2 * Filters implementation helper functions
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21 #ifndef AVFILTER_FILTERS_H
22 #define AVFILTER_FILTERS_H
25 * Filters implementation helper functions
31 * Mark a filter ready and schedule it for activation.
33 * This is automatically done when something happens to the filter (queued
34 * frame, status change, request on output).
35 * Filters implementing the activate callback can call it directly to
36 * perform one more round of processing later.
37 * It is also useful for filters reacting to external or asynchronous
40 void ff_filter_set_ready(AVFilterContext *filter, unsigned priority);
43 * Process the commands queued in the link up to the time of the frame.
44 * Commands will trigger the process_command() callback.
45 * @return >= 0 or AVERROR code.
47 int ff_inlink_process_commands(AVFilterLink *link, const AVFrame *frame);
50 * Evaluate the timeline expression of the link for the time and properties
52 * @return >0 if enabled, 0 if disabled
53 * @note It does not update link->dst->is_disabled.
55 int ff_inlink_evaluate_timeline_at_frame(AVFilterLink *link, const AVFrame *frame);
58 * Test if a frame is available on the link.
59 * @return >0 if a frame is available
61 int ff_inlink_check_available_frame(AVFilterLink *link);
64 * Test if enough samples are available on the link.
65 * @return >0 if enough samples are available
66 * @note on EOF and error, min becomes 1
68 int ff_inlink_check_available_samples(AVFilterLink *link, unsigned min);
71 * Take a frame from the link's FIFO and update the link's stats.
73 * If ff_inlink_check_available_frame() was previously called, the
74 * preferred way of expressing it is "av_assert1(ret);" immediately after
75 * ff_inlink_consume_frame(). Negative error codes must still be checked.
77 * @note May trigger process_command() and/or update is_disabled.
78 * @return >0 if a frame is available,
79 * 0 and set rframe to NULL if no frame available,
82 int ff_inlink_consume_frame(AVFilterLink *link, AVFrame **rframe);
85 * Take samples from the link's FIFO and update the link's stats.
87 * If ff_inlink_check_available_samples() was previously called, the
88 * preferred way of expressing it is "av_assert1(ret);" immediately after
89 * ff_inlink_consume_samples(). Negative error codes must still be checked.
91 * @note May trigger process_command() and/or update is_disabled.
92 * @return >0 if a frame is available,
93 * 0 and set rframe to NULL if no frame available,
96 int ff_inlink_consume_samples(AVFilterLink *link, unsigned min, unsigned max,
100 * Make sure a frame is writable.
101 * This is similar to av_frame_make_writable() except it uses the link's
102 * buffer allocation callback, and therefore allows direct rendering.
104 int ff_inlink_make_frame_writable(AVFilterLink *link, AVFrame **rframe);
107 * Test and acknowledge the change of status on the link.
109 * Status means EOF or an error condition; a change from the normal (0)
110 * status to a non-zero status can be queued in a filter's input link, it
111 * becomes relevant after the frames queued in the link's FIFO are
112 * processed. This function tests if frames are still queued and if a queued
113 * status change has not yet been processed. In that case it performs basic
114 * treatment (updating the link's timestamp) and returns a positive value to
115 * let the filter do its own treatments (flushing...).
117 * Filters implementing the activate callback should call this function when
118 * they think it might succeed (usually after checking unsuccessfully for a
120 * Filters implementing the filter_frame and request_frame callbacks do not
121 * need to call that since the same treatment happens in ff_filter_frame().
123 * @param[out] rstatus new or current status
124 * @param[out] rpts current timestamp of the link in link time base
125 * @return >0 if status changed, <0 if status already acked, 0 otherwise
127 int ff_inlink_acknowledge_status(AVFilterLink *link, int *rstatus, int64_t *rpts);
130 * Mark that a frame is wanted on the link.
131 * Unlike ff_filter_frame(), it must not be called when the link has a
132 * non-zero status, and thus does not acknowledge it.
133 * Also it cannot fail.
135 void ff_inlink_request_frame(AVFilterLink *link);
137 #endif /* AVFILTER_FILTERS_H */