lavu: add a framework for handling hwaccel frames

1 files changed, 328 insertions, 0 deletions

diff --git a/libavutil/hwcontext.h b/libavutil/hwcontext.h
new file mode 100644
index 0000000000..b30a20a42c
--- /dev/null
+++ b/libavutil/hwcontext.h
@@ -0,0 +1,328 @@
+/*
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_HWCONTEXT_H
+#define AVUTIL_HWCONTEXT_H
+
+#include "buffer.h"
+#include "frame.h"
+#include "log.h"
+#include "pixfmt.h"
+
+enum AVHWDeviceType {
+    AV_HWDEVICE_TYPE_VDPAU,
+};
+
+typedef struct AVHWDeviceInternal AVHWDeviceInternal;
+
+/**
+ * This struct aggregates all the (hardware/vendor-specific) "high-level" state,
+ * i.e. state that is not tied to a concrete processing configuration.
+ * E.g., in an API that supports hardware-accelerated encoding and decoding,
+ * this struct will (if possible) wrap the state that is common to both encoding
+ * and decoding and from which specific instances of encoders or decoders can be
+ * derived.
+ *
+ * This struct is reference-counted with the AVBuffer mechanism. The
+ * av_hwdevice_ctx_alloc() constructor yields a reference, whose data field
+ * points to the actual AVHWDeviceContext. Further objects derived from
+ * AVHWDeviceContext (such as AVHWFramesContext, describing a frame pool with
+ * specific properties) will hold an internal reference to it. After all the
+ * references are released, the AVHWDeviceContext itself will be freed,
+ * optionally invoking a user-specified callback for uninitializing the hardware
+ * state.
+ */
+typedef struct AVHWDeviceContext {
+    /**
+     * A class for logging. Set by av_hwdevice_ctx_alloc().
+     */
+    const AVClass *av_class;
+
+    /**
+     * Private data used internally by libavutil. Must not be accessed in any
+     * way by the caller.
+     */
+    AVHWDeviceInternal *internal;
+
+    /**
+     * This field identifies the underlying API used for hardware access.
+     *
+     * This field is set when this struct is allocated and never changed
+     * afterwards.
+     */
+    enum AVHWDeviceType type;
+
+    /**
+     * The format-specific data, allocated and freed by libavutil along with
+     * this context.
+     *
+     * Should be cast by the user to the format-specific context defined in the
+     * corresponding header (hwcontext_*.h) and filled as described in the
+     * documentation before calling av_hwdevice_ctx_init().
+     *
+     * After calling av_hwdevice_ctx_init() this struct should not be modified
+     * by the caller.
+     */
+    void *hwctx;
+
+    /**
+     * This field may be set by the caller before calling av_hwdevice_ctx_init().
+     *
+     * If non-NULL, this callback will be called when the last reference to
+     * this context is unreferenced, immediately before it is freed.
+     *
+     * @note when other objects (e.g an AVHWFramesContext) are derived from this
+     *       struct, this callback will be invoked after all such child objects
+     *       are fully uninitialized and their respective destructors invoked.
+     */
+    void (*free)(struct AVHWDeviceContext *ctx);
+
+    /**
+     * Arbitrary user data, to be used e.g. by the free() callback.
+     */
+    void *user_opaque;
+} AVHWDeviceContext;
+
+typedef struct AVHWFramesInternal AVHWFramesInternal;
+
+/**
+ * This struct describes a set or pool of "hardware" frames (i.e. those with
+ * data not located in normal system memory). All the frames in the pool are
+ * assumed to be allocated in the same way and interchangeable.
+ *
+ * This struct is reference-counted with the AVBuffer mechanism and tied to a
+ * given AVHWDeviceContext instance. The av_hwframe_ctx_alloc() constructor
+ * yields a reference, whose data field points to the actual AVHWFramesContext
+ * struct.
+ */
+typedef struct AVHWFramesContext {
+    /**
+     * A class for logging.
+     */
+    const AVClass *av_class;
+
+    /**
+     * Private data used internally by libavutil. Must not be accessed in any
+     * way by the caller.
