Libav
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 #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 "libavformat/avformat.h"
45 #include "libavformat/internal.h"
46 
51 };
52 
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 };
62 
63 static enum AVPixelFormat get_pixfmt_from_fb_varinfo(struct fb_var_screeninfo *varinfo)
64 {
65  int i;
66 
67  for (i = 0; i < FF_ARRAY_ELEMS(rgb_pixfmt_map); i++) {
68  struct rgb_pixfmt_map_entry *entry = &rgb_pixfmt_map[i];
69  if (entry->bits_per_pixel == varinfo->bits_per_pixel &&
70  entry->red_offset == varinfo->red.offset &&
71  entry->green_offset == varinfo->green.offset &&
72  entry->blue_offset == varinfo->blue.offset)
73  return entry->pixfmt;
74  }
75 
76  return AV_PIX_FMT_NONE;
77 }
78 
79 typedef struct {
80  AVClass *class;
81  int frame_size;
83  char *framerate;
84  int64_t time_frame;
85 
86  int fd;
87  int width, height;
90 
91  struct fb_var_screeninfo varinfo;
92  struct fb_fix_screeninfo fixinfo;
93 
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  ret = av_parse_video_rate(&fbdev->framerate_q, fbdev->framerate);
105  if (ret < 0) {
106  av_log(avctx, AV_LOG_ERROR, "Could not parse framerate '%s'.\n", fbdev->framerate);
107  return ret;
108  }
109 
110  if (!(st = avformat_new_stream(avctx, NULL)))
111  return AVERROR(ENOMEM);
112  avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in microseconds */
113 
114  /* NONBLOCK is ignored by the fbdev driver, only set for consistency */
115  if (avctx->flags & AVFMT_FLAG_NONBLOCK)
116  flags |= O_NONBLOCK;
117 
118  if ((fbdev->fd = avpriv_open(avctx->filename, flags)) == -1) {
119  ret = AVERROR(errno);
120  av_log(avctx, AV_LOG_ERROR,
121  "Could not open framebuffer device '%s': %s\n",
122  avctx->filename, strerror(ret));
123  return ret;
124  }
125 
126  if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0) {
127  ret = AVERROR(errno);
128  av_log(avctx, AV_LOG_ERROR,
129  "FBIOGET_VSCREENINFO: %s\n", strerror(errno));
130  goto fail;
131  }
132 
133  if (ioctl(fbdev->fd, FBIOGET_FSCREENINFO, &fbdev->fixinfo) < 0) {
134  ret = AVERROR(errno);
135  av_log(avctx, AV_LOG_ERROR,
136  "FBIOGET_FSCREENINFO: %s\n", strerror(errno));
137  goto fail;
138  }
139 
140  pix_fmt = get_pixfmt_from_fb_varinfo(&fbdev->varinfo);
141  if (pix_fmt == AV_PIX_FMT_NONE) {
142  ret = AVERROR(EINVAL);
143  av_log(avctx, AV_LOG_ERROR,
144  "Framebuffer pixel format not supported.\n");
145  goto fail;
146  }
147 
148  fbdev->width = fbdev->varinfo.xres;
149  fbdev->height = fbdev->varinfo.yres;
150  fbdev->bytes_per_pixel = (fbdev->varinfo.bits_per_pixel + 7) >> 3;
151  fbdev->frame_linesize = fbdev->width * fbdev->bytes_per_pixel;
152  fbdev->frame_size = fbdev->frame_linesize * fbdev->height;
153  fbdev->time_frame = AV_NOPTS_VALUE;
154  fbdev->data = mmap(NULL, fbdev->fixinfo.smem_len, PROT_READ, MAP_SHARED, fbdev->fd, 0);
155  if (fbdev->data == MAP_FAILED) {
156  ret = AVERROR(errno);
157  av_log(avctx, AV_LOG_ERROR, "Error in mmap(): %s\n", strerror(errno));
158  goto fail;
159  }
160 
163  st->codec->width = fbdev->width;
