libavfilter/f_metadata.c - manifest_repos/ffmpeg - Git at Google

 /*
  * Copyright (c) 2016 Paul B Mahol
  *
  * 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 manipulating frame metadata
  */

 #include <float.h>

 #include "libavutil/avassert.h"
 #include "libavutil/avstring.h"
 #include "libavutil/eval.h"
 #include "libavutil/internal.h"
 #include "libavutil/opt.h"
 #include "libavutil/timestamp.h"
 #include "libavformat/avio.h"
 #include "avfilter.h"
 #include "audio.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"

 enum MetadataMode {
     METADATA_SELECT,
     METADATA_ADD,
     METADATA_MODIFY,
     METADATA_DELETE,
     METADATA_PRINT,
     METADATA_NB
 };

 enum MetadataFunction {
     METADATAF_SAME_STR,
     METADATAF_STARTS_WITH,
     METADATAF_LESS,
     METADATAF_EQUAL,
     METADATAF_GREATER,
     METADATAF_EXPR,
     METADATAF_ENDS_WITH,
     METADATAF_NB
 };

 static const char *const var_names[] = {
     "VALUE1",
     "VALUE2",
     NULL
 };

 enum var_name {
     VAR_VALUE1,
     VAR_VALUE2,
     VAR_VARS_NB
 };

 typedef struct MetadataContext {
     const AVClass *class;

     int mode;
     char *key;
     char *value;
     int function;

     char *expr_str;
     AVExpr *expr;
     double var_values[VAR_VARS_NB];

     AVIOContext* avio_context;
     char *file_str;

     int (*compare)(struct MetadataContext *s,
                    const char *value1, const char *value2);
     void (*print)(AVFilterContext *ctx, const char *msg, ...) av_printf_format(2, 3);

     int direct;    // reduces buffering when printing to user-supplied URL
 } MetadataContext;

 #define OFFSET(x) offsetof(MetadataContext, x)
 #define DEFINE_OPTIONS(filt_name, FLAGS) \
 static const AVOption filt_name##_options[] = { \
     { "mode", "set a mode of operation", OFFSET(mode),   AV_OPT_TYPE_INT,    {.i64 = 0 }, 0, METADATA_NB-1, FLAGS, "mode" }, \
     {   "select", "select frame",        0,              AV_OPT_TYPE_CONST,  {.i64 = METADATA_SELECT }, 0, 0, FLAGS, "mode" }, \
     {   "add",    "add new metadata",    0,              AV_OPT_TYPE_CONST,  {.i64 = METADATA_ADD },    0, 0, FLAGS, "mode" }, \
     {   "modify", "modify metadata",     0,              AV_OPT_TYPE_CONST,  {.i64 = METADATA_MODIFY }, 0, 0, FLAGS, "mode" }, \
     {   "delete", "delete metadata",     0,              AV_OPT_TYPE_CONST,  {.i64 = METADATA_DELETE }, 0, 0, FLAGS, "mode" }, \
     {   "print",  "print metadata",      0,              AV_OPT_TYPE_CONST,  {.i64 = METADATA_PRINT },  0, 0, FLAGS, "mode" }, \
     { "key",   "set metadata key",       OFFSET(key),    AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, FLAGS }, \
     { "value", "set metadata value",     OFFSET(value),  AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, FLAGS }, \
     { "function", "function for comparing values", OFFSET(function), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, METADATAF_NB-1, FLAGS, "function" }, \
     {   "same_str",    NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_SAME_STR },    0, 3, FLAGS, "function" }, \
     {   "starts_with", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_STARTS_WITH }, 0, 0, FLAGS, "function" }, \
     {   "less",        NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_LESS    },     0, 3, FLAGS, "function" }, \
     {   "equal",       NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_EQUAL   },     0, 3, FLAGS, "function" }, \
     {   "greater",     NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_GREATER },     0, 3, FLAGS, "function" }, \
     {   "expr",        NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_EXPR    },     0, 3, FLAGS, "function" }, \
     {   "ends_with",   NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_ENDS_WITH },   0, 0, FLAGS, "function" }, \
     { "expr", "set expression for expr function", OFFSET(expr_str), AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, FLAGS }, \
     { "file", "set file where to print metadata information", OFFSET(file_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS }, \
     { "direct", "reduce buffering when printing to user-set file or pipe", OFFSET(direct), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, FLAGS }, \
     { NULL } \
 }

