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vf_interlace.c
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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 "interlace.h"
37 #include "internal.h"
38 #include "video.h"
39 
40 #define OFFSET(x) offsetof(InterlaceContext, x)
41 #define V AV_OPT_FLAG_VIDEO_PARAM
42 static const AVOption interlace_options[] = {
43  { "scan", "scanning mode", OFFSET(scan),
44  AV_OPT_TYPE_INT, {.i64 = MODE_TFF }, 0, 1, .flags = V, .unit = "scan" },
45  { "tff", "top field first", 0,
46  AV_OPT_TYPE_CONST, {.i64 = MODE_TFF }, INT_MIN, INT_MAX, .flags = V, .unit = "scan" },
47  { "bff", "bottom field first", 0,
48  AV_OPT_TYPE_CONST, {.i64 = MODE_BFF }, INT_MIN, INT_MAX, .flags = V, .unit = "scan" },
49  { "lowpass", "enable vertical low-pass filter", OFFSET(lowpass),
50  AV_OPT_TYPE_INT, {.i64 = 1 }, 0, 1, .flags = V },
51  { NULL }
52 };
53 
54 AVFILTER_DEFINE_CLASS(interlace);
55 
56 static void lowpass_line_c(uint8_t *dstp, ptrdiff_t linesize,
57  const uint8_t *srcp,
58  const uint8_t *srcp_above,
59  const uint8_t *srcp_below)
60 {
61  int i;
62  for (i = 0; i < linesize; i++) {
63  // this calculation is an integer representation of
64  // '0.5 * current + 0.25 * above + 0.25 * below'
65  // '1 +' is for rounding.
66  dstp[i] = (1 + srcp[i] + srcp[i] + srcp_above[i] + srcp_below[i]) >> 2;
67  }
68 }
69 
70 static const enum AVPixelFormat formats_supported[] = {
75 };
76 
78 {
80  return 0;
81 }
82 
83 static av_cold void uninit(AVFilterContext *ctx)
84 {
85  InterlaceContext *s = ctx->priv;
86 
87  av_frame_free(&s->cur);
88  av_frame_free(&s->next);
89 }
90 
91 static int config_out_props(AVFilterLink *outlink)
92 {
93  AVFilterContext *ctx = outlink->src;
94  AVFilterLink *inlink = outlink->src->inputs[0];
95  InterlaceContext *s = ctx->priv;
96 
97  if (inlink->h < 2) {
98  av_log(ctx, AV_LOG_ERROR, "input video height is too small\n");
99  return AVERROR_INVALIDDATA;
100  }
101 
102  if (!s->lowpass)
103  av_log(ctx, AV_LOG_WARNING, "Lowpass filter is disabled, "
104  "the resulting video will be aliased rather than interlaced.\n");
105 
106  // same input size
107  outlink->w = inlink->w;
108  outlink->h = inlink->h;
109  outlink->time_base = inlink->time_base;
110  outlink->frame_rate = inlink->frame_rate;
111  // half framerate
112  outlink->time_base.num *= 2;
113  outlink->frame_rate.den *= 2;
114  outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
115 
116 
117  if (s->lowpass) {
119  if (ARCH_X86)
121  }
122 
123  av_log(ctx, AV_LOG_VERBOSE, "%s interlacing %s lowpass filter\n",
124  s->scan == MODE_TFF ? "tff" : "bff", (s->lowpass) ? "with" : "without");
125 
126  return 0;
127 }
128 
130  AVFrame *src_frame, AVFrame *dst_frame,
131  AVFilterLink *inlink, enum FieldType field_type,
132  int lowpass)
133 {
134  const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
135  int hsub = desc->log2_chroma_w;
136  int vsub = desc->log2_chroma_h;
137  int plane, j;
138 
139  for (plane = 0; plane < desc->nb_components; plane++) {
140  int cols = (plane == 1 || plane == 2) ? -(-inlink->w) >> hsub : inlink->w;
141  int lines = (plane == 1 || plane == 2) ? FF_CEIL_RSHIFT(inlink->h, vsub) : inlink->h;
