Lots of video filters use a very simple input or output: An array with a single AVFilterPad whose name is "default" and whose type is AVMEDIA_TYPE_VIDEO; everything else is unset. Given that we never use pointer equality for inputs or outputs*, we can simply use a single AVFilterPad instead of dozens; this even saves .data.rel.ro (8312B here) as well as relocations. *: In fact, several filters (like the filters in vf_lut.c) already use the same outputs; furthermore, ff_filter_alloc() duplicates the input and output pads so that we do not even work with the pads directly. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
		
			
				
	
	
		
			98 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			98 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * CEA-708 Closed Caption Repacker
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|  * Copyright (c) 2023 LTN Global Communications
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|  *
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|  * Author: Devin Heitmueller <dheitmueller@ltnglobal.com>
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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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| /*
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|  * Repackage CEA-708 arrays, which deals with incorrect cc_count for a given
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|  * output framerate, and incorrect 708 padding.
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|  *
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|  * See CEA CEA-10-A "EIA-708-B Implementation Guidance", Section 26.5
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|  * "Grouping DTVCC Data Within user_data() Structure"
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|  */
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| 
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| #include "avfilter.h"
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| #include "internal.h"
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| #include "ccfifo.h"
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| #include "video.h"
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| #include "libavutil/opt.h"
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| 
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| typedef struct CCRepackContext
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| {
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|     const AVClass *class;
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|     CCFifo cc_fifo;
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| } CCRepackContext;
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| 
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| static const AVOption ccrepack_options[] = {
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|     {  NULL }
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| };
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| 
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| AVFILTER_DEFINE_CLASS(ccrepack);
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| 
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| static int config_input(AVFilterLink *link)
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| {
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|     CCRepackContext *ctx = link->dst->priv;
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| 
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|     int ret = ff_ccfifo_init(&ctx->cc_fifo, link->frame_rate, ctx);
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|     if (ret < 0) {
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|         av_log(ctx, AV_LOG_ERROR, "Failure to setup CC FIFO queue\n");
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|         return ret;
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|     }
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| 
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|     return 0;
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| }
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| 
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| static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
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| {
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|     CCRepackContext *ctx = inlink->dst->priv;
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|     AVFilterLink *outlink = inlink->dst->outputs[0];
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| 
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|     ff_ccfifo_extract(&ctx->cc_fifo, frame);
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|     ff_ccfifo_inject(&ctx->cc_fifo, frame);
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| 
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|     return ff_filter_frame(outlink, frame);
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| }
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| 
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| static av_cold void uninit(AVFilterContext *ctx)
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| {
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|     CCRepackContext *s = ctx->priv;
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|     ff_ccfifo_uninit(&s->cc_fifo);
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| }
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| 
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| static const AVFilterPad avfilter_vf_ccrepack_inputs[] = {
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|     {
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|         .name         = "default",
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|         .type         = AVMEDIA_TYPE_VIDEO,
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|         .filter_frame = filter_frame,
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|         .config_props = config_input,
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|     },
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| };
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| 
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| const AVFilter ff_vf_ccrepack = {
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|     .name        = "ccrepack",
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|     .description = NULL_IF_CONFIG_SMALL("Repack CEA-708 closed caption metadata"),
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|     .uninit      = uninit,
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|     .priv_size   = sizeof(CCRepackContext),
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|     .priv_class  = &ccrepack_class,
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|     FILTER_INPUTS(avfilter_vf_ccrepack_inputs),
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|     FILTER_OUTPUTS(ff_video_default_filterpad),
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| };
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