[FFmpeg-cvslog] lavfi: add select filter
Stefano Sabatini
git at videolan.org
Sat Sep 17 22:45:11 CEST 2011
ffmpeg | branch: master | Stefano Sabatini <stefano.sabatini-lala at poste.it> | Sat May 7 02:06:25 2011 +0200| [d763fb7d47fdbd107ea65cdf511f2f21558f6610] | committer: Anton Khirnov
lavfi: add select filter
Signed-off-by: Anton Khirnov <anton at khirnov.net>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=d763fb7d47fdbd107ea65cdf511f2f21558f6610
---
Changelog | 1 +
doc/filters.texi | 116 +++++++++++++++
libavfilter/Makefile | 1 +
libavfilter/allfilters.c | 1 +
libavfilter/avfilter.h | 2 +-
libavfilter/vf_select.c | 353 ++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 473 insertions(+), 1 deletions(-)
diff --git a/Changelog b/Changelog
index d064a20..24fa85c 100644
--- a/Changelog
+++ b/Changelog
@@ -46,6 +46,7 @@ easier to use. The changes are:
- showinfo filter
- split filter
- libcdio-paranoia input device for audio CD grabbing
+- select filter
version 0.7:
diff --git a/doc/filters.texi b/doc/filters.texi
index d8d9062..a86b20e 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -1064,6 +1064,122 @@ scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
scale='min(500\, iw*3/2):-1'
@end example
+ at section select
+Select frames to pass in output.
+
+It accepts in input an expression, which is evaluated for each input
+frame. If the expression is evaluated to a non-zero value, the frame
+is selected and passed to the output, otherwise it is discarded.
+
+The expression can contain the following constants:
+
+ at table @option
+ at item PI
+Greek PI
+
+ at item PHI
+golden ratio
+
+ at item E
+Euler number
+
+ at item n
+the sequential number of the filtered frame, starting from 0
+
+ at item selected_n
+the sequential number of the selected frame, starting from 0
+
+ at item prev_selected_n
+the sequential number of the last selected frame, NAN if undefined
+
+ at item TB
+timebase of the input timestamps
+
+ at item pts
+the PTS (Presentation TimeStamp) of the filtered video frame,
+expressed in @var{TB} units, NAN if undefined
+
+ at item t
+the PTS (Presentation TimeStamp) of the filtered video frame,
+expressed in seconds, NAN if undefined
+
+ at item prev_pts
+the PTS of the previously filtered video frame, NAN if undefined
+
+ at item prev_selected_pts
+the PTS of the last previously filtered video frame, NAN if undefined
+
+ at item prev_selected_t
+the PTS of the last previously selected video frame, NAN if undefined
+
+ at item start_pts
+the PTS of the first video frame in the video, NAN if undefined
+
+ at item start_t
+the time of the first video frame in the video, NAN if undefined
+
+ at item pict_type
+the type of the filtered frame, can assume one of the following
+values:
+ at table @option
+ at item I
+ at item P
+ at item B
+ at item S
+ at item SI
+ at item SP
+ at item BI
+ at end table
+
+ at item interlace_type
+the frame interlace type, can assume one of the following values:
+ at table @option
+ at item PROGRESSIVE
+the frame is progressive (not interlaced)
+ at item TOPFIRST
+the frame is top-field-first
+ at item BOTTOMFIRST
+the frame is bottom-field-first
+ at end table
+
+ at item key
+1 if the filtered frame is a key-frame, 0 otherwise
+
+ at item pos
+the position in the file of the filtered frame, -1 if the information
+is not available (e.g. for synthetic video)
+ at end table
+
+The default value of the select expression is "1".
