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https://github.com/FFmpeg/FFmpeg.git
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0e12cdc69c
THis filter can correct certain issues seen from upstream sources where the cc_count is not properly set or the CEA-608 tuples are not at the start of the payload as expected. Make use of the ccfifo to extract and immediately repack the CEA-708 side data, thereby removing any extra padding and ensuring the 608 tuples are at the front of the payload. Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com> Signed-off-by: Limin Wang <lance.lmwang@gmail.com>
103 lines
2.8 KiB
C
103 lines
2.8 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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* 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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#include "avfilter.h"
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#include "internal.h"
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#include "ccfifo.h"
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#include "libavutil/opt.h"
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typedef struct CCRepackContext
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{
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const AVClass *class;
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AVCCFifo *cc_fifo;
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} CCRepackContext;
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static const AVOption ccrepack_options[] = {
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{ NULL }
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};
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AVFILTER_DEFINE_CLASS(ccrepack);
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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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if (!(ctx->cc_fifo = ff_ccfifo_alloc(link->frame_rate, ctx))) {
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av_log(ctx, AV_LOG_ERROR, "Failure to setup CC FIFO queue\n");
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return AVERROR(ENOMEM);
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}
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return 0;
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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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ff_ccfifo_extract(ctx->cc_fifo, frame);
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ff_ccfifo_inject(ctx->cc_fifo, frame);
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return ff_filter_frame(outlink, frame);
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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_freep(&s->cc_fifo);
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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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static const AVFilterPad avfilter_vf_ccrepack_outputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_VIDEO,
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},
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};
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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(avfilter_vf_ccrepack_outputs),
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};
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