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/time.h>
36#include <sys/mman.h>
37#include <time.h>
38#include <linux/fb.h>
39
40#include "libavutil/log.h"
41#include "libavutil/mem.h"
42#include "libavutil/opt.h"
43#include "libavutil/parseutils.h"
44#include "libavutil/pixdesc.h"
45#include "libavformat/avformat.h"
46#include "libavformat/internal.h"
47
48struct rgb_pixfmt_map_entry {
49    int bits_per_pixel;
50    int red_offset, green_offset, blue_offset, alpha_offset;
51    enum PixelFormat pixfmt;
52};
53
54static 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,   PIX_FMT_RGBA  },
57    {  32,      16,           8,           0,           24,   PIX_FMT_BGRA  },
58    {  32,       8,          16,          24,            0,   PIX_FMT_ARGB  },
59    {  32,       3,           2,           8,            0,   PIX_FMT_ABGR  },
60    {  24,       0,           8,          16,            0,   PIX_FMT_RGB24 },
61    {  24,      16,           8,           0,            0,   PIX_FMT_BGR24 },
62};
63
64static enum PixelFormat 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 PIX_FMT_NONE;
78}
79
80typedef 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
98av_cold static int fbdev_read_header(AVFormatContext *avctx,
99                                     AVFormatParameters *ap)
100{
101    FBDevContext *fbdev = avctx->priv_data;
102    AVStream *st = NULL;
103    enum PixelFormat pix_fmt;
104    int ret, flags = O_RDONLY;
105
106    ret = av_parse_video_rate(&fbdev->framerate_q, fbdev->framerate);
107    if (ret < 0) {
108        av_log(avctx, AV_LOG_ERROR, "Could not parse framerate '%s'.\n", fbdev->framerate);
109        return ret;
110    }
111
112    if (!(st = avformat_new_stream(avctx, NULL)))
113        return AVERROR(ENOMEM);
114    avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in microseconds */
115
116    /* NONBLOCK is ignored by the fbdev driver, only set for consistency */
117    if (avctx->flags & AVFMT_FLAG_NONBLOCK)
118        flags |= O_NONBLOCK;
119
120    if ((fbdev->fd = open(avctx->filename, flags)) == -1) {
121        ret = AVERROR(errno);
122        av_log(avctx, AV_LOG_ERROR,
123               "Could not open framebuffer device '%s': %s\n",
124               avctx->filename, strerror(ret));
125        return ret;
126    }
127
128    if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0) {
129        ret = AVERROR(errno);
130        av_log(avctx, AV_LOG_ERROR,
131               "FBIOGET_VSCREENINFO: %s\n", strerror(errno));
132        goto fail;
133    }
134
135    if (ioctl(fbdev->fd, FBIOGET_FSCREENINFO, &fbdev->fixinfo) < 0) {
136        ret = AVERROR(errno);
137        av_log(avctx, AV_LOG_ERROR,
138               "FBIOGET_FSCREENINFO: %s\n", strerror(errno));
139        goto fail;
140    }
141
142    pix_fmt = get_pixfmt_from_fb_varinfo(&fbdev->varinfo);
143    if (pix_fmt == PIX_FMT_NONE) {
144        ret = AVERROR(EINVAL);
145        av_log(avctx, AV_LOG_ERROR,
146               "Framebuffer pixel format not supported.\n");
147        goto fail;
148    }
149
150    fbdev->width           = fbdev->varinfo.xres;
151    fbdev->height          = fbdev->varinfo.yres;
152    fbdev->bytes_per_pixel = (fbdev->varinfo.bits_per_pixel + 7) >> 3;
153    fbdev->frame_linesize  = fbdev->width * fbdev->bytes_per_pixel;
154    fbdev->frame_size      = fbdev->frame_linesize * fbdev->height;
155    fbdev->time_frame      = AV_NOPTS_VALUE;
156    fbdev->data = mmap(NULL, fbdev->fixinfo.smem_len, PROT_READ, MAP_SHARED, fbdev->fd, 0);
157    if (fbdev->data == MAP_FAILED) {
158        ret = AVERROR(errno);
159        av_log(avctx, AV_LOG_ERROR, "Error in mmap(): %s\n", strerror(errno));
160        goto fail;
161    }
162
163    st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
