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1 /*
2  * Copyright (c) 2017 Thomas Mundt <tmundt75@gmail.com>
3  * Copyright (c) 2011 Stefano Sabatini
4  * Copyright (c) 2010 Baptiste Coudurier
5  * Copyright (c) 2003 Michael Zucchi <notzed@ximian.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  * temporal field interlace filter, ported from MPlayer/libmpcodecs
27  */
28 
29 #include "libavutil/opt.h"
30 #include "libavutil/imgutils.h"
31 #include "libavutil/avassert.h"
32 #include "avfilter.h"
33 #include "internal.h"
34 #include "tinterlace.h"
35 
36 #define OFFSET(x) offsetof(TInterlaceContext, x)
37 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
38 
39 static const AVOption tinterlace_options[] = {
40     {"mode",              "select interlace mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=MODE_MERGE}, 0, MODE_NB-1, FLAGS, "mode"},
41     {"merge",             "merge fields",                                 0, AV_OPT_TYPE_CONST, {.i64=MODE_MERGE},             INT_MIN, INT_MAX, FLAGS, "mode"},
42     {"drop_even",         "drop even fields",                             0, AV_OPT_TYPE_CONST, {.i64=MODE_DROP_EVEN},         INT_MIN, INT_MAX, FLAGS, "mode"},
43     {"drop_odd",          "drop odd fields",                              0, AV_OPT_TYPE_CONST, {.i64=MODE_DROP_ODD},          INT_MIN, INT_MAX, FLAGS, "mode"},
44     {"pad",               "pad alternate lines with black",               0, AV_OPT_TYPE_CONST, {.i64=MODE_PAD},               INT_MIN, INT_MAX, FLAGS, "mode"},
45     {"interleave_top",    "interleave top and bottom fields",             0, AV_OPT_TYPE_CONST, {.i64=MODE_INTERLEAVE_TOP},    INT_MIN, INT_MAX, FLAGS, "mode"},
46     {"interleave_bottom", "interleave bottom and top fields",             0, AV_OPT_TYPE_CONST, {.i64=MODE_INTERLEAVE_BOTTOM}, INT_MIN, INT_MAX, FLAGS, "mode"},
47     {"interlacex2",       "interlace fields from two consecutive frames", 0, AV_OPT_TYPE_CONST, {.i64=MODE_INTERLACEX2},       INT_MIN, INT_MAX, FLAGS, "mode"},
48     {"mergex2",           "merge fields keeping same frame rate",         0, AV_OPT_TYPE_CONST, {.i64=MODE_MERGEX2},           INT_MIN, INT_MAX, FLAGS, "mode"},
49 
50     {"flags",             "set flags", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = 0}, 0, INT_MAX, 0, "flags" },
51     {"low_pass_filter",   "enable vertical low-pass filter",              0, AV_OPT_TYPE_CONST, {.i64 = TINTERLACE_FLAG_VLPF}, INT_MIN, INT_MAX, FLAGS, "flags" },
52     {"vlpf",              "enable vertical low-pass filter",              0, AV_OPT_TYPE_CONST, {.i64 = TINTERLACE_FLAG_VLPF}, INT_MIN, INT_MAX, FLAGS, "flags" },
53     {"complex_filter",    "enable complex vertical low-pass filter",      0, AV_OPT_TYPE_CONST, {.i64 = TINTERLACE_FLAG_CVLPF},INT_MIN, INT_MAX, FLAGS, "flags" },
54     {"cvlpf",             "enable complex vertical low-pass filter",      0, AV_OPT_TYPE_CONST, {.i64 = TINTERLACE_FLAG_CVLPF},INT_MIN, INT_MAX, FLAGS, "flags" },
55     {"exact_tb",          "force a timebase which can represent timestamps exactly", 0, AV_OPT_TYPE_CONST, {.i64 = TINTERLACE_FLAG_EXACT_TB}, INT_MIN, INT_MAX, FLAGS, "flags" },
