1/* 2 * AviSynth/AvxSynth support 3 * Copyright (c) 2012 AvxSynth Team. 4 * 5 * This file is part of FFmpeg 6 * FFmpeg is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * FFmpeg is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with FFmpeg; if not, write to the Free Software 18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 19 */ 20 21#include "libavutil/internal.h" 22#include "libavcodec/internal.h" 23#include "avformat.h" 24#include "internal.h" 25 26/* Enable function pointer definitions for runtime loading. */ 27#define AVSC_NO_DECLSPEC 28 29/* Platform-specific directives for AviSynth vs AvxSynth. */ 30#ifdef _WIN32 31 #include <windows.h> 32 #undef EXTERN_C 33 #include "compat/avisynth/avisynth_c.h" 34 #include "compat/avisynth/avisynth_c_25.h" 35 #define AVISYNTH_LIB "avisynth" 36 #define USING_AVISYNTH 37#else 38 #include <dlfcn.h> 39 #include "compat/avisynth/avxsynth_c.h" 40 #if defined (__APPLE__) 41 #define AVISYNTH_LIB "libavxsynth.dylib" 42 #else 43 #define AVISYNTH_LIB "libavxsynth.so" 44 #endif 45 46 #define LoadLibrary(x) dlopen(x, RTLD_NOW | RTLD_GLOBAL) 47 #define GetProcAddress dlsym 48 #define FreeLibrary dlclose 49#endif 50 51typedef struct AviSynthLibrary { 52 void *library; 53#define AVSC_DECLARE_FUNC(name) name ## _func name 54 AVSC_DECLARE_FUNC(avs_bit_blt); 55 AVSC_DECLARE_FUNC(avs_clip_get_error); 56 AVSC_DECLARE_FUNC(avs_create_script_environment); 57 AVSC_DECLARE_FUNC(avs_delete_script_environment); 58 AVSC_DECLARE_FUNC(avs_get_audio); 59 AVSC_DECLARE_FUNC(avs_get_error); 60 AVSC_DECLARE_FUNC(avs_get_frame); 61 AVSC_DECLARE_FUNC(avs_get_version); 62 AVSC_DECLARE_FUNC(avs_get_video_info); 63 AVSC_DECLARE_FUNC(avs_invoke); 64 AVSC_DECLARE_FUNC(avs_release_clip); 65 AVSC_DECLARE_FUNC(avs_release_value); 66 AVSC_DECLARE_FUNC(avs_release_video_frame); 67 AVSC_DECLARE_FUNC(avs_take_clip); 68#undef AVSC_DECLARE_FUNC 69} AviSynthLibrary; 70 71typedef struct AviSynthContext { 72 AVS_ScriptEnvironment *env; 73 AVS_Clip *clip; 74 const AVS_VideoInfo *vi; 75 76 /* avisynth_read_packet_video() iterates over this. */ 77 int n_planes; 78 const int *planes; 79 80 int curr_stream; 81 int curr_frame; 82 int64_t curr_sample; 83 84 int error; 85 86 /* Linked list pointers. */ 87 struct AviSynthContext *next; 88} AviSynthContext; 89 90static const int avs_planes_packed[1] = { 0 }; 91static const int avs_planes_grey[1] = { AVS_PLANAR_Y }; 92static const int avs_planes_yuv[3] = { AVS_PLANAR_Y, AVS_PLANAR_U, 93 AVS_PLANAR_V }; 94 95/* A conflict between C++ global objects, atexit, and dynamic loading requires 96 * us to register our own atexit handler to prevent double freeing. */ 97static AviSynthLibrary avs_library; 98static int avs_atexit_called = 0; 99 100/* Linked list of AviSynthContexts. An atexit handler destroys this list. */ 101static AviSynthContext *avs_ctx_list = NULL; 102 103static av_cold void avisynth_atexit_handler(void); 104 105static av_cold int avisynth_load_library(void) 106{ 107 avs_library.library = LoadLibrary(AVISYNTH_LIB); 108 if (!avs_library.library) 109 return AVERROR_UNKNOWN; 110 111#define LOAD_AVS_FUNC(name, continue_on_fail) \ 