libavdevice/fbdev.c

   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
  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 /* #define DEBUG */
  31
  32 #include <unistd.h>
  33 #include <fcntl.h>
  34 #include <sys/ioctl.h>
  35 #include <sys/mman.h>
  36 #include <time.h>
  37 #include <linux/fb.h>
  38
  39 #include "libavutil/log.h"
  40 #include "libavutil/mem.h"
  41 #include "libavutil/opt.h"
  42 #include "libavutil/time.h"
  43 #include "libavutil/parseutils.h"
  44 #include "libavutil/pixdesc.h"
  45 #include "libavformat/avformat.h"
  46 #include "libavformat/internal.h"
  47
  48 struct rgb_pixfmt_map_entry {
  49     int bits_per_pixel;
  50     int red_offset, green_offset, blue_offset, alpha_offset;
  51     enum AVPixelFormat pixfmt;
  52 };
  53
  54 static struct rgb_pixfmt_map_entry rgb_pixfmt_map[] = {
  55     // bpp, red_offset,  green_offset, blue_offset, alpha_offset, pixfmt
  56     {  32,       0,           8,          16,           24,   AV_PIX_FMT_RGBA  },
  57     {  32,      16,           8,           0,           24,   AV_PIX_FMT_BGRA  },
  58     {  32,       8,          16,          24,            0,   AV_PIX_FMT_ARGB  },
  59     {  32,       3,           2,           8,            0,   AV_PIX_FMT_ABGR  },
  60     {  24,       0,           8,          16,            0,   AV_PIX_FMT_RGB24 },
  61     {  24,      16,           8,           0,            0,   AV_PIX_FMT_BGR24 },
  62 };
  63
  64 static enum AVPixelFormat 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 AV_PIX_FMT_NONE;
  78 }
  79
  80 typedef struct {
  81     AVClass *class;          ///< class for private options
  82     int frame_size;          ///< size in bytes of a grabbed frame
  83     AVRational framerate_q;  ///< framerate
  84     char *framerate;         ///< framerate string set by a private option
  85     int64_t time_frame;      ///< time for the next frame to output (in 1/1000000 units)
  86
  87     int fd;                  ///< framebuffer device file descriptor
  88     int width, height;       ///< assumed frame resolution
  89     int frame_linesize;      ///< linesize of the output frame, it is assumed to be constant
  90     int bytes_per_pixel;
  91
  92     struct fb_var_screeninfo varinfo; ///< variable info;
  93     struct fb_fix_screeninfo fixinfo; ///< fixed    info;
  94
  95     uint8_t *data;           ///< framebuffer data
  96 } FBDevContext;
  97
  98 static av_cold int fbdev_read_header(AVFormatContext *avctx)
  99 {
 100     FBDevContext *fbdev = avctx->priv_data;
 101     AVStream *st = NULL;
 102     enum AVPixelFormat pix_fmt;
 103     int ret, flags = O_RDONLY;
 104
 105     ret = av_parse_video_rate(&fbdev->framerate_q, fbdev->framerate);
 106     if (ret < 0) {
 107         av_log(avctx, AV_LOG_ERROR, "Could not parse framerate '%s'.\n", fbdev->framerate);
 108         return ret;
 109     }
 110
 111     if (!(st = avformat_new_stream(avctx, NULL)))
 112         return AVERROR(ENOMEM);
 113     avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in microseconds */
 114
 115     /* NONBLOCK is ignored by the fbdev driver, only set for consistency */
 116     if (avctx->flags & AVFMT_FLAG_NONBLOCK)
 117         flags |= O_NONBLOCK;
 118
 119     if ((fbdev->fd = open(avctx->filename, flags)) == -1) {
 120         ret = AVERROR(errno);
 121         av_log(avctx, AV_LOG_ERROR,
 122                "Could not open framebuffer device '%s': %s\n",
 123                avctx->filename, strerror(ret));
 124         return ret;
 125     }
 126
 127     if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0) {
 128         ret = AVERROR(errno);
 129         av_log(avctx, AV_LOG_ERROR,
 130                "FBIOGET_VSCREENINFO: %s\n", strerror(errno));
 131         goto fail;
 132     }
 133
 134     if (ioctl(fbdev->fd, FBIOGET_FSCREENINFO, &fbdev->fixinfo) < 0) {
 135         ret = AVERROR(errno);
 136         av_log(avctx, AV_LOG_ERROR,
 137                "FBIOGET_FSCREENINFO: %s\n", strerror(errno));
 138         goto fail;
 139     }
 140
 141     pix_fmt = get_pixfmt_from_fb_varinfo(&fbdev->varinfo);
 142     if (pix_fmt == AV_PIX_FMT_NONE) {
 143         ret = AVERROR(EINVAL);
 144         av_log(avctx, AV_LOG_ERROR,
 145                "Framebuffer pixel format not supported.\n");
 146         goto fail;
 147     }
 148
 149     fbdev->width           = fbdev->varinfo.xres;
 150     fbdev->height          = fbdev->varinfo.yres;
 151     fbdev->bytes_per_pixel = (fbdev->varinfo.bits_per_pixel + 7) >> 3;
