libavfilter/trim.c

   1 /*
   2  * This file is part of Libav.
   3  *
   4  * Libav is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * Libav is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with Libav; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19 #include <float.h>
  20 #include <math.h>
  21 #include <stdint.h>
  22
  23 #include "config.h"
  24
  25 #include "libavutil/avassert.h"
  26 #include "libavutil/channel_layout.h"
  27 #include "libavutil/common.h"
  28 #include "libavutil/log.h"
  29 #include "libavutil/mathematics.h"
  30 #include "libavutil/opt.h"
  31 #include "libavutil/samplefmt.h"
  32
  33 #include "audio.h"
  34 #include "avfilter.h"
  35 #include "internal.h"
  36
  37 typedef struct TrimContext {
  38     const AVClass *class;
  39
  40     /*
  41      * AVOptions
  42      */
  43     double duration;
  44     double start_time, end_time;
  45     int64_t start_frame, end_frame;
  46     /*
  47      * in the link timebase for video,
  48      * in 1/samplerate for audio
  49      */
  50     int64_t start_pts, end_pts;
  51     int64_t start_sample, end_sample;
  52
  53     /*
  54      * number of video frames that arrived on this filter so far
  55      */
  56     int64_t nb_frames;
  57     /*
  58      * number of audio samples that arrived on this filter so far
  59      */
  60     int64_t nb_samples;
  61     /*
  62      * timestamp of the first frame in the output, in the timebase units
  63      */
  64     int64_t first_pts;
  65     /*
  66      * duration in the timebase units
  67      */
  68     int64_t duration_tb;
  69
  70     int64_t next_pts;
  71
  72     int eof;
  73     int got_output;
  74 } TrimContext;
  75
  76 static int init(AVFilterContext *ctx)
  77 {
  78     TrimContext *s = ctx->priv;
  79
  80     s->first_pts = AV_NOPTS_VALUE;
  81
  82     return 0;
  83 }
  84
  85 static int config_input(AVFilterLink *inlink)
  86 {
  87     AVFilterContext *ctx = inlink->dst;
  88     TrimContext       *s = ctx->priv;
  89     AVRational tb = (inlink->type == AVMEDIA_TYPE_VIDEO) ?
  90                      inlink->time_base : (AVRational){ 1, inlink->sample_rate };
  91
  92     if (s->start_time != DBL_MAX) {
  93         int64_t start_pts = lrintf(s->start_time / av_q2d(tb));
  94         if (s->start_pts == AV_NOPTS_VALUE || start_pts < s->start_pts)
  95             s->start_pts = start_pts;
  96     }
  97     if (s->end_time != DBL_MAX) {
  98         int64_t end_pts = lrintf(s->end_time / av_q2d(tb));
  99         if (s->end_pts == AV_NOPTS_VALUE || end_pts > s->end_pts)
 100             s->end_pts = end_pts;
 101     }
 102     if (s->duration)
 103         s->duration_tb = lrintf(s->duration / av_q2d(tb));
 104
 105     return 0;
 106 }
 107
 108 static int request_frame(AVFilterLink *outlink)
 109 {
 110     AVFilterContext *ctx = outlink->src;
 111     TrimContext       *s = ctx->priv;
 112     int ret;
 113
 114     s->got_output = 0;
 115     while (!s->got_output) {
 116         if (s->eof)
 117             return AVERROR_EOF;
 118
 119         ret = ff_request_frame(ctx->inputs[0]);
 120         if (ret < 0)
 121             return ret;
 122     }
 123
 124     return 0;
 125 }
 126
 127 #define OFFSET(x) offsetof(TrimContext, x)
 128 #define COMMON_OPTS                                                                                                                                                         \
 129     { "start",       "Timestamp in seconds of the first frame that "                                                                                                        \