112 avs_library.name = \ 113 (void *)GetProcAddress(avs_library.library, #name); \ 114 if (!continue_on_fail && !avs_library.name) \ 115 goto fail; 116 117 LOAD_AVS_FUNC(avs_bit_blt, 0); 118 LOAD_AVS_FUNC(avs_clip_get_error, 0); 119 LOAD_AVS_FUNC(avs_create_script_environment, 0); 120 LOAD_AVS_FUNC(avs_delete_script_environment, 0); 121 LOAD_AVS_FUNC(avs_get_audio, 0); 122 LOAD_AVS_FUNC(avs_get_error, 1); // New to AviSynth 2.6 123 LOAD_AVS_FUNC(avs_get_frame, 0); 124 LOAD_AVS_FUNC(avs_get_version, 0); 125 LOAD_AVS_FUNC(avs_get_video_info, 0); 126 LOAD_AVS_FUNC(avs_invoke, 0); 127 LOAD_AVS_FUNC(avs_release_clip, 0); 128 LOAD_AVS_FUNC(avs_release_value, 0); 129 LOAD_AVS_FUNC(avs_release_video_frame, 0); 130 LOAD_AVS_FUNC(avs_take_clip, 0); 131#undef LOAD_AVS_FUNC 132 133 atexit(avisynth_atexit_handler); 134 return 0; 135 136fail: 137 FreeLibrary(avs_library.library); 138 return AVERROR_UNKNOWN; 139} 140 141/* Note that avisynth_context_create and avisynth_context_destroy 142 * do not allocate or free the actual context! That is taken care of 143 * by libavformat. */ 144static av_cold int avisynth_context_create(AVFormatContext *s) 145{ 146 AviSynthContext *avs = s->priv_data; 147 int ret; 148 149 if (!avs_library.library) 150 if (ret = avisynth_load_library()) 151 return ret; 152 153 avs->env = avs_library.avs_create_script_environment(3); 154 if (avs_library.avs_get_error) { 155 const char *error = avs_library.avs_get_error(avs->env); 156 if (error) { 157 av_log(s, AV_LOG_ERROR, "%s\n", error); 158 return AVERROR_UNKNOWN; 159 } 160 } 161 162 if (!avs_ctx_list) { 163 avs_ctx_list = avs; 164 } else { 165 avs->next = avs_ctx_list; 166 avs_ctx_list = avs; 167 } 168 169 return 0; 170} 171 172static av_cold void avisynth_context_destroy(AviSynthContext *avs) 173{ 174 if (avs_atexit_called) 175 return; 176 177 if (avs == avs_ctx_list) { 178 avs_ctx_list = avs->next; 179 } else { 180 AviSynthContext *prev = avs_ctx_list; 181 while (prev->next != avs) 182 prev = prev->next; 183 prev->next = avs->next; 184 } 185 186 if (avs->clip) { 187 avs_library.avs_release_clip(avs->clip); 188 avs->clip = NULL; 189 } 190 if (avs->env) { 191 avs_library.avs_delete_script_environment(avs->env); 192 avs->env = NULL; 193 } 194} 195 196static av_cold void avisynth_atexit_handler(void) 197{ 198 AviSynthContext *avs = avs_ctx_list; 199 200 while (avs) { 201 AviSynthContext *next = avs->next; 202 avisynth_context_destroy(avs); 203 avs = next; 204 } 205 FreeLibrary(avs_library.library); 206 207 avs_atexit_called = 1; 208} 209 210/* Create AVStream from audio and video data. */ 211static int avisynth_create_stream_video(AVFormatContext *s, AVStream *st) 212{ 213 AviSynthContext *avs = s->priv_data; 214 int planar = 0; // 0: packed, 1: YUV, 2: Y8 215 216 st->codec->codec_type = AVMEDIA_TYPE_VIDEO; 217 st->codec->codec_id = AV_CODEC_ID_RAWVIDEO; 218 st->codec->width = avs->vi->width; 219 st->codec->height = avs->vi->height; 220 221 st->time_base = (AVRational) { avs->vi->fps_denominator, 222 avs->vi->fps_numerator }; 223 st->avg_frame_rate = (AVRational) { avs->vi->fps_numerator, 224 