lavfi: add inverse telecine filter

Approved-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Changelog

@@ -9,6 +9,7 @@ version <next>:
 - libdcadec wrapper
 - Drop support for nvenc API before 5.0
 - nvenc H265 encoder
+- Detelecine filter
 
 
 version 2.6:

doc/filters.texi

@@ -3728,6 +3728,33 @@ FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
 
 @end table
 
+@section detelecine
+
+Apply an exact inverse of the telecine operation. It requires a predefined
+pattern specified using the pattern option which must be the same as that passed
+to the telecine filter.
+
+This filter accepts the following options:
+
+@table @option
+@item first_field
+@table @samp
+@item top, t
+top field first
+@item bottom, b
+bottom field first
+The default value is @code{top}.
+@end table
+
+@item pattern
+A string of numbers representing the pulldown pattern you wish to apply.
+The default value is @code{23}.
+
+@item start_frame
+A number representing position of the first frame with respect to the telecine
+pattern. This is to be used if the stream is cut. The default value is @code{0}.
+@end table
+
 @section drawbox
 
 Draw a colored box on the input image.

libavfilter/Makefile

@@ -112,6 +112,7 @@ OBJS-$(CONFIG_DECIMATE_FILTER)               += vf_decimate.o
 OBJS-$(CONFIG_DEJUDDER_FILTER)               += vf_dejudder.o
 OBJS-$(CONFIG_DELOGO_FILTER)                 += vf_delogo.o
 OBJS-$(CONFIG_DESHAKE_FILTER)                += vf_deshake.o
+OBJS-$(CONFIG_DETELECINE_FILTER)             += vf_detelecine.o
 OBJS-$(CONFIG_DRAWBOX_FILTER)                += vf_drawbox.o
 OBJS-$(CONFIG_DRAWGRID_FILTER)               += vf_drawbox.o
 OBJS-$(CONFIG_DRAWTEXT_FILTER)               += vf_drawtext.o

libavfilter/allfilters.c

@@ -128,6 +128,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(DEJUDDER,       dejudder,       vf);
     REGISTER_FILTER(DELOGO,         delogo,         vf);
     REGISTER_FILTER(DESHAKE,        deshake,        vf);
+    REGISTER_FILTER(DETELECINE,     detelecine,     vf);
     REGISTER_FILTER(DRAWBOX,        drawbox,        vf);
     REGISTER_FILTER(DRAWGRID,       drawgrid,       vf);
     REGISTER_FILTER(DRAWTEXT,       drawtext,       vf);

