From 141d3b3593722eb3d588e7c4b1542f810bc25853 Mon Sep 17 00:00:00 2001
From: Koen Kooi <koen@dominion.thruhere.net>
Date: Thu, 5 Jun 2014 11:29:20 -0500
Subject: [PATCH] Add stdout mode to allow streaming over the network with nc

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
Signed-off-by: Chase Maupin <Chase.Maupin@ti.com>
---
 yavta.c |  315 ++++++++++++++++++++++++++++++++++-----------------------------
 1 file changed, 169 insertions(+), 146 deletions(-)

diff --git a/yavta.c b/yavta.c
index 32adc26..b398da0 100644
--- a/yavta.c
+++ b/yavta.c
@@ -309,7 +309,7 @@ static bool video_has_fd(struct device *dev)
 static int video_set_fd(struct device *dev, int fd)
 {
 	if (video_has_fd(dev)) {
-		printf("Can't set fd (already open).\n");
+		fprintf(stderr, "Can't set fd (already open).\n");
 		return -1;
 	}
 
@@ -321,18 +321,18 @@ static int video_set_fd(struct device *dev, int fd)
 static int video_open(struct device *dev, const char *devname)
 {
 	if (video_has_fd(dev)) {
-		printf("Can't open device (already open).\n");
+		fprintf(stderr, "Can't open device (already open).\n");
 		return -1;
 	}
 
 	dev->fd = open(devname, O_RDWR);
 	if (dev->fd < 0) {
-		printf("Error opening device %s: %s (%d).\n", devname,
+		fprintf(stderr, "Error opening device %s: %s (%d).\n", devname,
 		       strerror(errno), errno);
 		return dev->fd;
 	}
 
-	printf("Device %s opened.\n", devname);
+	fprintf(stderr, "Device %s opened.\n", devname);
 
 	dev->opened = 1;
 
@@ -352,7 +352,7 @@ static int video_querycap(struct device *dev, unsigned int *capabilities)
 	*capabilities = cap.capabilities & V4L2_CAP_DEVICE_CAPS
 		     ? cap.device_caps : cap.capabilities;
 
-	printf("Device `%s' on `%s' is a video %s (%s mplanes) device.\n",
+	fprintf(stderr, "Device `%s' on `%s' is a video %s (%s mplanes) device.\n",
 		cap.card, cap.bus_info,
 		video_is_capture(dev) ? "capture" : "output",
 		video_is_mplane(dev) ? "with" : "without");
@@ -370,7 +370,7 @@ static int cap_get_buf_type(unsigned int capabilities)
 	} else if (capabilities & V4L2_CAP_VIDEO_OUTPUT) {
 		return V4L2_BUF_TYPE_VIDEO_OUTPUT;
 	} else {
-		printf("Device supports neither capture nor output.\n");
+		fprintf(stderr, "Device supports neither capture nor output.\n");
 		return -EINVAL;
 	}
 
@@ -440,7 +440,7 @@ static int get_control(struct device *dev, unsigned int id, int type,
 		}
 	}
 
-	printf("unable to get control 0x%8.8x: %s (%d).\n",
+	fprintf(stderr, "unable to get control 0x%8.8x: %s (%d).\n",
 		id, strerror(errno), errno);
 	return -1;
 }
@@ -484,12 +484,12 @@ static void set_control(struct device *dev, unsigned int id, int type,
 			val = old.value;
 	}
 	if (ret == -1) {
-		printf("unable to set control 0x%8.8x: %s (%d).\n",
+		fprintf(stderr, "unable to set control 0x%8.8x: %s (%d).\n",
 			id, strerror(errno), errno);
 		return;
 	}
 
-	printf("Control 0x%08x set to %" PRId64 ", is %" PRId64 "\n",
+	fprintf(stderr, "Control 0x%08x set to %" PRId64 ", is %" PRId64 "\n",
 	       id, old_val, val);
 }
 
@@ -504,7 +504,7 @@ static int video_get_format(struct device *dev)
 
 	ret = ioctl(dev->fd, VIDIOC_G_FMT, &fmt);
 	if (ret < 0) {
-		printf("Unable to get format: %s (%d).\n", strerror(errno),
+		fprintf(stderr, "Unable to get format: %s (%d).\n", strerror(errno),
 			errno);
 		return ret;
 	}
@@ -514,7 +514,7 @@ static int video_get_format(struct device *dev)
 		dev->height = fmt.fmt.pix_mp.height;
 		dev->num_planes = fmt.fmt.pix_mp.num_planes;
 
-		printf("Video format: %s (%08x) %ux%u field %s, %u planes: \n",
+	    fprintf(stderr, "Video format: %s (%08x) %ux%u field %s, %u planes: \n",
 			v4l2_format_name(fmt.fmt.pix_mp.pixelformat), fmt.fmt.pix_mp.pixelformat,
 			fmt.fmt.pix_mp.width, fmt.fmt.pix_mp.height,
 			v4l2_field_name(fmt.fmt.pix_mp.field),
@@ -527,7 +527,7 @@ static int video_get_format(struct device *dev)
 					fmt.fmt.pix_mp.plane_fmt[i].bytesperline ?
 						fmt.fmt.pix_mp.plane_fmt[i].sizeimage : 0;
 
-			printf(" * Stride %u, buffer size %u\n",
+			fprintf(stderr, " * Stride %u, buffer size %u\n",
 				fmt.fmt.pix_mp.plane_fmt[i].bytesperline,
 				fmt.fmt.pix_mp.plane_fmt[i].sizeimage);
 		}
@@ -539,7 +539,7 @@ static int video_get_format(struct device *dev)
 		dev->plane_fmt[0].bytesperline = fmt.fmt.pix.bytesperline;
 		dev->plane_fmt[0].sizeimage = fmt.fmt.pix.bytesperline ? fmt.fmt.pix.sizeimage : 0;
 
