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 35 enum V4L2Buffer_status { 36 V4L2BUF_AVAILABLE, 37 V4L2BUF_IN_DRIVER, 38 V4L2BUF_RET_USER, 39 }; 40 41 /** 42 * V4L2Buffer (wrapper for v4l2_buffer management) 43 */ 44 typedef 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 */ 80 int 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 */ 92 int 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 */ 102 int 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 */ 112 int 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 */ 122 int 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 */ 131 int ff_v4l2_buffer_enqueue(V4L2Buffer* avbuf); 132 133 134 #endif // AVCODEC_V4L2_BUFFERS_H 135