libavfilter/vf_detelecine.c

@@ -0,0 +1,346 @@
+/*
+ * Copyright (c) 2015 Himangi Saraogi <himangi774@gmail.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file detelecine filter.
+ */
+
+
+#include "libavutil/avstring.h"
+#include "libavutil/imgutils.h"
+#include "libavutil/opt.h"
+#include "libavutil/pixdesc.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+typedef struct {
+    const AVClass *class;
+    int first_field;
+    char *pattern;
+    int start_frame;
+    unsigned int pattern_pos;
+    unsigned int nskip_fields;
+    int64_t start_time;
+
+    AVRational pts;
+    AVRational ts_unit;
+    int occupied;
+
+    int nb_planes;
+    int planeheight[4];
+    int stride[4];
+
+    AVFrame *frame;
+    AVFrame *temp;
+} DetelecineContext;
+
+#define OFFSET(x) offsetof(DetelecineContext, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+
+static const AVOption detelecine_options[] = {
+    {"first_field", "select first field", OFFSET(first_field), AV_OPT_TYPE_INT,   {.i64=0}, 0, 1, FLAGS, "field"},
+        {"top",    "select top field first",                0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "field"},
+        {"t",      "select top field first",                0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "field"},
+        {"bottom", "select bottom field first",             0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "field"},
+        {"b",      "select bottom field first",             0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "field"},
+    {"pattern", "pattern that describe for how many fields a frame is to be displayed", OFFSET(pattern), AV_OPT_TYPE_STRING, {.str="23"}, 0, 0, FLAGS},
+    {"start_frame", "position of first frame with respect to the pattern if stream is cut", OFFSET(start_frame), AV_OPT_TYPE_INT, {.i64=0}, 0, 13, FLAGS},
+    {NULL}
+};
+
+AVFILTER_DEFINE_CLASS(detelecine);
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    DetelecineContext *s = ctx->priv;
+    const char *p;
+    int max = 0;
+
+    if (!strlen(s->pattern)) {
+        av_log(ctx, AV_LOG_ERROR, "No pattern provided.\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    for (p = s->pattern; *p; p++) {
+        if (!av_isdigit(*p)) {
+            av_log(ctx, AV_LOG_ERROR, "Provided pattern includes non-numeric characters.\n");
+            return AVERROR_INVALIDDATA;
+        }
+
+        max = FFMAX(*p - '0', max);
+        s->pts.num += *p - '0';
+        s->pts.den += 2;
+    }
+
+    s->nskip_fields = 0;
+    s->pattern_pos = 0;
+    s->start_time = AV_NOPTS_VALUE;
+
+    if (s->start_frame != 0) {
+        int nfields = 0;
+        for (p = s->pattern; *p; p++) {
+            nfields += *p - '0';
+            s->pattern_pos++;
+            if (nfields >= 2*s->start_frame) {
+                s->nskip_fields = nfields - 2*s->start_frame;
+                break;
+            }
+        }
+    }
+
+    av_log(ctx, AV_LOG_INFO, "Detelecine pattern %s removes up to %d frames per frame, pts advance factor: %d/%d\n",
+           s->pattern, (max + 1) / 2, s->pts.num, s->pts.den);
+
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    AVFilterFormats *pix_fmts = NULL;
+    int fmt;
+
+    for (fmt = 0; av_pix_fmt_desc_get(fmt); fmt++) {
+        const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);
+        if (!(desc->flags & AV_PIX_FMT_FLAG_HWACCEL ||
+              desc->flags & AV_PIX_FMT_FLAG_PAL     ||
+              desc->flags & AV_PIX_FMT_FLAG_BITSTREAM))
+            ff_add_format(&pix_fmts, fmt);
+    }
+
+    ff_set_common_formats(ctx, pix_fmts);
+    return 0;
+}
+
+static int config_input(AVFilterLink *inlink)
+{
+    DetelecineContext *s = inlink->dst->priv;
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+    int ret;
+
+    s->temp = ff_get_video_buffer(inlink, inlink->w, inlink->h);
+    if (!s->temp)
+        return AVERROR(ENOMEM);
+
+    s->frame = ff_get_video_buffer(inlink, inlink->w, inlink->h);
+    if (!s->frame)
+        return AVERROR(ENOMEM);
+
+    if ((ret = av_image_fill_linesizes(s->stride, inlink->format, inlink->w)) < 0)
+        return ret;
+
+    s->planeheight[1] = s->planeheight[2] = FF_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
+    s->planeheight[0] = s->planeheight[3] = inlink->h;
+
+    s->nb_planes = av_pix_fmt_count_planes(inlink->format);
+
+    return 0;
+}
+
+static int config_output(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    DetelecineContext *s = ctx->priv;
+    const AVFilterLink *inlink = ctx->inputs[0];
+    AVRational fps = inlink->frame_rate;
+
+    if (!fps.num || !fps.den) {
+        av_log(ctx, AV_LOG_ERROR, "The input needs a constant frame rate; "
+               "current rate of %d/%d is invalid\n", fps.num, fps.den);
+        return AVERROR(EINVAL);
+    }
+    fps = av_mul_q(fps, av_inv_q(s->pts));
+    av_log(ctx, AV_LOG_VERBOSE, "FPS: %d/%d -> %d/%d\n",
+           inlink->frame_rate.num, inlink->frame_rate.den, fps.num, fps.den);
+
+    outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
+    outlink->frame_rate = fps;
+    outlink->time_base = av_mul_q(inlink->time_base, s->pts);
+    av_log(ctx, AV_LOG_VERBOSE, "TB: %d/%d -> %d/%d\n",
+           inlink->time_base.num, inlink->time_base.den, outlink->time_base.num, outlink->time_base.den);
+
+    s->ts_unit = av_inv_q(av_mul_q(fps, outlink->time_base));
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *inpicref)
+{
+    AVFilterContext *ctx = inlink->dst;
+    AVFilterLink *outlink = ctx->outputs[0];
