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f80b381bfd
Fix crash in create_filter() which occurrs if a scale filter with no args is provided. Signed-off-by: Anton Khirnov <anton@khirnov.net>
404 lines
12 KiB
C
404 lines
12 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 Libav.
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*
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* Libav 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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* Libav 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 Libav; 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 "libavutil/avstring.h"
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#include "avfilter.h"
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#include "avfiltergraph.h"
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#define WHITESPACES " \n\t"
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/**
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* Link two filters together.
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*
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* @see avfilter_link()
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*/
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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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int ret;
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if ((ret = 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 ret;
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}
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return 0;
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}
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/**
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* Parse the name of a link, which has the format "[linkname]".
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*
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* @return a pointer (that need to be freed after use) to the name
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* between 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 = av_get_token(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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/**
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* Create an instance of a filter, initialize and insert it in the
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* filtergraph in *ctx.
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*
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* @param ctx the filtergraph context
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* @param put here a filter context in case of successful creation and configuration, NULL otherwise.
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* @param index an index which is supposed to be unique for each filter instance added to the filtergraph
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* @param filt_name the name of the filter to create
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* @param args the arguments provided to the filter during its initialization
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* @param log_ctx the log context to use
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* @return 0 in case of success, a negative AVERROR code otherwise
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*/
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static int create_filter(AVFilterContext **filt_ctx, AVFilterGraph *ctx, int index,
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const char *filt_name, const char *args, AVClass *log_ctx)
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{
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AVFilter *filt;
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char inst_name[30];
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char tmp_args[256];
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int ret;
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snprintf(inst_name, sizeof(inst_name), "Parsed filter %d %s", index, filt_name);
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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 AVERROR(EINVAL);
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}
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ret = avfilter_open(filt_ctx, 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 ret;
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}
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if ((ret = avfilter_graph_add_filter(ctx, *filt_ctx)) < 0) {
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avfilter_free(*filt_ctx);
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return ret;
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}
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if (!strcmp(filt_name, "scale") && args && !strstr(args, "flags")) {
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snprintf(tmp_args, sizeof(tmp_args), "%s:%s",
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args, ctx->scale_sws_opts);
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args = tmp_args;
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}
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if ((ret = avfilter_init_filter(*filt_ctx, args, NULL)) < 0) {
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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 ret;
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}
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return 0;
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}
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/**
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* Parse a string of the form FILTER_NAME[=PARAMS], and create a
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* corresponding filter instance which is added to graph with
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* create_filter().
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*
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* @param filt_ctx put here a pointer to the created filter context on
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* success, NULL otherwise
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* @param buf pointer to the buffer to parse, *buf will be updated to
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* point to the char next after the parsed string
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* @param index an index which is assigned to the created filter
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* instance, and which is supposed to be unique for each filter
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* instance added to the filtergraph
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* @return 0 in case of success, a negative AVERROR code otherwise
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*/
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static int parse_filter(AVFilterContext **filt_ctx, 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 = av_get_token(buf, "=,;[\n");
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int ret;
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if (**buf == '=') {
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(*buf)++;
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opts = av_get_token(buf, "[],;\n");
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}
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ret = create_filter(filt_ctx, 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 *filt_ctx,
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AVFilterInOut **curr_inputs,
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AVFilterInOut **open_inputs, AVClass *log_ctx)
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{
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int pad = filt_ctx->input_count, ret;
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while (pad--) {
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AVFilterInOut *p = *curr_inputs;
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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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filt_ctx->filter->name);
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return AVERROR(EINVAL);
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}
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*curr_inputs = (*curr_inputs)->next;
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if (p->filter_ctx) {
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if ((ret = link_filter(p->filter_ctx, p->pad_idx, filt_ctx, pad, log_ctx)) < 0)
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return ret;
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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_ctx = filt_ctx;
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p->pad_idx = pad;
