gstreamer/sys/v4l2/v4l2src_calls.c

/* G-Streamer Video4linux2 video-capture plugin - system calls
 * Copyright (C) 2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <string.h>
#include <errno.h>
#include "v4l2src_calls.h"
#include <sys/time.h>

#define DEBUG(format, args...) \
	GST_DEBUG_ELEMENT(GST_CAT_PLUGIN_INFO, \
		GST_ELEMENT(v4l2src), \
		"V4L2SRC: " format, ##args)

#define MIN_BUFFERS_QUEUED 2

/* On some systems MAP_FAILED seems to be missing */
#ifndef MAP_FAILED
#define MAP_FAILED ( (caddr_t) -1 )
#endif


/******************************************************
 * gst_v4l2src_fill_format_list():
 *   create list of supported capture formats
 * return value: TRUE on success, FALSE on error
 ******************************************************/

gboolean
gst_v4l2src_fill_format_list (GstV4l2Src *v4l2src)
{
	gint n;

	DEBUG("getting src format enumerations");

	/* format enumeration */
	for (n=0;;n++) {
		struct v4l2_fmtdesc format, *fmtptr;
		format.index = n;
		format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		if (ioctl(GST_V4L2ELEMENT(v4l2src)->video_fd, VIDIOC_ENUM_FMT, &format) < 0) {
			if (errno == EINVAL)
				break; /* end of enumeration */
			else {
				gst_element_error(GST_ELEMENT(v4l2src),
					"Failed to get no. %d in pixelformat enumeration for %s: %s",
					n, GST_V4L2ELEMENT(v4l2src)->device, g_strerror(errno));
				return FALSE;
			}
		}
		fmtptr = g_malloc(sizeof(format));
		memcpy(fmtptr, &format, sizeof(format));
		v4l2src->formats = g_list_append(v4l2src->formats, fmtptr);

		v4l2src->format_list = g_list_append(v4l2src->format_list, fmtptr->description);
	}

	return TRUE;
}


/******************************************************
 * gst_v4l2src_empty_format_list():
 *   free list of supported capture formats
 * return value: TRUE on success, FALSE on error
 ******************************************************/

gboolean
gst_v4l2src_empty_format_list (GstV4l2Src *v4l2src)
{
	while (g_list_length(v4l2src->formats) > 0) {
		gpointer data = g_list_nth_data(v4l2src->formats, 0);
		v4l2src->formats = g_list_remove(v4l2src->formats, data);
		g_free(data);
	}
	g_list_free(v4l2src->format_list);
	v4l2src->format_list = NULL;

	return TRUE;
}


/******************************************************
 * gst_v4l2src_queue_frame():
 *   queue a frame for capturing
 * return value: TRUE on success, FALSE on error
 ******************************************************/

static gboolean
gst_v4l2src_queue_frame (GstV4l2Src *v4l2src,
                         gint        num)
{
	DEBUG("queueing frame %d", num);

	v4l2src->bufsettings.index = num;
	if (ioctl(GST_V4L2ELEMENT(v4l2src)->video_fd, VIDIOC_QBUF, &v4l2src->bufsettings) < 0) {
		gst_element_error(GST_ELEMENT(v4l2src),
			"Error queueing buffer %d on device %s: %s",
			num, GST_V4L2ELEMENT(v4l2src)->device, g_strerror(errno));
		return FALSE;
	}

	return TRUE;
}


/******************************************************
 * gst_v4lsrc_sync_frame():
 *   sync on a frame for capturing
 * return value: TRUE on success, FALSE on error
 ******************************************************/

static gboolean
gst_v4l2src_sync_next_frame (GstV4l2Src *v4l2src,
                             gint       *num)
{
	if (ioctl(GST_V4L2ELEMENT(v4l2src)->video_fd, VIDIOC_DQBUF, &v4l2src->bufsettings) < 0) {
		gst_element_error(GST_ELEMENT(v4l2src),
			"Error syncing on a buffer on device %s: %s",
			GST_V4L2ELEMENT(v4l2src)->device, g_strerror(errno));
		return FALSE;
	}
	DEBUG("synced on frame %d", v4l2src->bufsettings.index);
	*num = v4l2src->bufsettings.index;

	return TRUE;
}


/******************************************************
 * gst_v4l2src_get_capture():
 *   get capture parameters
 * return value: TRUE on success, FALSE on error
 ******************************************************/

gboolean
gst_v4l2src_get_capture (GstV4l2Src *v4l2src)
{
	DEBUG("Getting capture format");