+     */
+    AVHWFramesInternal *internal;
+
+    /**
+     * A reference to the parent AVHWDeviceContext. This reference is owned and
+     * managed by the enclosing AVHWFramesContext, but the caller may derive
+     * additional references from it.
+     */
+    AVBufferRef *device_ref;
+
+    /**
+     * The parent AVHWDeviceContext. This is simply a pointer to
+     * device_ref->data provided for convenience.
+     *
+     * Set by libavutil in av_hwframe_ctx_init().
+     */
+    AVHWDeviceContext *device_ctx;
+
+    /**
+     * The format-specific data, allocated and freed automatically along with
+     * this context.
+     *
+     * Should be cast by the user to the format-specific context defined in the
+     * corresponding header (hwframe_*.h) and filled as described in the
+     * documentation before calling av_hwframe_ctx_init().
+     *
+     * After any frames using this context are created, the contents of this
+     * struct should not be modified by the caller.
+     */
+    void *hwctx;
+
+    /**
+     * This field may be set by the caller before calling av_hwframe_ctx_init().
+     *
+     * If non-NULL, this callback will be called when the last reference to
+     * this context is unreferenced, immediately before it is freed.
+     */
+    void (*free)(struct AVHWFramesContext *ctx);
+
+    /**
+     * Arbitrary user data, to be used e.g. by the free() callback.
+     */
+    void *user_opaque;
+
+    /**
+     * A pool from which the frames are allocated by av_hwframe_get_buffer().
+     * This field may be set by the caller before calling av_hwframe_ctx_init().
+     * The buffers returned by calling av_buffer_pool_get() on this pool must
+     * have the properties described in the documentation in the correponding hw
+     * type's header (hwcontext_*.h). The pool will be freed strictly before
+     * this struct's free() callback is invoked.
+     *
+     * This field may be NULL, then libavutil will attempt to allocate a pool
+     * internally. Note that certain device types enforce pools allocated at
+     * fixed size (frame count), which cannot be extended dynamically. In such a
+     * case, initial_pool_size must be set appropriately.
+     */
+    AVBufferPool *pool;
+
+    /**
+     * Initial size of the frame pool. If a device type does not support
+     * dynamically resizing the pool, then this is also the maximum pool size.
+     *
+     * May be set by the caller before calling av_hwframe_ctx_init(). Must be
+     * set if pool is NULL and the device type does not support dynamic pools.
+     */
+    int initial_pool_size;
+
+    /**
+     * The pixel format identifying the underlying HW surface type.
+     *
+     * Must be a hwaccel format, i.e. the corresponding descriptor must have the
+     * AV_PIX_FMT_FLAG_HWACCEL flag set.
+     *
+     * Must be set by the user before calling av_hwframe_ctx_init().
+     */
+    enum AVPixelFormat format;
+
+    /**
+     * The pixel format identifying the actual data layout of the hardware
+     * frames.
+     *
+     * Must be set by the caller before calling av_hwframe_ctx_init().
+     *
+     * @note when the underlying API does not provide the exact data layout, but
+     * only the colorspace/bit depth, this field should be set to the fully
+     * planar version of that format (e.g. for 8-bit 420 YUV it should be
+     * AV_PIX_FMT_YUV420P, not AV_PIX_FMT_NV12 or anything else).
+     */
+    enum AVPixelFormat sw_format;
+
+    /**
+     * The allocated dimensions of the frames in this pool.
+     *
+     * Must be set by the user before calling av_hwframe_ctx_init().
+     */
+    int width, height;
+} AVHWFramesContext;
+
+/**
+ * Allocate an AVHWDeviceContext for a given pixel format.
+ *
+ * @param format a hwaccel pixel format (AV_PIX_FMT_FLAG_HWACCEL must be set
+ *               on the corresponding format descriptor)
+ * @return a reference to the newly created AVHWDeviceContext on success or NULL
+ *         on failure.
+ */
+AVBufferRef *av_hwdevice_ctx_alloc(enum AVHWDeviceType type);
+
+/**
+ * Finalize the device context before use. This function must be called after
+ * the context is filled with all the required information and before it is
+ * used in any way.