 152     fbdev->frame_linesize  = fbdev->width * fbdev->bytes_per_pixel;
 153     fbdev->frame_size      = fbdev->frame_linesize * fbdev->height;
 154     fbdev->time_frame      = AV_NOPTS_VALUE;
 155     fbdev->data = mmap(NULL, fbdev->fixinfo.smem_len, PROT_READ, MAP_SHARED, fbdev->fd, 0);
 156     if (fbdev->data == MAP_FAILED) {
 157         ret = AVERROR(errno);
 158         av_log(avctx, AV_LOG_ERROR, "Error in mmap(): %s\n", strerror(errno));
 159         goto fail;
 160     }
 161
 162     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
 163     st->codec->codec_id   = AV_CODEC_ID_RAWVIDEO;
 164     st->codec->width      = fbdev->width;
 165     st->codec->height     = fbdev->height;
 166     st->codec->pix_fmt    = pix_fmt;
 167     st->codec->time_base  = (AVRational){fbdev->framerate_q.den, fbdev->framerate_q.num};
 168     st->codec->bit_rate   =
 169         fbdev->width * fbdev->height * fbdev->bytes_per_pixel * av_q2d(fbdev->framerate_q) * 8;
 170
 171     av_log(avctx, AV_LOG_INFO,
 172            "w:%d h:%d bpp:%d pixfmt:%s fps:%d/%d bit_rate:%d\n",
 173            fbdev->width, fbdev->height, fbdev->varinfo.bits_per_pixel,
 174            av_get_pix_fmt_name(pix_fmt),
 175            fbdev->framerate_q.num, fbdev->framerate_q.den,
 176            st->codec->bit_rate);
 177     return 0;
 178
 179 fail:
 180     close(fbdev->fd);
 181     return ret;
 182 }
 183
 184 static int fbdev_read_packet(AVFormatContext *avctx, AVPacket *pkt)
 185 {
 186     FBDevContext *fbdev = avctx->priv_data;
 187     int64_t curtime, delay;
 188     struct timespec ts;
 189     int i, ret;
 190     uint8_t *pin, *pout;
 191
 192     if (fbdev->time_frame == AV_NOPTS_VALUE)
 193         fbdev->time_frame = av_gettime();
 194
 195     /* wait based on the frame rate */
 196     curtime = av_gettime();
 197     delay = fbdev->time_frame - curtime;
 198     av_dlog(avctx,
 199             "time_frame:%"PRId64" curtime:%"PRId64" delay:%"PRId64"\n",
 200             fbdev->time_frame, curtime, delay);
 201     if (delay > 0) {
 202         if (avctx->flags & AVFMT_FLAG_NONBLOCK)
 203             return AVERROR(EAGAIN);
 204         ts.tv_sec  =  delay / 1000000;
 205         ts.tv_nsec = (delay % 1000000) * 1000;
 206         while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
 207     }
 208     /* compute the time of the next frame */
 209     fbdev->time_frame += INT64_C(1000000) / av_q2d(fbdev->framerate_q);
 210
 211     if ((ret = av_new_packet(pkt, fbdev->frame_size)) < 0)
 212         return ret;
 213
 214     /* refresh fbdev->varinfo, visible data position may change at each call */
 215     if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0)
 216         av_log(avctx, AV_LOG_WARNING,
 217                "Error refreshing variable info: %s\n", strerror(errno));
 218
 219     pkt->pts = curtime;
 220
 221     /* compute visible data offset */
 222     pin = fbdev->data + fbdev->bytes_per_pixel * fbdev->varinfo.xoffset +
 223                         fbdev->varinfo.yoffset * fbdev->fixinfo.line_length;
 224     pout = pkt->data;
 225
 226     // TODO it'd be nice if the lines were aligned
 227     for (i = 0; i < fbdev->height; i++) {
 228         memcpy(pout, pin, fbdev->frame_linesize);
 229         pin  += fbdev->fixinfo.line_length;
 230         pout += fbdev->frame_linesize;
 231     }
 232
 233     return fbdev->frame_size;
 234 }
 235
 236 static av_cold int fbdev_read_close(AVFormatContext *avctx)
 237 {
 238     FBDevContext *fbdev = avctx->priv_data;
 239
 240     munmap(fbdev->data, fbdev->frame_size);
 241     close(fbdev->fd);
 242
 243     return 0;
 244 }
 245
 246 #define OFFSET(x) offsetof(FBDevContext, x)
 247 #define DEC AV_OPT_FLAG_DECODING_PARAM
 248 static const AVOption options[] = {
 249     { "framerate","", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = "25"}, 0, 0, DEC },
 250     { NULL },
 251 };
 252
 253 static const AVClass fbdev_class = {
 254     .class_name = "fbdev indev",
 255     .item_name  = av_default_item_name,
 256     .option     = options,
 257     .version    = LIBAVUTIL_VERSION_INT,
 258 };
 259
 260 AVInputFormat ff_fbdev_demuxer = {
 261     .name           = "fbdev",
 262     .long_name      = NULL_IF_CONFIG_SMALL("Linux framebuffer"),
 263     .priv_data_size = sizeof(FBDevContext),
 264     .read_header    = fbdev_read_header,
 265     .read_packet    = fbdev_read_packet,
 266     .read_close     = fbdev_read_close,
 267     .flags          = AVFMT_NOFILE,
 268     .priv_class     = &fbdev_class,
 269 };