1/*
2 * Copyright (c) 2011 Mark Himsley
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/**
22 * @file
23 * video field order filter, heavily influenced by vf_pad.c
24 */
25
26#include "libavutil/imgutils.h"
27#include "libavutil/internal.h"
28#include "libavutil/opt.h"
29#include "libavutil/pixdesc.h"
30#include "avfilter.h"
31#include "formats.h"
32#include "internal.h"
33#include "video.h"
34
35typedef struct FieldOrderContext {
36    const AVClass *class;
37    int dst_tff;               ///< output bff/tff
38    int          line_size[4]; ///< bytes of pixel data per line for each plane
39} FieldOrderContext;
40
41static int query_formats(AVFilterContext *ctx)
42{
43    AVFilterFormats  *formats;
44    enum AVPixelFormat pix_fmt;
45    int              ret;
46
47    /** accept any input pixel format that is not hardware accelerated, not
48     *  a bitstream format, and does not have vertically sub-sampled chroma */
49    if (ctx->inputs[0]) {
50        const AVPixFmtDescriptor *desc = NULL;
51        formats = NULL;
52        while ((desc = av_pix_fmt_desc_next(desc))) {
53            pix_fmt = av_pix_fmt_desc_get_id(desc);
54            if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL ||
55                  desc->flags & AV_PIX_FMT_FLAG_PAL     ||
56                  desc->flags & AV_PIX_FMT_FLAG_BITSTREAM) &&
57                desc->nb_components && !desc->log2_chroma_h &&
58                (ret = ff_add_format(&formats, pix_fmt)) < 0) {
59                ff_formats_unref(&formats);
60                return ret;
61            }
62        }
63        ff_formats_ref(formats, &ctx->inputs[0]->out_formats);
64        ff_formats_ref(formats, &ctx->outputs[0]->in_formats);
65    }
66
67    return 0;
68}
69
70static int config_input(AVFilterLink *inlink)
71{
72    AVFilterContext   *ctx = inlink->dst;
73    FieldOrderContext *s   = ctx->priv;
74
75    return av_image_fill_linesizes(s->line_size, inlink->format, inlink->w);
76}
77
78static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
79{
80    AVFilterContext   *ctx     = inlink->dst;
81    FieldOrderContext *s       = ctx->priv;
82    AVFilterLink      *outlink = ctx->outputs[0];
83    int h, plane, src_line_step, dst_line_step, line_size, line;
84    uint8_t *dst, *src;
85    AVFrame *out;
86
87    if (!frame->interlaced_frame ||
88        frame->top_field_first == s->dst_tff) {
89        av_log(ctx, AV_LOG_VERBOSE,
90               "Skipping %s.\n",
91               frame->interlaced_frame ?
92               "frame with same field order" : "progressive frame");
93        return ff_filter_frame(outlink, frame);
94    }
95
96    if (av_frame_is_writable(frame)) {
97        out = frame;
98    } else {
99        out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
100        if (!out) {
101            av_frame_free(&frame);
102            return AVERROR(ENOMEM);
103        }
104        av_frame_copy_props(out, frame);
105    }
106
107    av_dlog(ctx,
108            "picture will move %s one line\n",
109            s->dst_tff ? "up" : "down");
110    h = frame->height;
111    for (plane = 0; plane < 4 && frame->data[plane] && frame->linesize[plane]; plane++) {
112        dst_line_step = out->linesize[plane];
113        src_line_step = frame->linesize[plane];
114        line_size = s->line_size[plane];
115        dst = out->data[plane];
116        src = frame->data[plane];
117        if (s->dst_tff) {
118            /** Move every line up one line, working from
119             *  the top to the bottom of the frame.
120             *  The original top line is lost.
121             *  The new last line is created as a copy of the
122             *  penultimate line from that field. */
123            for (line = 0; line < h; line++) {
124                if (1 + line < frame->height) {
125                    memcpy(dst, src + src_line_step, line_size);
126                } else {
127                    memcpy(dst, src - 2 * src_line_step, line_size);
128                }
129                dst += dst_line_step;
130                src += src_line_step;
131            }
132        } else {
133            /** Move every line down one line, working from
134             *  the bottom to the top of the frame.
135             *  The original bottom line is lost.
136             *  The new first line is created as a copy of the
137             *  second line from that field. */
138            dst += (h - 1) * dst_line_step;
139            src += (h - 1) * src_line_step;
140            for (line = h - 1; line >= 0 ; line--) {
141                if (line > 0) {
142                    memcpy(dst, src - src_line_step, line_size);
143                } else {
144                    memcpy(dst, src + 2 * src_line_step, line_size);
145                }
146                dst -= dst_line_step;
147                src -= src_line_step;
148            }
149        }
150    }
151    out->top_field_first = s->dst_tff;
152
153    if (frame != out)
154        av_frame_free(&frame);
155    return ff_filter_frame(outlink, out);
156}
157
158#define OFFSET(x) offsetof(FieldOrderContext, x)
159#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
160
161static const AVOption fieldorder_options[] = {
162    { "order", "output field order", OFFSET(dst_tff), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, FLAGS, "order" },
163        { "bff", "bottom field first", 0, AV_OPT_TYPE_CONST, { .i64 = 0 }, .flags=FLAGS, .unit = "order" },
164        { "tff", "top field first",    0, AV_OPT_TYPE_CONST, { .i64 = 1 }, .flags=FLAGS, .unit = "order" },
165    { NULL }
166};
167
168AVFILTER_DEFINE_CLASS(fieldorder);
169
170static const AVFilterPad avfilter_vf_fieldorder_inputs[] = {
171    {
172        .name         = "default",
173        .type         = AVMEDIA_TYPE_VIDEO,
174        .config_props = config_input,
175        .filter_frame = filter_frame,
176    },
177    { NULL }
178};
179
180static const AVFilterPad avfilter_vf_fieldorder_outputs[] = {
181    {
182        .name = "default",
183        .type = AVMEDIA_TYPE_VIDEO,
184    },
185    { NULL }
186};
187
188AVFilter ff_vf_fieldorder = {
189    .name          = "fieldorder",
190    .description   = NULL_IF_CONFIG_SMALL("Set the field order."),
191    .priv_size     = sizeof(FieldOrderContext),
192    .priv_class    = &fieldorder_class,
193    .query_formats = query_formats,
194    .inputs        = avfilter_vf_fieldorder_inputs,
195    .outputs       = avfilter_vf_fieldorder_outputs,
196    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
197};
198