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graphparser: add avfilter_graph_parse2(). 

Unlike avfilter_graph_parse(), it returns unlinked inputs and outputs
to the caller, which allows parsing of graphs where inputs/outputs are
not known in advance.
This commit is contained in:
Anton Khirnov 2012-03-21 07:46:56 +01:00
parent 7ae7c41413
commit d7bcc71dad
2 changed files with 141 additions and 39 deletions
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44
libavfilter/avfiltergraph.h
View File

@ -91,11 +91,11 @@ void avfilter_graph_free(AVFilterGraph **graph);
/**
* A linked-list of the inputs/outputs of the filter chain.
*
* This is mainly useful for avfilter_graph_parse(), since this
* function may accept a description of a graph with not connected
* input/output pads. This struct specifies, per each not connected
* pad contained in the graph, the filter context and the pad index
* required for establishing a link.
* This is mainly useful for avfilter_graph_parse() / avfilter_graph_parse2(),
* where it is used to communicate open (unlinked) inputs and outputs from and
* to the caller.
* This struct specifies, per each not connected pad contained in the graph, the
* filter context and the pad index required for establishing a link.
*/
typedef struct AVFilterInOut {
/** unique name for this input/output in the list */
@ -124,4 +124,38 @@ int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
AVFilterInOut *inputs, AVFilterInOut *outputs,
void *log_ctx);
/**
* Add a graph described by a string to a graph.
*
* @param[in] graph the filter graph where to link the parsed graph context
* @param[in] filters string to be parsed
* @param[out] inputs a linked list of all free (unlinked) inputs of the
* parsed graph will be returned here. It is to be freed
* by the caller using avfilter_inout_free().
* @param[out] outputs a linked list of all free (unlinked) outputs of the
* parsed graph will be returned here. It is to be freed by the
* caller using avfilter_inout_free().
* @return zero on success, a negative AVERROR code on error
*
* @note the difference between avfilter_graph_parse2() and
* avfilter_graph_parse() is that in avfilter_graph_parse(), the caller provides
* the lists of inputs and outputs, which therefore must be known before calling
* the function. On the other hand, avfilter_graph_parse2() \em returns the
* inputs and outputs that are left unlinked after parsing the graph and the
* caller then deals with them. Another difference is that in
* avfilter_graph_parse(), the inputs parameter describes inputs of the
* <em>already existing</em> part of the graph; i.e. from the point of view of
* the newly created part, they are outputs. Similarly the outputs parameter
* describes outputs of the already existing filters, which are provided as
* inputs to the parsed filters.
* avfilter_graph_parse2() takes the opposite approach -- it makes no reference
* whatsoever to already existing parts of the graph and the inputs parameter
* will on return contain inputs of the newly parsed part of the graph.
* Analogously the outputs parameter will contain outputs of the newly created
* filters.
*/
int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
AVFilterInOut **inputs,
AVFilterInOut **outputs);
#endif /* AVFILTER_AVFILTERGRAPH_H */

136
libavfilter/graphparser.c
View File

@ -184,13 +184,15 @@ static AVFilterInOut *extract_inout(const char *label, AVFilterInOut **links)
{
AVFilterInOut *ret;
while (*links && strcmp((*links)->name, label))
while (*links && (!(*links)->name || strcmp((*links)->name, label)))
links = &((*links)->next);
ret = *links;
if (ret)
if (ret) {
*links = ret->next;
ret->next = NULL;
}
return ret;
}
@ -201,6 +203,18 @@ static void insert_inout(AVFilterInOut **inouts, AVFilterInOut *element)
*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)
@ -209,14 +223,11 @@ static int link_filter_inouts(AVFilterContext *filt_ctx,
while (pad--) {
AVFilterInOut *p = *curr_inputs;
if (!p) {
av_log(log_ctx, AV_LOG_ERROR,
"Not enough inputs specified for the \"%s\" filter.\n",
filt_ctx->filter->name);
return AVERROR(EINVAL);
}
*curr_inputs = (*curr_inputs)->next;
if (p)
*curr_inputs = (*curr_inputs)->next;
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)
@ -329,18 +340,22 @@ static int parse_outputs(const char **buf, AVFilterInOut **curr_inputs,
return pad;
}
int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
AVFilterInOut *open_inputs,
AVFilterInOut *open_outputs, void *log_ctx)
#if FF_API_GRAPH_AVCLASS
#define log_ctx graph
#else
#define log_ctx NULL
#endif
int avfilter_graph_parse2(AVFilterGraph *graph, const char *filters,
AVFilterInOut **inputs,
AVFilterInOut **outputs)
{
int index = 0, ret;
char chr = 0;
AVFilterInOut *curr_inputs = NULL;
AVFilterInOut *curr_inputs = NULL, *open_inputs = NULL, *open_outputs = NULL;
do {
AVFilterContext *filter;
const char *filterchain = filters;
filters += strspn(filters, WHITESPACES);
if ((ret = parse_inputs(&filters, &curr_inputs, &open_outputs, log_ctx)) < 0)
@ -349,12 +364,6 @@ int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
if ((ret = parse_filter(&filter, &filters, graph, index, log_ctx)) < 0)
goto fail;
if (filter->input_count == 1 && !curr_inputs && !index) {
/* First input can be omitted if it is "[in]" */
const char *tmp = "[in]";
if ((ret = parse_inputs(&tmp, &curr_inputs, &open_outputs, log_ctx)) < 0)
goto fail;
}
if ((ret = link_filter_inouts(filter, &curr_inputs, &open_inputs, log_ctx)) < 0)
goto fail;
@ -366,13 +375,8 @@ int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
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 fail;
}
if (chr == ';' && curr_inputs)
append_inout(&open_outputs, &curr_inputs);
index++;
} while (chr == ',' || chr == ';');
@ -384,14 +388,10 @@ int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
goto fail;
}
if (open_inputs && !strcmp(open_inputs->name, "out") && curr_inputs) {
/* Last output can be omitted if it is "[out]" */
const char *tmp = "[out]";
if ((ret = parse_outputs(&tmp, &curr_inputs, &open_inputs, &open_outputs,
log_ctx)) < 0)
goto fail;
}
append_inout(&open_outputs, &curr_inputs);
*inputs = open_inputs;
*outputs = open_outputs;
return 0;
fail:
@ -401,5 +401,73 @@ int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
free_inout(open_inputs);
free_inout(open_outputs);
free_inout(curr_inputs);
*inputs = NULL;
*outputs = NULL;
return ret;
}
#undef log_ctx
int avfilter_graph_parse(AVFilterGraph *graph, const char *filters,
AVFilterInOut *open_inputs,
AVFilterInOut *open_outputs, void *log_ctx)
{
int ret;
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);
free_inout(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);
free_inout(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);
}
free_inout(inputs);
free_inout(outputs);
free_inout(open_inputs);
free_inout(open_outputs);
return ret;
}