+ *
+ * @param ref a reference to the AVHWDeviceContext
+ * @return 0 on success, a negative AVERROR code on failure
+ */
+int av_hwdevice_ctx_init(AVBufferRef *ref);
+
+/**
+ * Allocate an AVHWFramesContext tied to a given device context.
+ *
+ * @param device_ctx a reference to a AVHWDeviceContext. This function will make
+ *                   a new reference for internal use, the one passed to the
+ *                   function remains owned by the caller.
+ * @return a reference to the newly created AVHWFramesContext on success or NULL
+ *         on failure.
+ */
+AVBufferRef *av_hwframe_ctx_alloc(AVBufferRef *device_ctx);
+
+/**
+ * Finalize the context before use. This function must be called after the
+ * context is filled with all the required information and before it is attached
+ * to any frames.
+ *
+ * @param ref a reference to the AVHWFramesContext
+ * @return 0 on success, a negative AVERROR code on failure
+ */
+int av_hwframe_ctx_init(AVBufferRef *ref);
+
+/**
+ * Allocate a new frame attached to the given AVHWFramesContext.
+ *
+ * @param hwframe_ctx a reference to an AVHWFramesContext
+ * @param frame an empty (freshly allocated or unreffed) frame to be filled with
+ *              newly allocated buffers.
+ * @param flags currently unused, should be set to zero
+ * @return 0 on success, a negative AVERROR code on failure
+ */
+int av_hwframe_get_buffer(AVBufferRef *hwframe_ctx, AVFrame *frame, int flags);
+
+/**
+ * Copy data to or from a hw surface. At least one of dst/src must have an
+ * AVHWFramesContext attached.
+ *
+ * If src has an AVHWFramesContext attached, then the format of dst (if set)
+ * must use one of the formats returned by av_hwframe_transfer_get_formats(src,
+ * AV_HWFRAME_TRANSFER_DIRECTION_FROM).
+ * If dst has an AVHWFramesContext attached, then the format of src must use one
+ * of the formats returned by av_hwframe_transfer_get_formats(dst,
+ * AV_HWFRAME_TRANSFER_DIRECTION_TO)
+ *
+ * dst may be "clean" (i.e. with data/buf pointers unset), in which case the
+ * data buffers will be allocated by this function using av_frame_get_buffer().
+ * If dst->format is set, then this format will be used, otherwise (when
+ * dst->format is AV_PIX_FMT_NONE) the first acceptable format will be chosen.
+ *
+ * @param dst the destination frame. dst is not touched on failure.
+ * @param src the source frame.
+ * @param flags currently unused, should be set to zero
+ * @return 0 on success, a negative AVERROR error code on failure.
+ */
+int av_hwframe_transfer_data(AVFrame *dst, const AVFrame *src, int flags);
+
+enum AVHWFrameTransferDirection {
+    /**
+     * Transfer the data from the queried hw frame.
+     */
+    AV_HWFRAME_TRANSFER_DIRECTION_FROM,
+
+    /**
+     * Transfer the data to the queried hw frame.
+     */
+    AV_HWFRAME_TRANSFER_DIRECTION_TO,
+};
+
+/**
+ * Get a list of possible source or target formats usable in
+ * av_hwframe_transfer_data().
+ *
+ * @param hwframe_ctx the frame context to obtain the information for
+ * @param dir the direction of the transfer
+ * @param formats the pointer to the output format list will be written here.
+ *                The list is terminated with AV_PIX_FMT_NONE and must be freed
+ *                by the caller when no longer needed using av_free().
+ *                If this function returns successfully, the format list will
+ *                have at least one item (not counting the terminator).
+ *                On failure, the contents of this pointer are unspecified.
+ * @param flags currently unused, should be set to zero
+ * @return 0 on success, a negative AVERROR code on failure.
+ */
+int av_hwframe_transfer_get_formats(AVBufferRef *hwframe_ctx,
+                                    enum AVHWFrameTransferDirection dir,
+                                    enum AVPixelFormat **formats, int flags);
+
+
+#endif /* AVUTIL_HWCONTEXT_H */