-		printf("Video format: %s (%08x) %ux%u (stride %u) field %s buffer size %u\n",
+		fprintf(stderr, "Video format: %s (%08x) %ux%u (stride %u) field %s buffer size %u\n",
 			v4l2_format_name(fmt.fmt.pix.pixelformat), fmt.fmt.pix.pixelformat,
 			fmt.fmt.pix.width, fmt.fmt.pix.height, fmt.fmt.pix.bytesperline,
 			v4l2_field_name(fmt.fmt.pix_mp.field),
@@ -581,25 +581,25 @@ static int video_set_format(struct device *dev, unsigned int w, unsigned int h,
 
 	ret = ioctl(dev->fd, VIDIOC_S_FMT, &fmt);
 	if (ret < 0) {
-		printf("Unable to set format: %s (%d).\n", strerror(errno),
+		fprintf(stderr, "Unable to set format: %s (%d).\n", strerror(errno),
 			errno);
 		return ret;
 	}
 
 	if (video_is_mplane(dev)) {
-		printf("Video format set: %s (%08x) %ux%u field %s, %u planes: \n",
+		fprintf(stderr, "Video format set: %s (%08x) %ux%u field %s, %u planes: \n",
 			v4l2_format_name(fmt.fmt.pix_mp.pixelformat), fmt.fmt.pix_mp.pixelformat,
 			fmt.fmt.pix_mp.width, fmt.fmt.pix_mp.height,
 			v4l2_field_name(fmt.fmt.pix_mp.field),
 			fmt.fmt.pix_mp.num_planes);
 
 		for (i = 0; i < fmt.fmt.pix_mp.num_planes; i++) {
-			printf(" * Stride %u, buffer size %u\n",
+			fprintf(stderr, " * Stride %u, buffer size %u\n",
 				fmt.fmt.pix_mp.plane_fmt[i].bytesperline,
 				fmt.fmt.pix_mp.plane_fmt[i].sizeimage);
 		}
 	} else {
-		printf("Video format set: %s (%08x) %ux%u (stride %u) field %s buffer size %u\n",
+		fprintf(stderr, "Video format set: %s (%08x) %ux%u (stride %u) field %s buffer size %u\n",
 			v4l2_format_name(fmt.fmt.pix.pixelformat), fmt.fmt.pix.pixelformat,
 			fmt.fmt.pix.width, fmt.fmt.pix.height, fmt.fmt.pix.bytesperline,
 			v4l2_field_name(fmt.fmt.pix.field),
@@ -619,16 +619,16 @@ static int video_set_framerate(struct device *dev, struct v4l2_fract *time_per_f
 
 	ret = ioctl(dev->fd, VIDIOC_G_PARM, &parm);
 	if (ret < 0) {
-		printf("Unable to get frame rate: %s (%d).\n",
+		fprintf(stderr, "Unable to get frame rate: %s (%d).\n",
 			strerror(errno), errno);
 		return ret;
 	}
 
-	printf("Current frame rate: %u/%u\n",
+	fprintf(stderr, "Current frame rate: %u/%u\n",
 		parm.parm.capture.timeperframe.numerator,
 		parm.parm.capture.timeperframe.denominator);
 
-	printf("Setting frame rate to: %u/%u\n",
+	fprintf(stderr, "Setting frame rate to: %u/%u\n",
 		time_per_frame->numerator,
 		time_per_frame->denominator);
 
@@ -637,19 +637,19 @@ static int video_set_framerate(struct device *dev, struct v4l2_fract *time_per_f
 
 	ret = ioctl(dev->fd, VIDIOC_S_PARM, &parm);
 	if (ret < 0) {
-		printf("Unable to set frame rate: %s (%d).\n", strerror(errno),
+		fprintf(stderr, "Unable to set frame rate: %s (%d).\n", strerror(errno),
 			errno);
 		return ret;
 	}
 
 	ret = ioctl(dev->fd, VIDIOC_G_PARM, &parm);
 	if (ret < 0) {
-		printf("Unable to get frame rate: %s (%d).\n", strerror(errno),
+		fprintf(stderr, "Unable to get frame rate: %s (%d).\n", strerror(errno),
 			errno);
 		return ret;
 	}
 
-	printf("Frame rate set: %u/%u\n",
+	fprintf(stderr, "Frame rate set: %u/%u\n",
 		parm.parm.capture.timeperframe.numerator,
 		parm.parm.capture.timeperframe.denominator);
 	return 0;
@@ -674,7 +674,7 @@ static int video_buffer_mmap(struct device *dev, struct buffer *buffer,
 		buffer->mem[i] = mmap(0, length, PROT_READ | PROT_WRITE, MAP_SHARED,
 				      dev->fd, offset);
 		if (buffer->mem[i] == MAP_FAILED) {
-			printf("Unable to map buffer %u/%u: %s (%d)\n",
+			fprintf(stderr, "Unable to map buffer %u/%u: %s (%d)\n",
 			       buffer->idx, i, strerror(errno), errno);
 			return -1;
 		}
@@ -682,7 +682,7 @@ static int video_buffer_mmap(struct device *dev, struct buffer *buffer,
 		buffer->size[i] = length;
 		buffer->padding[i] = 0;
 
-		printf("Buffer %u/%u mapped at address %p.\n",
+		fprintf(stderr, "Buffer %u/%u mapped at address %p.\n",
 		       buffer->idx, i, buffer->mem[i]);
 	}
 
@@ -697,7 +697,7 @@ static int video_buffer_munmap(struct device *dev, struct buffer *buffer)
 	for (i = 0; i < dev->num_planes; i++) {
 		ret = munmap(buffer->mem[i], buffer->size[i]);
 		if (ret < 0) {
-			printf("Unable to unmap buffer %u/%u: %s (%d)\n",
+			fprintf(stderr, "Unable to unmap buffer %u/%u: %s (%d)\n",
 			       buffer->idx, i, strerror(errno), errno);
 		}
 
