[FFmpeg-cvslog] lavfi/tinterlace: add low-pass-filter for top/bottom interleave modes
Mark Himsley
git at videolan.org
Sun Dec 30 15:21:14 CET 2012
ffmpeg | branch: master | Mark Himsley <mark at mdsh.com> | Sun Dec 30 15:02:16 2012 +0100| [8997a0fa79cc4d20e78fd6f0de40f7127828978a] | committer: Stefano Sabatini
lavfi/tinterlace: add low-pass-filter for top/bottom interleave modes
Signed-off-by: Stefano Sabatini <stefasab at gmail.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=8997a0fa79cc4d20e78fd6f0de40f7127828978a
---
doc/filters.texi | 37 ++++++++++++++++++++++--
libavfilter/version.h | 2 +-
libavfilter/vf_tinterlace.c | 66 +++++++++++++++++++++++++++++++++++--------
3 files changed, 89 insertions(+), 16 deletions(-)
diff --git a/doc/filters.texi b/doc/filters.texi
index 56add6b..76e8fb5 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -4077,9 +4077,21 @@ Perform various types of temporal field interlacing.
Frames are counted starting from 1, so the first input frame is
considered odd.
-This filter accepts a single option @option{mode} specifying the mode,
-which can be specified either by specyfing @code{mode=VALUE} either
-specifying the value alone. Available values are:
+This filter accepts options in the form of @var{key}=@var{value} pairs
+separated by ":".
+Alternatively, the @var{mode} option can be specified as a value alone,
+optionally followed by a ":" and further ":" separated @var{key}=@var{value}
+pairs.
+
+A description of the accepted options follows.
+
+ at table @option
+
+ at item mode
+Specify the mode of the interlacing. This option can also be specified
+as a value alone. See below for a list of values for this option.
+
+Available values are:
@table @samp
@item merge, 0
@@ -4119,6 +4131,25 @@ compatibility reasons.
Default mode is @code{merge}.
+ at item flags
+Specify flags influencing the filter process.
+
+Available value for @var{flags} is:
+
+ at table @option
+ at item low_pass_filter, vlfp
+Enable vertical low-pass filtering in the filter.
+Vertical low-pass filtering is required when creating an interlaced
+destination from a progressive source which contains high-frequency
+vertical detail. Filtering will reduce interlace 'twitter' and Moire
+patterning.
+
+Vertical low-pass filtering can only be enabled for @option{mode}
+ at var{interleave_top} and @var{interleave_bottom}.
+
+ at end table
+ at end table
+
@section transpose
Transpose rows with columns in the input video and optionally flip it.
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 7aab1d3..3cc91fb 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -30,7 +30,7 @@
#define LIBAVFILTER_VERSION_MAJOR 3
#define LIBAVFILTER_VERSION_MINOR 30
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MICRO 102
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
LIBAVFILTER_VERSION_MINOR, \
diff --git a/libavfilter/vf_tinterlace.c b/libavfilter/vf_tinterlace.c
index 843a66c..e34a7d2 100644
--- a/libavfilter/vf_tinterlace.c
+++ b/libavfilter/vf_tinterlace.c
@@ -45,6 +45,7 @@ enum TInterlaceMode {
typedef struct {
const AVClass *class;
enum TInterlaceMode mode; ///< interlace mode selected
+ int flags; ///< flags affecting interlacing algorithm
int frame; ///< number of the output frame
int vsub; ///< chroma vertical subsampling
AVFilterBufferRef *cur;
@@ -55,6 +56,7 @@ typedef struct {
#define OFFSET(x) offsetof(TInterlaceContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+#define TINTERLACE_FLAG_VLPF 01
static const AVOption tinterlace_options[] = {
{"mode", "select interlace mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=MODE_MERGE}, 0, MODE_NB-1, FLAGS, "mode"},
@@ -66,6 +68,10 @@ static const AVOption tinterlace_options[] = {
{"interleave_bottom", "interleave bottom and top fields", 0, AV_OPT_TYPE_CONST, {.i64=MODE_INTERLEAVE_BOTTOM}, INT_MIN, INT_MAX, FLAGS, "mode"},
{"interlacex2", "interlace fields from two consecutive frames", 0, AV_OPT_TYPE_CONST, {.i64=MODE_INTERLACEX2}, INT_MIN, INT_MAX, FLAGS, "mode"},
+ {"flags", "set flags", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = 0}, 0, INT_MAX, 0, "flags" },
+ {"low_pass_filter", "enable vertical low-pass filter", 0, AV_OPT_TYPE_CONST, {.i64 = TINTERLACE_FLAG_VLPF}, INT_MIN, INT_MAX, FLAGS, "flags" },
+ {"vlpf", "enable vertical low-pass filter", 0, AV_OPT_TYPE_CONST, {.i64 = TINTERLACE_FLAG_VLPF}, INT_MIN, INT_MAX, FLAGS, "flags" },
+
{NULL}
};
@@ -142,8 +148,16 @@ static int config_out_props(AVFilterLink *outlink)
tinterlace->black_linesize[i] * h);
}
}
- av_log(ctx, AV_LOG_VERBOSE, "mode:%d h:%d -> h:%d\n",
- tinterlace->mode, inlink->h, outlink->h);
+ if ((tinterlace->flags & TINTERLACE_FLAG_VLPF)
+ && !(tinterlace->mode == MODE_INTERLEAVE_TOP
+ || tinterlace->mode == MODE_INTERLEAVE_BOTTOM)) {
+ av_log(ctx, AV_LOG_WARNING, "low_pass_filter flag ignored with mode %d\n",
+ tinterlace->mode);
+ tinterlace->flags &= !TINTERLACE_FLAG_VLPF;
+ }
+ av_log(ctx, AV_LOG_VERBOSE, "mode:%d filter:%s h:%d -> h:%d\n",
+ tinterlace->mode, (tinterlace->flags & TINTERLACE_FLAG_VLPF) ? "on" : "off",
+ inlink->h, outlink->h);
return 0;
}
@@ -159,12 +173,14 @@ static int config_out_props(AVFilterLink *outlink)
* @param interleave leave a padding line between each copied line
* @param dst_field copy to upper or lower field,
* only meaningful when interleave is selected
+ * @param flags context flags
*/
static inline
void copy_picture_field(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 src_field, int interleave, int dst_field,
+ int flags)
{
const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(format);
int plane, vsub = desc->log2_chroma_h;
@@ -184,8 +200,30 @@ void copy_picture_field(uint8_t *dst[4], int dst_linesize[4],
srcp += src_linesize[plane];
if (interleave && dst_field == FIELD_LOWER)
dstp += dst_linesize[plane];
- av_image_copy_plane(dstp, dst_linesize[plane] * (interleave ? 2 : 1),
+ if (flags & TINTERLACE_FLAG_VLPF) {
+ // Low-pass filtering is required when creating an interlaced destination from
+ // a progressive source which contains high-frequency vertical detail.
