vf_select.c 11.4 KB
Newer Older
Stefano Sabatini's avatar
Stefano Sabatini committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
/*
 * 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"
28
#include "libavutil/internal.h"
Stefano Sabatini's avatar
Stefano Sabatini committed
29 30
#include "libavutil/mathematics.h"
#include "avfilter.h"
31
#include "internal.h"
32
#include "video.h"
Stefano Sabatini's avatar
Stefano Sabatini committed
33

34
static const char *const var_names[] = {
Stefano Sabatini's avatar
Stefano Sabatini committed
35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125
    "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;

126
static av_cold int init(AVFilterContext *ctx, const char *args)
Stefano Sabatini's avatar
Stefano Sabatini committed
127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230
{
    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;
}

231
static int start_frame(AVFilterLink *inlink, AVFilterBufferRef *picref)
Stefano Sabatini's avatar
Stefano Sabatini committed
232 233 234 235 236
{
    SelectContext *select = inlink->dst->priv;

    select->select = select_frame(inlink->dst, picref);
    if (select->select) {
237
        AVFilterBufferRef *buf_out;
Stefano Sabatini's avatar
Stefano Sabatini committed
238 239 240 241 242 243 244 245
        /* 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);
246
            return 0;
Stefano Sabatini's avatar
Stefano Sabatini committed
247
        }
248 249 250 251
        buf_out = avfilter_ref_buffer(picref, ~0);
        if (!buf_out)
            return AVERROR(ENOMEM);
        return ff_start_frame(inlink->dst->outputs[0], buf_out);
Stefano Sabatini's avatar
Stefano Sabatini committed
252
    }
253 254

    return 0;
Stefano Sabatini's avatar
Stefano Sabatini committed
255 256
}

257
static int draw_slice(AVFilterLink *inlink, int y, int h, int slice_dir)
Stefano Sabatini's avatar
Stefano Sabatini committed
258 259 260 261
{
    SelectContext *select = inlink->dst->priv;

    if (select->select && !select->cache_frames)
262 263
        return ff_draw_slice(inlink->dst->outputs[0], y, h, slice_dir);
    return 0;
Stefano Sabatini's avatar
Stefano Sabatini committed
264 265
}

266
static int end_frame(AVFilterLink *inlink)
Stefano Sabatini's avatar
Stefano Sabatini committed
267 268 269 270 271
{
    SelectContext *select = inlink->dst->priv;

    if (select->select) {
        if (select->cache_frames)
272 273
            return 0;
        return ff_end_frame(inlink->dst->outputs[0]);
Stefano Sabatini's avatar
Stefano Sabatini committed
274
    }
275
    return 0;
Stefano Sabatini's avatar
Stefano Sabatini committed
276 277 278 279 280 281 282 283 284 285 286
}

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;
287 288
        int ret;

Stefano Sabatini's avatar
Stefano Sabatini committed
289
        av_fifo_generic_read(select->pending_frames, &picref, sizeof(picref), NULL);
290
        if ((ret = ff_start_frame(outlink, picref)) < 0 ||
291 292 293 294
            (ret = ff_draw_slice(outlink, 0, outlink->h, 1)) < 0 ||
            (ret = ff_end_frame(outlink)) < 0);

        return ret;
Stefano Sabatini's avatar
Stefano Sabatini committed
295 296 297
    }

    while (!select->select) {
298
        int ret = ff_request_frame(inlink);
Stefano Sabatini's avatar
Stefano Sabatini committed
299 300 301 302 303 304 305 306 307 308 309 310 311 312
        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)) {
313
        if ((count = ff_poll_frame(inlink)) <= 0)
Stefano Sabatini's avatar
Stefano Sabatini committed
314 315 316 317
            return count;
        /* request frame from input, and apply select condition to it */
        select->cache_frames = 1;
        while (count-- && av_fifo_space(select->pending_frames)) {
318
            ret = ff_request_frame(inlink);
Stefano Sabatini's avatar
Stefano Sabatini committed
319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350
            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),

351 352 353 354 355 356 357 358 359 360 361 362 363
    .inputs    = (const AVFilterPad[]) {{ .name             = "default",
                                          .type             = AVMEDIA_TYPE_VIDEO,
                                          .get_video_buffer = ff_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}},
Stefano Sabatini's avatar
Stefano Sabatini committed
364
};