/* * 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 #include #include "graphparser.h" #include "avfilter.h" #include "avfiltergraph.h" 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; } static int consume_whitespace(const char *buf) { return strspn(buf, " \n\t"); } /** * Consumes a string from *buf. * @return a copy of the consumed string, which should be free'd after use */ static char *consume_string(const char **buf) { char *out = av_malloc(strlen(*buf) + 1); char *ret = out; *buf += consume_whitespace(*buf); do{ char c = *(*buf)++; switch (c) { case '\\': *out++ = *(*buf)++; break; case '\'': while(**buf && **buf != '\'') *out++ = *(*buf)++; if(**buf) (*buf)++; break; case 0: case ']': case '[': case '=': case ',': case ';': case ' ': case '\n': *out++ = 0; break; default: *out++ = c; } } while(out[-1]); (*buf)--; *buf += consume_whitespace(*buf); return ret; } /** * Parse "[linkname]" * @arg name a pointer (that need to be free'd after use) to the name between * parenthesis */ static void parse_link_name(const char **buf, char **name, AVClass *log_ctx) { const char *start = *buf; (*buf)++; *name = consume_string(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); } } static AVFilterContext *create_filter(AVFilterGraph *ctx, int index, const char *name, const char *args, AVClass *log_ctx) { AVFilterContext *filt; AVFilter *filterdef; char inst_name[30]; snprintf(inst_name, sizeof(inst_name), "Parsed filter %d", index); if(!(filterdef = avfilter_get_by_name(name))) { av_log(log_ctx, AV_LOG_ERROR, "no such filter: '%s'\n", name); return NULL; } if(!(filt = avfilter_open(filterdef, inst_name))) { av_log(log_ctx, AV_LOG_ERROR, "error creating filter '%s'\n", name); return NULL; } if(avfilter_graph_add_filter(ctx, filt) < 0) return NULL; if(avfilter_init_filter(filt, args, NULL)) { av_log(log_ctx, AV_LOG_ERROR, "error initializing filter '%s' with args '%s'\n", name, args); return NULL; } return filt; } /** * Parse "filter=params" * @arg name a pointer (that need to be free'd after use) to the name of the * filter * @arg ars a pointer (that need to be free'd after use) to the args of the * filter */ static AVFilterContext *parse_filter(const char **buf, AVFilterGraph *graph, int index, AVClass *log_ctx) { char *opts; char *name = consume_string(buf); if(**buf == '=') { (*buf)++; opts = consume_string(buf); } else { opts = NULL; } return create_filter(graph, index, name, opts, log_ctx); } static void free_inout(AVFilterInOut *head) { while(head) { AVFilterInOut *next = head->next; 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 int link_filter_inouts(AVFilterContext *filter, AVFilterInOut **currInputs, AVFilterInOut **openLinks, AVClass *log_ctx) { int pad = 0; pad = filter->input_count; while(pad--) { AVFilterInOut *p = *currInputs; *currInputs = (*currInputs)->next; if(!p) { av_log(log_ctx, AV_LOG_ERROR, "Not enough inputs specified for the \"%s\" filter.\n", filter->name); return -1; } if(p->filter) { if(link_filter(p->filter, p->pad_idx, filter, pad, log_ctx)) return -1; av_free(p); } else { p->filter = filter; p->pad_idx = pad; p->next = *openLinks; *openLinks = p; } } if(*currInputs) { av_log(log_ctx, AV_LOG_ERROR, "Too many inputs specified for the \"%s\" filter.\n", filter->name); return -1; } pad = filter->output_count; while(pad--) { AVFilterInOut *currlinkn = av_malloc(sizeof(AVFilterInOut)); currlinkn->name = NULL; currlinkn->type = LinkTypeOut; currlinkn->filter = filter; currlinkn->pad_idx = pad; currlinkn->next = *currInputs; *currInputs = currlinkn; } return 0; } static int parse_inputs(const char **buf, AVFilterInOut **currInputs, AVFilterInOut **openLinks, AVClass *log_ctx) { int pad = 0; while(**buf == '[') { char *name; AVFilterInOut *link_to_add; AVFilterInOut *match; parse_link_name(buf, &name, log_ctx); if(!name) return -1; /* First check if the label is not in the openLinks list */ match = extract_inout(name, openLinks); if(match) { /* A label of a open link. Make it one of the inputs of the next filter */ if(match->type != LinkTypeOut) { av_log(log_ctx, AV_LOG_ERROR, "Label \"%s\" appears twice as input!\n", match->name); return -1; } link_to_add = match; } else { /* Not in the list, so add it as an input */ link_to_add = av_malloc(sizeof(AVFilterInOut)); link_to_add->name = name; link_to_add->type = LinkTypeIn; link_to_add->filter = NULL; link_to_add->pad_idx = pad; } link_to_add->next = *currInputs; *currInputs = link_to_add; *buf += consume_whitespace(*buf); pad++; } return pad; } static int parse_outputs(const char **buf, AVFilterInOut **currInputs, AVFilterInOut **openLinks, AVClass *log_ctx) { int pad = 0; while(**buf == '[') { char *name; AVFilterInOut *match; AVFilterInOut *input = *currInputs; *currInputs = (*currInputs)->next; parse_link_name(buf, &name, log_ctx); if(!name) return -1; /* First check if the label is not in the openLinks list */ match = extract_inout(name, openLinks); if(match) { /* A label of a open link. Link it. */ if(match->type != LinkTypeIn) { av_log(log_ctx, AV_LOG_ERROR, "Label \"%s\" appears twice as output!\n", match->name); return -1; } if(link_filter(input->filter, input->pad_idx, match->filter, match->pad_idx, log_ctx) < 0) return -1; av_free(match); av_free(input); } else { /* Not in the list, so add the first input as a openLink */ input->next = *openLinks; input->type = LinkTypeOut; input->name = name; *openLinks = input; } *buf += consume_whitespace(*buf); pad++; } return pad; } /** * Parse a string describing a filter graph. */ int avfilter_parse_graph(AVFilterGraph *graph, const char *filters, AVFilterInOut *openLinks, AVClass *log_ctx) { int index = 0; char chr = 0; int pad = 0; AVFilterInOut *currInputs = NULL; do { AVFilterContext *filter; filters += consume_whitespace(filters); pad = parse_inputs(&filters, &currInputs, &openLinks, log_ctx); if(pad < 0) goto fail; if(!(filter = parse_filter(&filters, graph, index, log_ctx))) goto fail; if(filter->input_count == 1 && !currInputs && !index) { // First input can be ommitted if it is "[in]" const char *tmp = "[in]"; pad = parse_inputs(&tmp, &currInputs, &openLinks, log_ctx); if(pad < 0) goto fail; } if(link_filter_inouts(filter, &currInputs, &openLinks, log_ctx) < 0) goto fail; pad = parse_outputs(&filters, &currInputs, &openLinks, log_ctx); if(pad < 0) goto fail; filters += consume_whitespace(filters); chr = *filters++; if(chr == ';' && currInputs) { 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(openLinks && !strcmp(openLinks->name, "out") && currInputs) { // Last output can be ommitted if it is "[out]" const char *tmp = "[out]"; if(parse_outputs(&tmp, &currInputs, &openLinks, log_ctx) < 0) goto fail; } return 0; fail: avfilter_destroy_graph(graph); free_inout(openLinks); free_inout(currInputs); return -1; }