--- /dev/null
+/**
+ * @file shm.c
+ * @brief Shared memory frame buffer capture module for VLC media player
+ */
+/*****************************************************************************
+ * Copyright © 2011 Rémi Denis-Courmont
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1
+ * of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ ****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <stdarg.h>
+#include <fcntl.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <sys/mman.h>
+
+#include <vlc_common.h>
+#include <vlc_demux.h>
+#include <vlc_fs.h>
+#include <vlc_plugin.h>
+
+#define CACHING_TEXT N_("Caching value in ms")
+#define CACHING_LONGTEXT N_( \
+ "Caching value for frame buffer capture. " \
+ "This value should be set in milliseconds.")
+
+#define FPS_TEXT N_("Frame rate")
+#define FPS_LONGTEXT N_( \
+ "How many times the screen content should be refreshed per second.")
+
+#define WIDTH_TEXT N_("Frame buffer width")
+#define WIDTH_LONGTEXT N_( \
+ "Pixel width of the frame buffer")
+
+#define HEIGHT_TEXT N_("Frame buffer height")
+#define HEIGHT_LONGTEXT N_( \
+ "Pixel height of the frame buffer")
+
+#define DEPTH_TEXT N_("Frame buffer depth")
+#define DEPTH_LONGTEXT N_( \
+ "Pixel depth of the frame buffer")
+
+#define ID_TEXT N_("Frame buffer segment ID")
+#define ID_LONGTEXT N_( \
+ "System V shared memory segment ID of the frame buffer " \
+ "(this is ignored if --shm-file is specified).")
+
+#define FILE_TEXT N_("Frame buffer file")
+#define FILE_LONGTEXT N_( \
+ "Path of the memory mapped file of the frame buffer")
+
+static int Open (vlc_object_t *);
+static void Close (vlc_object_t *);
+
+static const int depths[] = {
+ 8, 15, 16, 24, 32,
+};
+
+static const char *const depth_texts[] = {
+ N_("8 bits"), N_("15 bits"), N_("16 bits"), N_("24 bits"), N_("32 bits"),
+};
+
+/*
+ * Module descriptor
+ */
+vlc_module_begin ()
+ set_shortname (N_("Framebuffer input"))
+ set_description (N_("Shared memory framebuffer"))
+ set_category (CAT_INPUT)
+ set_subcategory (SUBCAT_INPUT_ACCESS)
+ set_capability ("access_demux", 0)
+ set_callbacks (Open, Close)
+
+ add_integer ("shm-caching", DEFAULT_PTS_DELAY * 1000 / CLOCK_FREQ,
+ CACHING_TEXT, CACHING_LONGTEXT, true)
+ add_float ("shm-fps", 10.0, FPS_TEXT, FPS_LONGTEXT, true)
+ add_integer ("shm-width", 800, WIDTH_TEXT, WIDTH_LONGTEXT, false)
+ change_integer_range (0, 65535)
+ change_safe ()
+ add_integer ("shm-height", 480, HEIGHT_TEXT, HEIGHT_LONGTEXT, false)
+ change_integer_range (0, 65535)
+ change_safe ()
+ add_integer ("shm-depth", 32, DEPTH_TEXT, DEPTH_LONGTEXT, true)
+ change_integer_list (depths, depth_texts)
+ change_safe ()
+
+ /* We need to "trust" the memory segment. If it were shrunk while we copy
