/* * 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 "libavutil/avstring.h" #include "avfilter.h" #include "avfiltergraph.h" #define WHITESPACES " \n\t" /** * Link two filters together. * * @see avfilter_link() */ static int link_filter(AVFilterContext *src, int srcpad, AVFilterContext *dst, int dstpad, void *log_ctx) { int ret; if ((ret = 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 ret; } return 0; } /** * Parse the name of a link, which has the format "[linkname]". * * @return a pointer (that need to be freed after use) to the name * between parenthesis */ static char *parse_link_name(const char **buf, void *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; } /** * Create an instance of a filter, initialize and insert it in the * filtergraph in *ctx. * * @param filt_ctx put here a filter context in case of successful creation and configuration, NULL otherwise. * @param ctx the filtergraph context * @param index an index which is supposed to be unique for each filter instance added to the filtergraph * @param filt_name the name of the filter to create * @param args the arguments provided to the filter during its initialization * @param log_ctx the log context to use * @return 0 in case of success, a negative AVERROR code otherwise */ static int create_filter(AVFilterContext **filt_ctx, AVFilterGraph *ctx, int index, const char *filt_name, const char *args, void *log_ctx) { AVFilter *filt; char inst_name[30]; char tmp_args[256]; int ret; snprintf(inst_name, sizeof(inst_name), "Parsed_%s_%d", filt_name, 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 AVERROR(EINVAL); } ret = avfilter_open(filt_ctx, filt, inst_name); if (!*filt_ctx) { av_log(log_ctx, AV_LOG_ERROR, "Error creating filter '%s'\n", filt_name); return ret; } if ((ret = avfilter_graph_add_filter(ctx, *filt_ctx)) < 0) { avfilter_free(*filt_ctx); return ret; } if (!strcmp(filt_name, "scale") && args && !strstr(args, "flags")) { snprintf(tmp_args, sizeof(tmp_args), "%s:%s", args, ctx->scale_sws_opts); args = tmp_args; } if ((ret = avfilter_init_filter(*filt_ctx, args, NULL)) < 0) { av_log(log_ctx, AV_LOG_ERROR, "Error initializing filter '%s' with args '%s'\n", filt_name, args); return ret; } return 0; } /** * Parse a string of the form FILTER_NAME[=PARAMS], and create a * corresponding filter instance which is added to graph with * create_filter(). * * @param filt_ctx Pointer that is set to the created and configured filter * context on success, set to NULL on failure. * @param filt_ctx put here a pointer to the created filter context on * success, NULL otherwise * @param buf pointer to the buffer to parse, *buf will be updated to * point to the char next after the parsed string * @param index an index which is assigned to the created filter * instance, and which is supposed to be unique for each filter * instance added to the filtergraph * @return 0 in case of success, a negative AVERROR code otherwise */ static int parse_filter(AVFilterContext **filt_ctx, const char **buf, AVFilterGraph *graph, int index, void *log_ctx) { char *opts = NULL; char *name = av_get_token(buf, "=,;[\n"); int ret; if (**buf == '=') { (*buf)++; opts = av_get_token(buf, "[],;\n"); } ret = create_filter(filt_ctx, graph, index, name, opts, log_ctx); av_free(name); av_free(opts); return ret; } AVFilterInOut *avfilter_inout_alloc(void) { return av_mallocz(sizeof(AVFilterInOut)); } void avfilter_inout_free(AVFilterInOut **inout) { while (*inout) { AVFilterInOut *next = (*inout)->next; av_freep(&(*inout)->name); av_freep(inout); *inout = next; } } static AVFilterInOut *extract_inout(const char *label, AVFilterInOut **links) { AVFilterInOut *ret; while (*links && (!(*links)->name || strcmp((*links)->name, label))) links = &((*links)->next); ret = *links; if (ret) { *links = ret->next; ret->next = NULL; } return ret; } static void insert_inout(AVFilterInOut **inouts, AVFilterInOut *element) { element->next = *inouts; *inouts = element; } static void append_inout(AVFilterInOut **inouts, AVFilterInOut **element) { while (*inouts && (*inouts)->next) inouts = &((*inouts)->next); if (!