164  st->codec->height = fbdev->height;
165  st->codec->pix_fmt = pix_fmt;
166  st->codec->time_base = (AVRational){fbdev->framerate_q.den, fbdev->framerate_q.num};
167  st->codec->bit_rate =
168  fbdev->width * fbdev->height * fbdev->bytes_per_pixel * av_q2d(fbdev->framerate_q) * 8;
169 
170  av_log(avctx, AV_LOG_INFO,
171  "w:%d h:%d bpp:%d pixfmt:%s fps:%d/%d bit_rate:%d\n",
172  fbdev->width, fbdev->height, fbdev->varinfo.bits_per_pixel,
173  av_get_pix_fmt_name(pix_fmt),
174  fbdev->framerate_q.num, fbdev->framerate_q.den,
175  st->codec->bit_rate);
176  return 0;
177 
178 fail:
179  close(fbdev->fd);
180  return ret;
181 }
182 
184 {
185  FBDevContext *fbdev = avctx->priv_data;
186  int64_t curtime, delay;
187  struct timespec ts;
188  int i, ret;
189  uint8_t *pin, *pout;
190 
191  if (fbdev->time_frame == AV_NOPTS_VALUE)
192  fbdev->time_frame = av_gettime();
193 
194  /* wait based on the frame rate */
195  curtime = av_gettime();
196  delay = fbdev->time_frame - curtime;
197  av_dlog(avctx,
198  "time_frame:%"PRId64" curtime:%"PRId64" delay:%"PRId64"\n",
199  fbdev->time_frame, curtime, delay);
200  if (delay > 0) {
201  if (avctx->flags & AVFMT_FLAG_NONBLOCK)
202  return AVERROR(EAGAIN);
203  ts.tv_sec = delay / 1000000;
204  ts.tv_nsec = (delay % 1000000) * 1000;
205  while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
206  }
207  /* compute the time of the next frame */
208  fbdev->time_frame += INT64_C(1000000) / av_q2d(fbdev->framerate_q);
209 
210  if ((ret = av_new_packet(pkt, fbdev->frame_size)) < 0)
211  return ret;
212 
213  /* refresh fbdev->varinfo, visible data position may change at each call */
214  if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0)
215  av_log(avctx, AV_LOG_WARNING,
216  "Error refreshing variable info: %s\n", strerror(errno));
217 
218  pkt->pts = curtime;
219 
220  /* compute visible data offset */
221  pin = fbdev->data + fbdev->bytes_per_pixel * fbdev->varinfo.xoffset +
222  fbdev->varinfo.yoffset * fbdev->fixinfo.line_length;
223  pout = pkt->data;
224 
225  // TODO it'd be nice if the lines were aligned
226  for (i = 0; i < fbdev->height; i++) {
227  memcpy(pout, pin, fbdev->frame_linesize);
228  pin += fbdev->fixinfo.line_length;
229  pout += fbdev->frame_linesize;
230  }
231 
232  return fbdev->frame_size;
233 }
234 
236 {
237  FBDevContext *fbdev = avctx->priv_data;
238 
239  munmap(fbdev->data, fbdev->frame_size);
240  close(fbdev->fd);
241 
242  return 0;
243 }
244 
245 #define OFFSET(x) offsetof(FBDevContext, x)
246 #define DEC AV_OPT_FLAG_DECODING_PARAM
247 static const AVOption options[] = {
248  { "framerate","", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = "25"}, 0, 0, DEC },
249  { NULL },
250 };
251 
252 static const AVClass fbdev_class = {
253  .class_name = "fbdev indev",
254  .item_name = av_default_item_name,
255  .option = options,
256  .version = LIBAVUTIL_VERSION_INT,
257 };
258 
260  .name = "fbdev",
261  .long_name = NULL_IF_CONFIG_SMALL("Linux framebuffer"),
262  .priv_data_size = sizeof(FBDevContext),
266  .flags = AVFMT_NOFILE,
267  .priv_class = &fbdev_class,
268 };