vf_interlace: do not process an already interlaced frame
[libav.git] / libavfilter / vf_interlace.c
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1/*
2 * This file is part of Libav.
3 *
4 * Libav is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * Libav is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License along
15 * with Libav; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
17 */
18
19/**
20 * @file
21 * progressive to interlaced content filter, inspired by heavy debugging of tinterlace filter
22 */
23
24#include "libavutil/common.h"
25#include "libavutil/opt.h"
26#include "libavutil/imgutils.h"
27#include "libavutil/avassert.h"
28
29#include "formats.h"
30#include "avfilter.h"
31#include "internal.h"
32#include "video.h"
33
34enum ScanMode {
35 MODE_TFF = 0,
36 MODE_BFF = 1,
37};
38
39enum FieldType {
40 FIELD_UPPER = 0,
41 FIELD_LOWER = 1,
42};
43
44typedef struct {
45 const AVClass *class;
46 enum ScanMode scan; // top or bottom field first scanning
47 int lowpass; // enable or disable low pass filterning
48 AVFrame *cur, *next; // the two frames from which the new one is obtained
49 int got_output; // signal an output frame is reday to request_frame()
50} InterlaceContext;
51
52#define OFFSET(x) offsetof(InterlaceContext, x)
53#define V AV_OPT_FLAG_VIDEO_PARAM
54static const AVOption options[] = {
55 { "scan", "scanning mode", OFFSET(scan),
56 AV_OPT_TYPE_INT, {.i64 = MODE_TFF }, 0, 1, .flags = V, .unit = "scan" },
57 { "tff", "top field first", 0,
58 AV_OPT_TYPE_CONST, {.i64 = MODE_TFF }, INT_MIN, INT_MAX, .flags = V, .unit = "scan" },
59 { "bff", "bottom field first", 0,
60 AV_OPT_TYPE_CONST, {.i64 = MODE_BFF }, INT_MIN, INT_MAX, .flags = V, .unit = "scan" },
61 { "lowpass", "enable vertical low-pass filter", OFFSET(lowpass),
62 AV_OPT_TYPE_INT, {.i64 = 1 }, 0, 1, .flags = V },
63 { NULL }
64};
65
66static const AVClass class = {
67 .class_name = "interlace filter",
68 .item_name = av_default_item_name,
69 .option = options,
70 .version = LIBAVUTIL_VERSION_INT,
71};
72
73
74static const enum AVPixelFormat formats_supported[] = {
75 AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV444P,
76 AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUVA420P,
77 AV_PIX_FMT_GRAY8, AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
78 AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_NONE
79};
80
81static int query_formats(AVFilterContext *ctx)
82{
83 ff_set_common_formats(ctx, ff_make_format_list(formats_supported));
84 return 0;
85}
86
87static av_cold void uninit(AVFilterContext *ctx)
88{
89 InterlaceContext *s = ctx->priv;
90
91 av_frame_free(&s->cur);
92 av_frame_free(&s->next);
93
94 av_opt_free(s);
95}
96
97static int config_out_props(AVFilterLink *outlink)
98{
99 AVFilterContext *ctx = outlink->src;
100 AVFilterLink *inlink = outlink->src->inputs[0];
101 InterlaceContext *s = ctx->priv;
102
103 if (inlink->h < 2) {
104 av_log(ctx, AV_LOG_ERROR, "input video height is too small\n");
105 return AVERROR_INVALIDDATA;
106 }
107 // same input size
108 outlink->w = inlink->w;
109 outlink->h = inlink->h;
110 outlink->time_base = inlink->time_base;
111 // half framerate
112 outlink->time_base.num *= 2;
113
114 av_log(ctx, AV_LOG_VERBOSE, "%s interlacing %s lowpass filter\n",
115 s->scan == MODE_TFF ? "tff" : "bff", (s->lowpass) ? "with" : "without");
116
117 return 0;
118}
119
120static void copy_picture_field(AVFrame *src_frame, AVFrame *dst_frame,
121 AVFilterLink *inlink, enum FieldType field_type,
122 int lowpass)
123{
124 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
125 int vsub = desc->log2_chroma_h;
126 int plane, i, j;
127
128 for (plane = 0; plane < desc->nb_components; plane++) {
bec509db 129 int lines = (plane == 1 || plane == 2) ? -(-inlink->h) >> vsub : inlink->h;
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130 int linesize = av_image_get_linesize(inlink->format, inlink->w, plane);
131 uint8_t *dstp = dst_frame->data[plane];
132 const uint8_t *srcp = src_frame->data[plane];
133
134 av_assert0(linesize >= 0);
135
bec509db 136 lines = (lines + (field_type == FIELD_UPPER)) / 2;
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137 if (field_type == FIELD_LOWER)
138 srcp += src_frame->linesize[plane];
139 if (field_type == FIELD_LOWER)
140 dstp += dst_frame->linesize[plane];
141 if (lowpass) {
142 int srcp_linesize = src_frame->linesize[plane] * 2;
143 int dstp_linesize = dst_frame->linesize[plane] * 2;
144 for (j = lines; j > 0; j--) {
145 const uint8_t *srcp_above = srcp - src_frame->linesize[plane];
146 const uint8_t *srcp_below = srcp + src_frame->linesize[plane];
147 if (j == lines)
148 srcp_above = srcp; // there is no line above
149 if (j == 1)
150 srcp_below = srcp; // there is no line below
151 for (i = 0; i < linesize; i++) {
152 // this calculation is an integer representation of
cd0faeee 153 // '0.5 * current + 0.25 * above + 0.25 * below'
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154 // '1 +' is for rounding.