*inouts) *inouts = *element; else (*inouts)->next = *element; *element = NULL; } static int link_filter_inouts(AVFilterContext *filt_ctx, AVFilterInOut **curr_inputs, AVFilterInOut **open_inputs, void *log_ctx) { int pad, ret; for (pad = 0; pad < filt_ctx->nb_inputs; pad++) { AVFilterInOut *p = *curr_inputs; if (p) { *curr_inputs = (*curr_inputs)->next; p->next = NULL; } else if (!(p = av_mallocz(sizeof(*p)))) return AVERROR(ENOMEM); if (p->filter_ctx) { if ((ret = link_filter(p->filter_ctx, p->pad_idx, filt_ctx, pad, log_ctx)) < 0) return ret; av_free(p->name); av_free(p); } else { p->filter_ctx = filt_ctx; p->pad_idx = pad; append_inout(open_inputs, &p); } } if (*curr_inputs) { av_log(log_ctx, AV_LOG_ERROR, "Too many inputs specified for the \"%s\" filter.\n", filt_ctx->filter->name); return AVERROR(EINVAL); } pad = filt_ctx->nb_outputs; while (pad--) { AVFilterInOut *currlinkn = av_mallocz(sizeof(AVFilterInOut)); if (!currlinkn) return AVERROR(ENOMEM); currlinkn->filter_ctx = filt_ctx; currlinkn->pad_idx = pad; insert_inout(curr_inputs, currlinkn); } return 0; } static int parse_inputs(const char **buf, AVFilterInOut **curr_inputs, AVFilterInOut **open_outputs, void *log_ctx) { AVFilterInOut *parsed_inputs = NULL; int pad = 0; while (**buf == '[') { char *name = parse_link_name(buf, log_ctx); AVFilterInOut *match; if (!name) return AVERROR(EINVAL); /* 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 */ if (!(match = av_mallocz(sizeof(AVFilterInOut)))) return AVERROR(ENOMEM); match->name = name; match->pad_idx = pad; } append_inout(&parsed_inputs, &match); *buf += strspn(*buf, WHITESPACES); pad++; } append_inout(&parsed_inputs, curr_inputs); *curr_inputs = parsed_inputs; return pad; } static int parse_outputs(const char **buf, AVFilterInOut **curr_inputs, AVFilterInOut **open_inputs, AVFilterInOut **open_outputs, void *log_ctx) { int ret, pad = 0; while (**buf == '[') { char *name = parse_link_name(buf, log_ctx); AVFilterInOut *match; AVFilterInOut *input = *curr_inputs; if (!input) { av_log(log_ctx, AV_LOG_ERROR, "No output pad can be associated to link label '%s'.\n", name); return AVERROR(EINVAL); } *curr_inputs = (*curr_inputs)->next; if (!name) return AVERROR(EINVAL); /* First check if the label is not in the open_inputs list */ match = extract_inout(name, open_inputs); if (match) { if ((ret = link_filter(input->filter_ctx, input->pad_idx, match->filter_ctx, match->pad_idx, log_ctx)) < 0) return ret; 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; } static int parse_sws_flags(const char **buf, AVFilterGraph *graph) { char *p = strchr(*buf, ';'); if (strncmp(*buf, "sws_flags=", 10)) return 0; if (!p) { av_log(graph, AV_LOG_ERROR, "sws_flags not terminated with ';'.\n"); return AVERROR(EINVAL); } *buf += 4; // keep the 'flags=' part av_freep(&graph->scale_sws_opts); if (!(graph->scale_sws_opts = av_mallocz(p - *buf + 1))) return AVERROR(ENOMEM); av_strlcpy(graph->scale_sws_opts, *buf, p - *buf + 1); *buf = p + 1; return 0; } int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters, AVFilterInOut **inputs, AVFilterInOut **outputs) { int index = 0, ret = 0; char chr = 0; AVFilterInOut *curr_inputs = NULL, *open_inputs = NULL, *open_outputs = NULL; filters += strspn(filters, WHITESPACES); if ((ret = parse_sws_flags(&filters, graph)) < 0) goto fail; do { AVFilterContext *filter; filters += strspn(filters, WHITESPACES); if ((ret = parse_inputs(&filters, &curr_inputs, &open_outputs, graph)) < 0) goto end; if ((ret = parse_filter(&filter, &filters, graph, index, graph)) < 0) goto end; if ((ret = link_filter_inouts(filter, &curr_inputs, &open_inputs, graph)) < 0) goto end; if ((ret = parse_outputs(&filters, &curr_inputs, &open_inputs, &open_outputs, graph)) < 0) goto end; filters += strspn(filters, WHITESPACES); chr = *filters++; if (chr == ';' && curr_inputs) append_inout(&open_outputs, &curr_inputs); index++; } while (chr == ',' || chr == ';'); if (chr) { av_log(graph, AV_LOG_ERROR, "Unable to parse graph description substring: \"%s\"\n", filters - 1); ret = AVERROR(EINVAL); goto end; } append_inout(&open_outputs, &curr_inputs); *inputs = open_inputs; *outputs = open_outputs; return 0; fail:end: for (; graph->filter_count > 0; graph->filter_count--) avfilter_free(graph->filters[graph->filter_count - 