+ // Filtering will reduce interlace 'twitter' and Moire patterning.
+ int srcp_linesize = src_linesize[plane] * k;
+ int dstp_linesize = dst_linesize[plane] * (interleave ? 2 : 1);
+ for (int h = lines; h > 0; h--) {
+ const uint8_t *srcp_above = srcp - src_linesize[plane];
+ const uint8_t *srcp_below = srcp + src_linesize[plane];
+ if (h == lines) srcp_above = srcp; // there is no line above
+ if (h == 1) srcp_below = srcp; // there is no line below
+ for (int 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;
+ }
+ } else {
+ av_image_copy_plane(dstp, dst_linesize[plane] * (interleave ? 2 : 1),
srcp, src_linesize[plane]*k, linesize, lines);
+ }
}
}
@@ -222,12 +260,12 @@ static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
copy_picture_field(out->data, out->linesize,
(const uint8_t **)cur->data, cur->linesize,
inlink->format, inlink->w, inlink->h,
- FIELD_UPPER_AND_LOWER, 1, FIELD_UPPER);
+ FIELD_UPPER_AND_LOWER, 1, FIELD_UPPER, tinterlace->flags);
/* write even frame lines into the lower field of the new frame */
copy_picture_field(out->data, out->linesize,
(const uint8_t **)next->data, next->linesize,
inlink->format, inlink->w, inlink->h,
- FIELD_UPPER_AND_LOWER, 1, FIELD_LOWER);
+ FIELD_UPPER_AND_LOWER, 1, FIELD_LOWER, tinterlace->flags);
avfilter_unref_bufferp(&tinterlace->next);
break;
@@ -248,12 +286,12 @@ static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
copy_picture_field(out->data, out->linesize,
(const uint8_t **)cur->data, cur->linesize,
inlink->format, inlink->w, inlink->h,
- FIELD_UPPER_AND_LOWER, 1, field);
+ FIELD_UPPER_AND_LOWER, 1, field, tinterlace->flags);
/* pad with black the other field */
copy_picture_field(out->data, out->linesize,
(const uint8_t **)tinterlace->black_data, tinterlace->black_linesize,
inlink->format, inlink->w, inlink->h,
- FIELD_UPPER_AND_LOWER, 1, !field);
+ FIELD_UPPER_AND_LOWER, 1, !field, tinterlace->flags);
break;
/* interleave upper/lower lines from odd frames with lower/upper lines from even frames,
@@ -272,12 +310,14 @@ static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
copy_picture_field(out->data, out->linesize,
(const uint8_t **)cur->data, cur->linesize,
inlink->format, inlink->w, inlink->h,
- tff ? FIELD_UPPER : FIELD_LOWER, 1, tff ? FIELD_UPPER : FIELD_LOWER);
+ tff ? FIELD_UPPER : FIELD_LOWER, 1, tff ? FIELD_UPPER : FIELD_LOWER,
+ tinterlace->flags);
/* copy lower/upper field from next */
copy_picture_field(out->data, out->linesize,
(const uint8_t **)next->data, next->linesize,
inlink->format, inlink->w, inlink->h,
- tff ? FIELD_LOWER : FIELD_UPPER, 1, tff ? FIELD_LOWER : FIELD_UPPER);
+ tff ? FIELD_LOWER : FIELD_UPPER, 1, tff ? FIELD_LOWER : FIELD_UPPER,
+ tinterlace->flags);
avfilter_unref_bufferp(&tinterlace->next);
break;
case MODE_INTERLACEX2: /* re-interlace preserving image height, double frame rate */
@@ -302,12 +342,14 @@ static int filter_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
copy_picture_field(out->data, out->linesize,
(const uint8_t **)cur->data, cur->linesize,
inlink->format, inlink->w, inlink->h,
- tff ? FIELD_LOWER : FIELD_UPPER, 1, tff ? FIELD_LOWER : FIELD_UPPER);
+ tff ? FIELD_LOWER : FIELD_UPPER, 1, tff ? FIELD_LOWER : FIELD_UPPER,
+ tinterlace->flags);
/* write next frame first field lines into the first field of the new frame */
copy_picture_field(out->data, out->linesize,
(const uint8_t **)next->data, next->linesize,
inlink->format, inlink->w, inlink->h,
- tff ? FIELD_UPPER : FIELD_LOWER, 1, tff ? FIELD_UPPER : FIELD_LOWER);
+ tff ? FIELD_UPPER : FIELD_LOWER, 1, tff ? FIELD_UPPER : FIELD_LOWER,
+ tinterlace->flags);
break;
default:
av_assert0(0);
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