mirror of https://git.ffmpeg.org/ffmpeg.git
396 lines
10 KiB
C
396 lines
10 KiB
C
/*
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* filter graph parser
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* copyright (c) 2008 Vitor Sessak
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* copyright (c) 2007 Bobby Bingham
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <ctype.h>
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#include <string.h>
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#include "graphparser.h"
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#include "avfilter.h"
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#include "avfiltergraph.h"
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static int link_filter(AVFilterContext *src, int srcpad,
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AVFilterContext *dst, int dstpad,
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AVClass *log_ctx)
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{
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if(avfilter_link(src, srcpad, dst, dstpad)) {
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av_log(log_ctx, AV_LOG_ERROR,
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"cannot create the link %s:%d -> %s:%d\n",
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src->filter->name, srcpad, dst->filter->name, dstpad);
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return -1;
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}
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return 0;
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}
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static int consume_whitespace(const char *buf)
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{
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return strspn(buf, " \n\t");
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}
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/**
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* Consumes a string from *buf.
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* @return a copy of the consumed string, which should be free'd after use
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*/
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static char *consume_string(const char **buf)
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{
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char *out = av_malloc(strlen(*buf) + 1);
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char *ret = out;
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*buf += consume_whitespace(*buf);
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do{
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char c = *(*buf)++;
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switch (c) {
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case '\\':
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*out++ = *(*buf)++;
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break;
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case '\'':
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while(**buf && **buf != '\'')
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*out++ = *(*buf)++;
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if(**buf) (*buf)++;
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break;
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case 0:
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case ']':
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case '[':
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case '=':
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case ',':
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case ';':
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case ' ':
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case '\n':
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*out++ = 0;
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break;
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default:
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*out++ = c;
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}
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} while(out[-1]);
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(*buf)--;
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*buf += consume_whitespace(*buf);
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return ret;
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}
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/**
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* Parse "[linkname]"
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* @param name a pointer (that need to be free'd after use) to the name between
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* parenthesis
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*/
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static char *parse_link_name(const char **buf, AVClass *log_ctx)
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{
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const char *start = *buf;
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char *name;
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(*buf)++;
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name = consume_string(buf);
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if(!name[0]) {
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av_log(log_ctx, AV_LOG_ERROR,
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"Bad (empty?) label found in the following: \"%s\".\n", start);
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goto fail;
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}
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if(*(*buf)++ != ']') {
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av_log(log_ctx, AV_LOG_ERROR,
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"Mismatched '[' found in the following: \"%s\".\n", start);
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fail:
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av_freep(&name);
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}
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return name;
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}
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static AVFilterContext *create_filter(AVFilterGraph *ctx, int index,
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const char *filt_name, const char *args,
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AVClass *log_ctx)
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{
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AVFilterContext *filt_ctx;
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AVFilter *filt;
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char inst_name[30];
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snprintf(inst_name, sizeof(inst_name), "Parsed filter %d", index);
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filt = avfilter_get_by_name(filt_name);
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if(!filt) {
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av_log(log_ctx, AV_LOG_ERROR,
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"no such filter: '%s'\n", filt_name);
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return NULL;
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}
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filt_ctx = avfilter_open(filt, inst_name);
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if(!filt_ctx) {
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av_log(log_ctx, AV_LOG_ERROR,
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"error creating filter '%s'\n", filt_name);
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return NULL;
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}
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if(avfilter_graph_add_filter(ctx, filt_ctx) < 0) {
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avfilter_destroy(filt_ctx);
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return NULL;
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}
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if(avfilter_init_filter(filt_ctx, args, NULL)) {
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av_log(log_ctx, AV_LOG_ERROR,
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"error initializing filter '%s' with args '%s'\n", filt_name, args);
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return NULL;
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}
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return filt_ctx;
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}
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/**
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* Parse "filter=params"
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*/
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static AVFilterContext *parse_filter(const char **buf, AVFilterGraph *graph,
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int index, AVClass *log_ctx)
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{
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char *opts = NULL;
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char *name = consume_string(buf);
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AVFilterContext *ret;
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if(**buf == '=') {
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(*buf)++;
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opts = consume_string(buf);
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}
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ret = create_filter(graph, index, name, opts, log_ctx);
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av_free(name);
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av_free(opts);
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return ret;
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}
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static void free_inout(AVFilterInOut *head)
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{
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while(head) {
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AVFilterInOut *next = head->next;
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av_free(head->name);
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av_free(head);
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head = next;
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}
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}
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static AVFilterInOut *extract_inout(const char *label, AVFilterInOut **links)
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{
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AVFilterInOut *ret;
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while(*links && strcmp((*links)->name, label))
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links = &((*links)->next);
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ret = *links;
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if(ret)
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*links = ret->next;
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return ret;
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}
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static void insert_inout(AVFilterInOut **inouts, AVFilterInOut *element)
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{
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element->next = *inouts;