 static int same_str(MetadataContext *s, const char *value1, const char *value2)
 {
     return !strcmp(value1, value2);
 }

 static int starts_with(MetadataContext *s, const char *value1, const char *value2)
 {
     return !strncmp(value1, value2, strlen(value2));
 }

 static int ends_with(MetadataContext *s, const char *value1, const char *value2)
 {
     const int len1 = strlen(value1);
     const int len2 = strlen(value2);

     return !strncmp(value1 + FFMAX(len1 - len2, 0), value2, len2);
 }

 static int equal(MetadataContext *s, const char *value1, const char *value2)
 {
     float f1, f2;

     if (sscanf(value1, "%f", &f1) + sscanf(value2, "%f", &f2) != 2)
         return 0;

     return fabsf(f1 - f2) < FLT_EPSILON;
 }

 static int less(MetadataContext *s, const char *value1, const char *value2)
 {
     float f1, f2;

     if (sscanf(value1, "%f", &f1) + sscanf(value2, "%f", &f2) != 2)
         return 0;

     return (f1 - f2) < FLT_EPSILON;
 }

 static int greater(MetadataContext *s, const char *value1, const char *value2)
 {
     float f1, f2;

     if (sscanf(value1, "%f", &f1) + sscanf(value2, "%f", &f2) != 2)
         return 0;

     return (f2 - f1) < FLT_EPSILON;
 }

 static int parse_expr(MetadataContext *s, const char *value1, const char *value2)
 {
     double f1, f2;

     if (sscanf(value1, "%lf", &f1) + sscanf(value2, "%lf", &f2) != 2)
         return 0;

     s->var_values[VAR_VALUE1] = f1;
     s->var_values[VAR_VALUE2] = f2;

     return av_expr_eval(s->expr, s->var_values, NULL);
 }

 static void print_log(AVFilterContext *ctx, const char *msg, ...)
 {
     va_list argument_list;

     va_start(argument_list, msg);
     if (msg)
         av_vlog(ctx, AV_LOG_INFO, msg, argument_list);
     va_end(argument_list);
 }

 static void print_file(AVFilterContext *ctx, const char *msg, ...)
 {
     MetadataContext *s = ctx->priv;
     va_list argument_list;

     va_start(argument_list, msg);
     if (msg) {
         char buf[128];
         vsnprintf(buf, sizeof(buf), msg, argument_list);
         avio_write(s->avio_context, buf, av_strnlen(buf, sizeof(buf)));
     }
     va_end(argument_list);
 }

 static av_cold int init(AVFilterContext *ctx)
 {
     MetadataContext *s = ctx->priv;
     int ret;

     if (!s->key && s->mode != METADATA_PRINT && s->mode != METADATA_DELETE) {
         av_log(ctx, AV_LOG_WARNING, "Metadata key must be set\n");
         return AVERROR(EINVAL);
     }

     if ((s->mode == METADATA_MODIFY ||
         s->mode == METADATA_ADD) && !s->value) {
         av_log(ctx, AV_LOG_WARNING, "Missing metadata value\n");
         return AVERROR(EINVAL);
     }

     switch (s->function) {
     case METADATAF_SAME_STR:
         s->compare = same_str;
         break;
     case METADATAF_STARTS_WITH:
         s->compare = starts_with;
         break;
     case METADATAF_ENDS_WITH:
         s->compare = ends_with;
         break;
     case METADATAF_LESS:
         s->compare = less;
         break;
     case METADATAF_EQUAL:
         s->compare = equal;
         break;
     case METADATAF_GREATER:
         s->compare = greater;
         break;
     case METADATAF_EXPR:
         s->compare = parse_expr;
         break;
     default:
         av_assert0(0);
     };