+ * its content our process may crash - or worse. So we pass the shared
+ * memory location via an unsafe variable rather than the URL. */
+ add_string ("shm-file", NULL, FILE_TEXT, FILE_LONGTEXT, false)
+ change_volatile ()
+ add_integer ("shm-id", (int64_t)IPC_PRIVATE, ID_TEXT, ID_LONGTEXT, false)
+ change_volatile ()
+
+ add_shortcut ("shm")
+vlc_module_end ()
+
+static void Demux (void *);
+static int Control (demux_t *, int, va_list);
+static void map_detach (demux_sys_t *);
+static void sysv_detach (demux_sys_t *);
+static void no_detach (demux_sys_t *);
+
+struct demux_sys_t
+{
+ const void *addr;
+ size_t length;
+ es_out_id_t *es;
+ mtime_t pts, interval;
+ /* pts is protected by the lock. The rest is read-only. */
+ vlc_mutex_t lock;
+ vlc_timer_t timer;
+ void (*detach) (demux_sys_t *);
+};
+
+static int Open (vlc_object_t *obj)
+{
+ demux_t *demux = (demux_t *)obj;
+
+ long pagesize = sysconf (_SC_PAGE_SIZE);
+ if (pagesize == -1)
+ return VLC_EGENERIC;
+
+ demux_sys_t *sys = malloc (sizeof (*sys));
+ if (unlikely(sys == NULL))
+ return VLC_ENOMEM;
+ sys->detach = no_detach;
+
+ uint16_t width = var_InheritInteger (demux, "shm-width");
+ uint16_t height = var_InheritInteger (demux, "shm-height");
+ uint32_t chroma;
+ uint8_t bpp;
+ switch (var_InheritInteger (demux, "shm-depth"))
+ {
+ case 32:
+ chroma = VLC_CODEC_RGB32; bpp = 32;
+ break;
+ case 24:
+ chroma = VLC_CODEC_RGB24; bpp = 24;
+ break;
+ case 16:
+ chroma = VLC_CODEC_RGB16; bpp = 16;
+ break;
+ case 15:
+ chroma = VLC_CODEC_RGB15; bpp = 16;
+ break;
+ case 8:
+ chroma = VLC_CODEC_RGB8; bpp = 8;
+ break;
+ default:
+ goto error;
+ }
+
+ sys->length = width * height * (bpp >> 3);
+ if (sys->length == 0)
+ goto error;
+ pagesize--;
+ sys->length = (sys->length + pagesize) & ~pagesize; /* pad */
+
+ char *path = var_InheritString (demux, "shm-file");
+ if (path != NULL)
+ {
+ int fd = vlc_open (path, O_RDONLY);
+ if (fd == -1)
+ {
+ msg_Err (demux, "cannot open file %s: %m", path);
+ free (path);
+ goto error;
+ }
+
+ void *mem = mmap (NULL, sys->length, PROT_READ, MAP_SHARED, fd, 0);
+ close (fd);
+ if (mem == MAP_FAILED)
+ {
+ msg_Err (demux, "cannot map file %s: %m", path);
+ free (path);
+ goto error;
+ }
+ free (path);
+ sys->addr = mem;
+ sys->detach = map_detach;
+ }
+ else
+ {
+ int id = var_InheritInteger (demux, "shm-id");
+ if (id == IPC_PRIVATE)
+ goto error;
+ void *mem = shmat (id, NULL, SHM_RDONLY);
+
+ if (mem == (const void *)(-1))
+ {
+ msg_Err (demux, "cannot attach segment %d: %m", id);
+ goto error;
+ }
+ sys->addr = mem;
+ sys->detach = sysv_detach;
+ }
+
+ /* Initializes format */
+ float rate = var_InheritFloat (obj, "shm-fps");
+ if (rate <= 0.)
