14e83175a6
The video buffer took ownership of the producer frame (so that it could swap frames quickly). In order to support multiple sinks plugged to the decoder, the decoded frame must not be consumed by the display video buffer. Therefore, move the producer and consumer frames out of the video buffer, and use FFmpeg AVFrame refcounting to share ownership while avoiding copies.
69 lines
2.0 KiB
C
69 lines
2.0 KiB
C
#ifndef VIDEO_BUFFER_H
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#define VIDEO_BUFFER_H
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#include "common.h"
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#include <stdbool.h>
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#include "fps_counter.h"
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#include "util/thread.h"
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// forward declarations
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typedef struct AVFrame AVFrame;
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/**
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* A video buffer holds 1 pending frame, which is the last frame received from
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* the producer (typically, the decoder).
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*
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* If a pending frame has not been consumed when the producer pushes a new
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* frame, then it is lost. The intent is to always provide access to the very
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* last frame to minimize latency.
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*
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* The producer and the consumer typically do not live in the same thread.
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* That's the reason why the callback on_frame_available() does not provide the
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* frame as parameter: the consumer might post an event to its own thread to
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* retrieve the pending frame from there, and that frame may have changed since
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* the callback if producer pushed a new one in between.
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*/
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struct video_buffer {
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AVFrame *pending_frame;
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AVFrame *tmp_frame; // To preserve the pending frame on error
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sc_mutex mutex;
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bool pending_frame_consumed;
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const struct video_buffer_callbacks *cbs;
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void *cbs_userdata;
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};
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struct video_buffer_callbacks {
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// Called when a new frame can be consumed.
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// This callback is mandatory (it must not be NULL).
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void (*on_frame_available)(struct video_buffer *vb, void *userdata);
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// Called when a pending frame has been overwritten by the producer.
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// This callback is optional (it may be NULL).
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void (*on_frame_skipped)(struct video_buffer *vb, void *userdata);
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};
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bool
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video_buffer_init(struct video_buffer *vb);
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void
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video_buffer_destroy(struct video_buffer *vb);
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void
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video_buffer_set_consumer_callbacks(struct video_buffer *vb,
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const struct video_buffer_callbacks *cbs,
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void *cbs_userdata);
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bool
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video_buffer_push(struct video_buffer *vb, const AVFrame *frame);
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void
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video_buffer_consume(struct video_buffer *vb, AVFrame *dst);
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#endif
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