From d226df26e50aff2e231f8373591562800971031b Mon Sep 17 00:00:00 2001 From: Anton Khirnov Date: Thu, 19 Jan 2023 13:54:44 +0100 Subject: fftools/ffmpeg: add special syntax for loading filter options from files TODO: elaborate --- doc/filters.texi | 11 ++++ fftools/ffmpeg_filter.c | 154 +++++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 163 insertions(+), 2 deletions(-) diff --git a/doc/filters.texi b/doc/filters.texi index be70a2396b..7ff9948239 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -171,6 +171,17 @@ within the quoted text; otherwise the argument string is considered terminated when the next special character (belonging to the set @samp{[]=;,}) is encountered. +A special syntax implemented in the @command{ffmpeg} CLI tool allows loading +option values from files. This is done be prepending a slash '/' to the option +name, then the supplied value is interpreted as a path from which the actual +value is loaded. E.g. +@example +ffmpeg -i -vf drawtext=/text=/tmp/some_text +@end example +will load the text to be drawn from @file{/tmp/some_text}. API users wishing to +implement a similar feature should use the @code{avfilter_graph_segment_*()} +functions together with custom IO code. + The name and arguments of the filter are optionally preceded and followed by a list of link labels. A link label allows one to name a link and associate it to a filter output diff --git a/fftools/ffmpeg_filter.c b/fftools/ffmpeg_filter.c index 7eb656dbe5..3f79133f75 100644 --- a/fftools/ffmpeg_filter.c +++ b/fftools/ffmpeg_filter.c @@ -314,6 +314,156 @@ static void init_input_filter(FilterGraph *fg, AVFilterInOut *in) ist->filters[ist->nb_filters - 1] = ifilter; } +static int read_binary(const char *path, uint8_t **data, int *len) +{ + AVIOContext *io = NULL; + int64_t fsize; + int ret; + + *data = NULL; + *len = 0; + + ret = avio_open2(&io, path, AVIO_FLAG_READ, &int_cb, NULL); + if (ret < 0) { + av_log(NULL, AV_LOG_ERROR, "Cannot open file '%s': %s\n", + path, av_err2str(ret)); + return ret; + } + + fsize = avio_size(io); + if (fsize < 0 || fsize > INT_MAX) { + av_log(NULL, AV_LOG_ERROR, "Cannot obtain size of file %s\n", path); + ret = AVERROR(EIO); + goto fail; + } + + *data = av_malloc(fsize); + if (!*data) { + ret = AVERROR(ENOMEM); + goto fail; + } + + ret = avio_read(io, *data, fsize); + if (ret != fsize) { + av_log(NULL, AV_LOG_ERROR, "Error reading file %s\n", path); + ret = ret < 0 ? ret : AVERROR(EIO); + goto fail; + } + + *len = fsize; + + return 0; +fail: + avio_close(io); + av_freep(data); + *len = 0; + return ret; +} + +static int filter_opt_apply(AVFilterContext *f, const char *key, const char *val) +{ + const AVOption *o; + int ret; + + ret = av_opt_set(f, key, val, AV_OPT_SEARCH_CHILDREN); + if (ret >= 0) + return 0; + + if (ret == AVERROR_OPTION_NOT_FOUND && key[0] == '/') + o = av_opt_find(f, key + 1, NULL, 0, AV_OPT_SEARCH_CHILDREN); + if (!o) + goto err_apply; + + // key is a valid option name prefixed with '/' + // interpret value as a path from which to load the actual option value + key++; + + if (o->type == AV_OPT_TYPE_BINARY) { + uint8_t *data; + int len; + + ret = read_binary(val, &data, &len); + if (ret < 0) + goto err_load; + + ret = av_opt_set_bin(f, key, data, len, AV_OPT_SEARCH_CHILDREN); + av_freep(&data); + } else { + char *data = file_read(val); + if (!val) { + ret = AVERROR(EIO); + goto err_load; + } + + ret = av_opt_set(f, key, data, AV_OPT_SEARCH_CHILDREN); + av_freep(&data); + } + if (ret < 0) + goto err_apply; + + return 0; + +err_apply: + av_log(NULL, AV_LOG_ERROR, + "Error applying option '%s' to filter '%s': %s\n", + key, f->filter->name, av_err2str(ret)); + return ret; +err_load: + av_log(NULL, AV_LOG_ERROR, + "Error loading value for option '%s' from file '%s'\n", + key, val); + return ret; +} + +static int graph_opts_apply(AVFilterGraphSegment *seg) +{ + for (size_t i = 0; i < seg->nb_chains; i++) { + AVFilterChain *ch = seg->chains[i]; + + for (size_t j = 0; j < ch->nb_filters; j++) { + AVFilterParams *p = ch->filters[j]; + const AVDictionaryEntry *e = NULL; + + av_assert0(p->filter); + + while ((e = av_dict_iterate(p->opts, e))) { + int ret = filter_opt_apply(p->filter, e->key, e->value); + if (ret < 0) + return ret; + } + + av_dict_free(&p->opts); + } + } + + return 0; +} + +static int graph_parse(AVFilterGraph *graph, const char *desc, + AVFilterInOut **inputs, AVFilterInOut **outputs) +{ + AVFilterGraphSegment *seg; + int ret; + + ret = avfilter_graph_segment_parse(graph, desc, 0, &seg); + if (ret < 0) + return ret; + + ret = avfilter_graph_segment_create_filters(seg, 0); + if (ret < 0) + goto fail; + + ret = graph_opts_apply(seg); + if (ret < 0) + goto fail; + + ret = avfilter_graph_segment_apply(seg, 0, inputs, outputs); + +fail: + avfilter_graph_segment_free(&seg); + return ret; +} + int init_complex_filtergraph(FilterGraph *fg) { AVFilterInOut *inputs, *outputs, *cur; @@ -327,7 +477,7 @@ int init_complex_filtergraph(FilterGraph *fg) return AVERROR(ENOMEM); graph->nb_threads = 1; - ret = avfilter_graph_parse2(graph, fg->graph_desc, &inputs, &outputs); + ret = graph_parse(graph, fg->graph_desc, &inputs, &outputs); if (ret < 0) goto fail; @@ -1004,7 +1154,7 @@ int configure_filtergraph(FilterGraph *fg) fg->graph->nb_threads = filter_complex_nbthreads; } - if ((ret = avfilter_graph_parse2(fg->graph, graph_desc, &inputs, &outputs)) < 0) + if ((ret = graph_parse(fg->graph, graph_desc, &inputs, &outputs)) < 0) goto fail; ret = hw_device_setup_for_filter(fg); -- cgit v1.2.3