.o +OBJS-$(CONFIG_FADE_FILTER) += vf_fade.o OBJS-$(CONFIG_FIFO_FILTER) += vf_fifo.o OBJS-$(CONFIG_FORMAT_FILTER) += vf_format.o OBJS-$(CONFIG_FPS_FILTER) += vf_fps.o _______________________________________________ FFmpeg-soc mailing list [email protected] https://lists.mplayerhq.hu/mailman/listinfo/ffmpeg-soc