+
+Some examples follow:
+
+ at example
+# select all frames in input
+select
+
+# the above is the same as:
+select=1
+
+# skip all frames:
+select=0
+
+# select only I-frames
+select='eq(pict_type\,I)'
+
+# select one frame every 100
+select='not(mod(n\,100))'
+
+# select only frames contained in the 10-20 time interval
+select='gte(t\,10)*lte(t\,20)'
+
+# select only I frames contained in the 10-20 time interval
+select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
+
+# select frames with a minimum distance of 10 seconds
+select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
+ at end example
+
@anchor{setdar}
@section setdar
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 5844dd0..4bd06e9 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -40,6 +40,7 @@ OBJS-$(CONFIG_OVERLAY_FILTER) += vf_overlay.o
OBJS-$(CONFIG_PAD_FILTER) += vf_pad.o
OBJS-$(CONFIG_PIXDESCTEST_FILTER) += vf_pixdesctest.o
OBJS-$(CONFIG_SCALE_FILTER) += vf_scale.o
+OBJS-$(CONFIG_SELECT_FILTER) += vf_select.o
OBJS-$(CONFIG_SETDAR_FILTER) += vf_aspect.o
OBJS-$(CONFIG_SETPTS_FILTER) += vf_setpts.o
OBJS-$(CONFIG_SETSAR_FILTER) += vf_aspect.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 11e9d7d..dbbe441 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -61,6 +61,7 @@ void avfilter_register_all(void)
REGISTER_FILTER (PAD, pad, vf);
REGISTER_FILTER (PIXDESCTEST, pixdesctest, vf);
REGISTER_FILTER (SCALE, scale, vf);
+ REGISTER_FILTER (SELECT, select, vf);
REGISTER_FILTER (SETDAR, setdar, vf);
REGISTER_FILTER (SETPTS, setpts, vf);
REGISTER_FILTER (SETSAR, setsar, vf);
diff --git a/libavfilter/avfilter.h b/libavfilter/avfilter.h
index 3fcc847..b9af1c4 100644
--- a/libavfilter/avfilter.h
+++ b/libavfilter/avfilter.h
@@ -29,7 +29,7 @@
#include "libavutil/rational.h"
#define LIBAVFILTER_VERSION_MAJOR 2
-#define LIBAVFILTER_VERSION_MINOR 6
+#define LIBAVFILTER_VERSION_MINOR 7
#define LIBAVFILTER_VERSION_MICRO 0
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
diff --git a/libavfilter/vf_select.c b/libavfilter/vf_select.c
new file mode 100644
index 0000000..0ec443a
--- /dev/null
+++ b/libavfilter/vf_select.c
@@ -0,0 +1,353 @@
+/*
+ * Copyright (c) 2011 Stefano Sabatini
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * filter for selecting which frame passes in the filterchain
+ */
+
+#include "libavutil/eval.h"
+#include "libavutil/fifo.h"
+#include "libavutil/mathematics.h"
+#include "avfilter.h"
+
+static const char *var_names[] = {
+ "E", ///< Euler number
+ "PHI", ///< golden ratio
+ "PI", ///< greek pi
+
+ "TB", ///< timebase
+
+ "pts", ///< original pts in the file of the frame
+ "start_pts", ///< first PTS in the stream, expressed in TB units
+ "prev_pts", ///< previous frame PTS
+ "prev_selected_pts", ///< previous selected frame PTS
+
+ "t", ///< first PTS in seconds
+ "start_t", ///< first PTS in the stream, expressed in seconds
+ "prev_t", ///< previous frame time
+ "prev_selected_t", ///< previously selected time
+
+ "pict_type", ///< the type of picture in the movie
+ "I",
+ "P",
+ "B",
+ "S",
+ "SI",
+ "SP",
+ "BI",
+
+ "interlace_type", ///< the frame interlace type
+ "PROGRESSIVE",
+ "TOPFIRST",
+ "BOTTOMFIRST",
+
+ "n", ///< frame number (starting from zero)
+ "selected_n", ///< selected frame number (starting from zero)
+ "prev_selected_n", ///< number of the last selected frame
+
+ "key", ///< tell if the frame is a key frame
+ "pos", ///< original position in the file of the frame
+
+ NULL
+};
+
+enum var_name {
+ VAR_E,
+ VAR_PHI,
+ VAR_PI,
+
+ VAR_TB,
+
+ VAR_PTS,
+ VAR_START_PTS,
+ VAR_PREV_PTS,
+ VAR_PREV_SELECTED_PTS,
+
+ VAR_T,
+ VAR_START_T,
+ VAR_PREV_T,
+ VAR_PREV_SELECTED_T,
+
+ VAR_PICT_TYPE,
+ VAR_PICT_TYPE_I,
+ VAR_PICT_TYPE_P,
+ VAR_PICT_TYPE_B,
+ VAR_PICT_TYPE_S,
+ VAR_PICT_TYPE_SI,
+ VAR_PICT_TYPE_SP,
+ VAR_PICT_TYPE_BI,
+
+ VAR_INTERLACE_TYPE,
