1/*
2 * Copyright (c) 2003 Michael Zucchi <notzed@ximian.com>
3 * Copyright (c) 2010 Baptiste Coudurier
4 * Copyright (c) 2011 Stefano Sabatini
5 * Copyright (c) 2013 Vittorio Giovara <vittorio.giovara@gmail.com>
6 *
7 * This file is part of FFmpeg.
8 *
9 * FFmpeg is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License along
20 * with FFmpeg; if not, write to the Free Software Foundation, Inc.,
21 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
22 */
23
24/**
25 * @file
26 * progressive to interlaced content filter, inspired by heavy debugging of tinterlace filter
27 */
28
29#include "libavutil/common.h"
30#include "libavutil/opt.h"
31#include "libavutil/imgutils.h"
32#include "libavutil/avassert.h"
33
34#include "formats.h"
35#include "avfilter.h"
36#include "internal.h"
37#include "version.h"
38#include "video.h"
39
40enum ScanMode {
41    MODE_TFF = 0,
42    MODE_BFF = 1,
43};
44
45enum FieldType {
46    FIELD_UPPER = 0,
47    FIELD_LOWER = 1,
48};
49
50typedef struct InterlaceContext {
51    const AVClass *class;
52    enum ScanMode scan;    // top or bottom field first scanning
53#if FF_API_INTERLACE_LOWPASS_SET
54    int lowpass;           // enable or disable low pass filterning
55#endif
56    AVFrame *cur, *next;   // the two frames from which the new one is obtained
57} InterlaceContext;
58
59#define OFFSET(x) offsetof(InterlaceContext, x)
60#define V AV_OPT_FLAG_VIDEO_PARAM
61static const AVOption interlace_options[] = {
62    { "scan", "scanning mode", OFFSET(scan),
63        AV_OPT_TYPE_INT,   {.i64 = MODE_TFF }, 0, 1, .flags = V, .unit = "scan" },
64    { "tff", "top field first", 0,
65        AV_OPT_TYPE_CONST, {.i64 = MODE_TFF }, INT_MIN, INT_MAX, .flags = V, .unit = "scan" },
66    { "bff", "bottom field first", 0,
67        AV_OPT_TYPE_CONST, {.i64 = MODE_BFF }, INT_MIN, INT_MAX, .flags = V, .unit = "scan" },
68#if FF_API_INTERLACE_LOWPASS_SET
69    { "lowpass", "(deprecated, this option is always set)", OFFSET(lowpass),
70        AV_OPT_TYPE_INT,   {.i64 = 1 },        0, 1, .flags = V },
71#endif
72    { NULL }
73};
74
75AVFILTER_DEFINE_CLASS(interlace);
76
77static const enum AVPixelFormat formats_supported[] = {
78    AV_PIX_FMT_YUV420P,  AV_PIX_FMT_YUV422P,  AV_PIX_FMT_YUV444P,
79    AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUV410P,  AV_PIX_FMT_YUVA420P,
80    AV_PIX_FMT_GRAY8,    AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
81    AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_NONE
82};
83
84static int query_formats(AVFilterContext *ctx)
85{
86    ff_set_common_formats(ctx, ff_make_format_list(formats_supported));
87    return 0;
88}
89
90static av_cold void uninit(AVFilterContext *ctx)
91{
92    InterlaceContext *s = ctx->priv;
93
94    av_frame_free(&s->cur);
95    av_frame_free(&s->next);
96}
97
98static int config_out_props(AVFilterLink *outlink)
99{
100    AVFilterContext *ctx = outlink->src;
101    AVFilterLink *inlink = outlink->src->inputs[0];
102    InterlaceContext *s = ctx->priv;
103
104#if FF_API_INTERLACE_LOWPASS_SET
105    if (!s->lowpass)
106        av_log(ctx, AV_LOG_WARNING, "This option is deprecated and always set.\n");
107#endif
108
109    if (inlink->h < 2) {
110        av_log(ctx, AV_LOG_ERROR, "input video height is too small\n");
111        return AVERROR_INVALIDDATA;
112    }
113    // same input size
114    outlink->w = inlink->w;
115    outlink->h = inlink->h;
116    outlink->time_base = inlink->time_base;
117    outlink->frame_rate = inlink->frame_rate;
118    // half framerate
119    outlink->time_base.num *= 2;
120    outlink->frame_rate.den *= 2;
121    outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
122
123    av_log(ctx, AV_LOG_VERBOSE, "%s interlacing\n",
124           s->scan == MODE_TFF ? "tff" : "bff");
125
126    return 0;
127}
128
129static void copy_picture_field(AVFrame *src_frame, AVFrame *dst_frame,
130                               AVFilterLink *inlink, enum FieldType field_type)
131{
132    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
133    int vsub = desc->log2_chroma_h;
