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fbdev_dec.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 "libavformat/internal.h"
45 #include "avdevice.h"
46 #include "fbdev_common.h"
47 
48 typedef struct {
49  AVClass *class; ///< class for private options
50  int frame_size; ///< size in bytes of a grabbed frame
51  AVRational framerate_q; ///< framerate
52  int64_t time_frame; ///< time for the next frame to output (in 1/1000000 units)
53 
54  int fd; ///< framebuffer device file descriptor
55  int width, height; ///< assumed frame resolution
56  int frame_linesize; ///< linesize of the output frame, it is assumed to be constant
58 
59  struct fb_var_screeninfo varinfo; ///< variable info;
60  struct fb_fix_screeninfo fixinfo; ///< fixed info;
61 
62  uint8_t *data; ///< framebuffer data
63 } FBDevContext;
64 
66 {
67  FBDevContext *fbdev = avctx->priv_data;
68  AVStream *st = NULL;
70  int ret, flags = O_RDONLY;
71 
72  if (!(st = avformat_new_stream(avctx, NULL)))
73  return AVERROR(ENOMEM);
74  avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in microseconds */
75 
76  /* NONBLOCK is ignored by the fbdev driver, only set for consistency */
77  if (avctx->flags & AVFMT_FLAG_NONBLOCK)
78  flags |= O_NONBLOCK;
79 
80  if ((fbdev->fd = avpriv_open(avctx->filename, flags)) == -1) {
81  ret = AVERROR(errno);
82  av_log(avctx, AV_LOG_ERROR,
83  "Could not open framebuffer device '%s': %s\n",
84  avctx->filename, av_err2str(ret));
85  return ret;
86  }
87 
88  if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0) {
89  ret = AVERROR(errno);
90  av_log(avctx, AV_LOG_ERROR,
91  "FBIOGET_VSCREENINFO: %s\n", av_err2str(ret));
92  goto fail;
93  }
94 
95  if (ioctl(fbdev->fd, FBIOGET_FSCREENINFO, &fbdev->fixinfo) < 0) {
96  ret = AVERROR(errno);
97  av_log(avctx, AV_LOG_ERROR,
98  "FBIOGET_FSCREENINFO: %s\n", av_err2str(ret));
99  goto fail;
100  }
101 
102  pix_fmt = ff_get_pixfmt_from_fb_varinfo(&fbdev->varinfo);
103  if (pix_fmt == AV_PIX_FMT_NONE) {
104  ret = AVERROR(EINVAL);
105  av_log(avctx, AV_LOG_ERROR,
106  "Framebuffer pixel format not supported.\n");
107  goto fail;
108  }
109 
110  fbdev->width = fbdev->varinfo.xres;
111  fbdev->height = fbdev->varinfo.yres;
112  fbdev->bytes_per_pixel = (fbdev->varinfo.bits_per_pixel + 7) >> 3;
113  fbdev->frame_linesize = fbdev->width * fbdev->bytes_per_pixel;
114  fbdev->frame_size = fbdev->frame_linesize * fbdev->height;
115  fbdev->time_frame = AV_NOPTS_VALUE;
116  fbdev->data = mmap(NULL, fbdev->fixinfo.smem_len, PROT_READ, MAP_SHARED, fbdev->fd, 0);
117  if (fbdev->data == MAP_FAILED) {
118  ret = AVERROR(errno);
119  av_log(avctx, AV_LOG_ERROR, "Error in mmap(): %s\n", av_err2str(ret));
120  goto fail;
121  }
122 
125  st->codec->width = fbdev->width;
126  st->codec->height = fbdev->height;
127  st->codec->pix_fmt = pix_fmt;
128  st->codec->time_base = av_inv_q(fbdev->framerate_q);
129  st->codec->bit_rate =
130  fbdev->width * fbdev->height * fbdev->bytes_per_pixel * av_q2d(fbdev->framerate_q) * 8;
131 
132  av_log(avctx, AV_LOG_INFO,
133  "w:%d h:%d bpp:%d pixfmt:%s fps:%d/%d bit_rate:%d\n",
134  fbdev->width, fbdev->height, fbdev->varinfo.bits_per_pixel,
135  av_get_pix_fmt_name(pix_fmt),
136  fbdev->framerate_q.num, fbdev->framerate_q.den,
137  st->codec->bit_rate);
138  return 0;
139 
140 fail:
141  close(fbdev->fd);
142  return ret;
143 }
144 
146 {
147  FBDevContext *fbdev = avctx->priv_data;
148  int64_t curtime, delay;
149  struct timespec ts;
150  int i, ret;
151  uint8_t *pin, *pout;
152 
153  if (fbdev->time_frame == AV_NOPTS_VALUE)
154  fbdev->time_frame = av_gettime();
155 
156  /* wait based on the frame rate */
157  while (1) {
158  curtime = av_gettime();
159  delay = fbdev->time_frame - curtime;
160  av_dlog(avctx,
161  "time_frame:%"PRId64" curtime:%"PRId64" delay:%"PRId64"\n",
162  fbdev->time_frame, curtime, delay);
163  if (delay <= 0) {
164  fbdev->time_frame += INT64_C(1000000) / av_q2d(fbdev->framerate_q);
165  break;
166  }
167  if (avctx->flags & AVFMT_FLAG_NONBLOCK)
168  return AVERROR(EAGAIN);
169  ts.tv_sec = delay / 1000000;
170  ts.tv_nsec = (delay % 1000000) * 1000;
171  while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
172  }
173 
174  if ((ret = av_new_packet(pkt, fbdev->frame_size)) < 0)
175  return ret;
176 
177  /* refresh fbdev->varinfo, visible data position may change at each call */
178  if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0)
179  av_log(avctx, AV_LOG_WARNING,
180  "Error refreshing variable info: %s\n", av_err2str(ret));
181 
182  pkt->pts = curtime;
183 
184  /* compute visible data offset */
185  pin = fbdev->data + fbdev->bytes_per_pixel * fbdev->varinfo.xoffset +
186  fbdev->varinfo.yoffset * fbdev->fixinfo.line_length;
187  pout = pkt->data;
188 
189  for (i = 0; i < fbdev->height; i++) {
190  memcpy(pout, pin, fbdev->frame_linesize);
191  pin += fbdev->fixinfo.line_length;
192  pout += fbdev->frame_linesize;
193  }
194 
195  return fbdev->frame_size;
196 }
197 
199 {
200  FBDevContext *fbdev = avctx->priv_data;
201 
202  munmap(fbdev->data, fbdev->fixinfo.smem_len);
203  close(fbdev->fd);
204 
205  return 0;
206 }
207 
208 #define OFFSET(x) offsetof(FBDevContext, x)
209 #define DEC AV_OPT_FLAG_DECODING_PARAM
210 static const AVOption options[] = {
211  { "framerate","", OFFSET(framerate_q), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, 0, DEC },
212  { NULL },
213 };
214 
215 static const AVClass fbdev_class = {
216  .class_name = "fbdev indev",
217  .item_name = av_default_item_name,
218  .option = options,
219  .version = LIBAVUTIL_VERSION_INT,
220 };
221 
223  .name = "fbdev",
224  .long_name = NULL_IF_CONFIG_SMALL("Linux framebuffer"),
225  .priv_data_size = sizeof(FBDevContext),
229  .flags = AVFMT_NOFILE,
230  .priv_class = &fbdev_class,
231 };