164    st->codec->codec_id   = CODEC_ID_RAWVIDEO;
165    st->codec->width      = fbdev->width;
166    st->codec->height     = fbdev->height;
167    st->codec->pix_fmt    = pix_fmt;
168    st->codec->time_base  = (AVRational){fbdev->framerate_q.den, fbdev->framerate_q.num};
169    st->codec->bit_rate   =
170        fbdev->width * fbdev->height * fbdev->bytes_per_pixel * av_q2d(fbdev->framerate_q) * 8;
171
172    av_log(avctx, AV_LOG_INFO,
173           "w:%d h:%d bpp:%d pixfmt:%s fps:%d/%d bit_rate:%d\n",
174           fbdev->width, fbdev->height, fbdev->varinfo.bits_per_pixel,
175           av_pix_fmt_descriptors[pix_fmt].name,
176           fbdev->framerate_q.num, fbdev->framerate_q.den,
177           st->codec->bit_rate);
178    return 0;
179
180fail:
181    close(fbdev->fd);
182    return ret;
183}
184
185static int fbdev_read_packet(AVFormatContext *avctx, AVPacket *pkt)
186{
187    FBDevContext *fbdev = avctx->priv_data;
188    int64_t curtime, delay;
189    struct timespec ts;
190    int i, ret;
191    uint8_t *pin, *pout;
192
193    if (fbdev->time_frame == AV_NOPTS_VALUE)
194        fbdev->time_frame = av_gettime();
195
196    /* wait based on the frame rate */
197    curtime = av_gettime();
198    delay = fbdev->time_frame - curtime;
199    av_dlog(avctx,
200            "time_frame:%"PRId64" curtime:%"PRId64" delay:%"PRId64"\n",
201            fbdev->time_frame, curtime, delay);
202    if (delay > 0) {
203        if (avctx->flags & AVFMT_FLAG_NONBLOCK)
204            return AVERROR(EAGAIN);
205        ts.tv_sec  =  delay / 1000000;
206        ts.tv_nsec = (delay % 1000000) * 1000;
207        while (nanosleep(&ts, &ts) < 0 && errno == EINTR);
208    }
209    /* compute the time of the next frame */
210    fbdev->time_frame += INT64_C(1000000) / av_q2d(fbdev->framerate_q);
211
212    if ((ret = av_new_packet(pkt, fbdev->frame_size)) < 0)
213        return ret;
214
215    /* refresh fbdev->varinfo, visible data position may change at each call */
216    if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0)
217        av_log(avctx, AV_LOG_WARNING,
218               "Error refreshing variable info: %s\n", strerror(errno));
219
220    pkt->pts = curtime;
221
222    /* compute visible data offset */
223    pin = fbdev->data + fbdev->bytes_per_pixel * fbdev->varinfo.xoffset +
224                        fbdev->varinfo.yoffset * fbdev->fixinfo.line_length;
225    pout = pkt->data;
226
227    // TODO it'd be nice if the lines were aligned
228    for (i = 0; i < fbdev->height; i++) {
229        memcpy(pout, pin, fbdev->frame_linesize);
230        pin  += fbdev->fixinfo.line_length;
231        pout += fbdev->frame_linesize;
232    }
233
234    return fbdev->frame_size;
235}
236
237av_cold static int fbdev_read_close(AVFormatContext *avctx)
238{
239    FBDevContext *fbdev = avctx->priv_data;
240
241    munmap(fbdev->data, fbdev->frame_size);
242    close(fbdev->fd);
243
244    return 0;
245}
246
247#define OFFSET(x) offsetof(FBDevContext, x)
248#define DEC AV_OPT_FLAG_DECODING_PARAM
249static const AVOption options[] = {
250    { "framerate","", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = "25"}, 0, 0, DEC },
251    { NULL },
252};
253
254static const AVClass fbdev_class = {
255    .class_name = "fbdev indev",
256    .item_name  = av_default_item_name,
257    .option     = options,
258    .version    = LIBAVUTIL_VERSION_INT,
259};
260
261AVInputFormat ff_fbdev_demuxer = {
262    .name           = "fbdev",
263    .long_name      = NULL_IF_CONFIG_SMALL("Linux framebuffer"),
264    .priv_data_size = sizeof(FBDevContext),
265    .read_header    = fbdev_read_header,
266    .read_packet    = fbdev_read_packet,
267    .read_close     = fbdev_read_close,
268    .flags          = AVFMT_NOFILE,
269    .priv_class     = &fbdev_class,
270};
271