diff --git a/doc/filters.texi b/doc/filters.texi
index a7919a3506f092fbea9d0f5f380366b106fc3c01..c5caa77d997d3cfea897219a8d1207d79f3a73c2 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -5454,8 +5454,7 @@ Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code
Simple interlacing filter from progressive contents. This interleaves upper (or
lower) lines from odd frames with lower (or upper) lines from even frames,
-halving the frame rate and preserving image height. A vertical lowpass filter
-is always applied in order to avoid twitter effects and reduce moiré patterns.
+halving the frame rate and preserving image height.
@example
Original Original New Frame
@@ -5475,6 +5474,10 @@ It accepts the following optional parameters:
@item scan
This determines whether the interlaced frame is taken from the even
(tff - default) or odd (bff) lines of the progressive frame.
+
+@item lowpass
+Enable (default) or disable the vertical lowpass filter to avoid twitter
+interlacing and reduce moire patterns.
@end table
@section kerndeint
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 9f2c36494c0f42f4e0401c52826db3b19fd1939a..1a43dc51a9da9bf42233e4d9acd2b61c1b1e432a 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -88,8 +88,5 @@
#ifndef FF_API_NOCONST_GET_NAME
#define FF_API_NOCONST_GET_NAME (LIBAVFILTER_VERSION_MAJOR < 5)
#endif
-#ifndef FF_API_INTERLACE_LOWPASS_SET
-#define FF_API_INTERLACE_LOWPASS_SET (LIBAVFILTER_VERSION_MAJOR < 5)
-#endif
#endif /* AVFILTER_VERSION_H */
diff --git a/libavfilter/vf_interlace.c b/libavfilter/vf_interlace.c
index 0929a7107ad3a4408669cc987e149f1430f78e8f..e07963f79a4688410f07be836649553b0a2dbfb9 100644
--- a/libavfilter/vf_interlace.c
+++ b/libavfilter/vf_interlace.c
@@ -34,7 +34,6 @@
#include "formats.h"
#include "avfilter.h"
#include "internal.h"
-#include "version.h"
#include "video.h"
enum ScanMode {
@@ -50,9 +49,7 @@ enum FieldType {
typedef struct InterlaceContext {
const AVClass *class;
enum ScanMode scan; // top or bottom field first scanning
-#if FF_API_INTERLACE_LOWPASS_SET
int lowpass; // enable or disable low pass filterning
-#endif
AVFrame *cur, *next; // the two frames from which the new one is obtained
} InterlaceContext;
@@ -65,10 +62,8 @@ static const AVOption interlace_options[] = {
AV_OPT_TYPE_CONST, {.i64 = MODE_TFF }, INT_MIN, INT_MAX, .flags = V, .unit = "scan" },
{ "bff", "bottom field first", 0,
AV_OPT_TYPE_CONST, {.i64 = MODE_BFF }, INT_MIN, INT_MAX, .flags = V, .unit = "scan" },
-#if FF_API_INTERLACE_LOWPASS_SET
- { "lowpass", "(deprecated, this option is always set)", OFFSET(lowpass),
+ { "lowpass", "enable vertical low-pass filter", OFFSET(lowpass),
AV_OPT_TYPE_INT, {.i64 = 1 }, 0, 1, .flags = V },
-#endif
{ NULL }
};
@@ -101,15 +96,15 @@ static int config_out_props(AVFilterLink *outlink)
AVFilterLink *inlink = outlink->src->inputs[0];
InterlaceContext *s = ctx->priv;
-#if FF_API_INTERLACE_LOWPASS_SET
- if (!s->lowpass)
- av_log(ctx, AV_LOG_WARNING, "This option is deprecated and always set.\n");
-#endif
-
if (inlink->h < 2) {
av_log(ctx, AV_LOG_ERROR, "input video height is too small\n");
return AVERROR_INVALIDDATA;
}
+
+ if (!s->lowpass)
+ av_log(ctx, AV_LOG_WARNING, "***warning*** Lowpass filter is disabled, "
+ "the resulting video will be aliased rather than interlaced.\n");
+
// same input size
outlink->w = inlink->w;