56     {"bypass_il",         "bypass already interlaced frames",             0, AV_OPT_TYPE_CONST, {.i64 = TINTERLACE_FLAG_BYPASS_IL}, INT_MIN, INT_MAX, FLAGS, "flags" },
57 
58     {NULL}
59 };
60 
61 AVFILTER_DEFINE_CLASS(tinterlace);
62 
63 static const AVOption interlace_options[] = {
64    { "scan",              "scanning mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64 = MODE_TFF}, 0, 1, FLAGS, "mode"},
65    { "tff",               "top field first",                              0, AV_OPT_TYPE_CONST, {.i64 = MODE_TFF}, INT_MIN, INT_MAX, FLAGS, .unit = "mode"},
66    { "bff",               "bottom field first",                           0, AV_OPT_TYPE_CONST, {.i64 = MODE_BFF}, INT_MIN, INT_MAX, FLAGS, .unit = "mode"},
67    { "lowpass",           "set vertical low-pass filter", OFFSET(lowpass), AV_OPT_TYPE_INT,   {.i64 = VLPF_LIN}, 0, 2, FLAGS, "lowpass" },
68    {     "off",           "disable vertical low-pass filter",             0, AV_OPT_TYPE_CONST, {.i64 = VLPF_OFF}, INT_MIN, INT_MAX, FLAGS, "lowpass" },
69    {     "linear",        "linear vertical low-pass filter",              0, AV_OPT_TYPE_CONST, {.i64 = VLPF_LIN}, INT_MIN, INT_MAX, FLAGS, "lowpass" },
70    {     "complex",       "complex vertical low-pass filter",             0, AV_OPT_TYPE_CONST, {.i64 = VLPF_CMP}, INT_MIN, INT_MAX, FLAGS, "lowpass" },
71 
72    { NULL }
73 };
74 
75 AVFILTER_DEFINE_CLASS(interlace);
76 
77 #define FULL_SCALE_YUVJ_FORMATS \
78     AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P
79 
80 static const enum AVPixelFormat full_scale_yuvj_pix_fmts[] = {
81     FULL_SCALE_YUVJ_FORMATS, AV_PIX_FMT_NONE
82 };
83 
84 static const AVRational standard_tbs[] = {
85     {1, 25},
86     {1, 30},
87     {1001, 30000},
88 };
89 
90 static const enum AVPixelFormat pix_fmts[] = {
91     AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P,
92     AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV422P,
93     AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUV444P,
94     AV_PIX_FMT_YUV420P10LE, AV_PIX_FMT_YUV422P10LE,
95     AV_PIX_FMT_YUV440P10LE, AV_PIX_FMT_YUV444P10LE,
96     AV_PIX_FMT_YUV420P12LE, AV_PIX_FMT_YUV422P12LE,
97     AV_PIX_FMT_YUV440P12LE, AV_PIX_FMT_YUV444P12LE,
98     AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA444P,
99     AV_PIX_FMT_YUVA420P10LE, AV_PIX_FMT_YUVA422P10LE, AV_PIX_FMT_YUVA444P10LE,
100     AV_PIX_FMT_GRAY8, FULL_SCALE_YUVJ_FORMATS,
101     AV_PIX_FMT_NONE
102 };
103 
lowpass_line_c(uint8_t * dstp,ptrdiff_t width,const uint8_t * srcp,ptrdiff_t mref,ptrdiff_t pref,int clip_max)104 static void lowpass_line_c(uint8_t *dstp, ptrdiff_t width, const uint8_t *srcp,
105                            ptrdiff_t mref, ptrdiff_t pref, int clip_max)
106 {
107     const uint8_t *srcp_above = srcp + mref;
108     const uint8_t *srcp_below = srcp + pref;
109     int i;
110     for (i = 0; i < width; i++) {
111         // this calculation is an integer representation of
112         // '0.5 * current + 0.25 * above + 0.25 * below'
113         // '1 +' is for rounding.