     if (s->function == METADATAF_EXPR) {
         if (!s->expr_str) {
             av_log(ctx, AV_LOG_WARNING, "expr option not set\n");
             return AVERROR(EINVAL);
         }
         if ((ret = av_expr_parse(&s->expr, s->expr_str,
                                  var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
             av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", s->expr_str);
             return ret;
         }
     }

     if (s->mode == METADATA_PRINT && s->file_str) {
         s->print = print_file;
     } else {
         s->print = print_log;
     }

     s->avio_context = NULL;
     if (s->file_str) {
         if (!strcmp("-", s->file_str)) {
             ret = avio_open(&s->avio_context, "pipe:1", AVIO_FLAG_WRITE);
         } else {
             ret = avio_open(&s->avio_context, s->file_str, AVIO_FLAG_WRITE);
         }

         if (ret < 0) {
             char buf[128];
             av_strerror(ret, buf, sizeof(buf));
             av_log(ctx, AV_LOG_ERROR, "Could not open %s: %s\n",
                    s->file_str, buf);
             return ret;
         }

         if (s->direct)
             s->avio_context->direct = AVIO_FLAG_DIRECT;
     }

     return 0;
 }

 static av_cold void uninit(AVFilterContext *ctx)
 {
     MetadataContext *s = ctx->priv;

     av_expr_free(s->expr);
     s->expr = NULL;
     if (s->avio_context) {
         avio_closep(&s->avio_context);
     }
 }

 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     MetadataContext *s = ctx->priv;
     AVDictionary **metadata = &frame->metadata;
     AVDictionaryEntry *e;

     if (!*metadata && s->mode != METADATA_ADD)
         return ff_filter_frame(outlink, frame);

     e = av_dict_get(*metadata, !s->key ? "" : s->key, NULL,
                     !s->key ? AV_DICT_IGNORE_SUFFIX: 0);

     switch (s->mode) {
     case METADATA_SELECT:
         if (!s->value && e && e->value) {
             return ff_filter_frame(outlink, frame);
         } else if (s->value && e && e->value &&
                    s->compare(s, e->value, s->value)) {
             return ff_filter_frame(outlink, frame);
         }
         break;
     case METADATA_ADD:
         if (e && e->value) {
             ;
         } else {
             av_dict_set(metadata, s->key, s->value, 0);
         }
         return ff_filter_frame(outlink, frame);
     case METADATA_MODIFY:
         if (e && e->value) {
             av_dict_set(metadata, s->key, s->value, 0);
         }
         return ff_filter_frame(outlink, frame);
     case METADATA_PRINT:
         if (!s->key && e) {
             s->print(ctx, "frame:%-4"PRId64" pts:%-7s pts_time:%s\n",
                      inlink->frame_count_out, av_ts2str(frame->pts), av_ts2timestr(frame->pts, &inlink->time_base));
             s->print(ctx, "%s=%s\n", e->key, e->value);
             while ((e = av_dict_get(*metadata, "", e, AV_DICT_IGNORE_SUFFIX)) != NULL) {
                 s->print(ctx, "%s=%s\n", e->key, e->value);
             }
         } else if (e && e->value && (!s->value || (e->value && s->compare(s, e->value, s->value)))) {
             s->print(ctx, "frame:%-4"PRId64" pts:%-7s pts_time:%s\n",
                      inlink->frame_count_out, av_ts2str(frame->pts), av_ts2timestr(frame->pts, &inlink->time_base));
             s->print(ctx, "%s=%s\n", s->key, e->value);
         }
         return ff_filter_frame(outlink, frame);
     case METADATA_DELETE:
         if (!s->key) {
             av_dict_free(metadata);
         } else if (e && e->value && (!s->value || s->compare(s, e->value, s->value))) {
             av_dict_set(metadata, s->key, NULL, 0);
         }
         return ff_filter_frame(outlink, frame);
     default:
         av_assert0(0);
     };

     av_frame_free(&frame);

     return 0;
 }

 #if CONFIG_AMETADATA_FILTER

 DEFINE_OPTIONS(ametadata, AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM);
 AVFILTER_DEFINE_CLASS(ametadata);

 static const AVFilterPad ainputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
         .filter_frame = filter_frame,
     },
     { NULL }
 };

 static const AVFilterPad aoutputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_AUDIO,
     },
     { NULL }
 };