142  uint8_t *dstp = dst_frame->data[plane];
143  const uint8_t *srcp = src_frame->data[plane];
144 
145  av_assert0(cols >= 0 || lines >= 0);
146 
147  lines = (lines + (field_type == FIELD_UPPER)) / 2;
148  if (field_type == FIELD_LOWER) {
149  srcp += src_frame->linesize[plane];
150  dstp += dst_frame->linesize[plane];
151  }
152  if (lowpass) {
153  int srcp_linesize = src_frame->linesize[plane] * 2;
154  int dstp_linesize = dst_frame->linesize[plane] * 2;
155  for (j = lines; j > 0; j--) {
156  const uint8_t *srcp_above = srcp - src_frame->linesize[plane];
157  const uint8_t *srcp_below = srcp + src_frame->linesize[plane];
158  if (j == lines)
159  srcp_above = srcp; // there is no line above
160  if (j == 1)
161  srcp_below = srcp; // there is no line below
162  s->lowpass_line(dstp, cols, srcp, srcp_above, srcp_below);
163  dstp += dstp_linesize;
164  srcp += srcp_linesize;
165  }
166  } else {
167  av_image_copy_plane(dstp, dst_frame->linesize[plane] * 2,
168  srcp, src_frame->linesize[plane] * 2,
169  cols, lines);
170  }
171  }
172 }
173 
174 static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
175 {
176  AVFilterContext *ctx = inlink->dst;
177  AVFilterLink *outlink = ctx->outputs[0];
178  InterlaceContext *s = ctx->priv;
179  AVFrame *out;
180  int tff, ret;
181 
182  av_frame_free(&s->cur);
183  s->cur = s->next;
184  s->next = buf;
185 
186  /* we need at least two frames */
187  if (!s->cur || !s->next)
188  return 0;
189 
190  if (s->cur->interlaced_frame) {
191  av_log(ctx, AV_LOG_WARNING,
192  "video is already interlaced, adjusting framerate only\n");
193  out = av_frame_clone(s->cur);
194  if (!out)
195  return AVERROR(ENOMEM);
196  out->pts /= 2; // adjust pts to new framerate
197  ret = ff_filter_frame(outlink, out);
198  return ret;
199  }
200 
201  tff = (s->scan == MODE_TFF);
202  out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
203  if (!out)
204  return AVERROR(ENOMEM);
205 
206  av_frame_copy_props(out, s->cur);
207  out->interlaced_frame = 1;
208  out->top_field_first = tff;
209  out->pts /= 2; // adjust pts to new framerate
210 
211  /* copy upper/lower field from cur */
212  copy_picture_field(s, s->cur, out, inlink, tff ? FIELD_UPPER : FIELD_LOWER, s->lowpass);
213  av_frame_free(&s->cur);
214 
215  /* copy lower/upper field from next */
216  copy_picture_field(s, s->next, out, inlink, tff ? FIELD_LOWER : FIELD_UPPER, s->lowpass);
217  av_frame_free(&s->next);
218 
219  ret = ff_filter_frame(outlink, out);
220 
221  return ret;
222 }
223 
224 static const AVFilterPad inputs[] = {
225  {
226  .name = "default",
227  .type = AVMEDIA_TYPE_VIDEO,
228  .filter_frame = filter_frame,
229  },
230  { NULL }
231 };
232 
233 static const AVFilterPad outputs[] = {
234  {
235  .name = "default",
236  .type = AVMEDIA_TYPE_VIDEO,
237  .config_props = config_out_props,
238  },
239  { NULL }
240 };
241 
243  .name = "interlace",
244  .description = NULL_IF_CONFIG_SMALL("Convert progressive video into interlaced."),
245  .uninit = uninit,
246  .priv_class = &interlace_class,
247  .priv_size = sizeof(InterlaceContext),
249  .inputs = inputs,
250  .outputs = outputs,
251 };