114         dstp[i] = (1 + srcp[i] + srcp[i] + srcp_above[i] + srcp_below[i]) >> 2;
115     }
116 }
117 
lowpass_line_c_16(uint8_t * dst8,ptrdiff_t width,const uint8_t * src8,ptrdiff_t mref,ptrdiff_t pref,int clip_max)118 static void lowpass_line_c_16(uint8_t *dst8, ptrdiff_t width, const uint8_t *src8,
119                               ptrdiff_t mref, ptrdiff_t pref, int clip_max)
120 {
121     uint16_t *dstp = (uint16_t *)dst8;
122     const uint16_t *srcp = (const uint16_t *)src8;
123     const uint16_t *srcp_above = srcp + mref / 2;
124     const uint16_t *srcp_below = srcp + pref / 2;
125     int i, src_x;
126     for (i = 0; i < width; i++) {
127         // this calculation is an integer representation of
128         // '0.5 * current + 0.25 * above + 0.25 * below'
129         // '1 +' is for rounding.
130         src_x   = av_le2ne16(srcp[i]) << 1;
131         dstp[i] = av_le2ne16((1 + src_x + av_le2ne16(srcp_above[i])
132                              + av_le2ne16(srcp_below[i])) >> 2);
133     }
134 }
135 
lowpass_line_complex_c(uint8_t * dstp,ptrdiff_t width,const uint8_t * srcp,ptrdiff_t mref,ptrdiff_t pref,int clip_max)136 static void lowpass_line_complex_c(uint8_t *dstp, ptrdiff_t width, const uint8_t *srcp,
137                                    ptrdiff_t mref, ptrdiff_t pref, int clip_max)
138 {
139     const uint8_t *srcp_above = srcp + mref;
140     const uint8_t *srcp_below = srcp + pref;
141     const uint8_t *srcp_above2 = srcp + mref * 2;
142     const uint8_t *srcp_below2 = srcp + pref * 2;
143     int i, src_x, src_ab;
144     for (i = 0; i < width; i++) {
145         // this calculation is an integer representation of
146         // '0.75 * current + 0.25 * above + 0.25 * below - 0.125 * above2 - 0.125 * below2'
147         // '4 +' is for rounding.
148         src_x   = srcp[i] << 1;
149         src_ab  = srcp_above[i] + srcp_below[i];
150         dstp[i] = av_clip_uint8((4 + ((srcp[i] + src_x + src_ab) << 1)
151                                 - srcp_above2[i] - srcp_below2[i]) >> 3);
152         // Prevent over-sharpening:
153         // dst must not exceed src when the average of above and below
154         // is less than src. And the other way around.
155         if (src_ab > src_x) {
156             if (dstp[i] < srcp[i])
157                 dstp[i] = srcp[i];
158         } else if (dstp[i] > srcp[i])
159             dstp[i] = srcp[i];
160     }
161 }
162 
lowpass_line_complex_c_16(uint8_t * dst8,ptrdiff_t width,const uint8_t * src8,ptrdiff_t mref,ptrdiff_t pref,int clip_max)163 static void lowpass_line_complex_c_16(uint8_t *dst8, ptrdiff_t width, const uint8_t *src8,
164                                       ptrdiff_t mref, ptrdiff_t pref, int clip_max)
165 {
166     uint16_t *dstp = (uint16_t *)dst8;
167     const uint16_t *srcp = (const uint16_t *)src8;
168     const uint16_t *srcp_above = srcp + mref / 2;
169     const uint16_t *srcp_below = srcp + pref / 2;
170     const uint16_t *srcp_above2 = srcp + mref;
171     const uint16_t *srcp_below2 = srcp + pref;
172     int i, dst_le, src_le, src_x, src_ab;
173     for (i = 0; i < width; i++) {
174         // this calculation is an integer representation of
175         // '0.75 * current + 0.25 * above + 0.25 * below - 0.125 * above2 - 0.125 * below2'
176         // '4 +' is for rounding.
