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ffmpeg/libavfilter/graphparser.c

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/*
* filter graph parser
* copyright (c) 2008 Vitor Sessak
* copyright (c) 2007 Bobby Bingham
*
* 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
*/
#include <ctype.h>
#include <string.h>
#include "graphparser.h"
#include "avfilter.h"
#include "avfiltergraph.h"
#include "parseutils.h"
#define WHITESPACES " \n\t"
static int link_filter(AVFilterContext *src, int srcpad,
AVFilterContext *dst, int dstpad,
AVClass *log_ctx)
{
if(avfilter_link(src, srcpad, dst, dstpad)) {
av_log(log_ctx, AV_LOG_ERROR,
"cannot create the link %s:%d -> %s:%d\n",
src->filter->name, srcpad, dst->filter->name, dstpad);
return -1;
}
return 0;
}
/**
* Parse "[linkname]"
* @param name a pointer (that need to be free'd after use) to the name between
* parenthesis
*/
static char *parse_link_name(const char **buf, AVClass *log_ctx)
{
const char *start = *buf;
char *name;
(*buf)++;
name = av_get_token(buf, "]");
if(!name[0]) {
av_log(log_ctx, AV_LOG_ERROR,
"Bad (empty?) label found in the following: \"%s\".\n", start);
goto fail;
}
if(*(*buf)++ != ']') {
av_log(log_ctx, AV_LOG_ERROR,
"Mismatched '[' found in the following: \"%s\".\n", start);
fail:
av_freep(&name);
}
return name;
}
static AVFilterContext *create_filter(AVFilterGraph *ctx, int index,
const char *filt_name, const char *args,
AVClass *log_ctx)
{
AVFilterContext *filt_ctx;
AVFilter *filt;
char inst_name[30];
snprintf(inst_name, sizeof(inst_name), "Parsed filter %d", index);
filt = avfilter_get_by_name(filt_name);
if(!filt) {
av_log(log_ctx, AV_LOG_ERROR,
"no such filter: '%s'\n", filt_name);
return NULL;
}
filt_ctx = avfilter_open(filt, inst_name);
if(!filt_ctx) {
av_log(log_ctx, AV_LOG_ERROR,
"error creating filter '%s'\n", filt_name);
return NULL;
}
if(avfilter_graph_add_filter(ctx, filt_ctx) < 0) {
avfilter_destroy(filt_ctx);
return NULL;
}
if(avfilter_init_filter(filt_ctx, args, NULL)) {
av_log(log_ctx, AV_LOG_ERROR,
"error initializing filter '%s' with args '%s'\n", filt_name, args);
return NULL;
}
return filt_ctx;
}
/**
* Parse "filter=params"
*/
static AVFilterContext *parse_filter(const char **buf, AVFilterGraph *graph,
int index, AVClass *log_ctx)
{
char *opts = NULL;
char *name = av_get_token(buf, "=,[");
AVFilterContext *ret;
if(**buf == '=') {
(*buf)++;
opts = av_get_token(buf, "[],\n");
}
ret = create_filter(graph, index, name, opts, log_ctx);
av_free(name);
av_free(opts);
return ret;
}
static void free_inout(AVFilterInOut *head)
{
while(head) {
AVFilterInOut *next = head->next;
av_free(head->name);
av_free(head);
head = next;
}
}
static AVFilterInOut *extract_inout(const char *label, AVFilterInOut **links)
{
AVFilterInOut *ret;
while(*links && strcmp((*links)->name, label))
links = &((*links)->next);
ret = *links;
if(ret)
*links = ret->next;
return ret;
}
static void insert_inout(AVFilterInOut **inouts, AVFilterInOut *element)
{
element->next = *inouts;
*inouts = element;
}
static int link_filter_inouts(AVFilterContext *filter,
AVFilterInOut **curr_inputs,
AVFilterInOut **open_inputs, AVClass *log_ctx)
{
int pad = filter->input_count;
while(pad--) {
AVFilterInOut *p = *curr_inputs;
if(!p) {
av_log(log_ctx, AV_LOG_ERROR,
"Not enough inputs specified for the \"%s\" filter.\n",
filter->filter->name);
return -1;
}
*curr_inputs = (*curr_inputs)->next;
if(p->filter) {
if(link_filter(p->filter, p->pad_idx, filter, pad, log_ctx))
return -1;
av_free(p->name);