+    DetelecineContext *s = ctx->priv;
+    int i, len = 0, ret = 0, out = 0;
+
+    if (s->start_time == AV_NOPTS_VALUE)
+        s->start_time = inpicref->pts;
+
+    if (s->nskip_fields >= 2) {
+        s->nskip_fields -= 2;
+        return 0;
+    } else if (s->nskip_fields >= 1) {
+        if (s->occupied) {
+            s->occupied = 0;
+            s->nskip_fields--;
+        }
+        else {
+            for (i = 0; i < s->nb_planes; i++) {
+                av_image_copy_plane(s->temp->data[i], s->temp->linesize[i],
+                                    inpicref->data[i], inpicref->linesize[i],
+                                    s->stride[i],
+                                    s->planeheight[i]);
+            }
+            s->occupied = 1;
+            s->nskip_fields--;
+            return 0;
+        }
+    }
+
+    if (s->nskip_fields == 0) {
+        while(!len && s->pattern[s->pattern_pos]) {
+            len = s->pattern[s->pattern_pos] - '0';
+            s->pattern_pos++;
+        }
+
+        if (!s->pattern[s->pattern_pos])
+            s->pattern_pos = 0;
+
+        if(!len) { // do not output any field as the entire pattern is zero
+            av_frame_free(&inpicref);
+            return 0;
+        }
+
+        if (s->occupied) {
+            for (i = 0; i < s->nb_planes; i++) {
+                // fill in the EARLIER field from the new pic
+                av_image_copy_plane(s->frame->data[i] + s->frame->linesize[i] * s->first_field,
+                                    s->frame->linesize[i] * 2,
+                                    inpicref->data[i] + inpicref->linesize[i] * s->first_field,
+                                    inpicref->linesize[i] * 2,
+                                    s->stride[i],
+                                    (s->planeheight[i] - s->first_field + 1) / 2);
+                // fill in the LATER field from the buffered pic
+                av_image_copy_plane(s->frame->data[i] + s->frame->linesize[i] * !s->first_field,
+                                    s->frame->linesize[i] * 2,
+                                    s->temp->data[i] + s->temp->linesize[i] * !s->first_field,
+                                    s->temp->linesize[i] * 2,
+                                    s->stride[i],
+                                    (s->planeheight[i] - !s->first_field + 1) / 2);
+            }
+            len -= 2;
+            for (i = 0; i < s->nb_planes; i++) {
+                av_image_copy_plane(s->temp->data[i], s->temp->linesize[i],
+                                    inpicref->data[i], inpicref->linesize[i],
+                                    s->stride[i],
+                                    s->planeheight[i]);
+            }
+            s->occupied = 1;
+            out = 1;
+        } else {
+            if (len >= 2) {
+                // output THIS image as-is
+                for (i = 0; i < s->nb_planes; i++)
+                    av_image_copy_plane(s->frame->data[i], s->frame->linesize[i],
+                                        inpicref->data[i], inpicref->linesize[i],
+                                        s->stride[i],
+                                        s->planeheight[i]);
+                len -= 2;
+                out = 1;
+            } else if (len == 1) {
+                // fill in the EARLIER field from the new pic
+                av_image_copy_plane(s->frame->data[i] + s->frame->linesize[i] * s->first_field,
+                                    s->frame->linesize[i] * 2,
+                                    inpicref->data[i] + inpicref->linesize[i] * s->first_field,
+                                    inpicref->linesize[i] * 2,
+                                    s->stride[i],
+                                    (s->planeheight[i] - s->first_field + 1) / 2);
+                // TODO: not sure about the other field
+
+                len--;
+                out = 1;
+            }
+        }
+
+        if (len == 1 && s->occupied)
+        {
+            len--;
+            s->occupied = 0;
+        }
+    }
+    s->nskip_fields = len;
+
+    if (out) {
+        AVFrame *frame = av_frame_clone(s->frame);
+
+        if (!frame) {
+            av_frame_free(&inpicref);
+            return AVERROR(ENOMEM);
+        }
+
+        av_frame_copy_props(frame, inpicref);
+        frame->pts = ((s->start_time == AV_NOPTS_VALUE) ? 0 : s->start_time) +
+                     av_rescale(outlink->frame_count, s->ts_unit.num,
+                                s->ts_unit.den);
+        ret = ff_filter_frame(outlink, frame);
+    }
+
+    av_frame_free(&inpicref);
+
+    return ret;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    DetelecineContext *s = ctx->priv;
+
+    av_frame_free(&s->temp);
+    av_frame_free(&s->frame);
+}
+
+static const AVFilterPad detelecine_inputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .filter_frame  = filter_frame,
+        .config_props  = config_input,
+    },
+    { NULL }
+};
+
+static const AVFilterPad detelecine_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .config_props  = config_output,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_detelecine = {
+    .name          = "detelecine",
+    .description   = NULL_IF_CONFIG_SMALL("Apply an inverse telecine pattern."),
+    .priv_size     = sizeof(DetelecineContext),
+    .priv_class    = &detelecine_class,
+    .init          = init,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .inputs        = detelecine_inputs,
+    .outputs       = detelecine_outputs,
+};