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936b2fdfbc
Implement a new memory type wrapping CVPixelBuffer.
There are two immediate advantages:
a) Make the GstMemory itself retain the CVPixelBuffer. Previously,
the containing GstBuffer was solely responsible for the lifetime of
the backing CVPixelBuffer.
With this change, we remove the GST_MEMORY_FLAG_NO_SHARE so that
GstMemory objects be referenced by multiple GstBuffers (doing away
with the need to copy.)
b) Delay locking CVPixelBuffer into CPU memory until it's actually
mapped -- possibly never.
The CVPixelBuffer object is shared among references, shares and
(in planar formats) planes, so a wrapper GstAppleCoreVideoPixelBuffer
structure was introduced to manage locking.
https://bugzilla.gnome.org/show_bug.cgi?id=747216
109 lines
3.1 KiB
C
109 lines
3.1 KiB
C
/* GStreamer Apple Core Video memory
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* Copyright (C) 2015 Ilya Konstantinov
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#ifndef __GST_APPLE_CORE_VIDEO_MEMORY_H__
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#define __GST_APPLE_CORE_VIDEO_MEMORY_H__
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#include <gst/gst.h>
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#include "CoreVideo/CoreVideo.h"
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G_BEGIN_DECLS
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/**
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* GstAppleCoreVideoLockState:
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*
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* Specifies whether the backing CVPixelBuffer is locked for read-only
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* or read-write.
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*
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* Locking for reading only improves performance by preventing
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* Core Video from invalidating existing caches of the buffer’s contents.
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*/
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typedef enum
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{
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GST_APPLE_CORE_VIDEO_MEMORY_UNLOCKED,
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GST_APPLE_CORE_VIDEO_MEMORY_LOCKED_READONLY,
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GST_APPLE_CORE_VIDEO_MEMORY_LOCKED_READ_WRITE
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} GstAppleCoreVideoLockState;
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/**
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* GstAppleCoreVideoPixelBuffer:
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*
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* This structure wraps CVPixelBuffer, managing its lock states and reference count.
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* It will be referenced by one or more #GstAppleCoreVideoMemory.
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*/
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typedef struct
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{
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guint refcount;
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GMutex mutex;
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CVPixelBufferRef buf;
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/* Allows mem_map to refuse Read-Write locking a buffer that was previously
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* locked for Read-Only. */
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GstAppleCoreVideoLockState lock_state;
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/* Counts the number of times the buffer was locked.
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* Only the first lock affects whether it's just for reading
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* or for reading and writing, as reflected in @lock_state. */
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guint lock_count;
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} GstAppleCoreVideoPixelBuffer;
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/**
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* GST_APPLE_CORE_VIDEO_NO_PLANE:
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*
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* Indicates a non-planar pixel buffer.
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*/
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#define GST_APPLE_CORE_VIDEO_NO_PLANE ((size_t)-1)
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/**
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* GstAppleCoreVideoMemory:
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*
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* Represents a video plane or an entire (non-planar) video image,
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* backed by a CVPixelBuffer.
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*
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* This structure shares a #GstAppleCoreVideoPixelBuffer instance
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* with other instances.
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*/
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typedef struct
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{
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GstMemory mem;
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GstAppleCoreVideoPixelBuffer *gpixbuf;
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size_t plane;
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} GstAppleCoreVideoMemory;
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void
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gst_apple_core_video_memory_init (void);
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GstAppleCoreVideoPixelBuffer *
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gst_apple_core_video_pixel_buffer_new (CVPixelBufferRef pixbuf);
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GstAppleCoreVideoPixelBuffer *
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gst_apple_core_video_pixel_buffer_ref (GstAppleCoreVideoPixelBuffer * shared);
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void
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gst_apple_core_video_pixel_buffer_unref (GstAppleCoreVideoPixelBuffer * shared);
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gboolean
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gst_is_apple_core_video_memory (GstMemory * mem);
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GstMemory *
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gst_apple_core_video_memory_new_wrapped (GstAppleCoreVideoPixelBuffer * shared, gsize plane, gsize size);
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G_END_DECLS
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#endif /* __GST_APPLE_CORE_VIDEO_MEMORY_H__ */
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