av_free(p);
} else {
p->filter = filter;
p->pad_idx = pad;
insert_inout(open_inputs, p);
}
}
if(*curr_inputs) {
av_log(log_ctx, AV_LOG_ERROR,
"Too many inputs specified for the \"%s\" filter.\n",
filter->filter->name);
return -1;
}
pad = filter->output_count;
while(pad--) {
AVFilterInOut *currlinkn = av_mallocz(sizeof(AVFilterInOut));
currlinkn->filter = filter;
currlinkn->pad_idx = pad;
insert_inout(curr_inputs, currlinkn);
}
return 0;
}
static int parse_inputs(const char **buf, AVFilterInOut **curr_inputs,
AVFilterInOut **open_outputs, AVClass *log_ctx)
{
int pad = 0;
while(**buf == '[') {
char *name = parse_link_name(buf, log_ctx);
AVFilterInOut *match;
if(!name)
return -1;
/* First check if the label is not in the open_outputs list */
match = extract_inout(name, open_outputs);
if(match) {
av_free(name);
} else {
/* Not in the list, so add it as an input */
match = av_mallocz(sizeof(AVFilterInOut));
match->name = name;
match->pad_idx = pad;
}
insert_inout(curr_inputs, match);
*buf += strspn(*buf, WHITESPACES);
pad++;
}
return pad;
}
static int parse_outputs(const char **buf, AVFilterInOut **curr_inputs,
AVFilterInOut **open_inputs,
AVFilterInOut **open_outputs, AVClass *log_ctx)
{
int pad = 0;
while(**buf == '[') {
char *name = parse_link_name(buf, log_ctx);
AVFilterInOut *match;
AVFilterInOut *input = *curr_inputs;
*curr_inputs = (*curr_inputs)->next;
if(!name)
return -1;
/* First check if the label is not in the open_inputs list */
match = extract_inout(name, open_inputs);
if(match) {
if(link_filter(input->filter, input->pad_idx,
match->filter, match->pad_idx, log_ctx) < 0)
return -1;
av_free(match->name);
av_free(name);
av_free(match);
av_free(input);
} else {
/* Not in the list, so add the first input as a open_output */
input->name = name;
insert_inout(open_outputs, input);
}
*buf += strspn(*buf, WHITESPACES);
pad++;
}
return pad;
}
int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
AVFilterInOut *open_inputs,
AVFilterInOut *open_outputs, AVClass *log_ctx)
{
int index = 0;
char chr = 0;
AVFilterInOut *curr_inputs = NULL;
do {
AVFilterContext *filter;
filters += strspn(filters, WHITESPACES);
if(parse_inputs(&filters, &curr_inputs, &open_outputs, log_ctx) < 0)
goto fail;
filter = parse_filter(&filters, graph, index, log_ctx);
if(!filter)
goto fail;
if(filter->input_count == 1 && !curr_inputs && !index) {
/* First input can be omitted if it is "[in]" */
const char *tmp = "[in]";
if(parse_inputs(&tmp, &curr_inputs, &open_outputs, log_ctx) < 0)
goto fail;
}
if(link_filter_inouts(filter, &curr_inputs, &open_inputs, log_ctx) < 0)
goto fail;
if(parse_outputs(&filters, &curr_inputs, &open_inputs, &open_outputs,
log_ctx) < 0)
goto fail;
filters += strspn(filters, WHITESPACES);
chr = *filters++;
if(chr == ';' && curr_inputs) {
av_log(log_ctx, AV_LOG_ERROR,
"Could not find a output to link when parsing \"%s\"\n",
filters - 1);
goto fail;
}
index++;
} while(chr == ',' || chr == ';');
if (chr) {
av_log(log_ctx, AV_LOG_ERROR,
"Unable to parse graph description substring: \"%s\"\n",
filters - 1);
goto fail;
}
if(open_inputs && !strcmp(open_inputs->name, "out") && curr_inputs) {
/* Last output can be omitted if it is "[out]" */
const char *tmp = "[out]";
if(parse_outputs(&tmp, &curr_inputs, &open_inputs,
&open_outputs, log_ctx) < 0)
goto fail;
}
return 0;
fail:
avfilter_graph_destroy(graph);
free_inout(open_inputs);
free_inout(open_outputs);
free_inout(curr_inputs);
return -1;
}
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