1 files changed, 72 insertions, 0 deletions
diff --git a/filters/f_utils.h b/filters/f_utils.h
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+++ b/filters/f_utils.h
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+#pragma once
+
+#include "filter.h"
+
+// Filter that computes the exact duration of video frames by buffering 1 frame,
+// and taking the PTS difference. This supports video frames only, and stores
+// the duration in mp_image.pkt_duration. All other frame types are passed
+// through.
+struct mp_filter *mp_compute_frame_duration_create(struct mp_filter *parent);
+
+// Given the filters[0..num_filters] array, connect in with the input of the
+// first filter, connect the output of the first filter to the input to the
+// second filter, etc., until out. All filters are assumed to be bidrectional,
+// with input on pin 0 and output on pin 1. NULL entries are skipped.
+void mp_chain_filters(struct mp_pin *in, struct mp_pin *out,
+                      struct mp_filter **filters, int num_filters);
+
+// Helper for maintaining a sub-filter that is created or destroyed on demand,
+// because it might depend on frame input formats or is otherwise dynamically
+// changing. (This is overkill for more static sub filters, or entirely manual
+// filtering.)
+// To initialize this, zero-init all fields, and set the in/out fields.
+struct mp_subfilter {
+    // These two fields must be set on init. The pins must have a manual
+    // connection to the filter whose process() function calls the
+    // mp_subfilter_*() functions.
+    struct mp_pin *in, *out;
+    // Temporary buffered frame, as triggered by mp_subfilter_read(). You can
+    // not mutate this (unless you didn't create or destroy sub->filter).
+    struct mp_frame frame;
+    // The sub-filter, set by the user. Can be NULL if disabled. If set, this
+    // must be a bidirectional filter, with manual connections same as
+    // mp_sub_filter.in/out (to get the correct process() function called).
+    // Set this only if it's NULL. You should not overwrite this if it's set.
+    // Use either mp_subfilter_drain_destroy(), mp_subfilter_destroy(), or
+    // mp_subfilter_reset() to unset and destroy the filter gracefully.
+    struct mp_filter *filter;
+    // Internal state.
+    bool draining;
+};
+
+// Make requests for a new frame.
+// Returns whether sub->frame is set to anything. If true is returned, you
+// must either call mp_subfilter_continue() or mp_subfilter_drain_destroy()
+// once to continue data flow normally (otherwise it will stall). If you call
+// mp_subfilter_drain_destroy(), and it returns true, or you call
+// mp_subfilter_destroy(), you can call mp_subfilter_continue() once after it.
+// If this returns true, sub->frame is never unset (MP_FRAME_NONE).
+bool mp_subfilter_read(struct mp_subfilter *sub);
+
+// Clear internal state (usually to be called by parent filter's reset(), or
+// destroy()). This usually does not free sub->filter.
+void mp_subfilter_reset(struct mp_subfilter *sub);
+
+// Continue filtering sub->frame. This can happen after setting a new filter
+// too.
+void mp_subfilter_continue(struct mp_subfilter *sub);
+
+// Destroy the filter immediately (if it's set). You must call
+// mp_subfilter_continue() after this to propagate sub->frame.
+void mp_subfilter_destroy(struct mp_subfilter *sub);
+
+// Make sure the filter is destroyed. Returns true if the filter was destroyed.
+// If this returns false, exit your process() function, so dataflow can
+// continue normally. (process() is repeated until this function returns true,
+// which can take a while if sub->filter has many frames buffered).
+// If this returns true, call mp_subfilter_continue() to propagate sub->frame.
+// The filter is destroyed with talloc_free(sub->filter).
+bool mp_subfilter_drain_destroy(struct mp_subfilter *sub);
+
+// A bidrectional filter which passes through all data.
+struct mp_filter *mp_bidir_nop_filter_create(struct mp_filter *parent);