 AVFilter ff_af_ametadata = {
     .name          = "ametadata",
     .description   = NULL_IF_CONFIG_SMALL("Manipulate audio frame metadata."),
     .priv_size     = sizeof(MetadataContext),
     .priv_class    = &ametadata_class,
     .init          = init,
     .uninit        = uninit,
     .inputs        = ainputs,
     .outputs       = aoutputs,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
 };
 #endif /* CONFIG_AMETADATA_FILTER */

 #if CONFIG_METADATA_FILTER

 DEFINE_OPTIONS(metadata, AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM);
 AVFILTER_DEFINE_CLASS(metadata);

 static const AVFilterPad inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
     },
     { NULL }
 };

 static const AVFilterPad outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };

 AVFilter ff_vf_metadata = {
     .name        = "metadata",
     .description = NULL_IF_CONFIG_SMALL("Manipulate video frame metadata."),
     .priv_size   = sizeof(MetadataContext),
     .priv_class  = &metadata_class,
     .init        = init,
     .uninit      = uninit,
     .inputs      = inputs,
     .outputs     = outputs,
     .flags       = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
 };
 #endif /* CONFIG_METADATA_FILTER */
	/*
	* Copyright (c) 2016 Paul B Mahol
	*
	* 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 manipulating frame metadata
	*/

	#include <float.h>

	#include "libavutil/avassert.h"
	#include "libavutil/avstring.h"
	#include "libavutil/eval.h"
	#include "libavutil/internal.h"
	#include "libavutil/opt.h"
	#include "libavutil/timestamp.h"
	#include "libavformat/avio.h"
	#include "avfilter.h"
	#include "audio.h"
	#include "formats.h"
	#include "internal.h"
	#include "video.h"

	enum MetadataMode {
	METADATA_SELECT,
	METADATA_ADD,
	METADATA_MODIFY,
	METADATA_DELETE,
	METADATA_PRINT,
	METADATA_NB
	};

	enum MetadataFunction {
	METADATAF_SAME_STR,
	METADATAF_STARTS_WITH,
	METADATAF_LESS,
	METADATAF_EQUAL,
	METADATAF_GREATER,
	METADATAF_EXPR,
	METADATAF_ENDS_WITH,
	METADATAF_NB
	};

	static const char *const var_names[] = {
	"VALUE1",
	"VALUE2",
	NULL
	};

	enum var_name {
	VAR_VALUE1,
	VAR_VALUE2,
	VAR_VARS_NB
	};

	typedef struct MetadataContext {
	const AVClass *class;

	int mode;
	char *key;
	char *value;
	int function;

	char *expr_str;
	AVExpr *expr;
	double var_values[VAR_VARS_NB];

	AVIOContext* avio_context;
	char *file_str;

	int (compare)(struct MetadataContext s,
	const char value1, const char value2);
	void (print)(AVFilterContext ctx, const char *msg, ...) av_printf_format(2, 3);

	int direct; // reduces buffering when printing to user-supplied URL
	} MetadataContext;