avs->vi->fps_denominator }; 225 st->start_time = 0; 226 st->duration = avs->vi->num_frames; 227 st->nb_frames = avs->vi->num_frames; 228 229 switch (avs->vi->pixel_type) { 230#ifdef USING_AVISYNTH 231 case AVS_CS_YV24: 232 st->codec->pix_fmt = AV_PIX_FMT_YUV444P; 233 planar = 1; 234 break; 235 case AVS_CS_YV16: 236 st->codec->pix_fmt = AV_PIX_FMT_YUV422P; 237 planar = 1; 238 break; 239 case AVS_CS_YV411: 240 st->codec->pix_fmt = AV_PIX_FMT_YUV411P; 241 planar = 1; 242 break; 243 case AVS_CS_Y8: 244 st->codec->pix_fmt = AV_PIX_FMT_GRAY8; 245 planar = 2; 246 break; 247#endif 248 case AVS_CS_BGR24: 249 st->codec->pix_fmt = AV_PIX_FMT_BGR24; 250 break; 251 case AVS_CS_BGR32: 252 st->codec->pix_fmt = AV_PIX_FMT_RGB32; 253 break; 254 case AVS_CS_YUY2: 255 st->codec->pix_fmt = AV_PIX_FMT_YUYV422; 256 break; 257 case AVS_CS_YV12: 258 st->codec->pix_fmt = AV_PIX_FMT_YUV420P; 259 planar = 1; 260 break; 261 case AVS_CS_I420: // Is this even used anywhere? 262 st->codec->pix_fmt = AV_PIX_FMT_YUV420P; 263 planar = 1; 264 break; 265 default: 266 av_log(s, AV_LOG_ERROR, 267 "unknown AviSynth colorspace %d\n", avs->vi->pixel_type); 268 avs->error = 1; 269 return AVERROR_UNKNOWN; 270 } 271 272 switch (planar) { 273 case 2: // Y8 274 avs->n_planes = 1; 275 avs->planes = avs_planes_grey; 276 break; 277 case 1: // YUV 278 avs->n_planes = 3; 279 avs->planes = avs_planes_yuv; 280 break; 281 default: 282 avs->n_planes = 1; 283 avs->planes = avs_planes_packed; 284 } 285 return 0; 286} 287 288static int avisynth_create_stream_audio(AVFormatContext *s, AVStream *st) 289{ 290 AviSynthContext *avs = s->priv_data; 291 292 st->codec->codec_type = AVMEDIA_TYPE_AUDIO; 293 st->codec->sample_rate = avs->vi->audio_samples_per_second; 294 st->codec->channels = avs->vi->nchannels; 295 st->time_base = (AVRational) { 1, 296 avs->vi->audio_samples_per_second }; 297 st->duration = avs->vi->num_audio_samples; 298 299 switch (avs->vi->sample_type) { 300 case AVS_SAMPLE_INT8: 301 st->codec->codec_id = AV_CODEC_ID_PCM_U8; 302 break; 303 case AVS_SAMPLE_INT16: 304 st->codec->codec_id = AV_CODEC_ID_PCM_S16LE; 305 break; 306 case AVS_SAMPLE_INT24: 307 st->codec->codec_id = AV_CODEC_ID_PCM_S24LE; 308 break; 309 case AVS_SAMPLE_INT32: 310 st->codec->codec_id = AV_CODEC_ID_PCM_S32LE; 311 break; 312 case AVS_SAMPLE_FLOAT: 313 st->codec->codec_id = AV_CODEC_ID_PCM_F32LE; 314 break; 315 default: 316 av_log(s, AV_LOG_ERROR, 317 "unknown AviSynth sample type %d\n", avs->vi->sample_type); 318 avs->error = 1; 319 return AVERROR_UNKNOWN; 320 } 321 return 0; 322} 323 324static int avisynth_create_stream(AVFormatContext *s) 325{ 326 AviSynthContext *avs = s->priv_data; 327 AVStream *st; 328 int ret; 329 int id = 0; 330 331 if (avs_has_video(avs->vi)) { 332 st = avformat_new_stream(s, NULL); 333 if (!st) 334 return AVERROR_UNKNOWN; 335 st->id = id++; 336 if (ret = avisynth_create_stream_video(s, st)) 337 return ret; 338 } 339 if (avs_has_audio(avs->vi)) { 340 st = avformat_new_stream(s, NULL); 341 if (!st) 342 return AVERROR_UNKNOWN; 343 st->id = id++; 344 if (ret = avisynth_create_stream_audio(s, st)) 345 return ret; 346 } 347 