177         src_le = av_le2ne16(srcp[i]);
178         src_x  = src_le << 1;
179         src_ab = av_le2ne16(srcp_above[i]) + av_le2ne16(srcp_below[i]);
180         dst_le = av_clip((4 + ((src_le + src_x + src_ab) << 1)
181                          - av_le2ne16(srcp_above2[i])
182                          - av_le2ne16(srcp_below2[i])) >> 3, 0, clip_max);
183         // Prevent over-sharpening:
184         // dst must not exceed src when the average of above and below
185         // is less than src. And the other way around.
186         if (src_ab > src_x) {
187             if (dst_le < src_le)
188                 dstp[i] = av_le2ne16(src_le);
189             else
190                 dstp[i] = av_le2ne16(dst_le);
191         } else if (dst_le > src_le) {
192             dstp[i] = av_le2ne16(src_le);
193         } else
194             dstp[i] = av_le2ne16(dst_le);
195     }
196 }
197 
uninit(AVFilterContext * ctx)198 static av_cold void uninit(AVFilterContext *ctx)
199 {
200     TInterlaceContext *tinterlace = ctx->priv;
201 
202     av_frame_free(&tinterlace->cur );
203     av_frame_free(&tinterlace->next);
204     av_freep(&tinterlace->black_data[0]);
205 }
206 
config_out_props(AVFilterLink * outlink)207 static int config_out_props(AVFilterLink *outlink)
208 {
209     AVFilterContext *ctx = outlink->src;
210     AVFilterLink *inlink = outlink->src->inputs[0];
211     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(outlink->format);
212     TInterlaceContext *tinterlace = ctx->priv;
213     int i;
214 
215     tinterlace->vsub = desc->log2_chroma_h;
216     outlink->w = inlink->w;
217     outlink->h = tinterlace->mode == MODE_MERGE || tinterlace->mode == MODE_PAD || tinterlace->mode == MODE_MERGEX2?
218         inlink->h*2 : inlink->h;
219     if (tinterlace->mode == MODE_MERGE || tinterlace->mode == MODE_PAD || tinterlace->mode == MODE_MERGEX2)
220         outlink->sample_aspect_ratio = av_mul_q(inlink->sample_aspect_ratio,
221                                                 av_make_q(2, 1));
222 
223     if (tinterlace->mode == MODE_PAD) {
224         uint8_t black[4] = { 0, 0, 0, 16 };
225         int ret;
226         ff_draw_init(&tinterlace->draw, outlink->format, 0);
227         ff_draw_color(&tinterlace->draw, &tinterlace->color, black);
228         if (ff_fmt_is_in(outlink->format, full_scale_yuvj_pix_fmts))
229             tinterlace->color.comp[0].u8[0] = 0;
230         ret = av_image_alloc(tinterlace->black_data, tinterlace->black_linesize,
231                              outlink->w, outlink->h, outlink->format, 16);
232         if (ret < 0)
233             return ret;
234 
235         ff_fill_rectangle(&tinterlace->draw, &tinterlace->color, tinterlace->black_data,
236                           tinterlace->black_linesize, 0, 0, outlink->w, outlink->h);
237     }
238     if (tinterlace->flags & (TINTERLACE_FLAG_VLPF | TINTERLACE_FLAG_CVLPF)
239             && !(tinterlace->mode == MODE_INTERLEAVE_TOP
240               || tinterlace->mode == MODE_INTERLEAVE_BOTTOM)) {
241         av_log(ctx, AV_LOG_WARNING, "low_pass_filter flags ignored with mode %d\n",
242                 tinterlace->mode);
243         tinterlace->flags &= ~(TINTERLACE_FLAG_VLPF | TINTERLACE_FLAG_CVLPF);
244     }
245     tinterlace->preout_time_base = inlink->time_base;
246     if (tinterlace->mode == MODE_INTERLACEX2) {
247         tinterlace->preout_time_base.den *= 2;
248         outlink->frame_rate = av_mul_q(inlink->frame_rate, (AVRational){2,1});
249         outlink->time_base  = av_mul_q(inlink->time_base , (AVRational){1,2});
250     } else if (tinterlace->mode == MODE_MERGEX2) {
251         outlink->frame_rate = inlink->frame_rate;
252         outlink->time_base  = inlink->time_base;
253     } else if (tinterlace->mode != MODE_PAD) {