	#define OFFSET(x) offsetof(MetadataContext, x)
	#define DEFINE_OPTIONS(filt_name, FLAGS) \
	static const AVOption filt_name##_options[] = { \
	{ "mode", "set a mode of operation", OFFSET(mode), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, METADATA_NB-1, FLAGS, "mode" }, \
	{ "select", "select frame", 0, AV_OPT_TYPE_CONST, {.i64 = METADATA_SELECT }, 0, 0, FLAGS, "mode" }, \
	{ "add", "add new metadata", 0, AV_OPT_TYPE_CONST, {.i64 = METADATA_ADD }, 0, 0, FLAGS, "mode" }, \
	{ "modify", "modify metadata", 0, AV_OPT_TYPE_CONST, {.i64 = METADATA_MODIFY }, 0, 0, FLAGS, "mode" }, \
	{ "delete", "delete metadata", 0, AV_OPT_TYPE_CONST, {.i64 = METADATA_DELETE }, 0, 0, FLAGS, "mode" }, \
	{ "print", "print metadata", 0, AV_OPT_TYPE_CONST, {.i64 = METADATA_PRINT }, 0, 0, FLAGS, "mode" }, \
	{ "key", "set metadata key", OFFSET(key), AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, FLAGS }, \
	{ "value", "set metadata value", OFFSET(value), AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, FLAGS }, \
	{ "function", "function for comparing values", OFFSET(function), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, METADATAF_NB-1, FLAGS, "function" }, \
	{ "same_str", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_SAME_STR }, 0, 3, FLAGS, "function" }, \
	{ "starts_with", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_STARTS_WITH }, 0, 0, FLAGS, "function" }, \
	{ "less", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_LESS }, 0, 3, FLAGS, "function" }, \
	{ "equal", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_EQUAL }, 0, 3, FLAGS, "function" }, \
	{ "greater", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_GREATER }, 0, 3, FLAGS, "function" }, \
	{ "expr", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_EXPR }, 0, 3, FLAGS, "function" }, \
	{ "ends_with", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_ENDS_WITH }, 0, 0, FLAGS, "function" }, \
	{ "expr", "set expression for expr function", OFFSET(expr_str), AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, FLAGS }, \
	{ "file", "set file where to print metadata information", OFFSET(file_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS }, \
	{ "direct", "reduce buffering when printing to user-set file or pipe", OFFSET(direct), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, FLAGS }, \
	{ NULL } \
	}

	static int same_str(MetadataContext s, const char value1, const char *value2)
	{
	return !strcmp(value1, value2);
	}

	static int starts_with(MetadataContext s, const char value1, const char *value2)
	{
	return !strncmp(value1, value2, strlen(value2));
	}

	static int ends_with(MetadataContext s, const char value1, const char *value2)
	{
	const int len1 = strlen(value1);
	const int len2 = strlen(value2);

	return !strncmp(value1 + FFMAX(len1 - len2, 0), value2, len2);
	}

	static int equal(MetadataContext s, const char value1, const char *value2)
	{
	float f1, f2;

	if (sscanf(value1, "%f", &f1) + sscanf(value2, "%f", &f2) != 2)
	return 0;

	return fabsf(f1 - f2) < FLT_EPSILON;
	}

	static int less(MetadataContext s, const char value1, const char *value2)
	{
	float f1, f2;

	if (sscanf(value1, "%f", &f1) + sscanf(value2, "%f", &f2) != 2)
	return 0;

	return (f1 - f2) < FLT_EPSILON;
	}

	static int greater(MetadataContext s, const char value1, const char *value2)
	{
	float f1, f2;

	if (sscanf(value1, "%f", &f1) + sscanf(value2, "%f", &f2) != 2)
	return 0;

	return (f2 - f1) < FLT_EPSILON;
	}

	static int parse_expr(MetadataContext s, const char value1, const char *value2)
	{
	double f1, f2;

	if (sscanf(value1, "%lf", &f1) + sscanf(value2, "%lf", &f2) != 2)
	return 0;

	s->var_values[VAR_VALUE1] = f1;
	s->var_values[VAR_VALUE2] = f2;

	return av_expr_eval(s->expr, s->var_values, NULL);
	}

	static void print_log(AVFilterContext ctx, const char msg, ...)
	{
	va_list argument_list;

	va_start(argument_list, msg);
	if (msg)
	av_vlog(ctx, AV_LOG_INFO, msg, argument_list);
	va_end(argument_list);
	}

