Commit 63736fe4 authored by Anton Khirnov's avatar Anton Khirnov
Browse files

avfiltergraph: try to reduce format conversions in filters.

Current code, with a filterchain such as
(input - yuv411) -> (scale - any) -> (sink - any)
will result in yuv420 being chosen for the second link, which is clearly
not right.

This commit attempts to improve in the following way:
repeat until convergence:
  loop over all filters
    find input link with exactly one format
    force this format on all output links of the same type (if possible)
parent 996f9f0c
......@@ -214,6 +214,49 @@ static void pick_format(AVFilterLink *link)
avfilter_formats_unref(&link->out_formats);
}
static int reduce_formats_on_filter(AVFilterContext *filter)
{
int i, j, k, ret = 0;
for (i = 0; i < filter->input_count; i++) {
AVFilterLink *link = filter->inputs[i];
int format = link->out_formats->formats[0];
if (link->out_formats->format_count != 1)
continue;
for (j = 0; j < filter->output_count; j++) {
AVFilterLink *out_link = filter->outputs[j];
AVFilterFormats *fmts = out_link->in_formats;
if (link->type != out_link->type ||
out_link->in_formats->format_count == 1)
continue;
for (k = 0; k < out_link->in_formats->format_count; k++)
if (fmts->formats[k] == format) {
fmts->formats[0] = format;
fmts->format_count = 1;
ret = 1;
break;
}
}
}
return ret;
}
static void reduce_formats(AVFilterGraph *graph)
{
int i, reduced;
do {
reduced = 0;
for (i = 0; i < graph->filter_count; i++)
reduced |= reduce_formats_on_filter(graph->filters[i]);
} while (reduced);
}
static void pick_formats(AVFilterGraph *graph)
{
int i, j;
......@@ -237,7 +280,10 @@ int ff_avfilter_graph_config_formats(AVFilterGraph *graph, AVClass *log_ctx)
return ret;
/* Once everything is merged, it's possible that we'll still have
* multiple valid media format choices. We pick the first one. */
* multiple valid media format choices. We try to minimize the amount
* of format conversion inside filters */
reduce_formats(graph);
pick_formats(graph);
return 0;
......
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