155 dstp[i] = (1 + srcp[i] + srcp[i] + srcp_above[i] + srcp_below[i]) >> 2;
156 }
157 dstp += dstp_linesize;
158 srcp += srcp_linesize;
159 }
160 } else {
161 av_image_copy_plane(dstp, dst_frame->linesize[plane] * 2,
162 srcp, src_frame->linesize[plane] * 2,
163 linesize, lines);
164 }
165 }
166}
167
168static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
169{
170 AVFilterContext *ctx = inlink->dst;
171 AVFilterLink *outlink = ctx->outputs[0];
172 InterlaceContext *s = ctx->priv;
173 AVFrame *out;
174 int tff, ret;
175
176 av_frame_free(&s->cur);
177 s->cur = s->next;
178 s->next = buf;
179
180 /* we need at least two frames */
181 if (!s->cur || !s->next)
182 return 0;
183
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184 if (s->cur->interlaced_frame) {
185 av_log(ctx, AV_LOG_WARNING,
186 "video is already interlaced, adjusting framerate only\n");
187 out = av_frame_clone(s->cur);
188 out->pts /= 2; // adjust pts to new framerate
189 ret = ff_filter_frame(outlink, out);
190 s->got_output = 1;
191 return ret;
192 }
193
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194 tff = (s->scan == MODE_TFF);
195 out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
196 if (!out)
197 return AVERROR(ENOMEM);
198
199 av_frame_copy_props(out, s->cur);
200 out->interlaced_frame = 1;
201 out->top_field_first = tff;
202 out->pts /= 2; // adjust pts to new framerate
203
204 /* copy upper/lower field from cur */
205 copy_picture_field(s->cur, out, inlink, tff ? FIELD_UPPER : FIELD_LOWER, s->lowpass);
206 av_frame_free(&s->cur);
207
208 /* copy lower/upper field from next */
209 copy_picture_field(s->next, out, inlink, tff ? FIELD_LOWER : FIELD_UPPER, s->lowpass);
210 av_frame_free(&s->next);
211
212 ret = ff_filter_frame(outlink, out);
213 s->got_output = 1;
214
215 return ret;
216}
217
218static int request_frame(AVFilterLink *outlink)
219{
220 AVFilterContext *ctx = outlink->src;
221 InterlaceContext *s = ctx->priv;
222 int ret = 0;
223
224 s->got_output = 0;
225 while (ret >= 0 && !s->got_output)
226 ret = ff_request_frame(ctx->inputs[0]);
227
228 return ret;
229}
230
231static const AVFilterPad inputs[] = {
232 {
233 .name = "default",
234 .type = AVMEDIA_TYPE_VIDEO,
235 .filter_frame = filter_frame,
236 },
237 { NULL }
238};
239
240static const AVFilterPad outputs[] = {
241 {
242 .name = "default",
243 .type = AVMEDIA_TYPE_VIDEO,
244 .config_props = config_out_props,
245 .request_frame = request_frame,
246 },
247 { NULL }
248};
249
250AVFilter avfilter_vf_interlace = {
251 .name = "interlace",
252 .description = NULL_IF_CONFIG_SMALL("Convert progressive video into interlaced."),
253 .uninit = uninit,
254
255 .priv_class = &class,
256 .priv_size = sizeof(InterlaceContext),
257 .query_formats = query_formats,
258
259 .inputs = inputs,
260 .outputs = outputs,
261};
262