134    int plane, i, j;
135
136    for (plane = 0; plane < desc->nb_components; plane++) {
137        int lines = (plane == 1 || plane == 2) ? FF_CEIL_RSHIFT(inlink->h, vsub) : inlink->h;
138        int linesize = av_image_get_linesize(inlink->format, inlink->w, plane);
139        uint8_t *dstp = dst_frame->data[plane];
140        const uint8_t *srcp = src_frame->data[plane];
141        int srcp_linesize;
142        int dstp_linesize;
143
144        av_assert0(linesize >= 0);
145
146        lines = (lines + (field_type == FIELD_UPPER)) / 2;
147        if (field_type == FIELD_LOWER)
148            srcp += src_frame->linesize[plane];
149        if (field_type == FIELD_LOWER)
150            dstp += dst_frame->linesize[plane];
151
152        srcp_linesize = src_frame->linesize[plane] * 2;
153        dstp_linesize = dst_frame->linesize[plane] * 2;
154        for (j = lines; j > 0; j--) {
155            const uint8_t *srcp_above = srcp - src_frame->linesize[plane];
156            const uint8_t *srcp_below = srcp + src_frame->linesize[plane];
157            if (j == lines)
158                srcp_above = srcp; // there is no line above
159            if (j == 1)
160                srcp_below = srcp; // there is no line below
161            for (i = 0; i < linesize; i++) {
162                // this calculation is an integer representation of
163                // '0.5 * current + 0.25 * above + 0.25 * below'
164                // '1 +' is for rounding.
165                dstp[i] = (1 + srcp[i] + srcp[i] + srcp_above[i] + srcp_below[i]) >> 2;
166            }
167            dstp += dstp_linesize;
168            srcp += srcp_linesize;
169        }
170    }
171}
172
173static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
174{
175    AVFilterContext *ctx = inlink->dst;
176    AVFilterLink *outlink = ctx->outputs[0];
177    InterlaceContext *s = ctx->priv;
178    AVFrame *out;
179    int tff, ret;
180
181    av_frame_free(&s->cur);
182    s->cur  = s->next;
183    s->next = buf;
184
185    /* we need at least two frames */
186    if (!s->cur || !s->next)
187        return 0;
188
189    if (s->cur->interlaced_frame) {
190        av_log(ctx, AV_LOG_WARNING,
191               "video is already interlaced, adjusting framerate only\n");
192        out = av_frame_clone(s->cur);
193        if (!out)
194            return AVERROR(ENOMEM);
195        out->pts /= 2;  // adjust pts to new framerate
196        ret = ff_filter_frame(outlink, out);
197        return ret;
198    }
199
200    tff = (s->scan == MODE_TFF);
201    out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
202    if (!out)
203        return AVERROR(ENOMEM);
204
205    av_frame_copy_props(out, s->cur);
206    out->interlaced_frame = 1;
207    out->top_field_first  = tff;
208    out->pts             /= 2;  // adjust pts to new framerate
209
210    /* copy upper/lower field from cur */
211    copy_picture_field(s->cur, out, inlink, tff ? FIELD_UPPER : FIELD_LOWER);
212    av_frame_free(&s->cur);
213
214    /* copy lower/upper field from next */
215    copy_picture_field(s->next, out, inlink, tff ? FIELD_LOWER : FIELD_UPPER);
216    av_frame_free(&s->next);
217
218    ret = ff_filter_frame(outlink, out);
219
220    return ret;
221}
222
223static const AVFilterPad inputs[] = {
224    {
225        .name         = "default",
226        .type         = AVMEDIA_TYPE_VIDEO,
227        .filter_frame = filter_frame,
228    },
229    { NULL }
230};
231
232static const AVFilterPad outputs[] = {
233    {
234        .name         = "default",
235        .type         = AVMEDIA_TYPE_VIDEO,
236        .config_props = config_out_props,
237    },
238    { NULL }
239};
240
241AVFilter ff_vf_interlace = {
242    .name          = "interlace",
243    .description   = NULL_IF_CONFIG_SMALL("Convert progressive video into interlaced."),
244    .uninit        = uninit,
245    .priv_class    = &interlace_class,
246    .priv_size     = sizeof(InterlaceContext),
247    .query_formats = query_formats,
248    .inputs        = inputs,
249    .outputs       = outputs,
250};
251