Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
tree: 6bd643a676
Fetching contributors…

Cannot retrieve contributors at this time

341 lines (282 sloc) 11.192 kb
/*
* Copyright (c) 2011 Stefano Sabatini
*
* 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
* filter for selecting which frame passes in the filterchain
*/
#include "libavutil/eval.h"
#include "libavutil/fifo.h"
#include "avfilter.h"
static const char * const var_names[] = {
"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_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_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 = (const 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 = (const AVFilterPad[]) {{ .name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.poll_frame = poll_frame,
.request_frame = request_frame, },
{ .name = NULL}},
};
Jump to Line
Something went wrong with that request. Please try again.