diff options
Diffstat (limited to 'filters/filter.h')
| -rw-r--r-- | filters/filter.h | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/filters/filter.h b/filters/filter.h index 5e09a17ee7..34146af98d 100644 --- a/filters/filter.h +++ b/filters/filter.h @@ -217,12 +217,6 @@ const char *mp_pin_get_name(struct mp_pin *p); * call the first filter's process() function, which will filter and output * the frame, and the frame is iteratively filtered until it reaches the output. * - * (The mp_pin_* calls can recursively start filtering, but this is only the - * case if you access a separate graph with a different filter root. Most - * importantly, calling them from outside the filter's process() function (e.g. - * an outside filter user) will enter filtering. Within the filter, mp_pin_* - * will usually only set or query flags.) - * * --- General rules for thread safety: * * Filters are by default not thread safe. However, some filters can be @@ -231,6 +225,14 @@ const char *mp_pin_get_name(struct mp_pin *p); * for some utility functions explicitly marked as such, and which are meant * to make implementing threaded filters easier. * + * (Semi-)automatic filter communication such as pins must always be within the + * same root filter. This is meant to help with ensuring thread-safety. Every + * thread that wants to run filters "on its own" should use a different filter + * graph, and disallowing different root filters ensures these graphs are not + * accidentally connected using non-thread safe mechanisms. Actual threaded + * filter graphs would use several independent graphs connected by asynchronous + * helpers (such as queues instead of mp_pin connections). + * * --- Rules for manual connections: * * A pin can be marked for manual connection via mp_pin_set_manual_connection(). @@ -272,6 +274,11 @@ const char *mp_pin_get_name(struct mp_pin *p); * For running parts of a filter graph on a different thread, f_async_queue.h * can be used. * + * With different filter graphs working asynchronously, reset handling and start + * of filtering becomes more difficult. Since filtering is always triggered by + * requesting output from a filter, a simple way to solve this is to trigger + * resets from the consumer, and to synchronously reset the producer. + * * --- Format conversions and mid-stream format changes: * * Generally, all filters must support all formats, as well as mid-stream @@ -402,8 +409,6 @@ struct AVBufferRef *mp_filter_load_hwdec_device(struct mp_filter *f, int avtype) // Perform filtering. This runs until the filter graph is blocked (due to // missing external input or unread output). It returns whether any outside // pins have changed state. -// Does not perform recursive filtering to connected filters with different -// root filter, though it notifies them. bool mp_filter_run(struct mp_filter *f); // Create a root dummy filter with no inputs or outputs. This fulfills the |