FFmpeg
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->url[0])
82  device = avctx->url;
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->codecpar->width = fbdev->width;
132  st->codecpar->height = fbdev->height;
133  st->codecpar->format = pix_fmt;
134  st->avg_frame_rate = fbdev->framerate_q;
135  st->codecpar->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:%"PRId64"\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->codecpar->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_log(avctx, AV_LOG_TRACE,
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, INT_MAX, 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),
242  .get_device_list = fbdev_get_device_list,
243  .flags = AVFMT_NOFILE,
244  .priv_class = &fbdev_class,
245 };
int height
assumed frame resolution
Definition: fbdev_dec.c:55
#define DEC
Definition: fbdev_dec.c:221
#define NULL
Definition: coverity.c:32
static enum AVPixelFormat pix_fmt
AVOption.
Definition: opt.h:246
static const AVClass fbdev_class
Definition: fbdev_dec.c:227
#define AV_LOG_WARNING
Something somehow does not look correct.
Definition: log.h:182
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
Memory handling functions.
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4882
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3953
int num
Numerator.
Definition: rational.h:59
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:191
static AVPacket pkt
const char * ff_fbdev_default_device()
Definition: fbdev_common.c:64
int frame_linesize
linesize of the output frame, it is assumed to be constant
Definition: fbdev_dec.c:56
#define OFFSET(x)
Definition: fbdev_dec.c:220
int frame_size
size in bytes of a grabbed frame
Definition: fbdev_dec.c:50
Format I/O context.
Definition: avformat.h:1358
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
#define AVFMT_FLAG_NONBLOCK
Do not block when reading packets from input.
Definition: avformat.h:1492
uint8_t
#define av_cold
Definition: attributes.h:82
int width
Video only.
Definition: avcodec.h:4019
AVOptions.
#define AV_LOG_TRACE
Extremely verbose debugging, useful for libav* development.
Definition: log.h:202
struct fb_var_screeninfo varinfo
variable info;
Definition: fbdev_dec.c:59
AVStream * avformat_new_stream(AVFormatContext *s, const AVCodec *c)
Add a new stream to a media file.
Definition: utils.c:4455
int avpriv_open(const char *filename, int flags,...)
A wrapper for open() setting O_CLOEXEC.
Definition: file_open.c:66
int64_t time_frame
time for the next frame to output (in 1/1000000 units)
Definition: fbdev_dec.c:52
int flags
Flags modifying the (de)muxer behaviour.
Definition: avformat.h:1489
uint8_t * data
Definition: avcodec.h:1477
static double av_q2d(AVRational a)
Convert an AVRational to a double.
Definition: rational.h:104
static av_cold int read_close(AVFormatContext *ctx)
Definition: libcdio.c:145
#define av_log(a,...)
int64_t bit_rate
The average bitrate of the encoded data (in bits per second).
Definition: avcodec.h:3982
Main libavdevice API header.
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition: avpacket.c:86
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:260
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
char * url
input or output URL.
Definition: avformat.h:1454
static int fbdev_read_packet(AVFormatContext *avctx, AVPacket *pkt)
Definition: fbdev_dec.c:151
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3949
AVRational avg_frame_rate
Average framerate.
Definition: avformat.h:954
static av_cold int fbdev_read_close(AVFormatContext *avctx)
Definition: fbdev_dec.c:205
#define fail()
Definition: checkasm.h:120
struct fb_fix_screeninfo fixinfo
fixed info;
Definition: fbdev_dec.c:60
common internal API header
static const AVOption options[]
Definition: fbdev_dec.c:222
#define av_err2str(errnum)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: error.h:119
#define s(width, name)
Definition: cbs_vp9.c:257
AVRational framerate_q
framerate
Definition: fbdev_dec.c:51
static int read_header(FFV1Context *f)
Definition: ffv1dec.c:530
int64_t av_gettime(void)
Get the current time in microseconds.
Definition: time.c:39
Stream structure.
Definition: avformat.h:881
static int read_packet(void *opaque, uint8_t *buf, int buf_size)
Definition: avio_reading.c:42
#define AV_LOG_INFO
Standard information.
Definition: log.h:187
AVInputFormat ff_fbdev_demuxer
Definition: fbdev_dec.c:235
int bytes_per_pixel
Definition: fbdev_dec.c:57
int ff_fbdev_get_device_list(AVDeviceInfoList *device_list)
Definition: fbdev_common.c:72
static int fbdev_get_device_list(AVFormatContext *s, AVDeviceInfoList *device_list)
Definition: fbdev_dec.c:215
Describe the class of an AVClass context structure.
Definition: log.h:67
Rational number (pair of numerator and denominator).
Definition: rational.h:58
offset must point to AVRational
Definition: opt.h:236
misc parsing utilities
List of devices.
Definition: avdevice.h:460
#define flags(name, subs,...)
Definition: cbs_av1.c:561
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:463
enum AVPixelFormat ff_get_pixfmt_from_fb_varinfo(struct fb_var_screeninfo *varinfo)
Definition: fbdev_common.c:48
int den
Denominator.
Definition: rational.h:60
static av_cold int fbdev_read_header(AVFormatContext *avctx)
Definition: fbdev_dec.c:65
void * priv_data
Format private data.
Definition: avformat.h:1386
uint8_t * data
framebuffer data
Definition: fbdev_dec.c:62
const char * name
A comma separated list of short names for the format.
Definition: avformat.h:654
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
const char * av_get_pix_fmt_name(enum AVPixelFormat pix_fmt)
Return the short name for a pixel format, NULL in case pix_fmt is unknown.
Definition: pixdesc.c:2438
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
This structure stores compressed data.
Definition: avcodec.h:1454
int fd
framebuffer device file descriptor
Definition: fbdev_dec.c:54
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: avcodec.h:1470
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248