@@ -725,7 +725,7 @@ static int video_buffer_alloc_userptr(struct device *dev, struct buffer *buffer,
 		ret = posix_memalign(&buffer->mem[i], page_size,
 				     length + offset + padding);
 		if (ret < 0) {
-			printf("Unable to allocate buffer %u/%u (%d)\n",
+			fprintf(stderr, "Unable to allocate buffer %u/%u (%d)\n",
 			       buffer->idx, i, ret);
 			return -ENOMEM;
 		}
@@ -734,7 +734,7 @@ static int video_buffer_alloc_userptr(struct device *dev, struct buffer *buffer,
 		buffer->size[i] = length;
 		buffer->padding[i] = padding;
 
-		printf("Buffer %u/%u allocated at address %p.\n",
+		fprintf(stderr, "Buffer %u/%u allocated at address %p.\n",
 		       buffer->idx, i, buffer->mem[i]);
 	}
 
@@ -809,12 +809,12 @@ static int video_alloc_buffers(struct device *dev, int nbufs,
 
 	ret = ioctl(dev->fd, VIDIOC_REQBUFS, &rb);
 	if (ret < 0) {
-		printf("Unable to request buffers: %s (%d).\n", strerror(errno),
+		fprintf(stderr, "Unable to request buffers: %s (%d).\n", strerror(errno),
 			errno);
 		return ret;
 	}
 
-	printf("%u buffers requested.\n", rb.count);
+	fprintf(stderr, "%u buffers requested.\n", rb.count);
 
 	buffers = malloc(rb.count * sizeof buffers[0]);
 	if (buffers == NULL)
@@ -835,12 +835,12 @@ static int video_alloc_buffers(struct device *dev, int nbufs,
 
 		ret = ioctl(dev->fd, VIDIOC_QUERYBUF, &buf);
 		if (ret < 0) {
-			printf("Unable to query buffer %u: %s (%d).\n", i,
+			fprintf(stderr, "Unable to query buffer %u: %s (%d).\n", i,
 				strerror(errno), errno);
 			return ret;
 		}
 		get_ts_flags(buf.flags, &ts_type, &ts_source);
-		printf("length: %u offset: %u timestamp type/source: %s/%s\n",
+		fprintf(stderr, "length: %u offset: %u timestamp type/source: %s/%s\n",
 		       buf.length, buf.m.offset, ts_type, ts_source);
 
 		buffers[i].idx = i;
@@ -899,12 +899,12 @@ static int video_free_buffers(struct device *dev)
 
 	ret = ioctl(dev->fd, VIDIOC_REQBUFS, &rb);
 	if (ret < 0) {
-		printf("Unable to release buffers: %s (%d).\n",
+		fprintf(stderr, "Unable to release buffers: %s (%d).\n",
 			strerror(errno), errno);
 		return ret;
 	}
 
-	printf("%u buffers released.\n", dev->nbufs);
+	fprintf(stderr, "%u buffers released.\n", dev->nbufs);
 
 	free(dev->buffers);
 	dev->nbufs = 0;
@@ -974,7 +974,7 @@ static int video_queue_buffer(struct device *dev, int index, enum buffer_fill_mo
 
 	ret = ioctl(dev->fd, VIDIOC_QBUF, &buf);
 	if (ret < 0)
-		printf("Unable to queue buffer: %s (%d).\n",
+		fprintf(stderr, "Unable to queue buffer: %s (%d).\n",
 			strerror(errno), errno);
 
 	return ret;
@@ -987,7 +987,7 @@ static int video_enable(struct device *dev, int enable)
 
 	ret = ioctl(dev->fd, enable ? VIDIOC_STREAMON : VIDIOC_STREAMOFF, &type);
 	if (ret < 0) {
-		printf("Unable to %s streaming: %s (%d).\n",
+		fprintf(stderr, "Unable to %s streaming: %s (%d).\n",
 			enable ? "start" : "stop", strerror(errno), errno);
 		return ret;
 	}
@@ -1009,10 +1009,10 @@ static void video_query_menu(struct device *dev, struct v4l2_queryctrl *query,
 			continue;
 
 		if (query->type == V4L2_CTRL_TYPE_MENU)
-			printf("  %u: %.32s%s\n", menu.index, menu.name,
+			fprintf(stderr, "  %u: %.32s%s\n", menu.index, menu.name,
 			       menu.index == value ? " (*)" : "");
 		else
-			printf("  %u: %lld%s\n", menu.index, menu.value,
+			fprintf(stderr, "  %u: %lld%s\n", menu.index, menu.value,
 			       menu.index == value ? " (*)" : "");
 	};
 }
@@ -1043,7 +1043,7 @@ static void video_list_controls(struct device *dev)
 			continue;
 
 		if (query.type == V4L2_CTRL_TYPE_CTRL_CLASS) {
-			printf("--- %s (class 0x%08x) ---\n", query.name, query.id);
+			fprintf(stderr, "--- %s (class 0x%08x) ---\n", query.name, query.id);
 			continue;
 		}
 
@@ -1053,7 +1053,7 @@ static void video_list_controls(struct device *dev)
 		else
 			sprintf(value, "%" PRId64, val64);
 
-		printf("control 0x%08x `%s' min %d max %d step %d default %d current %s.\n",
+		fprintf(stderr, "control 0x%08x `%s' min %d max %d step %d default %d current %s.\n",
 			query.id, query.name, query.minimum, query.maximum,
 			query.step, query.default_value, value);
 