	GST_V4L2_CHECK_OPEN(GST_V4L2ELEMENT(v4l2src));

	v4l2src->format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
	if (ioctl(GST_V4L2ELEMENT(v4l2src)->video_fd, VIDIOC_G_FMT, &v4l2src->format) < 0) {
		gst_element_error(GST_ELEMENT(v4l2src),
			"Failed to get pixel format for device %s: %s",
			GST_V4L2ELEMENT(v4l2src)->device, g_strerror(errno));
		return FALSE;
	}

	return TRUE;
}


/******************************************************
 * gst_v4l2src_set_capture():
 *   set capture parameters
 * return value: TRUE on success, FALSE on error
 ******************************************************/

gboolean
gst_v4l2src_set_capture (GstV4l2Src          *v4l2src,
                         struct v4l2_fmtdesc *fmt,
                         gint                 width,
                         gint                 height)
{
	DEBUG("Setting capture format to %dx%d, format %s",
		width, height, fmt->description);

	GST_V4L2_CHECK_OPEN(GST_V4L2ELEMENT(v4l2src));
	GST_V4L2_CHECK_NOT_ACTIVE(GST_V4L2ELEMENT(v4l2src));

	memset(&v4l2src->format, 0, sizeof(struct v4l2_format));
	v4l2src->format.fmt.pix.width = width;
	v4l2src->format.fmt.pix.height = height;
	v4l2src->format.fmt.pix.pixelformat = fmt->pixelformat;
	v4l2src->format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

	if (ioctl(GST_V4L2ELEMENT(v4l2src)->video_fd, VIDIOC_S_FMT, &v4l2src->format) < 0) {
		gst_element_error(GST_ELEMENT(v4l2src),
			"Failed to set pixel format to %s @ %dx%d for device %s: %s",
			fmt->description, width, height,
			GST_V4L2ELEMENT(v4l2src)->device, g_strerror(errno));
		return FALSE;
	}

	return TRUE;
}


/******************************************************
 * gst_v4l2src_capture_init():
 *   initialize the capture system
 * return value: TRUE on success, FALSE on error
 ******************************************************/

gboolean
gst_v4l2src_capture_init (GstV4l2Src *v4l2src)
{
	gint n;
	gchar *desc = NULL;

	DEBUG("initting the capture system");

	GST_V4L2_CHECK_OPEN(GST_V4L2ELEMENT(v4l2src));
	GST_V4L2_CHECK_NOT_ACTIVE(GST_V4L2ELEMENT(v4l2src));

	/* request buffer info */
	if (v4l2src->breq.count < MIN_BUFFERS_QUEUED)
		v4l2src->breq.count = MIN_BUFFERS_QUEUED;
	v4l2src->breq.type = v4l2src->format.type;
	if (ioctl(GST_V4L2ELEMENT(v4l2src)->video_fd, VIDIOC_REQBUFS, &v4l2src->breq) < 0) {
		gst_element_error(GST_ELEMENT(v4l2src),
			"Error requesting buffers (%d) for %s: %s",
			v4l2src->breq.count, GST_V4L2ELEMENT(v4l2src)->device, g_strerror(errno));
		return FALSE;
	}

	if (v4l2src->breq.count < MIN_BUFFERS_QUEUED) {
		gst_element_error(GST_ELEMENT(v4l2src),
			"Too little buffers. We got %d, we want at least %d",
			v4l2src->breq.count, MIN_BUFFERS_QUEUED);
		return FALSE;
	}
	v4l2src->bufsettings.type = v4l2src->format.type;

	for (n=0;n<g_list_length(v4l2src->formats);n++) {
		struct v4l2_fmtdesc *fmt = (struct v4l2_fmtdesc *) g_list_nth_data(v4l2src->formats, n);
		if (v4l2src->format.fmt.pix.pixelformat == fmt->pixelformat) {
			desc = fmt->description;
			break;
		}
	}
	gst_info("Got %d buffers (%s) of size %d KB\n",
		v4l2src->breq.count, desc, v4l2src->format.fmt.pix.sizeimage/1024);

	/* Map the buffers */
	GST_V4L2ELEMENT(v4l2src)->buffer = (guint8 **) g_malloc(sizeof(guint8*) * v4l2src->breq.count);
	for (n=0;n<v4l2src->breq.count;n++) {
		GST_V4L2ELEMENT(v4l2src)->buffer[n] = mmap(0, v4l2src->format.fmt.pix.sizeimage, 
			PROT_READ|PROT_WRITE, MAP_SHARED, GST_V4L2ELEMENT(v4l2src)->video_fd, v4l2src->format.fmt.pix.sizeimage*n);
		if (GST_V4L2ELEMENT(v4l2src)->buffer[n] == MAP_FAILED) {
			gst_element_error(GST_ELEMENT(v4l2src),
				"Error mapping video buffer %d on device %s: %s",
				n, GST_V4L2ELEMENT(v4l2src)->device, g_strerror(errno));
			GST_V4L2ELEMENT(v4l2src)->buffer[n] = NULL;
			return FALSE;
		}
	}

	return TRUE;
}


/******************************************************
 * gst_v4l2src_capture_start():
 *   start streaming capture
 * return value: TRUE on success, FALSE on error
 ******************************************************/

gboolean
gst_v4l2src_capture_start (GstV4l2Src *v4l2src)
{
	gint n;