	static void print_file(AVFilterContext ctx, const char msg, ...)
	{
	MetadataContext *s = ctx->priv;
	va_list argument_list;

	va_start(argument_list, msg);
	if (msg) {
	char buf[128];
	vsnprintf(buf, sizeof(buf), msg, argument_list);
	avio_write(s->avio_context, buf, av_strnlen(buf, sizeof(buf)));
	}
	va_end(argument_list);
	}

	static av_cold int init(AVFilterContext *ctx)
	{
	MetadataContext *s = ctx->priv;
	int ret;

	if (!s->key && s->mode != METADATA_PRINT && s->mode != METADATA_DELETE) {
	av_log(ctx, AV_LOG_WARNING, "Metadata key must be set\n");
	return AVERROR(EINVAL);
	}

	if ((s->mode == METADATA_MODIFY \|\|
	s->mode == METADATA_ADD) && !s->value) {
	av_log(ctx, AV_LOG_WARNING, "Missing metadata value\n");
	return AVERROR(EINVAL);
	}

	switch (s->function) {
	case METADATAF_SAME_STR:
	s->compare = same_str;
	break;
	case METADATAF_STARTS_WITH:
	s->compare = starts_with;
	break;
	case METADATAF_ENDS_WITH:
	s->compare = ends_with;
	break;
	case METADATAF_LESS:
	s->compare = less;
	break;
	case METADATAF_EQUAL:
	s->compare = equal;
	break;
	case METADATAF_GREATER:
	s->compare = greater;
	break;
	case METADATAF_EXPR:
	s->compare = parse_expr;
	break;
	default:
	av_assert0(0);
	};

	if (s->function == METADATAF_EXPR) {
	if (!s->expr_str) {
	av_log(ctx, AV_LOG_WARNING, "expr option not set\n");
	return AVERROR(EINVAL);
	}
	if ((ret = av_expr_parse(&s->expr, s->expr_str,
	var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
	av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", s->expr_str);
	return ret;
	}
	}

	if (s->mode == METADATA_PRINT && s->file_str) {
	s->print = print_file;
	} else {
	s->print = print_log;
	}

	s->avio_context = NULL;
	if (s->file_str) {
	if (!strcmp("-", s->file_str)) {
	ret = avio_open(&s->avio_context, "pipe:1", AVIO_FLAG_WRITE);
	} else {
	ret = avio_open(&s->avio_context, s->file_str, AVIO_FLAG_WRITE);
	}

	if (ret < 0) {
	char buf[128];
	av_strerror(ret, buf, sizeof(buf));
	av_log(ctx, AV_LOG_ERROR, "Could not open %s: %s\n",
	s->file_str, buf);
	return ret;
	}

	if (s->direct)
	s->avio_context->direct = AVIO_FLAG_DIRECT;
	}

	return 0;
	}

	static av_cold void uninit(AVFilterContext *ctx)
	{
	MetadataContext *s = ctx->priv;

	av_expr_free(s->expr);
	s->expr = NULL;
	if (s->avio_context) {
	avio_closep(&s->avio_context);
	}
	}

	static int filter_frame(AVFilterLink inlink, AVFrame frame)
	{
	AVFilterContext *ctx = inlink->dst;
	AVFilterLink *outlink = ctx->outputs[0];
	MetadataContext *s = ctx->priv;
	AVDictionary **metadata = &frame->metadata;
	AVDictionaryEntry *e;

	if (!*metadata && s->mode != METADATA_ADD)
	return ff_filter_frame(outlink, frame);

	e = av_dict_get(*metadata, !s->key ? "" : s->key, NULL,
	!s->key ? AV_DICT_IGNORE_SUFFIX: 0);