outlink->h = inlink->h;
@@ -120,14 +115,15 @@ static int config_out_props(AVFilterLink *outlink)
outlink->frame_rate.den *= 2;
outlink->flags |= FF_LINK_FLAG_REQUEST_LOOP;
- av_log(ctx, AV_LOG_VERBOSE, "%s interlacing\n",
- s->scan == MODE_TFF ? "tff" : "bff");
+ av_log(ctx, AV_LOG_VERBOSE, "%s interlacing %s lowpass filter\n",
+ s->scan == MODE_TFF ? "tff" : "bff", (s->lowpass) ? "with" : "without");
return 0;
}
static void copy_picture_field(AVFrame *src_frame, AVFrame *dst_frame,
- AVFilterLink *inlink, enum FieldType field_type)
+ AVFilterLink *inlink, enum FieldType field_type,
+ int lowpass)
{
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
int vsub = desc->log2_chroma_h;
@@ -138,8 +134,6 @@ static void copy_picture_field(AVFrame *src_frame, AVFrame *dst_frame,
int linesize = av_image_get_linesize(inlink->format, inlink->w, plane);
uint8_t *dstp = dst_frame->data[plane];
const uint8_t *srcp = src_frame->data[plane];
- int srcp_linesize;
- int dstp_linesize;
av_assert0(linesize >= 0);
@@ -148,24 +142,29 @@ static void copy_picture_field(AVFrame *src_frame, AVFrame *dst_frame,
srcp += src_frame->linesize[plane];
if (field_type == FIELD_LOWER)
dstp += dst_frame->linesize[plane];
-
- srcp_linesize = src_frame->linesize[plane] * 2;
- dstp_linesize = dst_frame->linesize[plane] * 2;
- for (j = lines; j > 0; j--) {
- const uint8_t *srcp_above = srcp - src_frame->linesize[plane];
- const uint8_t *srcp_below = srcp + src_frame->linesize[plane];
- if (j == lines)
- srcp_above = srcp; // there is no line above
- if (j == 1)
- srcp_below = srcp; // there is no line below
- for (i = 0; i < linesize; i++) {
- // this calculation is an integer representation of
- // '0.5 * current + 0.25 * above + 0.25 * below'
- // '1 +' is for rounding.
- dstp[i] = (1 + srcp[i] + srcp[i] + srcp_above[i] + srcp_below[i]) >> 2;
+ if (lowpass) {
+ int srcp_linesize = src_frame->linesize[plane] * 2;
+ int dstp_linesize = dst_frame->linesize[plane] * 2;
+ for (j = lines; j > 0; j--) {
+ const uint8_t *srcp_above = srcp - src_frame->linesize[plane];
+ const uint8_t *srcp_below = srcp + src_frame->linesize[plane];
+ if (j == lines)
+ srcp_above = srcp; // there is no line above
+ if (j == 1)
+ srcp_below = srcp; // there is no line below
+ for (i = 0; i < linesize; i++) {
+ // this calculation is an integer representation of
+ // '0.5 * current + 0.25 * above + 0.25 * below'
+ // '1 +' is for rounding.
+ dstp[i] = (1 + srcp[i] + srcp[i] + srcp_above[i] + srcp_below[i]) >> 2;
+ }
+ dstp += dstp_linesize;
+ srcp += srcp_linesize;
}
- dstp += dstp_linesize;
- srcp += srcp_linesize;
+ } else {
+ av_image_copy_plane(dstp, dst_frame->linesize[plane] * 2,
+ srcp, src_frame->linesize[plane] * 2,
+ linesize, lines);
}
}
}
@@ -208,11 +207,11 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
out->pts /= 2; // adjust pts to new framerate
/* copy upper/lower field from cur */
- copy_picture_field(s->cur, out, inlink, tff ? FIELD_UPPER : FIELD_LOWER);
+ copy_picture_field(s->cur, out, inlink, tff ? FIELD_UPPER : FIELD_LOWER, s->lowpass);
av_frame_free(&s->cur);
/* copy lower/upper field from next */
- copy_picture_field(s->next, out, inlink, tff ? FIELD_LOWER : FIELD_UPPER);
+ copy_picture_field(s->next, out, inlink, tff ? FIELD_LOWER : FIELD_UPPER, s->lowpass);
av_frame_free(&s->next);
ret = ff_filter_frame(outlink, out);