1/*
2 * V4L2 buffer helper functions.
3 *
4 * Copyright (C) 2017 Alexis Ballier <aballier@gentoo.org>
5 * Copyright (C) 2017 Jorge Ramirez <jorge.ramirez-ortiz@linaro.org>
6 *
7 * This file is part of FFmpeg.
8 *
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24#ifndef AVCODEC_V4L2_BUFFERS_H
25#define AVCODEC_V4L2_BUFFERS_H
26
27#include <stdatomic.h>
28#include <stddef.h>
29#include <linux/videodev2.h>
30
31#include "libavutil/buffer.h"
32#include "libavutil/frame.h"
33#include "packet.h"
34
35enum V4L2Buffer_status {
36    V4L2BUF_AVAILABLE,
37    V4L2BUF_IN_DRIVER,
38    V4L2BUF_RET_USER,
39};
40
41/**
42 * V4L2Buffer (wrapper for v4l2_buffer management)
43 */
44typedef struct V4L2Buffer {
45    /* each buffer needs to have a reference to its context */
46    struct V4L2Context *context;
47
48    /* This object is refcounted per-plane, so we need to keep track
49     * of how many context-refs we are holding. */
50    AVBufferRef *context_ref;
51    atomic_uint context_refcount;
52
53    /* keep track of the mmap address and mmap length */
54    struct V4L2Plane_info {
55        int bytesperline;
56        void * mm_addr;
57        size_t length;
58    } plane_info[VIDEO_MAX_PLANES];
59
60    int num_planes;
61
62    /* the v4l2_buffer buf.m.planes pointer uses the planes[] mem */
63    struct v4l2_buffer buf;
64    struct v4l2_plane planes[VIDEO_MAX_PLANES];
65
66    int flags;
67    enum V4L2Buffer_status status;
68
69} V4L2Buffer;
70
71/**
72 * Extracts the data from a V4L2Buffer to an AVFrame
73 *
74 * @param[in] frame The AVFRame to push the information to
75 * @param[in] buf The V4L2Buffer to get the information from
76 *
77 * @returns 0 in case of success, AVERROR(EINVAL) if the number of planes is incorrect,
78 * AVERROR(ENOMEM) if the AVBufferRef can't be created.
79 */
80int ff_v4l2_buffer_buf_to_avframe(AVFrame *frame, V4L2Buffer *buf);
81
82/**
83 * Extracts the data from a V4L2Buffer to an AVPacket
84 *
85 * @param[in] pkt The AVPacket to push the information to
86 * @param[in] buf The V4L2Buffer to get the information from
87 *
88 * @returns 0 in case of success, AVERROR(EINVAL) if the number of planes is incorrect,
89 * AVERROR(ENOMEM) if the AVBufferRef can't be created.
90 *
91 */
92int ff_v4l2_buffer_buf_to_avpkt(AVPacket *pkt, V4L2Buffer *buf);
93
94/**
95 * Extracts the data from an AVPacket to a V4L2Buffer
96 *
97 * @param[in]  frame AVPacket to get the data from
98 * @param[in]  avbuf V4L2Bfuffer to push the information to
99 *
100 * @returns 0 in case of success, a negative AVERROR code otherwise
101 */
102int ff_v4l2_buffer_avpkt_to_buf(const AVPacket *pkt, V4L2Buffer *out);
103
104/**
105 * Extracts the data from an AVFrame to a V4L2Buffer
106 *
107 * @param[in]  frame AVFrame to get the data from
108 * @param[in]  avbuf V4L2Bfuffer to push the information to
109 *
110 * @returns 0 in case of success, a negative AVERROR code otherwise
111 */
112int ff_v4l2_buffer_avframe_to_buf(const AVFrame *frame, V4L2Buffer *out);
113
114/**
115 * Initializes a V4L2Buffer
116 *
117 * @param[in]  avbuf V4L2Bfuffer to initialize
118 * @param[in]  index v4l2 buffer id
119 *
120 * @returns 0 in case of success, a negative AVERROR code otherwise
121 */
122int ff_v4l2_buffer_initialize(V4L2Buffer* avbuf, int index);
123
124/**
125 * Enqueues a V4L2Buffer
126 *
127 * @param[in] avbuf V4L2Bfuffer to push to the driver
128 *
129 * @returns 0 in case of success, a negative AVERROR code otherwise
130 */
131int ff_v4l2_buffer_enqueue(V4L2Buffer* avbuf);
132
133
134#endif // AVCODEC_V4L2_BUFFERS_H
135