Imported Debian version 2.4.3~trusty1
[deb_ffmpeg.git] / ffmpeg / libavformat / avisynth.c
CommitLineData
2ba45a60
DM
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};