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fbdev.c
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1 /*
2  * Copyright (c) 2011 Stefano Sabatini
3  * Copyright (c) 2009 Giliard B. de Freitas <giliarde@gmail.com>
4  * Copyright (C) 2002 Gunnar Monell <gmo@linux.nu>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 /**
24  * @file
25  * Linux framebuffer input device,
26  * inspired by code from fbgrab.c by Gunnar Monell.
27  * @see http://linux-fbdev.sourceforge.net/
28  */
29 
30 #include <unistd.h>
31 #include <fcntl.h>
32 #include <sys/ioctl.h>
33 #include <sys/mman.h>
34 #include <time.h>
35 #include <linux/fb.h>
36 
37 #include "libavutil/internal.h"
38 #include "libavutil/log.h"
39 #include "libavutil/mem.h"
40 #include "libavutil/opt.h"
41 #include "libavutil/time.h"
42 #include "libavutil/parseutils.h"
43 #include "libavutil/pixdesc.h"
44 #include "avdevice.h"
45 #include "libavformat/internal.h"
46 
51 };
52 
53 static const struct rgb_pixfmt_map_entry rgb_pixfmt_map[] = {
54  // bpp, red_offset, green_offset, blue_offset, alpha_offset, pixfmt
55  { 32, 0, 8, 16, 24, AV_PIX_FMT_RGBA },
56  { 32, 16, 8, 0, 24, AV_PIX_FMT_BGRA },
57  { 32, 8, 16, 24, 0, AV_PIX_FMT_ARGB },
58  { 32, 3, 2, 8, 0, AV_PIX_FMT_ABGR },
59  { 24, 0, 8, 16, 0, AV_PIX_FMT_RGB24 },
60  { 24, 16, 8, 0, 0, AV_PIX_FMT_BGR24 },
61  { 16, 11, 5, 0, 16, AV_PIX_FMT_RGB565 },
62 };
63 
64 static enum AVPixelFormat get_pixfmt_from_fb_varinfo(struct fb_var_screeninfo *varinfo)
65 {
66  int i;
67 
68  for (i = 0; i < FF_ARRAY_ELEMS(rgb_pixfmt_map); i++) {
69  const struct rgb_pixfmt_map_entry *entry = &rgb_pixfmt_map[i];
70  if (entry->bits_per_pixel == varinfo->bits_per_pixel &&
71  entry->red_offset == varinfo->red.offset &&
72  entry->green_offset == varinfo->green.offset &&
73  entry->blue_offset == varinfo->blue.offset)
74  return entry->pixfmt;
75  }
76 
77  return AV_PIX_FMT_NONE;
78 }
79 
80 typedef struct {
81  AVClass *class; ///< class for private options
82  int frame_size; ///< size in bytes of a grabbed frame
83  AVRational framerate_q; ///< framerate
84  int64_t time_frame; ///< time for the next frame to output (in 1/1000000 units)
85 
86  int fd; ///< framebuffer device file descriptor
87  int width, height; ///< assumed frame resolution
88  int frame_linesize; ///< linesize of the output frame, it is assumed to be constant
90 
91  struct fb_var_screeninfo varinfo; ///< variable info;
92  struct fb_fix_screeninfo fixinfo; ///< fixed info;
93 
94  uint8_t *data; ///< framebuffer data
95 } FBDevContext;
96 
98 {
99  FBDevContext *fbdev = avctx->priv_data;
100  AVStream *st = NULL;
101  enum AVPixelFormat pix_fmt;
102  int ret, flags = O_RDONLY;
103 
104  if (!(st = avformat_new_stream(avctx, NULL)))
105  return AVERROR(ENOMEM);
106  avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in microseconds */
107 
108  /* NONBLOCK is ignored by the fbdev driver, only set for consistency */
109  if (avctx->flags & AVFMT_FLAG_NONBLOCK)
110  flags |= O_NONBLOCK;
111 
112  if ((fbdev->fd = avpriv_open(avctx->filename, flags)) == -1) {
113  ret = AVERROR(errno);
114  av_log(avctx, AV_LOG_ERROR,
115  "Could not open framebuffer device '%s': %s\n",
116  avctx->filename, av_err2str(ret));
117  return ret;
118  }
119 
120  if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0) {
121  ret = AVERROR(errno);
122  av_log(avctx, AV_LOG_ERROR,
123  "FBIOGET_VSCREENINFO: %s\n", av_err2str(ret));
124  goto fail;
125  }
126 
127  if (ioctl(fbdev->fd, FBIOGET_FSCREENINFO, &fbdev->fixinfo) < 0) {
128  ret = AVERROR(errno);
129  av_log(avctx, AV_LOG_ERROR,
130  "FBIOGET_FSCREENINFO: %s\n", av_err2str(ret));
131  goto fail;
132  }
133 
134  pix_fmt = get_pixfmt_from_fb_varinfo(&fbdev->varinfo);
135  if (pix_fmt == AV_PIX_FMT_NONE) {
136  ret = AVERROR(EINVAL);