+ VAR_INTERLACE_TYPE_P,
+ VAR_INTERLACE_TYPE_T,
+ VAR_INTERLACE_TYPE_B,
+
+ VAR_N,
+ VAR_SELECTED_N,
+ VAR_PREV_SELECTED_N,
+
+ VAR_KEY,
+ VAR_POS,
+
+ VAR_VARS_NB
+};
+
+#define FIFO_SIZE 8
+
+typedef struct {
+ AVExpr *expr;
+ double var_values[VAR_VARS_NB];
+ double select;
+ int cache_frames;
+ AVFifoBuffer *pending_frames; ///< FIFO buffer of video frames
+} SelectContext;
+
+static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
+{
+ SelectContext *select = ctx->priv;
+ int ret;
+
+ if ((ret = av_expr_parse(&select->expr, args ? args : "1",
+ var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
+ av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", args);
+ return ret;
+ }
+
+ select->pending_frames = av_fifo_alloc(FIFO_SIZE*sizeof(AVFilterBufferRef*));
+ if (!select->pending_frames) {
+ av_log(ctx, AV_LOG_ERROR, "Failed to allocate pending frames buffer.\n");
+ return AVERROR(ENOMEM);
+ }
+ return 0;
+}
+
+#define INTERLACE_TYPE_P 0
+#define INTERLACE_TYPE_T 1
+#define INTERLACE_TYPE_B 2
+
+static int config_input(AVFilterLink *inlink)
+{
+ SelectContext *select = inlink->dst->priv;
+
+ select->var_values[VAR_E] = M_E;
+ select->var_values[VAR_PHI] = M_PHI;
+ select->var_values[VAR_PI] = M_PI;
+
+ select->var_values[VAR_N] = 0.0;
+ select->var_values[VAR_SELECTED_N] = 0.0;
+
+ select->var_values[VAR_TB] = av_q2d(inlink->time_base);
+
+ select->var_values[VAR_PREV_PTS] = NAN;
+ select->var_values[VAR_PREV_SELECTED_PTS] = NAN;
+ select->var_values[VAR_PREV_SELECTED_T] = NAN;
+ select->var_values[VAR_START_PTS] = NAN;
+ select->var_values[VAR_START_T] = NAN;
+
+ select->var_values[VAR_PICT_TYPE_I] = AV_PICTURE_TYPE_I;
+ select->var_values[VAR_PICT_TYPE_P] = AV_PICTURE_TYPE_P;
+ select->var_values[VAR_PICT_TYPE_B] = AV_PICTURE_TYPE_B;
+ select->var_values[VAR_PICT_TYPE_SI] = AV_PICTURE_TYPE_SI;
+ select->var_values[VAR_PICT_TYPE_SP] = AV_PICTURE_TYPE_SP;
+
+ select->var_values[VAR_INTERLACE_TYPE_P] = INTERLACE_TYPE_P;
+ select->var_values[VAR_INTERLACE_TYPE_T] = INTERLACE_TYPE_T;
+ select->var_values[VAR_INTERLACE_TYPE_B] = INTERLACE_TYPE_B;;
+
+ return 0;
+}
+
+#define D2TS(d) (isnan(d) ? AV_NOPTS_VALUE : (int64_t)(d))
+#define TS2D(ts) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
+
+static int select_frame(AVFilterContext *ctx, AVFilterBufferRef *picref)
+{
+ SelectContext *select = ctx->priv;
+ AVFilterLink *inlink = ctx->inputs[0];
+ double res;
+
+ if (isnan(select->var_values[VAR_START_PTS]))
+ select->var_values[VAR_START_PTS] = TS2D(picref->pts);
+ if (isnan(select->var_values[VAR_START_T]))
+ select->var_values[VAR_START_T] = TS2D(picref->pts) * av_q2d(inlink->time_base);
+
+ select->var_values[VAR_PTS] = TS2D(picref->pts);
+ select->var_values[VAR_T ] = TS2D(picref->pts) * av_q2d(inlink->time_base);
+ select->var_values[VAR_POS] = picref->pos == -1 ? NAN : picref->pos;
+ select->var_values[VAR_PREV_PTS] = TS2D(picref ->pts);
+
+ select->var_values[VAR_INTERLACE_TYPE] =
+ !picref->video->interlaced ? INTERLACE_TYPE_P :
+ picref->video->top_field_first ? INTERLACE_TYPE_T : INTERLACE_TYPE_B;
+ select->var_values[VAR_PICT_TYPE] = picref->video->pict_type;
+
+ res = av_expr_eval(select->expr, select->var_values, NULL);
+ av_log(inlink->dst, AV_LOG_DEBUG,
+ "n:%d pts:%d t:%f pos:%d interlace_type:%c key:%d pict_type:%c "
+ "-> select:%f\n",
+ (int)select->var_values[VAR_N],
+ (int)select->var_values[VAR_PTS],
+ select->var_values[VAR_T],
+ (int)select->var_values[VAR_POS],
+ select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_P ? 'P' :
+ select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_T ? 'T' :
+ select->var_values[VAR_INTERLACE_TYPE] == INTERLACE_TYPE_B ? 'B' : '?',
+ (int)select->var_values[VAR_KEY],
+ av_get_picture_type_char(select->var_values[VAR_PICT_TYPE]),
+ res);
+
+ select->var_values[VAR_N] += 1.0;
+