 130         "should be passed",                                              OFFSET(start_time),  AV_OPT_TYPE_DOUBLE, { .dbl = DBL_MAX },       -DBL_MAX, DBL_MAX,     FLAGS }, \
 131     { "end",         "Timestamp in seconds of the first frame that "                                                                                                        \
 132         "should be dropped again",                                       OFFSET(end_time),    AV_OPT_TYPE_DOUBLE, { .dbl = DBL_MAX },       -DBL_MAX, DBL_MAX,     FLAGS }, \
 133     { "start_pts",   "Timestamp of the first frame that should be "                                                                                                         \
 134        " passed",                                                        OFFSET(start_pts),   AV_OPT_TYPE_INT64,  { .i64 = AV_NOPTS_VALUE }, INT64_MIN, INT64_MAX, FLAGS }, \
 135     { "end_pts",     "Timestamp of the first frame that should be "                                                                                                         \
 136         "dropped again",                                                 OFFSET(end_pts),     AV_OPT_TYPE_INT64,  { .i64 = AV_NOPTS_VALUE }, INT64_MIN, INT64_MAX, FLAGS }, \
 137     { "duration",    "Maximum duration of the output in seconds",        OFFSET(duration),    AV_OPT_TYPE_DOUBLE, { .dbl = 0 },                      0,   DBL_MAX, FLAGS },
 138
 139
 140 #if CONFIG_TRIM_FILTER
 141 static int trim_filter_frame(AVFilterLink *inlink, AVFrame *frame)
 142 {
 143     AVFilterContext *ctx = inlink->dst;
 144     TrimContext       *s = ctx->priv;
 145     int drop;
 146
 147     /* drop everything if EOF has already been returned */
 148     if (s->eof) {
 149         av_frame_free(&frame);
 150         return 0;
 151     }
 152
 153     if (s->start_frame >= 0 || s->start_pts != AV_NOPTS_VALUE) {
 154         drop = 1;
 155         if (s->start_frame >= 0 && s->nb_frames >= s->start_frame)
 156             drop = 0;
 157         if (s->start_pts != AV_NOPTS_VALUE && frame->pts != AV_NOPTS_VALUE &&
 158             frame->pts >= s->start_pts)
 159             drop = 0;
 160         if (drop)
 161             goto drop;
 162     }
 163
 164     if (s->first_pts == AV_NOPTS_VALUE && frame->pts != AV_NOPTS_VALUE)
 165         s->first_pts = frame->pts;
 166
 167     if (s->end_frame != INT64_MAX || s->end_pts != AV_NOPTS_VALUE || s->duration_tb) {
 168         drop = 1;
 169
 170         if (s->end_frame != INT64_MAX && s->nb_frames < s->end_frame)
 171             drop = 0;
 172         if (s->end_pts != AV_NOPTS_VALUE && frame->pts != AV_NOPTS_VALUE &&
 173             frame->pts < s->end_pts)
 174             drop = 0;
 175         if (s->duration_tb && frame->pts != AV_NOPTS_VALUE &&
 176             frame->pts - s->first_pts < s->duration_tb)
 177             drop = 0;
 178
 179         if (drop) {
 180             s->eof = 1;
 181             goto drop;
 182         }
 183     }
 184
 185     s->nb_frames++;
 186     s->got_output = 1;
 187
 188     return ff_filter_frame(ctx->outputs[0], frame);
 189
 190 drop:
 191     s->nb_frames++;
 192     av_frame_free(&frame);
 193     return 0;
 194 }
 195
 196 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM
 197 static const AVOption trim_options[] = {
 198     COMMON_OPTS
 199     { "start_frame", "Number of the first frame that should be passed "
 200         "to the output",                                                 OFFSET(start_frame), AV_OPT_TYPE_INT64,  { .i64 = -1 },       -1, INT64_MAX, FLAGS },
 201     { "end_frame",   "Number of the first frame that should be dropped "
