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 Libav.
7  *
8  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
30 /* #define DEBUG */
31 
32 #include <unistd.h>
33 #include <fcntl.h>
34 #include <sys/ioctl.h>
35 #include <sys/time.h>
36 #include <sys/mman.h>
37 #include <time.h>
38 #include <linux/fb.h>
39 
40 #include "libavutil/log.h"
41 #include "libavutil/mem.h"
42 #include "libavutil/opt.h"
43 #include "libavutil/parseutils.h"
44 #include "libavutil/pixdesc.h"
45 #include "libavformat/avformat.h"
46 #include "libavformat/internal.h"
47 
52 };
53 
55  // bpp, red_offset, green_offset, blue_offset, alpha_offset, pixfmt
56  { 32, 0, 8, 16, 24, PIX_FMT_RGBA },
57  { 32, 16, 8, 0, 24, PIX_FMT_BGRA },
58  { 32, 8, 16, 24, 0, PIX_FMT_ARGB },
59  { 32, 3, 2, 8, 0, PIX_FMT_ABGR },
60  { 24, 0, 8, 16, 0, PIX_FMT_RGB24 },
61  { 24, 16, 8, 0, 0, PIX_FMT_BGR24 },
62 };
63 
64 static enum PixelFormat 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  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 PIX_FMT_NONE;
78 }
79 
80 typedef struct {
81  AVClass *class;
82  int frame_size;
84  char *framerate;
85  int64_t time_frame;
86 
87  int fd;
88  int width, height;
91 
92  struct fb_var_screeninfo varinfo;
93  struct fb_fix_screeninfo fixinfo;
94 
95  uint8_t *data;
96 } FBDevContext;
97 
100 {
101  FBDevContext *fbdev = avctx->priv_data;
102  AVStream *st = NULL;
103  enum PixelFormat pix_fmt;
104  int ret, flags = O_RDONLY;
105 
106  ret = av_parse_video_rate(&fbdev->framerate_q, fbdev->framerate);
107  if (ret < 0) {
108  av_log(avctx, AV_LOG_ERROR, "Could not parse framerate '%s'.\n", fbdev->framerate);
109  return ret;
110  }
111 
112  if (!(st = avformat_new_stream(avctx, NULL)))
113  return AVERROR(ENOMEM);
114  avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in microseconds */
115 
116  /* NONBLOCK is ignored by the fbdev driver, only set for consistency */
117  if (avctx->flags & AVFMT_FLAG_NONBLOCK)
118  flags |= O_NONBLOCK;
119 
120  if ((fbdev->fd = open(avctx->filename, flags)) == -1) {
121  ret = AVERROR(errno);
122  av_log(avctx, AV_LOG_ERROR,
123  "Could not open framebuffer device '%s': %s\n",
124  avctx->filename, strerror(ret));
125  return ret;
126  }
127 
128  if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0) {
129  ret = AVERROR(errno);
130  av_log(avctx, AV_LOG_ERROR,
131  "FBIOGET_VSCREENINFO: %s\n", strerror(errno));
132  goto fail;
133  }
134 
135  if (ioctl(fbdev->fd, FBIOGET_FSCREENINFO, &fbdev->fixinfo) < 0) {
136  ret = AVERROR(errno);
137  av_log(avctx, AV_LOG_ERROR,
138  "FBIOGET_FSCREENINFO: %s\n", strerror(errno));
139  goto fail;
140  }
141 
142  pix_fmt = get_pixfmt_from_fb_varinfo(&fbdev->varinfo);
143  if (pix_fmt == PIX_FMT_NONE) {
144  ret = AVERROR(EINVAL);
145  av_log(avctx, AV_LOG_ERROR,
146  "Framebuffer pixel format not supported.\n");
147  goto fail;
148  }
149 
150  fbdev->width = fbdev->varinfo.xres;
151  fbdev->height = fbdev->varinfo.yres;
152  fbdev->bytes_per_pixel = (fbdev->varinfo.bits_per_pixel + 7) >> 3;
153  fbdev->frame_linesize = fbdev->width * fbdev->bytes_per_pixel;
154  fbdev->frame_size = fbdev->frame_linesize * fbdev->height;
155  fbdev->time_frame = AV_NOPTS_VALUE;
156  fbdev->data = mmap(NULL, fbdev->fixinfo.smem_len, PROT_READ, MAP_SHARED, fbdev->fd, 0);