return 0; 348} 349 350static int avisynth_open_file(AVFormatContext *s) 351{ 352 AviSynthContext *avs = s->priv_data; 353 AVS_Value arg, val; 354 int ret; 355#ifdef USING_AVISYNTH 356 char filename_ansi[MAX_PATH * 4]; 357 wchar_t filename_wc[MAX_PATH * 4]; 358#endif 359 360 if (ret = avisynth_context_create(s)) 361 return ret; 362 363#ifdef USING_AVISYNTH 364 /* Convert UTF-8 to ANSI code page */ 365 MultiByteToWideChar(CP_UTF8, 0, s->filename, -1, filename_wc, MAX_PATH * 4); 366 WideCharToMultiByte(CP_THREAD_ACP, 0, filename_wc, -1, filename_ansi, 367 MAX_PATH * 4, NULL, NULL); 368 arg = avs_new_value_string(filename_ansi); 369#else 370 arg = avs_new_value_string(s->filename); 371#endif 372 val = avs_library.avs_invoke(avs->env, "Import", arg, 0); 373 if (avs_is_error(val)) { 374 av_log(s, AV_LOG_ERROR, "%s\n", avs_as_error(val)); 375 ret = AVERROR_UNKNOWN; 376 goto fail; 377 } 378 if (!avs_is_clip(val)) { 379 av_log(s, AV_LOG_ERROR, "AviSynth script did not return a clip\n"); 380 ret = AVERROR_UNKNOWN; 381 goto fail; 382 } 383 384 avs->clip = avs_library.avs_take_clip(val, avs->env); 385 avs->vi = avs_library.avs_get_video_info(avs->clip); 386 387 /* Release the AVS_Value as it will go out of scope. */ 388 avs_library.avs_release_value(val); 389 390 if (ret = avisynth_create_stream(s)) 391 goto fail; 392 393 return 0; 394 395fail: 396 avisynth_context_destroy(avs); 397 return ret; 398} 399 400static void avisynth_next_stream(AVFormatContext *s, AVStream **st, 401 AVPacket *pkt, int *discard) 402{ 403 AviSynthContext *avs = s->priv_data; 404 405 avs->curr_stream++; 406 avs->curr_stream %= s->nb_streams; 407 408 *st = s->streams[avs->curr_stream]; 409 if ((*st)->discard == AVDISCARD_ALL) 410 *discard = 1; 411 else 412 *discard = 0; 413 414 return; 415} 416 417/* Copy AviSynth clip data into an AVPacket. */ 418static int avisynth_read_packet_video(AVFormatContext *s, AVPacket *pkt, 419 int discard) 420{ 421 AviSynthContext *avs = s->priv_data; 422 AVS_VideoFrame *frame; 423 unsigned char *dst_p; 424 const unsigned char *src_p; 425 int n, i, plane, rowsize, planeheight, pitch, bits; 426 const char *error; 427 428 if (avs->curr_frame >= avs->vi->num_frames) 429 return AVERROR_EOF; 430 431 /* This must happen even if the stream is discarded to prevent desync. */ 432 n = avs->curr_frame++; 433 if (discard) 434 return 0; 435 436#ifdef USING_AVISYNTH 437 /* Define the bpp values for the new AviSynth 2.6 colorspaces. 438 * Since AvxSynth doesn't have these functions, special-case 439 * it in order to avoid implicit declaration errors. */ 440 441 if (avs_is_yv24(avs->vi)) 442 bits = 24; 443 else if (avs_is_yv16(avs->vi)) 444 bits = 16; 445 else if (avs_is_yv411(avs->vi)) 446 bits = 12; 447 else if (avs_is_y8(avs->vi)) 448 bits = 8; 449 else 450#endif 451 bits = avs_bits_per_pixel(avs->vi); 452 453 /* Without the cast to int64_t, calculation overflows at about 9k x 9k 454 * resolution. */ 455 pkt->size = (((int64_t)avs->vi->width * 456 (int64_t)avs->vi->height) * bits) / 8; 457 if (!pkt->size) 458 return AVERROR_UNKNOWN; 459 460 if (av_new_packet(pkt, pkt->size) < 0) 461 return