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*inouts = element;
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}
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static int link_filter_inouts(AVFilterContext *filter,
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AVFilterInOut **currInputs,
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AVFilterInOut **openInputs, AVClass *log_ctx)
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{
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int pad = filter->input_count;
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while(pad--) {
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AVFilterInOut *p = *currInputs;
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if(!p) {
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av_log(log_ctx, AV_LOG_ERROR,
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"Not enough inputs specified for the \"%s\" filter.\n",
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filter->filter->name);
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return -1;
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}
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*currInputs = (*currInputs)->next;
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if(p->filter) {
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if(link_filter(p->filter, p->pad_idx, filter, pad, log_ctx))
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return -1;
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av_free(p->name);
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av_free(p);
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} else {
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p->filter = filter;
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p->pad_idx = pad;
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insert_inout(openInputs, p);
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}
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}
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if(*currInputs) {
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av_log(log_ctx, AV_LOG_ERROR,
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"Too many inputs specified for the \"%s\" filter.\n",
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filter->filter->name);
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return -1;
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}
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pad = filter->output_count;
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while(pad--) {
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AVFilterInOut *currlinkn = av_mallocz(sizeof(AVFilterInOut));
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currlinkn->filter = filter;
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currlinkn->pad_idx = pad;
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insert_inout(currInputs, currlinkn);
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}
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return 0;
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}
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static int parse_inputs(const char **buf, AVFilterInOut **currInputs,
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AVFilterInOut **openOutputs, AVClass *log_ctx)
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{
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int pad = 0;
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while(**buf == '[') {
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char *name = parse_link_name(buf, log_ctx);
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AVFilterInOut *match;
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if(!name)
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return -1;
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/* First check if the label is not in the openOutputs list */
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match = extract_inout(name, openOutputs);
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if(match) {
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av_free(name);
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} else {
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/* Not in the list, so add it as an input */
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match = av_mallocz(sizeof(AVFilterInOut));
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match->name = name;
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match->pad_idx = pad;
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}
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insert_inout(currInputs, match);
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*buf += consume_whitespace(*buf);
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pad++;
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}
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return pad;
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}
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static int parse_outputs(const char **buf, AVFilterInOut **currInputs,
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AVFilterInOut **openInputs,
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AVFilterInOut **openOutputs, AVClass *log_ctx)
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{
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int pad = 0;
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while(**buf == '[') {
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char *name = parse_link_name(buf, log_ctx);
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AVFilterInOut *match;
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AVFilterInOut *input = *currInputs;
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*currInputs = (*currInputs)->next;
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if(!name)
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return -1;
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/* First check if the label is not in the openInputs list */
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match = extract_inout(name, openInputs);
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if(match) {
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if(link_filter(input->filter, input->pad_idx,
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match->filter, match->pad_idx, log_ctx) < 0)
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return -1;
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av_free(match->name);
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av_free(name);
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av_free(match);
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av_free(input);
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} else {
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/* Not in the list, so add the first input as a openOutput */
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input->name = name;
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insert_inout(openOutputs, input);
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}
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*buf += consume_whitespace(*buf);
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pad++;
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}
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return pad;
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}
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int avfilter_parse_graph(AVFilterGraph *graph, const char *filters,
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AVFilterInOut *openInputs,
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AVFilterInOut *openOutputs, AVClass *log_ctx)
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{
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int index = 0;
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char chr = 0;
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AVFilterInOut *currInputs = NULL;
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do {
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AVFilterContext *filter;
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filters += consume_whitespace(filters);
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if(parse_inputs(&filters, &currInputs, &openOutputs, log_ctx) < 0)
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goto fail;
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filter = parse_filter(&filters, graph, index, log_ctx);
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if(!filter)
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goto fail;
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if(filter->input_count == 1 && !currInputs && !index) {
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/* First input can be ommitted if it is "[in]" */
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const char *tmp = "[in]";
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if(parse_inputs(&tmp, &currInputs, &openOutputs, log_ctx) < 0)
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goto fail;
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}
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if(link_filter_inouts(filter, &currInputs, &openInputs, log_ctx) < 0)
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goto fail;
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if(parse_outputs(&filters, &currInputs, &openInputs, &openOutputs,
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log_ctx) < 0)
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goto fail;
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filters += consume_whitespace(filters);
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chr = *filters++;
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if(chr == ';' && currInputs) {
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av_log(log_ctx, AV_LOG_ERROR,
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"Could not find a output to link when parsing \"%s\"\n",
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filters - 1);
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goto fail;
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}
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index++;
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} while(chr == ',' || chr == ';');
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if(openInputs && !strcmp(openInputs->name, "out") && currInputs) {
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/* Last output can be ommitted if it is "[out]" */
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const char *tmp = "[out]";
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if(parse_outputs(&tmp, &currInputs, &openInputs,
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&openOutputs, log_ctx) < 0)
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goto fail;
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}
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return 0;
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fail:
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avfilter_destroy_graph(graph);
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free_inout(openInputs);
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free_inout(openOutputs);
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free_inout(currInputs);
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return -1;
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}
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