 202         "again",                                                         OFFSET(end_frame),   AV_OPT_TYPE_INT64,  { .i64 = INT64_MAX }, 0, INT64_MAX, FLAGS },
 203     { NULL },
 204 };
 205 #undef FLAGS
 206
 207 static const AVClass trim_class = {
 208     .class_name = "trim",
 209     .item_name  = av_default_item_name,
 210     .option     = trim_options,
 211     .version    = LIBAVUTIL_VERSION_INT,
 212 };
 213
 214 static const AVFilterPad trim_inputs[] = {
 215     {
 216         .name         = "default",
 217         .type         = AVMEDIA_TYPE_VIDEO,
 218         .filter_frame = trim_filter_frame,
 219         .config_props = config_input,
 220     },
 221     { NULL }
 222 };
 223
 224 static const AVFilterPad trim_outputs[] = {
 225     {
 226         .name          = "default",
 227         .type          = AVMEDIA_TYPE_VIDEO,
 228         .request_frame = request_frame,
 229     },
 230     { NULL }
 231 };
 232
 233 AVFilter ff_vf_trim = {
 234     .name        = "trim",
 235     .description = NULL_IF_CONFIG_SMALL("Pick one continuous section from the input, drop the rest."),
 236
 237     .init        = init,
 238
 239     .priv_size   = sizeof(TrimContext),
 240     .priv_class  = &trim_class,
 241
 242     .inputs      = trim_inputs,
 243     .outputs     = trim_outputs,
 244 };
 245 #endif // CONFIG_TRIM_FILTER
 246
 247 #if CONFIG_ATRIM_FILTER
 248 static int atrim_filter_frame(AVFilterLink *inlink, AVFrame *frame)
 249 {
 250     AVFilterContext *ctx = inlink->dst;
 251     TrimContext       *s = ctx->priv;
 252     int64_t start_sample, end_sample = frame->nb_samples;
 253     int64_t pts;
 254     int drop;
 255
 256     /* drop everything if EOF has already been returned */
 257     if (s->eof) {
 258         av_frame_free(&frame);
 259         return 0;
 260     }
 261
 262     if (frame->pts != AV_NOPTS_VALUE)
 263         pts = av_rescale_q(frame->pts, inlink->time_base,
 264                            (AVRational){ 1, inlink->sample_rate });
 265     else
 266         pts = s->next_pts;
 267     s->next_pts = pts + frame->nb_samples;
 268
 269     /* check if at least a part of the frame is after the start time */
 270     if (s->start_sample < 0 && s->start_pts == AV_NOPTS_VALUE) {
 271         start_sample = 0;
 272     } else {
 273         drop = 1;
 274         start_sample = frame->nb_samples;
 275
 276         if (s->start_sample >= 0 &&
 277             s->nb_samples + frame->nb_samples > s->start_sample) {
 278             drop         = 0;
 279             start_sample = FFMIN(start_sample, s->start_sample - s->nb_samples);
 280         }
 281
 282         if (s->start_pts != AV_NOPTS_VALUE && pts != AV_NOPTS_VALUE &&
 283             pts + frame->nb_samples > s->start_pts) {
 284             drop = 0;
 285             start_sample = FFMIN(start_sample, s->start_pts - pts);
 286         }
 287
 288         if (drop)
 289             goto drop;
 290     }
 291
 292     if (s->first_pts == AV_NOPTS_VALUE)
 293         s->first_pts = pts + start_sample;
 294
 295     /* check if at least a part of the frame is before the end time */
 296     if (s->end_sample == INT64_MAX && s->end_pts == AV_NOPTS_VALUE && !s->duration_tb) {
 297         end_sample = frame->nb_samples;
 298     } else {
 299         drop       = 1;
 300         end_sample = 0;
 301
 302         if (s->end_sample != INT64_MAX &&
 303             s->nb_samples < s->end_sample) {
 304             drop       = 0;
 305             end_sample = FFMAX(end_sample, s->end_sample - s->nb_samples);
 306         }
 307