254         outlink->frame_rate = av_mul_q(inlink->frame_rate, (AVRational){1,2});
255         outlink->time_base  = av_mul_q(inlink->time_base , (AVRational){2,1});
256     }
257 
258     for (i = 0; i<FF_ARRAY_ELEMS(standard_tbs); i++){
259         if (!av_cmp_q(standard_tbs[i], outlink->time_base))
260             break;
261     }
262     if (i == FF_ARRAY_ELEMS(standard_tbs) ||
263         (tinterlace->flags & TINTERLACE_FLAG_EXACT_TB))
264         outlink->time_base = tinterlace->preout_time_base;
265 
266     tinterlace->csp = av_pix_fmt_desc_get(outlink->format);
267     if (tinterlace->flags & TINTERLACE_FLAG_CVLPF) {
268         if (tinterlace->csp->comp[0].depth > 8)
269             tinterlace->lowpass_line = lowpass_line_complex_c_16;
270         else
271             tinterlace->lowpass_line = lowpass_line_complex_c;
272 #if ARCH_X86
273         ff_tinterlace_init_x86(tinterlace);
274 #endif
275     } else if (tinterlace->flags & TINTERLACE_FLAG_VLPF) {
276         if (tinterlace->csp->comp[0].depth > 8)
277             tinterlace->lowpass_line = lowpass_line_c_16;
278         else
279             tinterlace->lowpass_line = lowpass_line_c;
280 #if ARCH_X86
281         ff_tinterlace_init_x86(tinterlace);
282 #endif
283     }
284 
285     av_log(ctx, AV_LOG_VERBOSE, "mode:%d filter:%s h:%d -> h:%d\n", tinterlace->mode,
286            (tinterlace->flags & TINTERLACE_FLAG_CVLPF) ? "complex" :
287            (tinterlace->flags & TINTERLACE_FLAG_VLPF) ? "linear" : "off",
288            inlink->h, outlink->h);
289 
290     return 0;
291 }
292 
293 #define FIELD_UPPER           0
294 #define FIELD_LOWER           1
295 #define FIELD_UPPER_AND_LOWER 2
296 
297 /**
298  * Copy picture field from src to dst.
299  *
300  * @param src_field copy from upper, lower field or both
301  * @param interleave leave a padding line between each copied line
302  * @param dst_field copy to upper or lower field,
303  *        only meaningful when interleave is selected
304  * @param flags context flags
305  */
306 static inline
copy_picture_field(TInterlaceContext * tinterlace,uint8_t * dst[4],int dst_linesize[4],const uint8_t * src[4],int src_linesize[4],enum AVPixelFormat format,int w,int src_h,int src_field,int interleave,int dst_field,int flags)307 void copy_picture_field(TInterlaceContext *tinterlace,
308                         uint8_t *dst[4], int dst_linesize[4],
309                         const uint8_t *src[4], int src_linesize[4],
310                         enum AVPixelFormat format, int w, int src_h,
311                         int src_field, int interleave, int dst_field,
312                         int flags)
313 {
314     const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(format);
315     int hsub = desc->log2_chroma_w;
316     int plane, vsub = desc->log2_chroma_h;
317     int k = src_field == FIELD_UPPER_AND_LOWER ? 1 : 2;
318     int h;
319 
320     for (plane = 0; plane < desc->nb_components; plane++) {
321         int lines = plane == 1 || plane == 2 ? AV_CEIL_RSHIFT(src_h, vsub) : src_h;
322         int cols  = plane == 1 || plane == 2 ? AV_CEIL_RSHIFT(    w, hsub) : w;
323         uint8_t *dstp = dst[plane];
324         const uint8_t *srcp = src[plane];
325         int srcp_linesize = src_linesize[plane] * k;
326         int dstp_linesize = dst_linesize[plane] * (interleave ? 2 : 1);
327         int clip_max = (1 << tinterlace->csp->comp[plane].depth) - 1;
328 
329         lines = (lines + (src_field == FIELD_UPPER)) / k;
330         if (src_field == FIELD_LOWER)
331             srcp += src_linesize[plane];
332         if (interleave && dst_field == FIELD_LOWER)
333             dstp += dst_linesize[plane];
334         // Low-pass filtering is required when creating an interlaced destination from
335         // a progressive source which contains high-frequency vertical detail.