+ if (res) {
+ select->var_values[VAR_PREV_SELECTED_N] = select->var_values[VAR_N];
+ select->var_values[VAR_PREV_SELECTED_PTS] = select->var_values[VAR_PTS];
+ select->var_values[VAR_PREV_SELECTED_T] = select->var_values[VAR_T];
+ select->var_values[VAR_SELECTED_N] += 1.0;
+ }
+ return res;
+}
+
+static void start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
+{
+ SelectContext *select = inlink->dst->priv;
+
+ select->select = select_frame(inlink->dst, picref);
+ if (select->select) {
+ /* frame was requested through poll_frame */
+ if (select->cache_frames) {
+ if (!av_fifo_space(select->pending_frames))
+ av_log(inlink->dst, AV_LOG_ERROR,
+ "Buffering limit reached, cannot cache more frames\n");
+ else
+ av_fifo_generic_write(select->pending_frames, &picref,
+ sizeof(picref), NULL);
+ return;
+ }
+ avfilter_start_frame(inlink->dst->outputs[0], avfilter_ref_buffer(picref, ~0));
+ }
+}
+
+static void draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
+{
+ SelectContext *select = inlink->dst->priv;
+
+ if (select->select && !select->cache_frames)
+ avfilter_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
+}
+
+static void end_frame(AVFilterLink *inlink)
+{
+ SelectContext *select = inlink->dst->priv;
+ AVFilterBufferRef *picref = inlink->cur_buf;
+
+ if (select->select) {
+ if (select->cache_frames)
+ return;
+ avfilter_end_frame(inlink->dst->outputs[0]);
+ }
+ avfilter_unref_buffer(picref);
+}
+
+static int request_frame(AVFilterLink *outlink)
+{
+ AVFilterContext *ctx = outlink->src;
+ SelectContext *select = ctx->priv;
+ AVFilterLink *inlink = outlink->src->inputs[0];
+ select->select = 0;
+
+ if (av_fifo_size(select->pending_frames)) {
+ AVFilterBufferRef *picref;
+ av_fifo_generic_read(select->pending_frames, &picref, sizeof(picref), NULL);
+ avfilter_start_frame(outlink, avfilter_ref_buffer(picref, ~0));
+ avfilter_draw_slice(outlink, 0, outlink->h, 1);
+ avfilter_end_frame(outlink);
+ avfilter_unref_buffer(picref);
+ return 0;
+ }
+
+ while (!select->select) {
+ int ret = avfilter_request_frame(inlink);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int poll_frame(AVFilterLink *outlink)
+{
+ SelectContext *select = outlink->src->priv;
+ AVFilterLink *inlink = outlink->src->inputs[0];
+ int count, ret;
+
+ if (!av_fifo_size(select->pending_frames)) {
+ if ((count = avfilter_poll_frame(inlink)) <= 0)
+ return count;
+ /* request frame from input, and apply select condition to it */
+ select->cache_frames = 1;
+ while (count-- && av_fifo_space(select->pending_frames)) {
+ ret = avfilter_request_frame(inlink);
+ if (ret < 0)
+ break;
+ }
+ select->cache_frames = 0;
+ }
+
+ return av_fifo_size(select->pending_frames)/sizeof(AVFilterBufferRef *);
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+ SelectContext *select = ctx->priv;
+ AVFilterBufferRef *picref;
+
+ av_expr_free(select->expr);
+ select->expr = NULL;
+
+ while (select->pending_frames &&
+ av_fifo_generic_read(select->pending_frames, &picref, sizeof(picref), NULL) == sizeof(picref))
+ avfilter_unref_buffer(picref);
+ av_fifo_free(select->pending_frames);
+ select->pending_frames = NULL;
+}
+
+AVFilter avfilter_vf_select = {
+ .name = "select",
+ .description = NULL_IF_CONFIG_SMALL("Select frames to pass in output."),
+ .init = init,
+ .uninit = uninit,
+
+ .priv_size = sizeof(SelectContext),
+
+ .inputs = (AVFilterPad[]) {{ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .get_video_buffer = avfilter_null_get_video_buffer,
+ .config_props = config_input,
+ .start_frame = start_frame,
+ .draw_slice = draw_slice,
+ .end_frame = end_frame },
+ { .name = NULL }},
+ .outputs = (AVFilterPad[]) {{ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .poll_frame = poll_frame,
+ .request_frame = request_frame, },
+ { .name = NULL}},
+};
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