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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 FBDevContext {
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  const char* device;
72 
73  if (!(st = avformat_new_stream(avctx, NULL)))
74  return AVERROR(ENOMEM);
75  avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in microseconds */
76 
77  /* NONBLOCK is ignored by the fbdev driver, only set for consistency */
78  if (avctx->flags & AVFMT_FLAG_NONBLOCK)
79  flags |= O_NONBLOCK;
80 
81  if (avctx->filename[0])
82  device = avctx->filename;
83  else
84  device = ff_fbdev_default_device();
85 
86  if ((fbdev->fd = avpriv_open(device, flags)) == -1) {
87  ret = AVERROR(errno);
88  av_log(avctx, AV_LOG_ERROR,
89  "Could not open framebuffer device '%s': %s\n",
90  device, av_err2str(ret));
91  return ret;
92  }
93 
94  if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0) {
95  ret = AVERROR(errno);
96  av_log(avctx, AV_LOG_ERROR,
97  "FBIOGET_VSCREENINFO: %s\n", av_err2str(ret));
98  goto fail;
99  }
100 
101  if (ioctl(fbdev->fd, FBIOGET_FSCREENINFO, &fbdev->fixinfo) < 0) {
102  ret = AVERROR(errno);
103  av_log(avctx, AV_LOG_ERROR,
104  "FBIOGET_FSCREENINFO: %s\n", av_err2str(ret));
105  goto fail;
106  }
107 
108  pix_fmt = ff_get_pixfmt_from_fb_varinfo(&fbdev->varinfo);
109  if (pix_fmt == AV_PIX_FMT_NONE) {
110  ret = AVERROR(EINVAL);
111  av_log(avctx, AV_LOG_ERROR,
112  "Framebuffer pixel format not supported.\n");
113  goto fail;
114  }
115 
116  fbdev->width = fbdev->varinfo.xres;
117  fbdev->height = fbdev->varinfo.yres;
118  fbdev->bytes_per_pixel = (fbdev->varinfo.bits_per_pixel + 7) >> 3;
119  fbdev->frame_linesize = fbdev->width * fbdev->bytes_per_pixel;
120  fbdev->frame_size = fbdev->frame_linesize * fbdev->height;
121  fbdev->time_frame = AV_NOPTS_VALUE;
122  fbdev->data = mmap(NULL, fbdev->fixinfo.smem_len, PROT_READ, MAP_SHARED, fbdev->fd, 0);
123  if (fbdev->data == MAP_FAILED) {
124  ret = AVERROR(errno);
125  av_log(avctx, AV_LOG_ERROR, "Error in mmap(): %s\n", av_err2str(ret));
126  goto fail;
127  }
128 
131  st->codec->width = fbdev->width;
132  st->codec->height = fbdev->height;
133  st->codec->pix_fmt = pix_fmt;
134  st->codec->time_base = av_inv_q(fbdev->framerate_q);
135  st->codec->bit_rate =
136  fbdev->width * fbdev->height * fbdev->bytes_per_pixel * av_q2d(fbdev->framerate_q) * 8;
137 
138  av_log(avctx, AV_LOG_INFO,
139  "w:%d h:%d bpp:%d pixfmt:%s fps:%d/%d bit_rate:%d\n",
140  fbdev->width, fbdev->height, fbdev->varinfo.bits_per_pixel,
141  av_get_pix_fmt_name(pix_fmt),
142  fbdev->framerate_q.num, fbdev->framerate_q.den,
143  st->codec->bit_rate);
144  return 0;
145 
146 fail:
147  close(fbdev->fd);
148  return ret;
149 }
150 
152 {
153  FBDevContext *fbdev = avctx->priv_data;
154  int64_t curtime, delay;
155  struct timespec ts;
156  int i, ret;
157  uint8_t *pin, *pout;
158 
159  if (fbdev->time_frame == AV_NOPTS_VALUE)
160  fbdev->time_frame = av_gettime();
161 
162  /* wait based on the frame rate */
163  while (1) {
164  curtime = av_gettime();
165  delay = fbdev->time_frame - curtime;
166  av_dlog(avctx,
167  "time_frame:%"PRId64" curtime:%"PRId64" delay:%"PRId64"\n",
168  fbdev->time_frame, curtime, delay);
169  if (delay <= 0) {
170  fbdev->time_frame += INT64_C(1000000) / av_q2d(fbdev->framerate_q);
171  break;
172  }
173  if (avctx->flags & AVFMT_FLAG_NONBLOCK)
174  return AVERROR(EAGAIN);
175  ts.tv_sec = delay / 1000000;
176  ts.tv_nsec = (delay % 1000000) * 1000;
177  while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
178  }
179 
180  if ((ret = av_new_packet(pkt, fbdev->frame_size)) < 0)
181  return ret;
182 
183  /* refresh fbdev->varinfo, visible data position may change at each call */
184  if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0) {
185  av_log(avctx, AV_LOG_WARNING,
186  "Error refreshing variable info: %s\n", av_err2str(AVERROR(errno)));
187  }
188 
189  pkt->pts = curtime;
190 
191  /* compute visible data offset */
192  pin = fbdev->data + fbdev->bytes_per_pixel * fbdev->varinfo.xoffset +
193  fbdev->varinfo.yoffset * fbdev->fixinfo.line_length;
194  pout = pkt->data;
195 
196  for (i = 0; i < fbdev->height; i++) {
197  memcpy(pout, pin, fbdev->frame_linesize);
198  pin += fbdev->fixinfo.line_length;
199  pout += fbdev->frame_linesize;
200  }
201 
202  return fbdev->frame_size;
203 }
204 
206 {
207  FBDevContext *fbdev = avctx->priv_data;
208 
209  munmap(fbdev->data, fbdev->fixinfo.smem_len);
210  close(fbdev->fd);
211 
212  return 0;
213 }
214 
216 {
217  return ff_fbdev_get_device_list(device_list);
218 }
219 
220 #define OFFSET(x) offsetof(FBDevContext, x)
221 #define DEC AV_OPT_FLAG_DECODING_PARAM
222 static const AVOption options[] = {
223  { "framerate","", OFFSET(framerate_q), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, 0, DEC },
224  { NULL },
225 };
226 
227 static const AVClass fbdev_class = {
228  .class_name = "fbdev indev",
229  .item_name = av_default_item_name,
230  .option = options,
231  .version = LIBAVUTIL_VERSION_INT,
233 };
234 
236  .name = "fbdev",
237  .long_name = NULL_IF_CONFIG_SMALL("Linux framebuffer"),
238  .priv_data_size = sizeof(FBDevContext),
243  .flags = AVFMT_NOFILE,
244  .priv_class = &fbdev_class,
245 };