336         // Filtering will reduce interlace 'twitter' and Moire patterning.
337         if (flags & (TINTERLACE_FLAG_VLPF | TINTERLACE_FLAG_CVLPF)) {
338             int x = !!(flags & TINTERLACE_FLAG_CVLPF);
339             for (h = lines; h > 0; h--) {
340                 ptrdiff_t pref = src_linesize[plane];
341                 ptrdiff_t mref = -pref;
342                 if (h >= (lines - x))  mref = 0; // there is no line above
343                 else if (h <= (1 + x)) pref = 0; // there is no line below
344 
345                 tinterlace->lowpass_line(dstp, cols, srcp, mref, pref, clip_max);
346                 dstp += dstp_linesize;
347                 srcp += srcp_linesize;
348             }
349         } else {
350             if (tinterlace->csp->comp[plane].depth > 8)
351                 cols *= 2;
352             av_image_copy_plane(dstp, dstp_linesize, srcp, srcp_linesize, cols, lines);
353         }
354     }
355 }
356 
filter_frame(AVFilterLink * inlink,AVFrame * picref)357 static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
358 {
359     AVFilterContext *ctx = inlink->dst;
360     AVFilterLink *outlink = ctx->outputs[0];
361     TInterlaceContext *tinterlace = ctx->priv;
362     AVFrame *cur, *next, *out;
363     int field, tff, ret;
364 
365     av_frame_free(&tinterlace->cur);
366     tinterlace->cur  = tinterlace->next;
367     tinterlace->next = picref;
368 
369     cur = tinterlace->cur;
370     next = tinterlace->next;
371     /* we need at least two frames */
372     if (!tinterlace->cur)
373         return 0;
374 
375     switch (tinterlace->mode) {
376     case MODE_MERGEX2: /* move the odd frame into the upper field of the new image, even into
377                         * the lower field, generating a double-height video at same framerate */
378     case MODE_MERGE: /* move the odd frame into the upper field of the new image, even into
379              * the lower field, generating a double-height video at half framerate */
380         out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
381         if (!out)
382             return AVERROR(ENOMEM);
383         av_frame_copy_props(out, cur);
384         out->height = outlink->h;
385         out->interlaced_frame = 1;
386         out->top_field_first = 1;
387         out->sample_aspect_ratio = av_mul_q(cur->sample_aspect_ratio, av_make_q(2, 1));
388 
389         /* write odd frame lines into the upper field of the new frame */
390         copy_picture_field(tinterlace, out->data, out->linesize,
391                            (const uint8_t **)cur->data, cur->linesize,
392                            inlink->format, inlink->w, inlink->h,
393                            FIELD_UPPER_AND_LOWER, 1, tinterlace->mode == MODE_MERGEX2 ? (1 + inlink->frame_count_out) & 1 ? FIELD_LOWER : FIELD_UPPER : FIELD_UPPER, tinterlace->flags);
394         /* write even frame lines into the lower field of the new frame */
395         copy_picture_field(tinterlace, out->data, out->linesize,
396                            (const uint8_t **)next->data, next->linesize,
397                            inlink->format, inlink->w, inlink->h,
398                            FIELD_UPPER_AND_LOWER, 1, tinterlace->mode == MODE_MERGEX2 ? (1 + inlink->frame_count_out) & 1 ? FIELD_UPPER : FIELD_LOWER : FIELD_LOWER, tinterlace->flags);
399         if (tinterlace->mode != MODE_MERGEX2)
400             av_frame_free(&tinterlace->next);
401         break;
402 
403     case MODE_DROP_ODD:  /* only output even frames, odd  frames are dropped; height unchanged, half framerate */
404     case MODE_DROP_EVEN: /* only output odd  frames, even frames are dropped; height unchanged, half framerate */
405         out = av_frame_clone(tinterlace->mode == MODE_DROP_EVEN ? cur : next);
