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 <linux/videodev2.h> 29 30 #include "avcodec.h" 31 32 enum V4L2Buffer_status { 33 V4L2BUF_AVAILABLE, 34 V4L2BUF_IN_DRIVER, 35 V4L2BUF_RET_USER, 36 }; 37 38 /** 39 * V4L2Buffer (wrapper for v4l2_buffer management) 40 */ 41 typedef struct V4L2Buffer { 42 /* each buffer needs to have a reference to its context */ 43 struct V4L2Context *context; 44 45 /* This object is refcounted per-plane, so we need to keep track 46 * of how many context-refs we are holding. */ 47 AVBufferRef *context_ref; 48 atomic_uint context_refcount; 49 50 /* keep track of the mmap address and mmap length */ 51 struct V4L2Plane_info { 52 int bytesperline; 53 void * mm_addr; 54 size_t length; 55 } plane_info[VIDEO_MAX_PLANES]; 56 57 int num_planes; 58 59 /* the v4l2_buffer buf.m.planes pointer uses the planes[] mem */ 60 struct v4l2_buffer buf; 61 struct v4l2_plane planes[VIDEO_MAX_PLANES]; 62 63 int flags; 64 enum V4L2Buffer_status status; 65 66 } V4L2Buffer; 67 68 /** 69 * Extracts the data from a V4L2Buffer to an AVFrame 70 * 71 * @param[in] frame The AVFRame to push the information to 72 * @param[in] buf The V4L2Buffer to get the information from 73 * 74 * @returns 0 in case of success, AVERROR(EINVAL) if the number of planes is incorrect, 75 * AVERROR(ENOMEM) if the AVBufferRef can't be created. 76 */ 77 int ff_v4l2_buffer_buf_to_avframe(AVFrame *frame, V4L2Buffer *buf); 78 79 /** 80 * Extracts the data from a V4L2Buffer to an AVPacket 81 * 82 * @param[in] pkt The AVPacket to push the information to 83 * @param[in] buf The V4L2Buffer to get the information from 84 * 85 * @returns 0 in case of success, AVERROR(EINVAL) if the number of planes is incorrect, 86 * AVERROR(ENOMEM) if the AVBufferRef can't be created. 87 * 88 */ 89 int ff_v4l2_buffer_buf_to_avpkt(AVPacket *pkt, V4L2Buffer *buf); 90 91 /** 92 * Extracts the data from an AVPacket to a V4L2Buffer 93 * 94 * @param[in] frame AVPacket to get the data from 95 * @param[in] avbuf V4L2Bfuffer to push the information to 96 * 97 * @returns 0 in case of success, a negative AVERROR code otherwise 98 */ 99 int ff_v4l2_buffer_avpkt_to_buf(const AVPacket *pkt, V4L2Buffer *out); 100 101 /** 102 * Extracts the data from an AVFrame to a V4L2Buffer 103 * 104 * @param[in] frame AVFrame to get the data from 105 * @param[in] avbuf V4L2Bfuffer to push the information to 106 * 107 * @returns 0 in case of success, a negative AVERROR code otherwise 108 */ 109 int ff_v4l2_buffer_avframe_to_buf(const AVFrame *frame, V4L2Buffer *out); 110 111 /** 112 * Initializes a V4L2Buffer 113 * 114 * @param[in] avbuf V4L2Bfuffer to initialize 115 * @param[in] index v4l2 buffer id 116 * 117 * @returns 0 in case of success, a negative AVERROR code otherwise 118 */ 119 int ff_v4l2_buffer_initialize(V4L2Buffer* avbuf, int index); 120 121 /** 122 * Enqueues a V4L2Buffer 123 * 124 * @param[in] avbuf V4L2Bfuffer to push to the driver 125 * 126 * @returns 0 in case of success, a negative AVERROR code otherwise 127 */ 128 int ff_v4l2_buffer_enqueue(V4L2Buffer* avbuf); 129 130 131 #endif // AVCODEC_V4L2_BUFFERS_H 132