[FFmpeg-devel] [PATCH] separatefields filter
Paul B Mahol
onemda at gmail.com
Wed Apr 10 01:55:15 CEST 2013
On 4/9/13, Clement Boesch <ubitux at gmail.com> wrote:
> On Tue, Apr 09, 2013 at 05:09:17PM +0000, Paul B Mahol wrote:
>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
>> ---
>> doc/filters.texi | 10 ++++
>> libavfilter/Makefile | 1 +
>> libavfilter/allfilters.c | 1 +
>> libavfilter/vf_separatefields.c | 108
>> ++++++++++++++++++++++++++++++++++++++++
>> 4 files changed, 120 insertions(+)
>> create mode 100644 libavfilter/vf_separatefields.c
>>
>> diff --git a/doc/filters.texi b/doc/filters.texi
>> index 483d8a1..8172a44 100644
>> --- a/doc/filters.texi
>> +++ b/doc/filters.texi
>> @@ -4896,6 +4896,16 @@ scale='min(500\, iw*3/2):-1'
>> @end example
>> @end itemize
>>
>> + at section separatefields
>> +
>> +Separate fields takes a frame-based video input and splits each frame
>
> "Separate fields" doesn't make much sense as name, maybe use
> @code{separatefields}/
Done.
>
>> +into its components fields, producing a new half height clip with
>> +twice the frame rate and twice the frame count.
>> +
>> +This filter use field-dominance information in frame to decide which
>> +of each pair of fields to place first in the output.
>> +If it gets it wrong use @code{setfield} filter before
>> @code{separatefields} filter.
>> +
>
> You could add an @anchor{setfield} above the appropriate section if not
> present, and use @ref{setfield}; it's handy for users to be able to jump
> directly to it, at least in html form.
>
Done.
>> @section setdar, setsar
>>
>> The @code{setdar} filter sets the Display Aspect Ratio for the filter
>> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
>> index e1eb35d..d91529d 100644
>> --- a/libavfilter/Makefile
>> +++ b/libavfilter/Makefile
>> @@ -148,6 +148,7 @@ OBJS-$(CONFIG_PERMS_FILTER) +=
>> f_perms.o
>> OBJS-$(CONFIG_PIXDESCTEST_FILTER) += vf_pixdesctest.o
>> OBJS-$(CONFIG_PP_FILTER) += vf_pp.o
>> OBJS-$(CONFIG_REMOVELOGO_FILTER) += bbox.o lswsutils.o
>> lavfutils.o vf_removelogo.o
>> +OBJS-$(CONFIG_SEPARATEFIELDS_FILTER) += vf_separatefields.o
>> OBJS-$(CONFIG_SCALE_FILTER) += vf_scale.o
>> OBJS-$(CONFIG_SELECT_FILTER) += f_select.o
>> OBJS-$(CONFIG_SENDCMD_FILTER) += f_sendcmd.o
>> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
>> index 4972322..e5c20ed 100644
>> --- a/libavfilter/allfilters.c
>> +++ b/libavfilter/allfilters.c
>> @@ -146,6 +146,7 @@ void avfilter_register_all(void)
>> REGISTER_FILTER(SCALE, scale, vf);
>> REGISTER_FILTER(SELECT, select, vf);
>> REGISTER_FILTER(SENDCMD, sendcmd, vf);
>> + REGISTER_FILTER(SEPARATEFIELDS, separatefields, vf);
>> REGISTER_FILTER(SETDAR, setdar, vf);
>> REGISTER_FILTER(SETFIELD, setfield, vf);
>> REGISTER_FILTER(SETPTS, setpts, vf);
>> diff --git a/libavfilter/vf_separatefields.c
>> b/libavfilter/vf_separatefields.c
>> new file mode 100644
>> index 0000000..ac4a1e8
>> --- /dev/null
>> +++ b/libavfilter/vf_separatefields.c
>> @@ -0,0 +1,108 @@
>> +/*
>> + * 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;
>> +} 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;
>> +
>> + 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 * inpicref->linesize[i];
>> + second->linesize[i] = 2 * second->linesize[i];
>
> *= 2
>
Done.
>> + }
>> +
>> + inpicref->pts *= 2;
>> + second->pts = inpicref->pts + 1;
>> +
>
> I wonder if that will really be accurate.
>
Fixed.
>> + ret = ff_filter_frame(outlink, inpicref);
>> + return ff_filter_frame(outlink, second) | ret;
>
> if both fails differently, the error code will make no sense.
>
Fixed.
>> +}
>> +
>> +static const AVFilterPad separatefields_inputs[] = {
>> + {
>> + .name = "default",
>> + .type = AVMEDIA_TYPE_VIDEO,
>
>> + .get_video_buffer = ff_null_get_video_buffer,
>
> Does this make any difference?
Removed.
>
>> + .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,
>> +};
>
> Rest LGTM. Don't forget the Changelog entry.
Applied.
>
> --
> Clement B.
>
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