@@ -1065,9 +1065,9 @@ static void video_list_controls(struct device *dev)
 	}
 
 	if (nctrls)
-		printf("%u control%s found.\n", nctrls, nctrls > 1 ? "s" : "");
+		fprintf(stderr, "%u control%s found.\n", nctrls, nctrls > 1 ? "s" : "");
 	else
-		printf("No control found.\n");
+		fprintf(stderr, "No control found.\n");
 }
 
 static void video_enum_frame_intervals(struct device *dev, __u32 pixelformat,
@@ -1088,30 +1088,30 @@ static void video_enum_frame_intervals(struct device *dev, __u32 pixelformat,
 			break;
 
 		if (i != ival.index)
-			printf("Warning: driver returned wrong ival index "
+			fprintf(stderr, "Warning: driver returned wrong ival index "
 				"%u.\n", ival.index);
 		if (pixelformat != ival.pixel_format)
-			printf("Warning: driver returned wrong ival pixel "
+			fprintf(stderr, "Warning: driver returned wrong ival pixel "
 				"format %08x.\n", ival.pixel_format);
 		if (width != ival.width)
-			printf("Warning: driver returned wrong ival width "
+			fprintf(stderr, "Warning: driver returned wrong ival width "
 				"%u.\n", ival.width);
 		if (height != ival.height)
-			printf("Warning: driver returned wrong ival height "
+			fprintf(stderr, "Warning: driver returned wrong ival height "
 				"%u.\n", ival.height);
 
 		if (i != 0)
-			printf(", ");
+			fprintf(stderr, ", ");
 
 		switch (ival.type) {
 		case V4L2_FRMIVAL_TYPE_DISCRETE:
-			printf("%u/%u",
+			fprintf(stderr, "%u/%u",
 				ival.discrete.numerator,
 				ival.discrete.denominator);
 			break;
 
 		case V4L2_FRMIVAL_TYPE_CONTINUOUS:
-			printf("%u/%u - %u/%u",
+			fprintf(stderr, "%u/%u - %u/%u",
 				ival.stepwise.min.numerator,
 				ival.stepwise.min.denominator,
 				ival.stepwise.max.numerator,
@@ -1119,7 +1119,7 @@ static void video_enum_frame_intervals(struct device *dev, __u32 pixelformat,
 			return;
 
 		case V4L2_FRMIVAL_TYPE_STEPWISE:
-			printf("%u/%u - %u/%u (by %u/%u)",
+			fprintf(stderr, "%u/%u - %u/%u (by %u/%u)",
 				ival.stepwise.min.numerator,
 				ival.stepwise.min.denominator,
 				ival.stepwise.max.numerator,
@@ -1149,23 +1149,23 @@ static void video_enum_frame_sizes(struct device *dev, __u32 pixelformat)
 			break;
 
 		if (i != frame.index)
-			printf("Warning: driver returned wrong frame index "
+			fprintf(stderr, "Warning: driver returned wrong frame index "
 				"%u.\n", frame.index);
 		if (pixelformat != frame.pixel_format)
-			printf("Warning: driver returned wrong frame pixel "
+			fprintf(stderr, "Warning: driver returned wrong frame pixel "
 				"format %08x.\n", frame.pixel_format);
 
 		switch (frame.type) {
 		case V4L2_FRMSIZE_TYPE_DISCRETE:
-			printf("\tFrame size: %ux%u (", frame.discrete.width,
+			fprintf(stderr, "\tFrame size: %ux%u (", frame.discrete.width,
 				frame.discrete.height);
 			video_enum_frame_intervals(dev, frame.pixel_format,
 				frame.discrete.width, frame.discrete.height);
-			printf(")\n");
+			fprintf(stderr, ")\n");
 			break;
 
 		case V4L2_FRMSIZE_TYPE_CONTINUOUS:
-			printf("\tFrame size: %ux%u - %ux%u (",
+			fprintf(stderr, "\tFrame size: %ux%u - %ux%u (",
 				frame.stepwise.min_width,
 				frame.stepwise.min_height,
 				frame.stepwise.max_width,
@@ -1173,11 +1173,11 @@ static void video_enum_frame_sizes(struct device *dev, __u32 pixelformat)
 			video_enum_frame_intervals(dev, frame.pixel_format,
 				frame.stepwise.max_width,
 				frame.stepwise.max_height);
-			printf(")\n");
+			fprintf(stderr, ")\n");
 			break;
 
 		case V4L2_FRMSIZE_TYPE_STEPWISE:
-			printf("\tFrame size: %ux%u - %ux%u (by %ux%u) (\n",
+			fprintf(stderr, "\tFrame size: %ux%u - %ux%u (by %ux%u) (\n",
 				frame.stepwise.min_width,
 				frame.stepwise.min_height,
 				frame.stepwise.max_width,
@@ -1187,7 +1187,7 @@ static void video_enum_frame_sizes(struct device *dev, __u32 pixelformat)
 			video_enum_frame_intervals(dev, frame.pixel_format,
 				frame.stepwise.max_width,
 				frame.stepwise.max_height);
-			printf(")\n");
+			fprintf(stderr, ")\n");
 			break;
 
 		default:
@@ -1211,19 +1211,19 @@ static void video_enum_formats(struct device *dev, enum v4l2_buf_type type)
 			break;
 
 		if (i != fmt.index)
-			printf("Warning: driver returned wrong format index "
+			fprintf(stderr, "Warning: driver returned wrong format index "
 				"%u.\n", fmt.index);
 		if (type != fmt.type)
-			printf("Warning: driver returned wrong format type "
+			fprintf(stderr, "Warning: driver returned wrong format type "
 				"%u.\n", fmt.type);
 
-		printf("\tFormat %u: %s (%08x)\n", i,
+		fprintf(stderr, "\tFormat %u: %s (%08x)\n", i,
 			v4l2_format_name(fmt.pixelformat), fmt.pixelformat);
-		printf("\tType: %s (%u)\n", v4l2_buf_type_name(fmt.type),
+		fprintf(stderr, "\tType: %s (%u)\n", v4l2_buf_type_name(fmt.type),
 			fmt.type);
-		printf("\tName: %.32s\n", fmt.description);
+		fprintf(stderr, "\tName: %.32s\n", fmt.description);
 		video_enum_frame_sizes(dev, fmt.pixelformat);
-		printf("\n");
+		fprintf(stderr, "\n");
 	}
 }
 
@@ -1241,13 +1241,13 @@ static void video_enum_inputs(struct device *dev)
 			break;
 
 		if (i != input.index)
-			printf("Warning: driver returned wrong input index "
+			fprintf(stderr, "Warning: driver returned wrong input index "
 				"%u.\n", input.index);
 