 308         if (s->end_pts != AV_NOPTS_VALUE && pts != AV_NOPTS_VALUE &&
 309             pts < s->end_pts) {
 310             drop       = 0;
 311             end_sample = FFMAX(end_sample, s->end_pts - pts);
 312         }
 313
 314         if (s->duration_tb && pts - s->first_pts < s->duration_tb) {
 315             drop       = 0;
 316             end_sample = FFMAX(end_sample, s->first_pts + s->duration_tb - pts);
 317         }
 318
 319         if (drop) {
 320             s->eof = 1;
 321             goto drop;
 322         }
 323     }
 324
 325     s->nb_samples += frame->nb_samples;
 326     start_sample   = FFMAX(0, start_sample);
 327     end_sample     = FFMIN(frame->nb_samples, end_sample);
 328     av_assert0(start_sample < end_sample);
 329
 330     if (start_sample) {
 331         AVFrame *out = ff_get_audio_buffer(ctx->outputs[0], end_sample - start_sample);
 332         if (!out) {
 333             av_frame_free(&frame);
 334             return AVERROR(ENOMEM);
 335         }
 336
 337         av_frame_copy_props(out, frame);
 338         av_samples_copy(out->extended_data, frame->extended_data, 0, start_sample,
 339                         out->nb_samples, av_get_channel_layout_nb_channels(frame->channel_layout),
 340                         frame->format);
 341         if (out->pts != AV_NOPTS_VALUE)
 342             out->pts += av_rescale_q(start_sample, (AVRational){ 1, out->sample_rate },
 343                                      inlink->time_base);
 344
 345         av_frame_free(&frame);
 346         frame = out;
 347     } else
 348         frame->nb_samples = end_sample;
 349
 350     s->got_output = 1;
 351     return ff_filter_frame(ctx->outputs[0], frame);
 352
 353 drop:
 354     s->nb_samples += frame->nb_samples;
 355     av_frame_free(&frame);
 356     return 0;
 357 }
 358
 359 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM
 360 static const AVOption atrim_options[] = {
 361     COMMON_OPTS
 362     { "start_sample", "Number of the first audio sample that should be "
 363         "passed to the output",                                          OFFSET(start_sample), AV_OPT_TYPE_INT64,  { .i64 = -1 },       -1, INT64_MAX, FLAGS },
 364     { "end_sample",   "Number of the first audio sample that should be "
 365         "dropped again",                                                 OFFSET(end_sample),   AV_OPT_TYPE_INT64,  { .i64 = INT64_MAX }, 0, INT64_MAX, FLAGS },
 366     { NULL },
 367 };
 368 #undef FLAGS
 369
 370 static const AVClass atrim_class = {
 371     .class_name = "atrim",
 372     .item_name  = av_default_item_name,
 373     .option     = atrim_options,
 374     .version    = LIBAVUTIL_VERSION_INT,
 375 };
 376
 377 static const AVFilterPad atrim_inputs[] = {
 378     {
 379         .name         = "default",
 380         .type         = AVMEDIA_TYPE_AUDIO,
 381         .filter_frame = atrim_filter_frame,
 382         .config_props = config_input,
 383     },
 384     { NULL }
 385 };
 386
 387 static const AVFilterPad atrim_outputs[] = {
 388     {
 389         .name          = "default",
 390         .type          = AVMEDIA_TYPE_AUDIO,
 391         .request_frame = request_frame,
 392     },
 393     { NULL }
 394 };
 395
 396 AVFilter ff_af_atrim = {
 397     .name        = "atrim",
 398     .description = NULL_IF_CONFIG_SMALL("Pick one continuous section from the input, drop the rest."),
 399
 400     .init        = init,
 401
 402     .priv_size   = sizeof(TrimContext),
 403     .priv_class  = &atrim_class,
 404
 405     .inputs      = atrim_inputs,
 406     .outputs     = atrim_outputs,
 407 };
 408 #endif // CONFIG_ATRIM_FILTER