1]); av_freep(&graph->filters); avfilter_inout_free(&open_inputs); avfilter_inout_free(&open_outputs); avfilter_inout_free(&curr_inputs); *inputs = NULL; *outputs = NULL; return ret; } int avfilter_graph_parse(AVFilterGraph *graph, const char *filters, AVFilterInOut **open_inputs_ptr, AVFilterInOut **open_outputs_ptr, void *log_ctx) { #if 0 int ret; AVFilterInOut *open_inputs = open_inputs_ptr ? *open_inputs_ptr : NULL; AVFilterInOut *open_outputs = open_outputs_ptr ? *open_outputs_ptr : NULL; AVFilterInOut *cur, *match, *inputs = NULL, *outputs = NULL; if ((ret = avfilter_graph_parse2(graph, filters, &inputs, &outputs)) < 0) goto fail; /* First input can be omitted if it is "[in]" */ if (inputs && !inputs->name) inputs->name = av_strdup("in"); for (cur = inputs; cur; cur = cur->next) { if (!cur->name) { av_log(log_ctx, AV_LOG_ERROR, "Not enough inputs specified for the \"%s\" filter.\n", cur->filter_ctx->filter->name); ret = AVERROR(EINVAL); goto fail; } if (!(match = extract_inout(cur->name, &open_outputs))) continue; ret = avfilter_link(match->filter_ctx, match->pad_idx, cur->filter_ctx, cur->pad_idx); avfilter_inout_free(&match); if (ret < 0) goto fail; } /* Last output can be omitted if it is "[out]" */ if (outputs && !outputs->name) outputs->name = av_strdup("out"); for (cur = outputs; cur; cur = cur->next) { if (!cur->name) { av_log(log_ctx, AV_LOG_ERROR, "Invalid filterchain containing an unlabelled output pad: \"%s\"\n", filters); ret = AVERROR(EINVAL); goto fail; } if (!(match = extract_inout(cur->name, &open_inputs))) continue; ret = avfilter_link(cur->filter_ctx, cur->pad_idx, match->filter_ctx, match->pad_idx); avfilter_inout_free(&match); if (ret < 0) goto fail; } fail: if (ret < 0) { for (; graph->filter_count > 0; graph->filter_count--) avfilter_free(graph->filters[graph->filter_count - 1]); av_freep(&graph->filters); } avfilter_inout_free(&inputs); avfilter_inout_free(&outputs); /* clear open_in/outputs only if not passed as parameters */ if (open_inputs_ptr) *open_inputs_ptr = open_inputs; else avfilter_inout_free(&open_inputs); if (open_outputs_ptr) *open_outputs_ptr = open_outputs; else avfilter_inout_free(&open_outputs); return ret; } #else int index = 0, ret = 0; char chr = 0; AVFilterInOut *curr_inputs = NULL; AVFilterInOut *open_inputs = open_inputs_ptr ? *open_inputs_ptr : NULL; AVFilterInOut *open_outputs = open_outputs_ptr ? *open_outputs_ptr : NULL; do { AVFilterContext *filter; const char *filterchain = filters; filters += strspn(filters, WHITESPACES); if ((ret = parse_inputs(&filters, &curr_inputs, &open_outputs, log_ctx)) < 0) goto end; if ((ret = parse_filter(&filter, &filters, graph, index, log_ctx)) < 0) goto end; if (filter->input_count == 1 && !curr_inputs && !index) { /* First input pad, assume it is "[in]" if not specified */ const char *tmp = "[in]"; if ((ret = parse_inputs(&tmp, &curr_inputs, &open_outputs, log_ctx)) < 0) goto end; } if ((ret = link_filter_inouts(filter, &curr_inputs, &open_inputs, log_ctx)) < 0) goto end; if ((ret = parse_outputs(&filters, &curr_inputs, &open_inputs, &open_outputs, log_ctx)) < 0) goto end; filters += strspn(filters, WHITESPACES); chr = *filters++; if (chr == ';' && curr_inputs) { av_log(log_ctx, AV_LOG_ERROR, "Invalid filterchain containing an unlabelled output pad: \"%s\"\n", filterchain); ret = AVERROR(EINVAL); goto end; } index++; } while (chr == ',' || chr == ';'); if (chr) { av_log(log_ctx, AV_LOG_ERROR, "Unable to parse graph description substring: \"%s\"\n", filters - 1); ret = AVERROR(EINVAL); goto end; } if (curr_inputs) { /* Last output pad, assume it is "[out]" if not specified */ const char *tmp = "[out]"; if ((ret = parse_outputs(&tmp, &curr_inputs, &open_inputs, &open_outputs, log_ctx)) < 0) goto end; } end: /* clear open_in/outputs only if not passed as parameters */ if (open_inputs_ptr) *open_inputs_ptr = open_inputs; else avfilter_inout_free(&open_inputs); if (open_outputs_ptr) *open_outputs_ptr = open_outputs; else avfilter_inout_free(&open_outputs); avfilter_inout_free(&curr_inputs); if (ret < 0) { for (; graph->filter_count > 0; graph->filter_count--) avfilter_free(graph->filters[graph->filter_count - 1]); av_freep(&graph->filters); } return ret; } #endif