2 * This file is part of Libav.
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.
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.
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.
21 * progressive to interlaced content filter, inspired by heavy debugging of tinterlace filter
24 #include "libavutil/common.h"
25 #include "libavutil/opt.h"
26 #include "libavutil/imgutils.h"
27 #include "libavutil/avassert.h"
45 typedef struct InterlaceContext {
47 enum ScanMode scan; // top or bottom field first scanning
48 #if FF_API_INTERLACE_LOWPASS_SET
49 int lowpass; // enable or disable low pass filterning
51 AVFrame *cur, *next; // the two frames from which the new one is obtained
52 int got_output; // signal an output frame is reday to request_frame()
55 #define OFFSET(x) offsetof(InterlaceContext, x)
56 #define V AV_OPT_FLAG_VIDEO_PARAM
57 static const AVOption options[] = {
58 { "scan", "scanning mode", OFFSET(scan),
59 AV_OPT_TYPE_INT, {.i64 = MODE_TFF }, 0, 1, .flags = V, .unit = "scan" },
60 { "tff", "top field first", 0,
61 AV_OPT_TYPE_CONST, {.i64 = MODE_TFF }, INT_MIN, INT_MAX, .flags = V, .unit = "scan" },
62 { "bff", "bottom field first", 0,
63 AV_OPT_TYPE_CONST, {.i64 = MODE_BFF }, INT_MIN, INT_MAX, .flags = V, .unit = "scan" },
64 #if FF_API_INTERLACE_LOWPASS_SET
65 { "lowpass", "(deprecated, this option is always set)", OFFSET(lowpass),
66 AV_OPT_TYPE_INT, {.i64 = 1 }, 0, 1, .flags = V },
71 static const AVClass class = {
72 .class_name = "interlace filter",
73 .item_name = av_default_item_name,
75 .version = LIBAVUTIL_VERSION_INT,
79 static const enum AVPixelFormat formats_supported[] = {
80 AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV444P,
81 AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUVA420P,
82 AV_PIX_FMT_GRAY8, AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P,
83 AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_NONE
86 static int query_formats(AVFilterContext *ctx)
88 ff_set_common_formats(ctx, ff_make_format_list(formats_supported));
92 static av_cold void uninit(AVFilterContext *ctx)
94 InterlaceContext *s = ctx->priv;
96 av_frame_free(&s->cur);
97 av_frame_free(&s->next);
102 static int config_out_props(AVFilterLink *outlink)
104 AVFilterContext *ctx = outlink->src;
105 AVFilterLink *inlink = outlink->src->inputs[0];
106 InterlaceContext *s = ctx->priv;
108 #if FF_API_INTERLACE_LOWPASS_SET
110 av_log(ctx, AV_LOG_WARNING, "This option is deprecated and always set.\n");
114 av_log(ctx, AV_LOG_ERROR, "input video height is too small\n");
115 return AVERROR_INVALIDDATA;
118 outlink->w = inlink->w;
119 outlink->h = inlink->h;
120 outlink->time_base = inlink->time_base;
122 outlink->time_base.num *= 2;
124 av_log(ctx, AV_LOG_VERBOSE, "%s interlacing\n",
125 s->scan == MODE_TFF ? "tff" : "bff");
130 static void copy_picture_field(AVFrame *src_frame, AVFrame *dst_frame,
131 AVFilterLink *inlink, enum FieldType field_type)
133 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
134 int vsub = desc->log2_chroma_h;
137 for (plane = 0; plane < desc->nb_components; plane++) {
138 int lines = (plane == 1 || plane == 2) ? -(-inlink->h) >> vsub : inlink->h;
139 int linesize = av_image_get_linesize(inlink->format, inlink->w, plane);
140 uint8_t *dstp = dst_frame->data[plane];
141 const uint8_t *srcp = src_frame->data[plane];
145 av_assert0(linesize >= 0);
147 lines = (lines + (field_type == FIELD_UPPER)) / 2;
148 if (field_type == FIELD_LOWER)
149 srcp += src_frame->linesize[plane];
150 if (field_type == FIELD_LOWER)
151 dstp += dst_frame->linesize[plane];
153 srcp_linesize = src_frame->linesize[plane] * 2;
154 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];
159 srcp_above = srcp; // there is no line above
161 srcp_below = srcp; // there is no line below
162 for (i = 0; i < linesize; i++) {
163 // this calculation is an integer representation of
164 // '0.5 * current + 0.25 * above + 0.25 * below'
165 // '1 +' is for rounding.
166 dstp[i] = (1 + srcp[i] + srcp[i] + srcp_above[i] + srcp_below[i]) >> 2;
168 dstp += dstp_linesize;
169 srcp += srcp_linesize;
174 static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
176 AVFilterContext *ctx = inlink->dst;
177 AVFilterLink *outlink = ctx->outputs[0];
178 InterlaceContext *s = ctx->priv;
182 av_frame_free(&s->cur);
186 /* we need at least two frames */
187 if (!s->cur || !s->next)
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);
195 return AVERROR(ENOMEM);
196 out->pts /= 2; // adjust pts to new framerate
197 ret = ff_filter_frame(outlink, out);
202 tff = (s->scan == MODE_TFF);
203 out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
205 return AVERROR(ENOMEM);
207 av_frame_copy_props(out, s->cur);
208 out->interlaced_frame = 1;
209 out->top_field_first = tff;
210 out->pts /= 2; // adjust pts to new framerate
212 /* copy upper/lower field from cur */
213 copy_picture_field(s->cur, out, inlink, tff ? FIELD_UPPER : FIELD_LOWER);
214 av_frame_free(&s->cur);
216 /* copy lower/upper field from next */
217 copy_picture_field(s->next, out, inlink, tff ? FIELD_LOWER : FIELD_UPPER);
218 av_frame_free(&s->next);
220 ret = ff_filter_frame(outlink, out);
226 static int request_frame(AVFilterLink *outlink)
228 AVFilterContext *ctx = outlink->src;
229 InterlaceContext *s = ctx->priv;
233 while (ret >= 0 && !s->got_output)
234 ret = ff_request_frame(ctx->inputs[0]);
239 static const AVFilterPad inputs[] = {
242 .type = AVMEDIA_TYPE_VIDEO,
243 .filter_frame = filter_frame,
248 static const AVFilterPad outputs[] = {
251 .type = AVMEDIA_TYPE_VIDEO,
252 .config_props = config_out_props,
253 .request_frame = request_frame,
258 AVFilter ff_vf_interlace = {
260 .description = NULL_IF_CONFIG_SMALL("Convert progressive video into interlaced."),
263 .priv_class = &class,
264 .priv_size = sizeof(InterlaceContext),
265 .query_formats = query_formats,