mirror of https://github.com/mpv-player/mpv
93 lines
4.4 KiB
C
93 lines
4.4 KiB
C
#pragma once
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#include "filter.h"
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// A thread safe queue, which buffers a configurable number of frames like a
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// FIFO. It's part of the filter framework, and intended to provide such a
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// queue between filters. Since a filter graph can't be used from multiple
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// threads without synchronization, this provides 2 filters, which are
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// implicitly connected. (This seemed much saner than having special thread
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// safe mp_pins or such in the filter framework.)
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struct mp_async_queue;
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// Create a blank queue. Can be freed with talloc_free(). To use it, you need
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// to create input and output filters with mp_async_queue_create_filter().
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// Note that freeing it will only unref it. (E.g. you can free it once you've
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// created the input and output filters.)
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struct mp_async_queue *mp_async_queue_create(void);
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// Clear all queued data and make the queue "inactive". The latter prevents any
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// further communication until mp_async_queue_resume() is called.
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// For correct operation, you also need to call reset on the access filters
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void mp_async_queue_reset(struct mp_async_queue *queue);
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// Put the queue into "active" mode. If it wasn't, then the consumer is woken
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// up (and if there is no data in the queue, this will in turn wake up the
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// producer, i.e. start transfers automatically).
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void mp_async_queue_resume(struct mp_async_queue *queue);
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// Create a filter to access the queue, and connect it. It's not allowed to
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// connect an already connected end of the queue. The filter can be freed at
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// any time.
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//
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// The queue starts out in "inactive" mode, where the queue does not allow
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// the producer to write any data. You need to call mp_async_queue_resume() to
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// start communication. Actual transfers happen only once the consumer filter
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// has read requests on its mp_pin.
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// Resetting any of the consumer/producer filters calls mp_async_queue_reset().
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// If the producer filter requested a new frame from its filter graph, and the
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// queue is asynchronously set to "inactive", then the requested frame will be
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// silently discarded once it reaches the producer filter.
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//
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// For proper global reset, this order should be preferred:
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// - mp_async_queue_reset()
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// - reset producer and consumer filters on their respective threads (in any
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// order)
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// - do whatever other reset work is required
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// - mp_async_queue_resume()
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//
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// parent: filter graph the filter should be part of (or for standalone use,
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// create one with mp_filter_create_root())
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// dir: MP_PIN_IN for a filter that writes to the queue, MP_PIN_OUT to read
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// queue: queue to attach to (which end of it depends on dir)
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// The returned filter will have exactly 1 pin with the requested dir.
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struct mp_filter *mp_async_queue_create_filter(struct mp_filter *parent,
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enum mp_pin_dir dir,
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struct mp_async_queue *queue);
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enum mp_async_queue_sample_unit {
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AQUEUE_UNIT_FRAME = 0, // a frame counts as 1 sample
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AQUEUE_UNIT_SAMPLES, // number of audio samples (1 for other media types)
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};
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// Setting this struct to all-0 is equivalent to defaults.
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struct mp_async_queue_config {
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// Maximum size of frames buffered. mp_frame_approx_size() is used. May be
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// overshot by up to 1 full frame. Clamped to [1, SIZE_MAX/2].
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int64_t max_bytes;
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// Defines what a "sample" is; affects the fields below.
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enum mp_async_queue_sample_unit sample_unit;
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// Maximum number of frames allowed to be buffered at a time (if
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// unit!=AQUEUE_UNIT_FRAME, can be overshot by the contents of 1 mp_frame).
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// 0 is treated as 1.
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int64_t max_samples;
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// Maximum allowed timestamp difference between 2 frames. This still allows
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// at least 2 samples. Behavior is unclear on timestamp resets (even if EOF
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// frames are between them). A value of 0 disables this completely.
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double max_duration;
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};
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// Configure the queue size. By default, the queue size is 1 frame.
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// The wakeup_threshold_* fields can be used to avoid too frequent wakeups by
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// delaying wakeups, and then making the producer to filter multiple frames at
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// once.
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// In all cases, the filters can still read/write if the producer/consumer got
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// woken up by something else.
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// If the current queue contains more frames than the new config allows, the
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// queue will remain over-allocated until these frames have been read.
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void mp_async_queue_set_config(struct mp_async_queue *queue,
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struct mp_async_queue_config cfg);
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