AVERROR(ENOMEM); 462 463 pkt->pts = n; 464 pkt->dts = n; 465 pkt->duration = 1; 466 pkt->stream_index = avs->curr_stream; 467 468 frame = avs_library.avs_get_frame(avs->clip, n); 469 error = avs_library.avs_clip_get_error(avs->clip); 470 if (error) { 471 av_log(s, AV_LOG_ERROR, "%s\n", error); 472 avs->error = 1; 473 av_packet_unref(pkt); 474 return AVERROR_UNKNOWN; 475 } 476 477 dst_p = pkt->data; 478 for (i = 0; i < avs->n_planes; i++) { 479 plane = avs->planes[i]; 480 src_p = avs_get_read_ptr_p(frame, plane); 481 pitch = avs_get_pitch_p(frame, plane); 482 483#ifdef USING_AVISYNTH 484 if (avs_library.avs_get_version(avs->clip) == 3) { 485 rowsize = avs_get_row_size_p_25(frame, plane); 486 planeheight = avs_get_height_p_25(frame, plane); 487 } else { 488 rowsize = avs_get_row_size_p(frame, plane); 489 planeheight = avs_get_height_p(frame, plane); 490 } 491#else 492 rowsize = avs_get_row_size_p(frame, plane); 493 planeheight = avs_get_height_p(frame, plane); 494#endif 495 496 /* Flip RGB video. */ 497 if (avs_is_rgb24(avs->vi) || avs_is_rgb(avs->vi)) { 498 src_p = src_p + (planeheight - 1) * pitch; 499 pitch = -pitch; 500 } 501 502 avs_library.avs_bit_blt(avs->env, dst_p, rowsize, src_p, pitch, 503 rowsize, planeheight); 504 dst_p += rowsize * planeheight; 505 } 506 507 avs_library.avs_release_video_frame(frame); 508 return 0; 509} 510 511static int avisynth_read_packet_audio(AVFormatContext *s, AVPacket *pkt, 512 int discard) 513{ 514 AviSynthContext *avs = s->priv_data; 515 AVRational fps, samplerate; 516 int samples; 517 int64_t n; 518 const char *error; 519 520 if (avs->curr_sample >= avs->vi->num_audio_samples) 521 return AVERROR_EOF; 522 523 fps.num = avs->vi->fps_numerator; 524 fps.den = avs->vi->fps_denominator; 525 samplerate.num = avs->vi->audio_samples_per_second; 526 samplerate.den = 1; 527 528 if (avs_has_video(avs->vi)) { 529 if (avs->curr_frame < avs->vi->num_frames) 530 samples = av_rescale_q(avs->curr_frame, samplerate, fps) - 531 avs->curr_sample; 532 else 533 samples = av_rescale_q(1, samplerate, fps); 534 } else { 535 samples = 1000; 536 } 537 538 /* After seeking, audio may catch up with video. */ 539 if (samples <= 0) { 540 pkt->size = 0; 541 pkt->data = NULL; 542 return 0; 543 } 544 545 if (avs->curr_sample + samples > avs->vi->num_audio_samples) 546 samples = avs->vi->num_audio_samples - avs->curr_sample; 547 548 /* This must happen even if the stream is discarded to prevent desync. */ 549 n = avs->curr_sample; 550 avs->curr_sample += samples; 551 if (discard) 552 return 0; 553 554 pkt->size = avs_bytes_per_channel_sample(avs->vi) * 555 samples * avs->vi->nchannels; 556 if (!pkt->size) 557 return AVERROR_UNKNOWN; 558 559 if (av_new_packet(pkt, pkt->size) < 0) 560 return AVERROR(ENOMEM); 561 562 pkt->pts = n; 563 pkt->dts = n; 564 pkt->duration = samples; 565 pkt->stream_index = avs->curr_stream; 566 567 avs_library.avs_get_audio(avs->clip, pkt->data, n, samples); 568 error = avs_library.avs_clip_get_error(avs->clip); 569 if (error) { 570 av_log(s, AV_LOG_ERROR, "%s\n", error); 571 avs->error = 1; 572 av_packet_unref(pkt); 573 return AVERROR_UNKNOWN; 574 } 575 return 0; 576} 577 578static av_cold int avisynth_read_header(AVFormatContext *s) 579{ 580 int ret; 581 582 // Calling library must implement a lock for thread-safe opens. 