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FFmpeg/libavfilter/vf_separatefields.c
Clément Bœsch d2e051e30c lavfi/separatefields: adjust tb to avoid rounding errors.
Since the PTS need double accuracy, the timebase denominator is doubled
as well, and this new time base is used for the timestamp unit.
2013-04-10 02:38:54 +02:00

113 lines
3.3 KiB
C

/*
* Copyright (c) 2013 Paul B Mahol
*
* 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
*/
#include "libavutil/pixdesc.h"
#include "avfilter.h"
#include "internal.h"
typedef struct {
int nb_planes;
int64_t frame_count;
double ts_unit;
} SeparateFieldsContext;
static int config_props_output(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
SeparateFieldsContext *sf = ctx->priv;
AVFilterLink *inlink = ctx->inputs[0];
sf->nb_planes = av_pix_fmt_count_planes(inlink->format);;
if (inlink->h & 1) {
av_log(ctx, AV_LOG_ERROR, "height must be even\n");
return AVERROR_INVALIDDATA;
}
outlink->time_base.num = inlink->time_base.num;
outlink->time_base.den = inlink->time_base.den * 2;
outlink->frame_rate.num = inlink->frame_rate.num * 2;
outlink->frame_rate.den = inlink->frame_rate.den;
outlink->w = inlink->w;
outlink->h = inlink->h / 2;
sf->ts_unit = av_q2d(av_inv_q(av_mul_q(outlink->frame_rate, outlink->time_base)));
return 0;
}
static int filter_frame(AVFilterLink *inlink, AVFrame *inpicref)
{
AVFilterContext *ctx = inlink->dst;
SeparateFieldsContext *sf = ctx->priv;
AVFilterLink *outlink = ctx->outputs[0];
AVFrame *second;
int i, ret;
inpicref->height = outlink->h;
inpicref->interlaced_frame = 0;
second = av_frame_clone(inpicref);
if (!second)
return AVERROR(ENOMEM);
for (i = 0; i < sf->nb_planes; i++) {
if (!inpicref->top_field_first)
inpicref->data[i] = inpicref->data[i] + inpicref->linesize[i];
else
second->data[i] = second->data[i] + second->linesize[i];
inpicref->linesize[i] *= 2;
second->linesize[i] *= 2;
}
inpicref->pts = sf->frame_count++ * sf->ts_unit;
second->pts = sf->frame_count++ * sf->ts_unit;
ret = ff_filter_frame(outlink, inpicref);
if (ret < 0)
return ret;
return ff_filter_frame(outlink, second);
}
static const AVFilterPad separatefields_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
},
{ NULL }
};
static const AVFilterPad separatefields_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_props_output,
},
{ NULL }
};
AVFilter avfilter_vf_separatefields = {
.name = "separatefields",
.description = NULL_IF_CONFIG_SMALL("Split input video frames into fields."),
.priv_size = sizeof(SeparateFieldsContext),
.inputs = separatefields_inputs,
.outputs = separatefields_outputs,
};