FFmpeg: libavdevice/fbdev_dec.c Source File

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libavdevice

fbdev_dec.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/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"

48 typedef struct {

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)

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

57 int bytes_per_pixel;

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

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

62 uint8_t *data; ///< framebuffer data

63 } FBDevContext;

65 static av_cold int fbdev_read_header(AVFormatContext *avctx)

66 {

67 FBDevContext *fbdev = avctx->priv_data;

68 AVStream *st = NULL;

69 enum AVPixelFormat pix_fmt;

70 int ret, flags = O_RDONLY;

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

73 return AVERROR(ENOMEM);

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

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

77 if (avctx->flags & AVFMT_FLAG_NONBLOCK)

78 flags |= O_NONBLOCK;

80 if ((fbdev->fd = avpriv_open(avctx->filename, flags)) == -1) {

81 ret = AVERROR(errno);

82 av_log(avctx, AV_LOG_ERROR,

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

84 avctx->filename, av_err2str(ret));

85 return ret;

86 }

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

89 ret = AVERROR(errno);

90 av_log(avctx, AV_LOG_ERROR,

91 "FBIOGET_VSCREENINFO: %s\n", av_err2str(ret));

92 goto fail;

93 }

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

96 ret = AVERROR(errno);

97 av_log(avctx, AV_LOG_ERROR,

98 "FBIOGET_FSCREENINFO: %s\n", av_err2str(ret));

99 goto fail;

100 }

101

102 pix_fmt = ff_get_pixfmt_from_fb_varinfo(&fbdev->varinfo);

103 if (pix_fmt == AV_PIX_FMT_NONE) {

104 ret = AVERROR(EINVAL);

105 av_log(avctx, AV_LOG_ERROR,

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

107 goto fail;

108 }

109

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

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

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

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

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

115 fbdev->time_frame = AV_NOPTS_VALUE;

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

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

118 ret = AVERROR(errno);

119 av_log(avctx, AV_LOG_ERROR, "Error in mmap(): %s\n", av_err2str(ret));

120 goto fail;

121 }

122

123 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

124 st->codec->codec_id = AV_CODEC_ID_RAWVIDEO;

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

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

127 st->codec->pix_fmt = pix_fmt;

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

129 st->codec->bit_rate =

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

131

132 av_log(avctx, AV_LOG_INFO,

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

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

135 av_get_pix_fmt_name(pix_fmt),

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

137 st->codec->bit_rate);

138 return 0;

139

140 fail:

141 close(fbdev->fd);

142 return ret;

143 }

144

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

146 {

147 FBDevContext *fbdev = avctx->priv_data;

148 int64_t curtime, delay;

149 struct timespec ts;

150 int i, ret;

151 uint8_t *pin, *pout;

152

153 if (fbdev->time_frame == AV_NOPTS_VALUE)

154 fbdev->time_frame = av_gettime();

155

156 /* wait based on the frame rate */

157 while (1) {

158 curtime = av_gettime();

159 delay = fbdev->time_frame - curtime;

160 av_dlog(avctx,

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

162 fbdev->time_frame, curtime, delay);

163 if (delay <= 0) {

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

165 break;

166 }

167 if (avctx->flags & AVFMT_FLAG_NONBLOCK)

168 return AVERROR(EAGAIN);

169 ts.tv_sec = delay / 1000000;

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

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

172 }

173

174 if ((ret = av_new_packet(pkt, fbdev->frame_size)) < 0)

175 return ret;

176

177 /* refresh fbdev->varinfo, visible data position may change at each call */

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

179 av_log(avctx, AV_LOG_WARNING,

180 "Error refreshing variable info: %s\n", av_err2str(ret));

181

182 pkt->pts = curtime;

183

184 /* compute visible data offset */

185 pin = fbdev->data + fbdev->bytes_per_pixel * fbdev->varinfo.xoffset +

186 fbdev->varinfo.yoffset * fbdev->fixinfo.line_length;

187 pout = pkt->data;

188

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

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

191 pin += fbdev->fixinfo.line_length;

192 pout += fbdev->frame_linesize;

193 }

194

195 return fbdev->frame_size;

196 }

197

198 static av_cold int fbdev_read_close(AVFormatContext *avctx)

199 {

200 FBDevContext *fbdev = avctx->priv_data;

201

202 munmap(fbdev->data, fbdev->fixinfo.smem_len);

203 close(fbdev->fd);

204

205 return 0;

206 }

207

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

209 #define DEC AV_OPT_FLAG_DECODING_PARAM

210 static const AVOption options[] = {

211 { "framerate","", OFFSET(framerate_q), AV_OPT_TYPE_VIDEO_RATE, {.str = "25"}, 0, 0, DEC },

212 { NULL },

213 };

214

215 static const AVClass fbdev_class = {

216 .class_name = "fbdev indev",

217 .item_name = av_default_item_name,

218 .option = options,

219 .version = LIBAVUTIL_VERSION_INT,

220 };

221

222 AVInputFormat ff_fbdev_demuxer = {

223 .name = "fbdev",

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

225 .priv_data_size = sizeof(FBDevContext),

226 .read_header = fbdev_read_header,

227 .read_packet = fbdev_read_packet,

228 .read_close = fbdev_read_close,

229 .flags = AVFMT_NOFILE,

230 .priv_class = &fbdev_class,

231 };

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