157  if (fbdev->data == MAP_FAILED) {
158  ret = AVERROR(errno);
159  av_log(avctx, AV_LOG_ERROR, "Error in mmap(): %s\n", strerror(errno));
160  goto fail;
161  }
162 
165  st->codec->width = fbdev->width;
166  st->codec->height = fbdev->height;
167  st->codec->pix_fmt = pix_fmt;
168  st->codec->time_base = (AVRational){fbdev->framerate_q.den, fbdev->framerate_q.num};
169  st->codec->bit_rate =
170  fbdev->width * fbdev->height * fbdev->bytes_per_pixel * av_q2d(fbdev->framerate_q) * 8;
171 
172  av_log(avctx, AV_LOG_INFO,
173  "w:%d h:%d bpp:%d pixfmt:%s fps:%d/%d bit_rate:%d\n",
174  fbdev->width, fbdev->height, fbdev->varinfo.bits_per_pixel,
175  av_pix_fmt_descriptors[pix_fmt].name,
176  fbdev->framerate_q.num, fbdev->framerate_q.den,
177  st->codec->bit_rate);
178  return 0;
179 
180 fail:
181  close(fbdev->fd);
182  return ret;
183 }
184 
186 {
187  FBDevContext *fbdev = avctx->priv_data;
188  int64_t curtime, delay;
189  struct timespec ts;
190  int i, ret;
191  uint8_t *pin, *pout;
192 
193  if (fbdev->time_frame == AV_NOPTS_VALUE)
194  fbdev->time_frame = av_gettime();
195 
196  /* wait based on the frame rate */
197  curtime = av_gettime();
198  delay = fbdev->time_frame - curtime;
199  av_dlog(avctx,
200  "time_frame:%"PRId64" curtime:%"PRId64" delay:%"PRId64"\n",
201  fbdev->time_frame, curtime, delay);
202  if (delay > 0) {
203  if (avctx->flags & AVFMT_FLAG_NONBLOCK)
204  return AVERROR(EAGAIN);
205  ts.tv_sec = delay / 1000000;
206  ts.tv_nsec = (delay % 1000000) * 1000;
207  while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
208  }
209  /* compute the time of the next frame */
210  fbdev->time_frame += INT64_C(1000000) / av_q2d(fbdev->framerate_q);
211 
212  if ((ret = av_new_packet(pkt, fbdev->frame_size)) < 0)
213  return ret;
214 
215  /* refresh fbdev->varinfo, visible data position may change at each call */
216  if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0)
217  av_log(avctx, AV_LOG_WARNING,
218  "Error refreshing variable info: %s\n", strerror(errno));
219 
220  pkt->pts = curtime;
221 
222  /* compute visible data offset */
223  pin = fbdev->data + fbdev->bytes_per_pixel * fbdev->varinfo.xoffset +
224  fbdev->varinfo.yoffset * fbdev->fixinfo.line_length;
225  pout = pkt->data;
226 
227  // TODO it'd be nice if the lines were aligned
228  for (i = 0; i < fbdev->height; i++) {
229  memcpy(pout, pin, fbdev->frame_linesize);
230  pin += fbdev->fixinfo.line_length;
231  pout += fbdev->frame_linesize;
232  }
233 
234  return fbdev->frame_size;
235 }
236 
238 {
239  FBDevContext *fbdev = avctx->priv_data;
240 
241  munmap(fbdev->data, fbdev->frame_size);
242  close(fbdev->fd);
243 
244  return 0;
245 }
246 
247 #define OFFSET(x) offsetof(FBDevContext, x)
248 #define DEC AV_OPT_FLAG_DECODING_PARAM
249 static const AVOption options[] = {
250  { "framerate","", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = "25"}, 0, 0, DEC },
251  { NULL },
252 };
253 
254 static const AVClass fbdev_class = {
255  .class_name = "fbdev indev",
256  .item_name = av_default_item_name,
257  .option = options,
258  .version = LIBAVUTIL_VERSION_INT,
259 };
260 
262  .name = "fbdev",
263  .long_name = NULL_IF_CONFIG_SMALL("Linux framebuffer"),
264  .priv_data_size = sizeof(FBDevContext),
268  .flags = AVFMT_NOFILE,
269  .priv_class = &fbdev_class,
270 };