406         if (!out)
407             return AVERROR(ENOMEM);
408         av_frame_free(&tinterlace->next);
409         break;
410 
411     case MODE_PAD: /* expand each frame to double height, but pad alternate
412                     * lines with black; framerate unchanged */
413         out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
414         if (!out)
415             return AVERROR(ENOMEM);
416         av_frame_copy_props(out, cur);
417         out->height = outlink->h;
418         out->sample_aspect_ratio = av_mul_q(cur->sample_aspect_ratio, av_make_q(2, 1));
419 
420         field = (1 + outlink->frame_count_in) & 1 ? FIELD_UPPER : FIELD_LOWER;
421         /* copy upper and lower fields */
422         copy_picture_field(tinterlace, out->data, out->linesize,
423                            (const uint8_t **)cur->data, cur->linesize,
424                            inlink->format, inlink->w, inlink->h,
425                            FIELD_UPPER_AND_LOWER, 1, field, tinterlace->flags);
426         /* pad with black the other field */
427         copy_picture_field(tinterlace, out->data, out->linesize,
428                            (const uint8_t **)tinterlace->black_data, tinterlace->black_linesize,
429                            inlink->format, inlink->w, inlink->h,
430                            FIELD_UPPER_AND_LOWER, 1, !field, tinterlace->flags);
431         break;
432 
433         /* interleave upper/lower lines from odd frames with lower/upper lines from even frames,
434          * halving the frame rate and preserving image height */
435     case MODE_INTERLEAVE_TOP:    /* top    field first */
436     case MODE_INTERLEAVE_BOTTOM: /* bottom field first */
437         if ((tinterlace->flags & TINTERLACE_FLAG_BYPASS_IL) && cur->interlaced_frame) {
438             av_log(ctx, AV_LOG_WARNING,
439                    "video is already interlaced, adjusting framerate only\n");
440             out = av_frame_clone(cur);
441             if (!out)
442                 return AVERROR(ENOMEM);
443             out->pts /= 2;  // adjust pts to new framerate
444             ret = ff_filter_frame(outlink, out);
445             return ret;
446         }
447         tff = tinterlace->mode == MODE_INTERLEAVE_TOP;
448         out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
449         if (!out)
450             return AVERROR(ENOMEM);
451         av_frame_copy_props(out, cur);
452         out->interlaced_frame = 1;
453         out->top_field_first = tff;
454 
455         /* copy upper/lower field from cur */
456         copy_picture_field(tinterlace, out->data, out->linesize,
457                            (const uint8_t **)cur->data, cur->linesize,
458                            inlink->format, inlink->w, inlink->h,
459                            tff ? FIELD_UPPER : FIELD_LOWER, 1, tff ? FIELD_UPPER : FIELD_LOWER,
460                            tinterlace->flags);
461         /* copy lower/upper field from next */
462         copy_picture_field(tinterlace, out->data, out->linesize,
463                            (const uint8_t **)next->data, next->linesize,
464                            inlink->format, inlink->w, inlink->h,
465                            tff ? FIELD_LOWER : FIELD_UPPER, 1, tff ? FIELD_LOWER : FIELD_UPPER,
466                            tinterlace->flags);
467         av_frame_free(&tinterlace->next);
468         break;
469     case MODE_INTERLACEX2: /* re-interlace preserving image height, double frame rate */
470         /* output current frame first */
471         out = av_frame_clone(cur);
472         if (!out)
473             return AVERROR(ENOMEM);
474         out->interlaced_frame = 1;
475         if (cur->pts != AV_NOPTS_VALUE)
476             out->pts = cur->pts*2;
477 