-		printf("\tInput %u: %s.\n", i, input.name);
+		fprintf(stderr, "\tInput %u: %s.\n", i, input.name);
 	}
 
-	printf("\n");
+	fprintf(stderr, "\n");
 }
 
 static int video_get_input(struct device *dev)
@@ -1257,7 +1257,7 @@ static int video_get_input(struct device *dev)
 
 	ret = ioctl(dev->fd, VIDIOC_G_INPUT, &input);
 	if (ret < 0) {
-		printf("Unable to get current input: %s (%d).\n",
+		fprintf(stderr, "Unable to get current input: %s (%d).\n",
 			strerror(errno), errno);
 		return ret;
 	}
@@ -1272,7 +1272,7 @@ static int video_set_input(struct device *dev, unsigned int input)
 
 	ret = ioctl(dev->fd, VIDIOC_S_INPUT, &_input);
 	if (ret < 0)
-		printf("Unable to select input %u: %s (%d).\n", input,
+		fprintf(stderr, "Unable to select input %u: %s (%d).\n", input,
 			strerror(errno), errno);
 
 	return ret;
@@ -1291,14 +1291,14 @@ static int video_set_quality(struct device *dev, unsigned int quality)
 
 	ret = ioctl(dev->fd, VIDIOC_S_JPEGCOMP, &jpeg);
 	if (ret < 0) {
-		printf("Unable to set quality to %u: %s (%d).\n", quality,
+		fprintf(stderr, "Unable to set quality to %u: %s (%d).\n", quality,
 			strerror(errno), errno);
 		return ret;
 	}
 
 	ret = ioctl(dev->fd, VIDIOC_G_JPEGCOMP, &jpeg);
 	if (ret >= 0)
-		printf("Quality set to %u\n", jpeg.quality);
+		fprintf(stderr, "Quality set to %u\n", jpeg.quality);
 
 	return 0;
 }
@@ -1313,7 +1313,7 @@ static int video_load_test_pattern(struct device *dev, const char *filename)
 	if (filename != NULL) {
 		fd = open(filename, O_RDONLY);
 		if (fd == -1) {
-			printf("Unable to open test pattern file '%s': %s (%d).\n",
+			fprintf(stderr, "Unable to open test pattern file '%s': %s (%d).\n",
 				filename, strerror(errno), errno);
 			return -errno;
 		}
@@ -1331,7 +1331,7 @@ static int video_load_test_pattern(struct device *dev, const char *filename)
 		if (filename != NULL) {
 			ret = read(fd, dev->pattern[plane], size);
 			if (ret != (int)size && dev->plane_fmt[plane].bytesperline != 0) {
-				printf("Test pattern file size %u doesn't match image size %u\n",
+				fprintf(stderr, "Test pattern file size %u doesn't match image size %u\n",
 					ret, size);
 				ret = -EINVAL;
 				goto done;
@@ -1341,7 +1341,7 @@ static int video_load_test_pattern(struct device *dev, const char *filename)
 			unsigned int i;
 
 			if (dev->plane_fmt[plane].bytesperline == 0) {
-				printf("Compressed format detected for plane %u and no test pattern filename given.\n"
+				fprintf(stderr, "Compressed format detected for plane %u and no test pattern filename given.\n"
 					"The test pattern can't be generated automatically.\n", plane);
 				ret = -EINVAL;
 				goto done;
@@ -1410,7 +1410,7 @@ static void video_verify_buffer(struct device *dev, struct v4l2_buffer *buf)
 
 		if (dev->plane_fmt[plane].sizeimage &&
 		    dev->plane_fmt[plane].sizeimage != length)
-			printf("Warning: bytes used %u != image size %u for plane %u\n",
+			fprintf(stderr, "Warning: bytes used %u != image size %u for plane %u\n",
 			       length, dev->plane_fmt[plane].sizeimage, plane);
 
 		if (buffer->padding[plane] == 0)
@@ -1424,16 +1424,16 @@ static void video_verify_buffer(struct device *dev, struct v4l2_buffer *buf)
 		}
 
 		if (errors) {
-			printf("Warning: %u bytes overwritten among %u first padding bytes for plane %u\n",
+			fprintf(stderr, "Warning: %u bytes overwritten among %u first padding bytes for plane %u\n",
 			       errors, dirty, plane);
 
 			dirty = (dirty + 15) & ~15;
 			dirty = dirty > 32 ? 32 : dirty;
 
 			for (i = 0; i < dirty; ++i) {
-				printf("%02x ", data[i]);
+				fprintf(stderr, "%02x ", data[i]);
 				if (i % 16 == 15)
-					printf("\n");
+					fprintf(stderr, "\n");
 			}
 		}
 	}
@@ -1481,18 +1481,32 @@ static void video_save_image(struct device *dev, struct v4l2_buffer *buf,
 
 		ret = write(fd, dev->buffers[buf->index].mem[i], length);
 		if (ret < 0) {
-			printf("write error: %s (%d)\n", strerror(errno), errno);
+			fprintf(stderr, "write error: %s (%d)\n", strerror(errno), errno);
 			break;
 		} else if (ret != (int)length)
-			printf("write error: only %d bytes written instead of %u\n",
+			fprintf(stderr, "write error: only %d bytes written instead of %u\n",
 			       ret, length);
 	}
 	close(fd);
 }
 
