FFmpeg: libavdevice/fbdev.c Source File

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libavdevice

fbdev.c

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1 /*

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 */

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 */

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>

37 #include "libavutil/log.h"

38 #include "libavutil/mem.h"

39 #include "libavutil/opt.h"

40 #include "libavutil/time.h"

41 #include "libavutil/parseutils.h"

42 #include "libavutil/pixdesc.h"

43 #include "avdevice.h"

44 #include "libavformat/internal.h"

46 struct rgb_pixfmt_map_entry {

47 int bits_per_pixel;

48 int red_offset, green_offset, blue_offset, alpha_offset;

49 enum AVPixelFormat pixfmt;

50 };

52 static const struct rgb_pixfmt_map_entry rgb_pixfmt_map[] = {

53 // bpp, red_offset, green_offset, blue_offset, alpha_offset, pixfmt

54 { 32, 0, 8, 16, 24, AV_PIX_FMT_RGBA },

55 { 32, 16, 8, 0, 24, AV_PIX_FMT_BGRA },

56 { 32, 8, 16, 24, 0, AV_PIX_FMT_ARGB },

57 { 32, 3, 2, 8, 0, AV_PIX_FMT_ABGR },

58 { 24, 0, 8, 16, 0, AV_PIX_FMT_RGB24 },

59 { 24, 16, 8, 0, 0, AV_PIX_FMT_BGR24 },

60 };

62 static enum AVPixelFormat get_pixfmt_from_fb_varinfo(struct fb_var_screeninfo *varinfo)

63 {

64 int i;

66 for (i = 0; i < FF_ARRAY_ELEMS(rgb_pixfmt_map); i++) {

67 const struct rgb_pixfmt_map_entry *entry = &rgb_pixfmt_map[i];

68 if (entry->bits_per_pixel == varinfo->bits_per_pixel &&

69 entry->red_offset == varinfo->red.offset &&

70 entry->green_offset == varinfo->green.offset &&

71 entry->blue_offset == varinfo->blue.offset)

72 return entry->pixfmt;

73 }

75 return AV_PIX_FMT_NONE;

76 }

78 typedef struct {

79 AVClass *class; ///< class for private options

80 int frame_size; ///< size in bytes of a grabbed frame

81 AVRational framerate_q; ///< framerate

82 char *framerate; ///< framerate string set by a private option

83 int64_t time_frame; ///< time for the next frame to output (in 1/1000000 units)

85 int fd; ///< framebuffer device file descriptor

86 int width, height; ///< assumed frame resolution

87 int frame_linesize; ///< linesize of the output frame, it is assumed to be constant

88 int bytes_per_pixel;

90 struct fb_var_screeninfo varinfo; ///< variable info;

91 struct fb_fix_screeninfo fixinfo; ///< fixed info;

93 uint8_t *data; ///< framebuffer data

94 } FBDevContext;

96 static av_cold int fbdev_read_header(AVFormatContext *avctx)

97 {

98 FBDevContext *fbdev = avctx->priv_data;

99 AVStream *st = NULL;

100 enum AVPixelFormat pix_fmt;

101 int ret, flags = O_RDONLY;

102

103 ret = av_parse_video_rate(&fbdev->framerate_q, fbdev->framerate);

104 if (ret < 0) {

105 av_log(avctx, AV_LOG_ERROR, "Could not parse framerate '%s'.\n", fbdev->framerate);

106 return ret;

107 }

108

109 if (!(st = avformat_new_stream(avctx, NULL)))

110 return AVERROR(ENOMEM);

111 avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in microseconds */

112

113 /* NONBLOCK is ignored by the fbdev driver, only set for consistency */

114 if (avctx->flags & AVFMT_FLAG_NONBLOCK)

115 flags |= O_NONBLOCK;

116

117 if ((fbdev->fd = open(avctx->filename, flags)) == -1) {

118 ret = AVERROR(errno);

119 av_log(avctx, AV_LOG_ERROR,

120 "Could not open framebuffer device '%s': %s\n",

121 avctx->filename, strerror(ret));

122 return ret;

123 }

124

125 if (ioctl(fbdev->fd, FBIOGET_VSCREENINFO, &fbdev->varinfo) < 0) {

126 ret = AVERROR(errno);

127 av_log(avctx, AV_LOG_ERROR,

128 "FBIOGET_VSCREENINFO: %s\n", strerror(errno));

129 goto fail;

130 }

131

132 if (ioctl(fbdev->fd, FBIOGET_FSCREENINFO, &fbdev->fixinfo) < 0) {

133 ret = AVERROR(errno);

134 av_log(avctx, AV_LOG_ERROR,

135 "FBIOGET_FSCREENINFO: %s\n", strerror(errno));

136 goto fail;

137 }

138

139 pix_fmt = get_pixfmt_from_fb_varinfo(&fbdev->varinfo);