478         out->pts = av_rescale_q(out->pts, tinterlace->preout_time_base, outlink->time_base);
479         if ((ret = ff_filter_frame(outlink, out)) < 0)
480             return ret;
481 
482         /* output mix of current and next frame */
483         tff = next->top_field_first;
484         out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
485         if (!out)
486             return AVERROR(ENOMEM);
487         av_frame_copy_props(out, next);
488         out->interlaced_frame = 1;
489         out->top_field_first = !tff;
490 
491         if (next->pts != AV_NOPTS_VALUE && cur->pts != AV_NOPTS_VALUE)
492             out->pts = cur->pts + next->pts;
493         else
494             out->pts = AV_NOPTS_VALUE;
495         /* write current frame second field lines into the second field of the new frame */
496         copy_picture_field(tinterlace, out->data, out->linesize,
497                            (const uint8_t **)cur->data, cur->linesize,
498                            inlink->format, inlink->w, inlink->h,
499                            tff ? FIELD_LOWER : FIELD_UPPER, 1, tff ? FIELD_LOWER : FIELD_UPPER,
500                            tinterlace->flags);
501         /* write next frame first field lines into the first field of the new frame */
502         copy_picture_field(tinterlace, out->data, out->linesize,
503                            (const uint8_t **)next->data, next->linesize,
504                            inlink->format, inlink->w, inlink->h,
505                            tff ? FIELD_UPPER : FIELD_LOWER, 1, tff ? FIELD_UPPER : FIELD_LOWER,
506                            tinterlace->flags);
507         break;
508     default:
509         av_assert0(0);
510     }
511 
512     out->pts = av_rescale_q(out->pts, tinterlace->preout_time_base, outlink->time_base);
513     ret = ff_filter_frame(outlink, out);
514 
515     return ret;
516 }
517 
init_interlace(AVFilterContext * ctx)518 static int init_interlace(AVFilterContext *ctx)
519 {
520     TInterlaceContext *tinterlace = ctx->priv;
521 
522     if (tinterlace->mode <= MODE_BFF)
523         tinterlace->mode += MODE_INTERLEAVE_TOP;
524 
525     tinterlace->flags |= TINTERLACE_FLAG_BYPASS_IL;
526     if (tinterlace->lowpass == VLPF_LIN)
527         tinterlace->flags |= TINTERLACE_FLAG_VLPF;
528     if (tinterlace->lowpass == VLPF_CMP)
529         tinterlace->flags |= TINTERLACE_FLAG_CVLPF;
530 
531     return 0;
532 }
533 
534 static const AVFilterPad tinterlace_inputs[] = {
535     {
536         .name         = "default",
537         .type         = AVMEDIA_TYPE_VIDEO,
538         .filter_frame = filter_frame,
539     },
540 };
541 
542 static const AVFilterPad tinterlace_outputs[] = {
543     {
544         .name         = "default",
545         .type         = AVMEDIA_TYPE_VIDEO,
546         .config_props = config_out_props,
547     },
548 };
549 
550 const AVFilter ff_vf_tinterlace = {
551     .name          = "tinterlace",
552     .description   = NULL_IF_CONFIG_SMALL("Perform temporal field interlacing."),
553     .priv_size     = sizeof(TInterlaceContext),
554     .uninit        = uninit,
555     FILTER_INPUTS(tinterlace_inputs),
556     FILTER_OUTPUTS(tinterlace_outputs),
557     FILTER_PIXFMTS_ARRAY(pix_fmts),
558     .priv_class    = &tinterlace_class,
559 };
560 
561 
562 const AVFilter ff_vf_interlace = {
563     .name          = "interlace",
564     .description   = NULL_IF_CONFIG_SMALL("Convert progressive video into interlaced."),
565     .priv_size     = sizeof(TInterlaceContext),
566     .init          = init_interlace,
567     .uninit        = uninit,
568     FILTER_INPUTS(tinterlace_inputs),
569     FILTER_OUTPUTS(tinterlace_outputs),
570     FILTER_PIXFMTS_ARRAY(pix_fmts),
571     .priv_class    = &interlace_class,
572 };
573