	DEBUG("starting the capturing");
	GST_V4L2_CHECK_OPEN(GST_V4L2ELEMENT(v4l2src));
	GST_V4L2_CHECK_ACTIVE(GST_V4L2ELEMENT(v4l2src));

	/* queue all buffers, this starts streaming capture */
	for (n=0;n<v4l2src->breq.count;n++)
		if (!gst_v4l2src_queue_frame(v4l2src, n))
			return FALSE;
	n = 1;
	if (ioctl(GST_V4L2ELEMENT(v4l2src)->video_fd, VIDIOC_STREAMON, &n) < 0) {
		gst_element_error(GST_ELEMENT(v4l2src),
			"Error starting streaming capture for %s: %s",
			GST_V4L2ELEMENT(v4l2src)->device, g_strerror(errno));
		return FALSE;
	}

	return TRUE;
}


/******************************************************
 * gst_v4l2src_grab_frame():
 *   capture one frame during streaming capture
 * return value: TRUE on success, FALSE on error
 ******************************************************/

gboolean
gst_v4l2src_grab_frame (GstV4l2Src *v4l2src,
                        gint       *num)
{
	DEBUG("syncing on the next frame");

	GST_V4L2_CHECK_OPEN(GST_V4L2ELEMENT(v4l2src));
	GST_V4L2_CHECK_ACTIVE(GST_V4L2ELEMENT(v4l2src));

	/* syncing on the buffer grabs it */
	if (!gst_v4l2src_sync_next_frame(v4l2src, num))
		return FALSE;

	return TRUE;
}


/******************************************************
 * gst_v4l2src_requeue_frame():
 *   re-queue a frame after we're done with the buffer
 * return value: TRUE on success, FALSE on error
 ******************************************************/

gboolean
gst_v4l2src_requeue_frame (GstV4l2Src *v4l2src,
                           gint        num)
{
	DEBUG("requeueing frame %d", num);
	GST_V4L2_CHECK_OPEN(GST_V4L2ELEMENT(v4l2src));
	GST_V4L2_CHECK_ACTIVE(GST_V4L2ELEMENT(v4l2src));

	/* and let's queue the buffer */
	if (!gst_v4l2src_queue_frame(v4l2src, num))
		return FALSE;

	return TRUE;
}


/******************************************************
 * gst_v4l2src_capture_stop():
 *   stop streaming capture
 * return value: TRUE on success, FALSE on error
 ******************************************************/

gboolean
gst_v4l2src_capture_stop (GstV4l2Src *v4l2src)
{
	gint n = 0;

	DEBUG("stopping capturing");
	GST_V4L2_CHECK_OPEN(GST_V4L2ELEMENT(v4l2src));
	GST_V4L2_CHECK_ACTIVE(GST_V4L2ELEMENT(v4l2src));

	/* we actually need to sync on all queued buffers but not on the non-queued ones */
	if (ioctl(GST_V4L2ELEMENT(v4l2src)->video_fd, VIDIOC_STREAMOFF, &n) < 0) {
		gst_element_error(GST_ELEMENT(v4l2src),
			"Error stopping streaming capture for %s: %s",
			GST_V4L2ELEMENT(v4l2src)->device, g_strerror(errno));
		return FALSE;
	}

	return TRUE;
}


/******************************************************
 * gst_v4l2src_capture_deinit():
 *   deinitialize the capture system
 * return value: TRUE on success, FALSE on error
 ******************************************************/

gboolean
gst_v4l2src_capture_deinit (GstV4l2Src *v4l2src)
{
	gint n;

	DEBUG("deinitting capture system");
	GST_V4L2_CHECK_OPEN(GST_V4L2ELEMENT(v4l2src));
	GST_V4L2_CHECK_ACTIVE(GST_V4L2ELEMENT(v4l2src));

	/* unmap the buffer */
	for (n=0;n<v4l2src->breq.count;n++) {
		if (!GST_V4L2ELEMENT(v4l2src)->buffer[n])
			break;
		munmap(GST_V4L2ELEMENT(v4l2src)->buffer[n], v4l2src->format.fmt.pix.sizeimage);
		GST_V4L2ELEMENT(v4l2src)->buffer[n] = NULL;
	}
	g_free(GST_V4L2ELEMENT(v4l2src)->buffer);
	GST_V4L2ELEMENT(v4l2src)->buffer = NULL;

	return TRUE;
}