140 if (pix_fmt == AV_PIX_FMT_NONE) {

141 ret = AVERROR(EINVAL);

142 av_log(avctx, AV_LOG_ERROR,

143 "Framebuffer pixel format not supported.\n");

144 goto fail;

145 }

146

147 fbdev->width = fbdev->varinfo.xres;

148 fbdev->height = fbdev->varinfo.yres;

149 fbdev->bytes_per_pixel = (fbdev->varinfo.bits_per_pixel + 7) >> 3;

150 fbdev->frame_linesize = fbdev->width * fbdev->bytes_per_pixel;

151 fbdev->frame_size = fbdev->frame_linesize * fbdev->height;

152 fbdev->time_frame = AV_NOPTS_VALUE;

153 fbdev->data = mmap(NULL, fbdev->fixinfo.smem_len, PROT_READ, MAP_SHARED, fbdev->fd, 0);

154 if (fbdev->data == MAP_FAILED) {

155 ret = AVERROR(errno);

156 av_log(avctx, AV_LOG_ERROR, "Error in mmap(): %s\n", strerror(errno));

157 goto fail;

158 }

159

160 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

161 st->codec->codec_id = AV_CODEC_ID_RAWVIDEO;

162 st->codec->width = fbdev->width;

163 st->codec->height = fbdev->height;

164 st->codec->pix_fmt = pix_fmt;

165 st->codec->time_base = av_inv_q(fbdev->framerate_q);

166 st->codec->bit_rate =

167 fbdev->width * fbdev->height * fbdev->bytes_per_pixel * av_q2d(fbdev->framerate_q) * 8;

168

169 av_log(avctx, AV_LOG_INFO,

170 "w:%d h:%d bpp:%d pixfmt:%s fps:%d/%d bit_rate:%d\n",

171 fbdev->width, fbdev->height, fbdev->varinfo.bits_per_pixel,

172 av_get_pix_fmt_name(pix_fmt),

173 fbdev->framerate_q.num, fbdev->framerate_q.den,

174 st->codec->bit_rate);

175 return 0;

176

177 fail:

178 close(fbdev->fd);

179 return ret;

180 }

181

182 static int fbdev_read_packet(AVFormatContext *avctx, AVPacket *pkt)

183 {

184 FBDevContext *fbdev = avctx->priv_data;

185 int64_t curtime, delay;

186 struct timespec ts;

187 int i, ret;

188 uint8_t *pin, *pout;

189

190 if (fbdev->time_frame == AV_NOPTS_VALUE)

191 fbdev->time_frame = av_gettime();

192

193 /* wait based on the frame rate */

194 while (1) {

195 curtime = av_gettime();

196 delay = fbdev->time_frame - curtime;

197 av_dlog(avctx,

198 "time_frame:%"PRId64" curtime:%"PRId64" delay:%"PRId64"\n",

199 fbdev->time_frame, curtime, delay);

200 if (delay <= 0) {

201 fbdev->time_frame += INT64_C(1000000) / av_q2d(fbdev->framerate_q);

202 break;

203 }

204 if (avctx->flags & AVFMT_FLAG_NONBLOCK)

205 return AVERROR(EAGAIN);

206 ts.tv_sec = delay / 1000000;

207 ts.tv_nsec = (delay % 1000000) * 1000;

208 while (nanosleep(&ts, &ts) < 0 && errno == EINTR);

209 }

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 for (i = 0; i < fbdev->height; i++) {

227 memcpy(pout, pin, fbdev->frame_linesize);

228 pin += fbdev->fixinfo.line_length;

229 pout += fbdev->frame_linesize;

230 }

231

232 return fbdev->frame_size;

233 }

234

235 static av_cold int fbdev_read_close(AVFormatContext *avctx)

236 {

237 FBDevContext *fbdev = avctx->priv_data;

238

239 munmap(fbdev->data, fbdev->frame_size);

240 close(fbdev->fd);

241

242 return 0;

243 }

244

245 #define OFFSET(x) offsetof(FBDevContext, x)

246 #define DEC AV_OPT_FLAG_DECODING_PARAM

247 static const AVOption options[] = {

248 { "framerate","", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = "25"}, 0, 0, DEC },

249 { NULL },

250 };

251

252 static const AVClass fbdev_class = {

253 .class_name = "fbdev indev",

254 .item_name = av_default_item_name,

255 .option = options,

256 .version = LIBAVUTIL_VERSION_INT,

257 };

258

259 AVInputFormat ff_fbdev_demuxer = {

260 .name = "fbdev",

261 .long_name = NULL_IF_CONFIG_SMALL("Linux framebuffer"),

262 .priv_data_size = sizeof(FBDevContext),

263 .read_header = fbdev_read_header,

264 .read_packet = fbdev_read_packet,

265 .read_close = fbdev_read_close,

266 .flags = AVFMT_NOFILE,

267 .priv_class = &fbdev_class,

268 };

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