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insert_inout(open_inputs, p);
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}
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}
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if (*curr_inputs) {
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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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filt_ctx->filter->name);
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return AVERROR(EINVAL);
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}
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pad = filt_ctx->output_count;
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while (pad--) {
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AVFilterInOut *currlinkn = av_mallocz(sizeof(AVFilterInOut));
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if (!currlinkn)
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return AVERROR(ENOMEM);
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currlinkn->filter_ctx = filt_ctx;
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currlinkn->pad_idx = pad;
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insert_inout(curr_inputs, 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 **curr_inputs,
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AVFilterInOut **open_outputs, 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 AVERROR(EINVAL);
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/* First check if the label is not in the open_outputs list */
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match = extract_inout(name, open_outputs);
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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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if (!(match = av_mallocz(sizeof(AVFilterInOut))))
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return AVERROR(ENOMEM);
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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(curr_inputs, match);
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*buf += strspn(*buf, WHITESPACES);
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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 **curr_inputs,
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AVFilterInOut **open_inputs,
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AVFilterInOut **open_outputs, AVClass *log_ctx)
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{
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int ret, 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 = *curr_inputs;
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if (!input) {
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av_log(log_ctx, AV_LOG_ERROR,
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"No output pad can be associated to link label '%s'.\n",
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name);
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return AVERROR(EINVAL);
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}
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*curr_inputs = (*curr_inputs)->next;
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if (!name)
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return AVERROR(EINVAL);
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/* First check if the label is not in the open_inputs list */
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match = extract_inout(name, open_inputs);
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if (match) {
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if ((ret = link_filter(input->filter_ctx, input->pad_idx,
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match->filter_ctx, match->pad_idx, log_ctx)) < 0)
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return ret;
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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 open_output */
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input->name = name;
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insert_inout(open_outputs, input);
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}
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*buf += strspn(*buf, WHITESPACES);
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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_graph_parse(AVFilterGraph *graph, const char *filters,
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AVFilterInOut *open_inputs,
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AVFilterInOut *open_outputs, AVClass *log_ctx)
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{
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int index = 0, ret;
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char chr = 0;
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AVFilterInOut *curr_inputs = NULL;
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do {
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AVFilterContext *filter;
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const char *filterchain = filters;
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filters += strspn(filters, WHITESPACES);
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if ((ret = parse_inputs(&filters, &curr_inputs, &open_outputs, log_ctx)) < 0)
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goto fail;
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if ((ret = parse_filter(&filter, &filters, graph, index, log_ctx)) < 0)
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goto fail;
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if (filter->input_count == 1 && !curr_inputs && !index) {
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/* First input can be omitted if it is "[in]" */
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const char *tmp = "[in]";
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if ((ret = parse_inputs(&tmp, &curr_inputs, &open_outputs, log_ctx)) < 0)
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goto fail;
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}
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if ((ret = link_filter_inouts(filter, &curr_inputs, &open_inputs, log_ctx)) < 0)
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goto fail;
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if ((ret = parse_outputs(&filters, &curr_inputs, &open_inputs, &open_outputs,
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log_ctx)) < 0)
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goto fail;
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filters += strspn(filters, WHITESPACES);
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chr = *filters++;
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if (chr == ';' && curr_inputs) {
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av_log(log_ctx, AV_LOG_ERROR,
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"Invalid filterchain containing an unlabelled output pad: \"%s\"\n",
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filterchain);
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ret = AVERROR(EINVAL);
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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 (chr) {
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av_log(log_ctx, AV_LOG_ERROR,
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"Unable to parse graph description substring: \"%s\"\n",
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filters - 1);
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ret = AVERROR(EINVAL);
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goto fail;
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}
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if (open_inputs && !strcmp(open_inputs->name, "out") && curr_inputs) {
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/* Last output can be omitted if it is "[out]" */
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const char *tmp = "[out]";
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if ((ret = parse_outputs(&tmp, &curr_inputs, &open_inputs, &open_outputs,
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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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for (; graph->filter_count > 0; graph->filter_count--)
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avfilter_free(graph->filters[graph->filter_count - 1]);
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av_freep(&graph->filters);
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free_inout(open_inputs);
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free_inout(open_outputs);
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free_inout(curr_inputs);
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return ret;
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}
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