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avfilter/avfilter: Add numbers of (in|out)pads directly to AVFilter
Up until now, an AVFilter's lists of input and output AVFilterPads were terminated by a sentinel and the only way to get the length of these lists was by using avfilter_pad_count(). This has two drawbacks: first, sizeof(AVFilterPad) is not negligible (i.e. 64B on 64bit systems); second, getting the size involves a function call instead of just reading the data. This commit therefore changes this. The sentinels are removed and new private fields nb_inputs and nb_outputs are added to AVFilter that contain the number of elements of the respective AVFilterPad array. Given that AVFilter.(in|out)puts are the only arrays of zero-terminated AVFilterPads an API user has access to (AVFilterContext.(in|out)put_pads are not zero-terminated and they already have a size field) the argument to avfilter_pad_count() is always one of these lists, so it just has to find the filter the list belongs to and read said number. This is slower than before, but a replacement function that just reads the internal numbers that users are expected to switch to will be added soon; and furthermore, avfilter_pad_count() is probably never called in hot loops anyway. This saves about 49KiB from the binary; notice that these sentinels are not in .bss despite being zeroed: they are in .data.rel.ro due to the non-sentinels. Reviewed-by: Nicolas George <george@nsup.org> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
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@@ -167,7 +167,6 @@ static const AVFilterPad repeatfields_inputs[] = {
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.filter_frame = filter_frame,
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.config_props = config_input,
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},
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{ NULL }
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};
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static const AVFilterPad repeatfields_outputs[] = {
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@@ -175,7 +174,6 @@ static const AVFilterPad repeatfields_outputs[] = {
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.name = "default",
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.type = AVMEDIA_TYPE_VIDEO,
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},
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{ NULL }
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};
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const AVFilter ff_vf_repeatfields = {
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@@ -183,7 +181,7 @@ const AVFilter ff_vf_repeatfields = {
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.description = NULL_IF_CONFIG_SMALL("Hard repeat fields based on MPEG repeat field flag."),
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.priv_size = sizeof(RepeatFieldsContext),
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.uninit = uninit,
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.inputs = repeatfields_inputs,
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.outputs = repeatfields_outputs,
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FILTER_INPUTS(repeatfields_inputs),
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FILTER_OUTPUTS(repeatfields_outputs),
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.query_formats = query_formats,
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};
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