+ goto error;
+
+ sys->interval = (float)CLOCK_FREQ / rate;
+ if (!sys->interval)
+ goto error;
+ sys->pts = VLC_TS_INVALID;
+
+ es_format_t fmt;
+ es_format_Init (&fmt, VIDEO_ES, chroma);
+ fmt.video.i_chroma = chroma;
+ fmt.video.i_bits_per_pixel = bpp;
+ fmt.video.i_sar_num = fmt.video.i_sar_den = 1;
+ fmt.video.i_frame_rate = 1000 * rate;
+ fmt.video.i_frame_rate_base = 1000;
+ fmt.video.i_visible_width = fmt.video.i_width = width;
+ fmt.video.i_visible_height = fmt.video.i_height = height;
+
+ sys->es = es_out_Add (demux->out, &fmt);
+
+ /* Initializes demux */
+ var_Create (obj, "shm-caching", VLC_VAR_INTEGER|VLC_VAR_DOINHERIT);
+
+ vlc_mutex_init (&sys->lock);
+ if (vlc_timer_create (&sys->timer, Demux, demux))
+ goto error;
+ vlc_timer_schedule (sys->timer, false, 1, sys->interval);
+
+ demux->p_sys = sys;
+ demux->pf_demux = NULL;
+ demux->pf_control = Control;
+ return VLC_SUCCESS;
+
+error:
+ sys->detach (sys);
+ free (sys);
+ return VLC_EGENERIC;
+}
+
+
+/**
+ * Releases resources
+ */
+static void Close (vlc_object_t *obj)
+{
+ demux_t *demux = (demux_t *)obj;
+ demux_sys_t *sys = demux->p_sys;
+
+ vlc_timer_destroy (sys->timer);
+ vlc_mutex_destroy (&sys->lock);
+ sys->detach (sys);
+ free (sys);
+}
+
+
+static void map_detach (demux_sys_t *sys)
+{
+ munmap ((void *)sys->addr, sys->length);
+}
+
+
+static void sysv_detach (demux_sys_t *sys)
+{
+ shmdt (sys->addr);
+}
+
+static void no_detach (demux_sys_t *sys)
+{
+ (void) sys;
+}
+
+/**
+ * Control callback
+ */
+static int Control (demux_t *demux, int query, va_list args)
+{
+ demux_sys_t *sys = demux->p_sys;
+
+ switch (query)
+ {
+ case DEMUX_GET_POSITION:
+ {
+ float *v = va_arg (args, float *);
+ *v = 0.;
+ return VLC_SUCCESS;
+ }
+
+ case DEMUX_GET_LENGTH:
+ case DEMUX_GET_TIME:
+ {
+ int64_t *v = va_arg (args, int64_t *);
+ *v = 0;
+ return VLC_SUCCESS;
+ }
+
+ case DEMUX_GET_PTS_DELAY:
+ {
+ int64_t *v = va_arg (args, int64_t *);
+ *v = var_GetInteger (demux, "shm-caching") * UINT64_C(1000);
+ return VLC_SUCCESS;
+ }
+
+ case DEMUX_CAN_PAUSE:
+ {
+ bool *v = (bool *)va_arg (args, bool *);
+ *v = true;
+ return VLC_SUCCESS;
+ }
+
+ case DEMUX_SET_PAUSE_STATE:
+ {
+ bool pausing = va_arg (args, int);
+
+ if (!pausing)
+ {
+ vlc_mutex_lock (&sys->lock);
+ sys->pts = VLC_TS_INVALID;
+ es_out_Control (demux->out, ES_OUT_RESET_PCR);
+ vlc_mutex_unlock (&sys->lock);
+ }
+ vlc_timer_schedule (sys->timer, false,
+ pausing ? 0 : 1, sys->interval);
+ return VLC_SUCCESS;
+ }
+
+ case DEMUX_CAN_CONTROL_PACE:
+ case DEMUX_CAN_CONTROL_RATE:
+ case DEMUX_CAN_SEEK:
+ {
+ bool *v = (bool *)va_arg (args, bool *);
+ *v = false;
+ return VLC_SUCCESS;
+ }
+ }
+
+ return VLC_EGENERIC;
+}
+
+
+/**
+ * Processing callback
+ */
+static void Demux (void *data)
+{
+ demux_t *demux = data;
+ demux_sys_t *sys = demux->p_sys;
+
+ /* Copy frame */
+ block_t *block = block_Alloc (sys->length);
+ if (block == NULL)
+ return;
+
+ vlc_memcpy (block->p_buffer, sys->addr, sys->length);
+
+ /* Send block */
+ vlc_mutex_lock (&sys->lock);
+ if (sys->pts == VLC_TS_INVALID)
+ sys->pts = mdate ();
+ block->i_pts = block->i_dts = sys->pts;
+
+ es_out_Control (demux->out, ES_OUT_SET_PCR, sys->pts);
+ es_out_Send (demux->out, sys->es, block);
+ sys->pts += sys->interval;
+ vlc_mutex_unlock (&sys->lock);
+}
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