+static void video_stdout_image(struct device *dev, struct v4l2_buffer *buf)
+{
+    int ret;
+
+    fprintf(stderr, "stdout");
+    ret = fwrite(dev->buffers[buf->index].mem, buf->bytesused, 1, stdout);
+
+    if (ret < 0)
+        fprintf(stderr, "write error: %s (%d)\n", strerror(errno), errno);
+    else if (ret != (int)buf->bytesused)
+        fprintf(stderr, "write error: only %d bytes written instead of %u\n",
+                ret, buf->bytesused);
+}
+
 static int video_do_capture(struct device *dev, unsigned int nframes,
 	unsigned int skip, unsigned int delay, const char *pattern,
-	int do_requeue_last, enum buffer_fill_mode fill)
+	int do_requeue_last, enum buffer_fill_mode fill, int do_stdout)
 {
 	struct v4l2_plane planes[VIDEO_MAX_PLANES];
 	struct v4l2_buffer buf;
@@ -1529,7 +1543,7 @@ static int video_do_capture(struct device *dev, unsigned int nframes,
 		ret = ioctl(dev->fd, VIDIOC_DQBUF, &buf);
 		if (ret < 0) {
 			if (errno != EIO) {
-				printf("Unable to dequeue buffer: %s (%d).\n",
+				fprintf(stderr, "Unable to dequeue buffer: %s (%d).\n",
 					strerror(errno), errno);
 				goto done;
 			}
@@ -1550,7 +1564,7 @@ static int video_do_capture(struct device *dev, unsigned int nframes,
 
 		clock_gettime(CLOCK_MONOTONIC, &ts);
 		get_ts_flags(buf.flags, &ts_type, &ts_source);
-		printf("%u (%u) [%c] %s %u %u B %ld.%06ld %ld.%06ld %.3f fps ts %s/%s\n", i, buf.index,
+		fprintf(stderr, "%u (%u) [%c] %s %u %u B %ld.%06ld %ld.%06ld %.3f fps ts %s/%s\n", i, buf.index,
 			(buf.flags & V4L2_BUF_FLAG_ERROR) ? 'E' : '-',
 			v4l2_field_name(buf.field),
 			buf.sequence, buf.bytesused, buf.timestamp.tv_sec,
@@ -1563,6 +1577,9 @@ static int video_do_capture(struct device *dev, unsigned int nframes,
 		if (video_is_capture(dev) && pattern && !skip)
 			video_save_image(dev, &buf, pattern, i);
 
+		if (video_is_capture(dev) && do_stdout && !skip)
+			video_stdout_image(dev, &buf);
+
 		if (skip)
 			--skip;
 
@@ -1577,7 +1594,7 @@ static int video_do_capture(struct device *dev, unsigned int nframes,
 
 		ret = video_queue_buffer(dev, buf.index, fill);
 		if (ret < 0) {
-			printf("Unable to requeue buffer: %s (%d).\n",
+			fprintf(stderr, "Unable to requeue buffer: %s (%d).\n",
 				strerror(errno), errno);
 			goto done;
 		}
@@ -1587,7 +1604,7 @@ static int video_do_capture(struct device *dev, unsigned int nframes,
 	video_enable(dev, 0);
 
 	if (nframes == 0) {
-		printf("No frames captured.\n");
+		fprintf(stderr, "No frames captured.\n");
 		goto done;
 	}
 
@@ -1604,7 +1621,7 @@ static int video_do_capture(struct device *dev, unsigned int nframes,
 	bps = size/(ts.tv_nsec/1000.0+1000000.0*ts.tv_sec)*1000000.0;
 	fps = i/(ts.tv_nsec/1000.0+1000000.0*ts.tv_sec)*1000000.0;
 
-	printf("Captured %u frames in %lu.%06lu seconds (%f fps, %f B/s).\n",
+	fprintf(stderr, "Captured %u frames in %lu.%06lu seconds (%f fps, %f B/s).\n",
 		i, ts.tv_sec, ts.tv_nsec/1000, fps, bps);
 
 done:
@@ -1616,42 +1633,42 @@ done:
 
