/*
* Copyright (c) 2003 Michael Zucchi <notzed@ximian.com>
* Copyright (c) 2010 Baptiste Coudurier
* Copyright (c) 2011 Stefano Sabatini
* Copyright (c) 2013 Vittorio Giovara <vittorio.giovara@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 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 General Public License for more details.
*
* You should have received a copy of the GNU 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.
*/
/**
* @file
* progressive to interlaced content filter, inspired by heavy debugging of tinterlace filter
*/
#include "libavutil/common.h"
#include "libavutil/opt.h"
#include "libavutil/imgutils.h"
#include "libavutil/avassert.h"
#include "formats.h"
#include "avfilter.h"
#include "internal.h"
#include "video.h"
enum ScanMode {
MODE_TFF = 0,
MODE_BFF = 1,
};
enum FieldType {
FIELD_UPPER = 0,
FIELD_LOWER = 1,
};
typedef struct {
const AVClass *class;
enum ScanMode scan; // top or bottom field first scanning
int lowpass; // enable or disable low pass filterning
AVFrame *cur, *next; // the two frames from which the new one is obtained
} InterlaceContext;
#define OFFSET(x) offsetof(InterlaceContext, x)
#define V AV_OPT_FLAG_VIDEO_PARAM
static const AVOption interlace_options[] = {
{ "scan", "scanning mode", OFFSET(scan),
AV_OPT_TYPE_INT, {.i64 = MODE_TFF }, 0, 1, .flags = V, .unit = "scan" },
{ "tff", "top field first", 0,
AV_OPT_TYPE_CONST, {.i64 = MODE_TFF }, INT_MIN, INT_MAX, .flags = V, .unit = "scan" },
{ "bff", "bottom field first", 0,
AV_OPT_TYPE_CONST, {.i64 = MODE_BFF }, INT_MIN, INT_MAX, .flags = V, .unit = "scan" },
{ "lowpass", "enable vertical low-pass filter", OFFSET(lowpass),
AV_OPT_TYPE_INT, {.i64 = 1 }, 0, 1, .flags = V },
{ NULL }
};
AVFILTER_DEFINE_CLASS(interlace);
static const enum AVPixelFormat formats_supported[] = {
AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV444P,
AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUVA420P,
AV_PIX_FMT_GRAY8, AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_NONE
};
static int query_formats(AVFilterContext *ctx)
{
ff_set_common_formats(ctx, ff_make_format_list(formats_supported));
return 0;
}
static av_cold void uninit(AVFilterContext *ctx)
{
InterlaceContext *s = ctx->priv;
av_frame_free(&s->cur);
av_frame_free(&s->next);
}
static int config_out_props(AVFilterLink *outlink)
{
AVFilterContext *ctx = outlink->src;
AVFilterLink *inlink = outlink->src->inputs[0];
InterlaceContext *s = ctx->priv;
if (inlink->h < 2) {
av_log(ctx, AV_LOG_ERROR, "input video height is too small\n");
return AVERROR_INVALIDDATA;
}
// same input size
outlink->w = inlink->w;
outlink->h = inlink->h;
outlink->time_base = inlink->time_base;
outlink->frame_rate = inlink->frame_rate;
// half framerate
outlink->time_base.num *= 2;
outlink->frame_rate.den *= 2;
outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
av_log(ctx, AV_LOG_VERBOSE, "%s interlacing %s lowpass filter\n",
s->scan == MODE_TFF ? "tff" : "bff", (s->lowpass) ? "with" : "without");
return 0;
}
static void copy_picture_field(AVFrame *src_frame, AVFrame *dst_frame,
AVFilterLink *inlink, enum FieldType field_type,
int lowpass)
{
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
int vsub = desc->log2_chroma_h;
int plane, i, j;
for (plane = 0; plane < desc->nb_components; plane++) {
int lines = (plane == 1 || plane == 2) ? FF_CEIL_RSHIFT(inlink->h, vsub) : inlink->h;
int linesize = av_image_get_linesize(inlink->format, inlink->w, plane);
uint8_t *dstp = dst_frame->data[plane];
const uint8_t *srcp = src_frame->data[plane];
av_assert0(linesize >= 0);
lines = (lines + (field_type == FIELD_UPPER)) / 2;
if (field_type == FIELD_LOWER)
srcp += src_frame->linesize[plane];
if (field_type == FIELD_LOWER)
dstp += dst_frame->linesize[plane];
if (lowpass) {
int srcp_linesize = src_frame->linesize[plane] * 2;
int dstp_linesize = dst_frame->linesize[plane] * 2;
for (j = lines; j > 0; j--) {
const uint8_t *srcp_above = srcp - src_frame->linesize[plane];
const uint8_t *srcp_below = srcp + src_frame->linesize[plane];
if (j == lines)
srcp_above = srcp; // there is no line above
if (j == 1)
srcp_below = srcp; // there is no line below
for (i = 0; i < linesize; i++) {
// this calculation is an integer representation of
// '0.5 * current + 0.25 * above + 0.25 * below'
// '1 +' is for rounding.
dstp[i] = (1 + srcp[i] + srcp[i] + srcp_above[i] + srcp_below[i]) >> 2;
}
dstp += dstp_linesize;
srcp += srcp_linesize;
}
} else {
av_image_copy_plane(dstp, dst_frame->linesize[plane] * 2,
srcp, src_frame->linesize[plane] * 2,
linesize, lines);
}
}
}
static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
{
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
InterlaceContext *s = ctx->priv;
AVFrame *out;
int tff, ret;
av_frame_free(&s->cur);
s->cur = s->next;
s->next = buf;
/* we need at least two frames */
if (!s->cur || !s->next)
return 0;
if (s->cur->interlaced_frame) {
av_log(ctx, AV_LOG_WARNING,
"video is already interlaced, adjusting framerate only\n");
out = av_frame_clone(s->cur);
out->pts /= 2; // adjust pts to new framerate
ret = ff_filter_frame(outlink, out);
return ret;
}
tff = (s->scan == MODE_TFF);
out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
if (!out)
return AVERROR(ENOMEM);
av_frame_copy_props(out, s->cur);
out->interlaced_frame = 1;
out->top_field_first = tff;
out->pts /= 2; // adjust pts to new framerate
/* copy upper/lower field from cur */
copy_picture_field(s->cur, out, inlink, tff ? FIELD_UPPER : FIELD_LOWER, s->lowpass);
av_frame_free(&s->cur);
/* copy lower/upper field from next */
copy_picture_field(s->next, out, inlink, tff ? FIELD_LOWER : FIELD_UPPER, s->lowpass);
av_frame_free(&s->next);
ret = ff_filter_frame(outlink, out);
return ret;
}
static const AVFilterPad inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.filter_frame = filter_frame,
},
{ NULL }
};
static const AVFilterPad outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.config_props = config_out_props,
},
{ NULL }
};
AVFilter avfilter_vf_interlace = {
.name = "interlace",
.description = NULL_IF_CONFIG_SMALL("Convert progressive video into interlaced."),
.uninit = uninit,
.priv_class = &interlace_class,
.priv_size = sizeof(InterlaceContext),
.query_formats = query_formats,
.inputs = inputs,
.outputs = outputs,
};