137  av_log(avctx, AV_LOG_ERROR,
138  "Framebuffer pixel format not supported.\n");
139  goto fail;
140  }
141 
142  fbdev->width = fbdev->varinfo.xres;
143  fbdev->height = fbdev->varinfo.yres;
144  fbdev->bytes_per_pixel = (fbdev->varinfo.bits_per_pixel + 7) >> 3;
145  fbdev->frame_linesize = fbdev->width * fbdev->bytes_per_pixel;
146  fbdev->frame_size = fbdev->frame_linesize * fbdev->height;
147  fbdev->time_frame = AV_NOPTS_VALUE;
148  fbdev->data = mmap(NULL, fbdev->fixinfo.smem_len, PROT_READ, MAP_SHARED, fbdev->fd, 0);
149  if (fbdev->data == MAP_FAILED) {
150  ret = AVERROR(errno);
151  av_log(avctx, AV_LOG_ERROR, "Error in mmap(): %s\n", av_err2str(ret));
152  goto fail;
153  }
154 
157  st->codec->width = fbdev->width;
158  st->codec->height = fbdev->height;
159  st->codec->pix_fmt = pix_fmt;
160  st->codec->time_base = av_inv_q(fbdev->framerate_q);
161  st->codec->bit_rate =
162  fbdev->width * fbdev->height * fbdev->bytes_per_pixel * av_q2d(fbdev->framerate_q) * 8;
163 
164  av_log(avctx, AV_LOG_INFO,
165  "w:%d h:%d bpp:%d pixfmt:%s fps:%d/%d bit_rate:%d\n",
166  fbdev->width, fbdev->height, fbdev->varinfo.bits_per_pixel,
167  av_get_pix_fmt_name(pix_fmt),
168  fbdev->framerate_q.num, fbdev->framerate_q.den,
169  st->codec->bit_rate);
170  return 0;
171 
172 fail:
173  close(fbdev->fd);
174  return ret;
175 }
176 
178 {
179  FBDevContext *fbdev = avctx->priv_data;
180  int64_t curtime, delay;
181  struct timespec ts;
182  int i, ret;
183  uint8_t *pin, *pout;
184 
185  if (fbdev->time_frame == AV_NOPTS_VALUE)
186  fbdev->time_frame = av_gettime();
187 
188  /* wait based on the frame rate */
189  while (1) {
190  curtime = av_gettime();
191  delay = fbdev->time_frame - curtime;
192  av_dlog(avctx,
193  "time_frame:%"PRId64" curtime:%"PRId64" delay:%"PRId64"\n",
194  fbdev->time_frame, curtime, delay);
195  if (delay <= 0) {
196  fbdev->time_frame += INT64_C(1000000) / av_q2d(fbdev->framerate_q);
197  break;
198  }
199  if (avctx->flags & AVFMT_FLAG_NONBLOCK)
200  return AVERROR(EAGAIN);
201  ts.tv_sec = delay / 1000000;
202  ts.tv_nsec = (delay % 1000000) * 1000;
203  while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
204  }
205 
206  if ((ret = av_new_packet(pkt, fbdev->frame_size)) < 0)
207  return ret;
208 
209  /* refresh fbdev->varinfo, visible data position may change at each call */
210  if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0)
211  av_log(avctx, AV_LOG_WARNING,
212  "Error refreshing variable info: %s\n", av_err2str(ret));
213 
214  pkt->pts = curtime;
215 
216  /* compute visible data offset */
217  pin = fbdev->data + fbdev->bytes_per_pixel * fbdev->varinfo.xoffset +
218  fbdev->varinfo.yoffset * fbdev->fixinfo.line_length;
219  pout = pkt->data;
220 
221  for (i = 0; i < fbdev->height; i++) {
222  memcpy(pout, pin, fbdev->frame_linesize);
223  pin += fbdev->fixinfo.line_length;
224  pout += fbdev->frame_linesize;
225  }
226 
227  return fbdev->frame_size;
228 }
229 
231 {
232  FBDevContext *fbdev = avctx->priv_data;
233 
234  munmap(fbdev->data, fbdev->fixinfo.smem_len);
235  close(fbdev->fd);
236 
237  return 0;
238 }
239 
240 #define OFFSET(x) offsetof(FBDevContext, x)
241 #define DEC AV_OPT_FLAG_DECODING_PARAM
242 static const AVOption options[] = {
243  { "framerate","", OFFSET(framerate_q), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, 0, DEC },
244  { NULL },
245 };
246 
247 static const AVClass fbdev_class = {
248  .class_name = "fbdev indev",
249  .item_name = av_default_item_name,
250  .option = options,
251  .version = LIBAVUTIL_VERSION_INT,
252 };
253 
255  .name = "fbdev",
256  .long_name = NULL_IF_CONFIG_SMALL("Linux framebuffer"),
257  .priv_data_size = sizeof(FBDevContext),
261  .flags = AVFMT_NOFILE,
262  .priv_class = &fbdev_class,
263 };