 static void usage(const char *argv0)
 {
-	printf("Usage: %s [options] device\n", argv0);
-	printf("Supported options:\n");
-	printf("-B, --buffer-type		Buffer type (\"capture\", \"output\",\n");
-	printf("                                \"capture-mplane\" or \"output-mplane\")\n");
-	printf("-c, --capture[=nframes]		Capture frames\n");
-	printf("-C, --check-overrun		Verify dequeued frames for buffer overrun\n");
-	printf("-d, --delay			Delay (in ms) before requeuing buffers\n");
-	printf("-f, --format format		Set the video format\n");
-	printf("-F, --file[=name]		Read/write frames from/to disk\n");
-	printf("\tFor video capture devices, the first '#' character in the file name is\n");
-	printf("\texpanded to the frame sequence number. The default file name is\n");
-	printf("\t'frame-#.bin'.\n");
-	printf("-h, --help			Show this help screen\n");
-	printf("-i, --input input		Select the video input\n");
-	printf("-I, --fill-frames		Fill frames with check pattern before queuing them\n");
-	printf("-l, --list-controls		List available controls\n");
-	printf("-n, --nbufs n			Set the number of video buffers\n");
-	printf("-p, --pause			Pause before starting the video stream\n");
-	printf("-q, --quality n			MJPEG quality (0-100)\n");
-	printf("-r, --get-control ctrl		Get control 'ctrl'\n");
-	printf("-R, --realtime=[priority]	Enable realtime RR scheduling\n");
-	printf("-s, --size WxH			Set the frame size\n");
-	printf("-t, --time-per-frame num/denom	Set the time per frame (eg. 1/25 = 25 fps)\n");
-	printf("-u, --userptr			Use the user pointers streaming method\n");
-	printf("-w, --set-control 'ctrl value'	Set control 'ctrl' to 'value'\n");
-	printf("    --enum-formats		Enumerate formats\n");
-	printf("    --enum-inputs		Enumerate inputs\n");
-	printf("    --fd                        Use a numeric file descriptor insted of a device\n");
-	printf("    --field			Interlaced format field order\n");
-	printf("    --no-query			Don't query capabilities on open\n");
-	printf("    --offset			User pointer buffer offset from page start\n");
-	printf("    --requeue-last		Requeue the last buffers before streamoff\n");
-	printf("    --timestamp-source		Set timestamp source on output buffers [eof, soe]\n");
-	printf("    --skip n			Skip the first n frames\n");
-	printf("    --sleep-forever		Sleep forever after configuring the device\n");
-	printf("    --stride value		Line stride in bytes\n");
+	fprintf(stderr, "Usage: %s [options] device\n", argv0);
+	fprintf(stderr, "Supported options:\n");
+	fprintf(stderr, "-B, --buffer-type		Buffer type (\"capture\", \"output\",\n");
+	fprintf(stderr, "                                \"capture-mplane\" or \"output-mplane\")\n");
+	fprintf(stderr, "-c, --capture[=nframes]		Capture frames\n");
+	fprintf(stderr, "-C, --check-overrun		Verify dequeued frames for buffer overrun\n");
+	fprintf(stderr, "-d, --delay			Delay (in ms) before requeuing buffers\n");
+	fprintf(stderr, "-f, --format format		Set the video format\n");
+	fprintf(stderr, "-F, --file[=name]		Read/write frames from/to disk\n");
+	fprintf(stderr, "\tFor video capture devices, the first '#' character in the file name is\n");
+	fprintf(stderr, "\texpanded to the frame sequence number. The default file name is\n");
+	fprintf(stderr, "\t'frame-#.bin'.\n");
+	fprintf(stderr, "-h, --help			Show this help screen\n");
+	fprintf(stderr, "-i, --input input		Select the video input\n");
+	fprintf(stderr, "-I, --fill-frames		Fill frames with check pattern before queuing them\n");
+	fprintf(stderr, "-l, --list-controls		List available controls\n");
+	fprintf(stderr, "-n, --nbufs n			Set the number of video buffers\n");
+	fprintf(stderr, "-p, --pause			Pause before starting the video stream\n");
+	fprintf(stderr, "-q, --quality n			MJPEG quality (0-100)\n");
+	fprintf(stderr, "-r, --get-control ctrl		Get control 'ctrl'\n");
+	fprintf(stderr, "-R, --realtime=[priority]	Enable realtime RR scheduling\n");
+	fprintf(stderr, "-s, --size WxH			Set the frame size\n");
+	fprintf(stderr, "-t, --time-per-frame num/denom	Set the time per frame (eg. 1/25 = 25 fps)\n");
+	fprintf(stderr, "-u, --userptr			Use the user pointers streaming method\n");
+	fprintf(stderr, "-w, --set-control 'ctrl value'	Set control 'ctrl' to 'value'\n");
+	fprintf(stderr, "    --enum-formats		Enumerate formats\n");
+	fprintf(stderr, "    --enum-inputs		Enumerate inputs\n");
+	fprintf(stderr, "    --fd                        Use a numeric file descriptor insted of a device\n");
+	fprintf(stderr, "    --field			Interlaced format field order\n");
+	fprintf(stderr, "    --no-query			Don't query capabilities on open\n");
+	fprintf(stderr, "    --offset			User pointer buffer offset from page start\n");
+	fprintf(stderr, "    --requeue-last		Requeue the last buffers before streamoff\n");
+	fprintf(stderr, "    --timestamp-source		Set timestamp source on output buffers [eof, soe]\n");
+	fprintf(stderr, "    --skip n			Skip the first n frames\n");
+	fprintf(stderr, "    --sleep-forever		Sleep forever after configuring the device\n");
+	fprintf(stderr, "    --stride value		Line stride in bytes\n");
 }
 
 #define OPT_ENUM_FORMATS	256
@@ -1665,6 +1682,7 @@ static void usage(const char *argv0)
 #define OPT_FD			264
 #define OPT_TSTAMP_SRC		265
 #define OPT_FIELD		266
+#define OPT_STDOUT		267
 
 static struct option opts[] = {
 	{"buffer-type", 1, 0, 'B'},
@@ -1677,6 +1695,7 @@ static struct option opts[] = {
 	{"field", 1, 0, OPT_FIELD},
 	{"file", 2, 0, 'F'},
 	{"fill-frames", 0, 0, 'I'},
+	{"stdout", 0, 0, OPT_STDOUT},
 	{"format", 1, 0, 'f'},
 	{"help", 0, 0, 'h'},
 	{"input", 1, 0, 'i'},
@@ -1717,7 +1736,8 @@ int main(int argc, char *argv[])
 	int do_list_controls = 0, do_get_control = 0, do_set_control = 0;
 	int do_sleep_forever = 0, do_requeue_last = 0;
 	int do_rt = 0;
-	int no_query = 0;
+	int no_query = 0; 
+	int do_stdout = 0;
 	char *endptr;
 	int c;
 