	switch (s->mode) {
	case METADATA_SELECT:
	if (!s->value && e && e->value) {
	return ff_filter_frame(outlink, frame);
	} else if (s->value && e && e->value &&
	s->compare(s, e->value, s->value)) {
	return ff_filter_frame(outlink, frame);
	}
	break;
	case METADATA_ADD:
	if (e && e->value) {
	;
	} else {
	av_dict_set(metadata, s->key, s->value, 0);
	}
	return ff_filter_frame(outlink, frame);
	case METADATA_MODIFY:
	if (e && e->value) {
	av_dict_set(metadata, s->key, s->value, 0);
	}
	return ff_filter_frame(outlink, frame);
	case METADATA_PRINT:
	if (!s->key && e) {
	s->print(ctx, "frame:%-4"PRId64" pts:%-7s pts_time:%s\n",
	inlink->frame_count_out, av_ts2str(frame->pts), av_ts2timestr(frame->pts, &inlink->time_base));
	s->print(ctx, "%s=%s\n", e->key, e->value);
	while ((e = av_dict_get(*metadata, "", e, AV_DICT_IGNORE_SUFFIX)) != NULL) {
	s->print(ctx, "%s=%s\n", e->key, e->value);
	}
	} else if (e && e->value && (!s->value \|\| (e->value && s->compare(s, e->value, s->value)))) {
	s->print(ctx, "frame:%-4"PRId64" pts:%-7s pts_time:%s\n",
	inlink->frame_count_out, av_ts2str(frame->pts), av_ts2timestr(frame->pts, &inlink->time_base));
	s->print(ctx, "%s=%s\n", s->key, e->value);
	}
	return ff_filter_frame(outlink, frame);
	case METADATA_DELETE:
	if (!s->key) {
	av_dict_free(metadata);
	} else if (e && e->value && (!s->value \|\| s->compare(s, e->value, s->value))) {
	av_dict_set(metadata, s->key, NULL, 0);
	}
	return ff_filter_frame(outlink, frame);
	default:
	av_assert0(0);
	};

	av_frame_free(&frame);

	return 0;
	}

	#if CONFIG_AMETADATA_FILTER

	DEFINE_OPTIONS(ametadata, AV_OPT_FLAG_AUDIO_PARAM\|AV_OPT_FLAG_FILTERING_PARAM);
	AVFILTER_DEFINE_CLASS(ametadata);

	static const AVFilterPad ainputs[] = {
	{
	.name = "default",
	.type = AVMEDIA_TYPE_AUDIO,
	.filter_frame = filter_frame,
	},
	{ NULL }
	};

	static const AVFilterPad aoutputs[] = {
	{
	.name = "default",
	.type = AVMEDIA_TYPE_AUDIO,
	},
	{ NULL }
	};

	AVFilter ff_af_ametadata = {
	.name = "ametadata",
	.description = NULL_IF_CONFIG_SMALL("Manipulate audio frame metadata."),
	.priv_size = sizeof(MetadataContext),
	.priv_class = &ametadata_class,
	.init = init,
	.uninit = uninit,
	.inputs = ainputs,
	.outputs = aoutputs,
	.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
	};
	#endif /* CONFIG_AMETADATA_FILTER */

	#if CONFIG_METADATA_FILTER

	DEFINE_OPTIONS(metadata, AV_OPT_FLAG_VIDEO_PARAM\|AV_OPT_FLAG_FILTERING_PARAM);
	AVFILTER_DEFINE_CLASS(metadata);

	static const AVFilterPad inputs[] = {
	{
	.name = "default",
	.type = AVMEDIA_TYPE_VIDEO,
	.filter_frame = filter_frame,
	},
	{ NULL }
	};

	static const AVFilterPad outputs[] = {
	{
	.name = "default",
	.type = AVMEDIA_TYPE_VIDEO,
	},
	{ NULL }
	};

	AVFilter ff_vf_metadata = {
	.name = "metadata",
	.description = NULL_IF_CONFIG_SMALL("Manipulate video frame metadata."),
	.priv_size = sizeof(MetadataContext),
	.priv_class = &metadata_class,
	.init = init,
	.uninit = uninit,
	.inputs = inputs,
	.outputs = outputs,
	.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
	};
	#endif /* CONFIG_METADATA_FILTER */