1 files changed, 131 insertions, 0 deletions
diff --git a/libavcodec/v4l2_buffers.h b/libavcodec/v4l2_buffers.h
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+++ b/libavcodec/v4l2_buffers.h
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+/*
+ * V4L2 buffer helper functions.
+ *
+ * Copyright (C) 2017 Alexis Ballier <aballier@gentoo.org>
+ * Copyright (C) 2017 Jorge Ramirez <jorge.ramirez-ortiz@linaro.org>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_V4L2_BUFFERS_H
+#define AVCODEC_V4L2_BUFFERS_H
+
+#include <stdatomic.h>
+#include <linux/videodev2.h>
+
+#include "avcodec.h"
+
+enum V4L2Buffer_status {
+    V4L2BUF_AVAILABLE,
+    V4L2BUF_IN_DRIVER,
+    V4L2BUF_RET_USER,
+};
+
+/**
+ * V4L2Buffer (wrapper for v4l2_buffer management)
+ */
+typedef struct V4L2Buffer {
+    /* each buffer needs to have a reference to its context */
+    struct V4L2Context *context;
+
+    /* This object is refcounted per-plane, so we need to keep track
+     * of how many context-refs we are holding. */
+    AVBufferRef *context_ref;
+    atomic_uint context_refcount;
+
+    /* keep track of the mmap address and mmap length */
+    struct V4L2Plane_info {
+        int bytesperline;
+        void * mm_addr;
+        size_t length;
+    } plane_info[VIDEO_MAX_PLANES];
+
+    int num_planes;
+
+    /* the v4l2_buffer buf.m.planes pointer uses the planes[] mem */
+    struct v4l2_buffer buf;
+    struct v4l2_plane planes[VIDEO_MAX_PLANES];
+
+    int flags;
+    enum V4L2Buffer_status status;
+
+} V4L2Buffer;
+
+/**
+ * Extracts the data from a V4L2Buffer to an AVFrame
+ *
+ * @param[in] frame The AVFRame to push the information to
+ * @param[in] buf The V4L2Buffer to get the information from
+ *
+ * @returns 0 in case of success, AVERROR(EINVAL) if the number of planes is incorrect,
+ * AVERROR(ENOMEM) if the AVBufferRef can't be created.
+ */
+int ff_v4l2_buffer_buf_to_avframe(AVFrame *frame, V4L2Buffer *buf);
+
+/**
+ * Extracts the data from a V4L2Buffer to an AVPacket
+ *
+ * @param[in] pkt The AVPacket to push the information to
+ * @param[in] buf The V4L2Buffer to get the information from
+ *
+ * @returns 0 in case of success, AVERROR(EINVAL) if the number of planes is incorrect,
+ * AVERROR(ENOMEM) if the AVBufferRef can't be created.
+ *
+ */
+int ff_v4l2_buffer_buf_to_avpkt(AVPacket *pkt, V4L2Buffer *buf);
+
+/**
+ * Extracts the data from an AVPacket to a V4L2Buffer
+ *
+ * @param[in]  frame AVPacket to get the data from
+ * @param[in]  avbuf V4L2Bfuffer to push the information to
+ *
+ * @returns 0 in case of success, a negative AVERROR code otherwise
+ */
+int ff_v4l2_buffer_avpkt_to_buf(const AVPacket *pkt, V4L2Buffer *out);
+
+/**
+ * Extracts the data from an AVFrame to a V4L2Buffer
+ *
+ * @param[in]  frame AVFrame to get the data from
+ * @param[in]  avbuf V4L2Bfuffer to push the information to
+ *
+ * @returns 0 in case of success, a negative AVERROR code otherwise
+ */
+int ff_v4l2_buffer_avframe_to_buf(const AVFrame *frame, V4L2Buffer* out);
+
+/**
+ * Initializes a V4L2Buffer
+ *
+ * @param[in]  avbuf V4L2Bfuffer to initialize
+ * @param[in]  index v4l2 buffer id
+ *
+ * @returns 0 in case of success, a negative AVERROR code otherwise
+ */
+int ff_v4l2_buffer_initialize(V4L2Buffer* avbuf, int index);
+
+/**
+ * Enqueues a V4L2Buffer
+ *
+ * @param[in] avbuf V4L2Bfuffer to push to the driver
+ *
+ * @returns 0 in case of success, a negative AVERROR code otherwise
+ */
+int ff_v4l2_buffer_enqueue(V4L2Buffer* avbuf);
+
+
+#endif // AVCODEC_V4L2_BUFFERS_H