@@ -1755,7 +1775,7 @@ int main(int argc, char *argv[])
 		case 'B':
 			ret = v4l2_buf_type_from_string(optarg);
 			if (ret == -1) {
-				printf("Bad buffer type \"%s\"\n", optarg);
+				fprintf(stderr, "Bad buffer type \"%s\"\n", optarg);
 				return 1;
 			}
 			video_set_buf_type(&dev, ret);
@@ -1775,7 +1795,7 @@ int main(int argc, char *argv[])
 			do_set_format = 1;
 			info = v4l2_format_by_name(optarg);
 			if (info == NULL) {
-				printf("Unsupported video format '%s'\n", optarg);
+				fprintf(stderr, "Unsupported video format '%s'\n", optarg);
 				return 1;
 			}
 			pixelformat = info->fourcc;
@@ -1812,7 +1832,7 @@ int main(int argc, char *argv[])
 		case 'r':
 			ctrl_name = strtol(optarg, &endptr, 0);
 			if (*endptr != 0) {
-				printf("Invalid control name '%s'\n", optarg);
+				fprintf(stderr, "Invalid control name '%s'\n", optarg);
 				return 1;
 			}
 			do_get_control = 1;
@@ -1826,12 +1846,12 @@ int main(int argc, char *argv[])
 			do_set_format = 1;
 			width = strtol(optarg, &endptr, 10);
 			if (*endptr != 'x' || endptr == optarg) {
-				printf("Invalid size '%s'\n", optarg);
+				fprintf(stderr, "Invalid size '%s'\n", optarg);
 				return 1;
 			}
 			height = strtol(endptr + 1, &endptr, 10);
 			if (*endptr != 0) {
-				printf("Invalid size '%s'\n", optarg);
+				fprintf(stderr, "Invalid size '%s'\n", optarg);
 				return 1;
 			}
 			break;
@@ -1839,12 +1859,12 @@ int main(int argc, char *argv[])
 			do_set_time_per_frame = 1;
 			time_per_frame.numerator = strtol(optarg, &endptr, 10);
 			if (*endptr != '/' || endptr == optarg) {
-				printf("Invalid time per frame '%s'\n", optarg);
+				fprintf(stderr, "Invalid time per frame '%s'\n", optarg);
 				return 1;
 			}
 			time_per_frame.denominator = strtol(endptr + 1, &endptr, 10);
 			if (*endptr != 0) {
-				printf("Invalid time per frame '%s'\n", optarg);
+				fprintf(stderr, "Invalid time per frame '%s'\n", optarg);
 				return 1;
 			}
 			break;
@@ -1854,12 +1874,12 @@ int main(int argc, char *argv[])
 		case 'w':
 			ctrl_name = strtol(optarg, &endptr, 0);
 			if (*endptr != ' ' || endptr == optarg) {
-				printf("Invalid control name '%s'\n", optarg);
+				fprintf(stderr, "Invalid control name '%s'\n", optarg);
 				return 1;
 			}
 			ctrl_value = strtol(endptr + 1, &endptr, 0);
 			if (*endptr != 0) {
-				printf("Invalid control value '%s'\n", optarg);
+				fprintf(stderr, "Invalid control value '%s'\n", optarg);
 				return 1;
 			}
 			do_set_control = 1;
@@ -1873,16 +1893,16 @@ int main(int argc, char *argv[])
 		case OPT_FD:
 			ret = atoi(optarg);
 			if (ret < 0) {
-				printf("Bad file descriptor %d\n", ret);
+				fprintf(stderr, "Bad file descriptor %d\n", ret);
 				return 1;
 			}
-			printf("Using file descriptor %d\n", ret);
+			fprintf(stderr, "Using file descriptor %d\n", ret);
 			video_set_fd(&dev, ret);
 			break;
 		case OPT_FIELD:
 			field = v4l2_field_from_string(optarg);
 			if (field == (enum v4l2_field)-1) {
-				printf("Invalid field order '%s'\n", optarg);
+				fprintf(stderr, "Invalid field order '%s'\n", optarg);
 				return 1;
 			}
 			break;
@@ -1907,22 +1927,25 @@ int main(int argc, char *argv[])
 			} else if (!strcmp(optarg, "soe")) {
 				dev.buffer_output_flags |= V4L2_BUF_FLAG_TSTAMP_SRC_SOE;
 			} else {
-				printf("Invalid timestamp source %s\n", optarg);
+				fprintf(stderr, "Invalid timestamp source %s\n", optarg);
 				return 1;
 			}
 			break;
 		case OPT_USERPTR_OFFSET:
 			userptr_offset = atoi(optarg);
 			break;
+		case OPT_STDOUT:
+			do_stdout = 1;
+			break;
 		default:
-			printf("Invalid option -%c\n", c);
-			printf("Run %s -h for help.\n", argv[0]);
+			fprintf(stderr, "Invalid option -%c\n", c);
+			fprintf(stderr, "Run %s -h for help.\n", argv[0]);
 			return 1;
 		}
 	}
 
 	if ((fill_mode & BUFFER_FILL_PADDING) && memtype != V4L2_MEMORY_USERPTR) {
-		printf("Buffer overrun can only be checked in USERPTR mode.\n");
+		fprintf(stderr, "Buffer overrun can only be checked in USERPTR mode.\n");
 		return 1;
 	}
 
@@ -1959,7 +1982,7 @@ int main(int argc, char *argv[])
 		ret = get_control(&dev, ctrl_name,
 				  get_control_type(&dev, ctrl_name), &val);
 		if (ret >= 0)
-			printf("Control 0x%08x value %" PRId64 "\n", ctrl_name, val);
+			fprintf(stderr, "Control 0x%08x value %" PRId64 "\n", ctrl_name, val);
 	}
 
 	if (do_set_control)
@@ -1970,7 +1993,7 @@ int main(int argc, char *argv[])
 		video_list_controls(&dev);
 
 	if (do_enum_formats) {
-		printf("- Available formats:\n");
+		fprintf(stderr, "- Available formats:\n");
 		video_enum_formats(&dev, V4L2_BUF_TYPE_VIDEO_CAPTURE);
 		video_enum_formats(&dev, V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE);
 		video_enum_formats(&dev, V4L2_BUF_TYPE_VIDEO_OUTPUT);
@@ -1979,14 +2002,14 @@ int main(int argc, char *argv[])
 	}
 
 	if (do_enum_inputs) {
-		printf("- Available inputs:\n");
+		fprintf(stderr, "- Available inputs:\n");
 		video_enum_inputs(&dev);
 	}
 
 	if (do_set_input) {
 		video_set_input(&dev, input);
 		ret = video_get_input(&dev);
-		printf("Input %d selected\n", ret);
+		fprintf(stderr, "Input %d selected\n", ret);
 	}
 
 	/* Set the video format. */
@@ -2028,7 +2051,7 @@ int main(int argc, char *argv[])
 	}
 
 	if (do_pause) {
-		printf("Press enter to start capture\n");
+		fprintf(stderr, "Press enter to start capture\n");
 		getchar();
 	}
 
@@ -2037,12 +2060,12 @@ int main(int argc, char *argv[])
 		sched.sched_priority = rt_priority;
 		ret = sched_setscheduler(0, SCHED_RR, &sched);
 		if (ret < 0)
-			printf("Failed to select RR scheduler: %s (%d)\n",
+			fprintf(stderr, "Failed to select RR scheduler: %s (%d)\n",
 				strerror(errno), errno);
 	}
 
 	if (video_do_capture(&dev, nframes, skip, delay, filename,
-			     do_requeue_last, fill_mode) < 0) {
+			     do_requeue_last, fill_mode, do_stdout) < 0) {
 		video_close(&dev);
 		return 1;
 	}
-- 
1.7.9.5