583 if (ret = avpriv_lock_avformat()) 584 return ret; 585 586 if (ret = avisynth_open_file(s)) { 587 avpriv_unlock_avformat(); 588 return ret; 589 } 590 591 avpriv_unlock_avformat(); 592 return 0; 593} 594 595static int avisynth_read_packet(AVFormatContext *s, AVPacket *pkt) 596{ 597 AviSynthContext *avs = s->priv_data; 598 AVStream *st; 599 int discard = 0; 600 int ret; 601 602 if (avs->error) 603 return AVERROR_UNKNOWN; 604 605 /* If either stream reaches EOF, try to read the other one before 606 * giving up. */ 607 avisynth_next_stream(s, &st, pkt, &discard); 608 if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) { 609 ret = avisynth_read_packet_video(s, pkt, discard); 610 if (ret == AVERROR_EOF && avs_has_audio(avs->vi)) { 611 avisynth_next_stream(s, &st, pkt, &discard); 612 return avisynth_read_packet_audio(s, pkt, discard); 613 } 614 } else { 615 ret = avisynth_read_packet_audio(s, pkt, discard); 616 if (ret == AVERROR_EOF && avs_has_video(avs->vi)) { 617 avisynth_next_stream(s, &st, pkt, &discard); 618 return avisynth_read_packet_video(s, pkt, discard); 619 } 620 } 621 622 return ret; 623} 624 625static av_cold int avisynth_read_close(AVFormatContext *s) 626{ 627 if (avpriv_lock_avformat()) 628 return AVERROR_UNKNOWN; 629 630 avisynth_context_destroy(s->priv_data); 631 avpriv_unlock_avformat(); 632 return 0; 633} 634 635static int avisynth_read_seek(AVFormatContext *s, int stream_index, 636 int64_t timestamp, int flags) 637{ 638 AviSynthContext *avs = s->priv_data; 639 AVStream *st; 640 AVRational fps, samplerate; 641 642 if (avs->error) 643 return AVERROR_UNKNOWN; 644 645 fps = (AVRational) { avs->vi->fps_numerator, 646 avs->vi->fps_denominator }; 647 samplerate = (AVRational) { avs->vi->audio_samples_per_second, 1 }; 648 649 st = s->streams[stream_index]; 650 if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) { 651 /* AviSynth frame counts are signed int. */ 652 if ((timestamp >= avs->vi->num_frames) || 653 (timestamp > INT_MAX) || 654 (timestamp < 0)) 655 return AVERROR_EOF; 656 avs->curr_frame = timestamp; 657 if (avs_has_audio(avs->vi)) 658 avs->curr_sample = av_rescale_q(timestamp, samplerate, fps); 659 } else { 660 if ((timestamp >= avs->vi->num_audio_samples) || (timestamp < 0)) 661 return AVERROR_EOF; 662 /* Force frame granularity for seeking. */ 663 if (avs_has_video(avs->vi)) { 664 avs->curr_frame = av_rescale_q(timestamp, fps, samplerate); 665 avs->curr_sample = av_rescale_q(avs->curr_frame, samplerate, fps); 666 } else { 667 avs->curr_sample = timestamp; 668 } 669 } 670 671 return 0; 672} 673 674AVInputFormat ff_avisynth_demuxer = { 675 .name = "avisynth", 676 .long_name = NULL_IF_CONFIG_SMALL("AviSynth script"), 677 .priv_data_size = sizeof(AviSynthContext), 678 .read_header = avisynth_read_header, 679 .read_packet = avisynth_read_packet, 680 .read_close = avisynth_read_close, 681 .read_seek = avisynth_read_seek, 682 .extensions = "avs", 683}; 684