live: Make the number of video buffers configurable

The -b argument can be used to set the number of video display buffers.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

3 files changed, 15 insertions, 5 deletions

diff --git a/live.c b/live.c
index 52c8cfd..90e0ab6 100644
--- a/live.c
+++ b/live.c
@@ -370,6 +370,7 @@ static void usage(const char *argv0)
 {
 	printf("Usage: %s [options]\n", argv0);
 	printf("Supported options:\n");
+	printf("-b, --buffers n		Use n display buffers\n");
 	printf("-h, --help		Show this help screen\n");
 	printf("-s, --skip n		Skip display of n frames out of n+1\n");
 }
@@ -385,6 +386,7 @@ int main(int argc __attribute__((__unused__)), char *argv[] __attribute__((__unu
 	struct v4l2_mbus_framefmt view_format;
 	struct v4l2_buffers_pool *pool = NULL;
 	struct timespec start, end;
+	unsigned int buffers = 3;
 	struct v4l2_rect rect;
 	int exit_code = EXIT_FAILURE;
 	const char *vo_devname;
@@ -392,8 +394,11 @@ int main(int argc __attribute__((__unused__)), char *argv[] __attribute__((__unu
 	int ret;
 	int c;
 
-	while ((c = getopt_long(argc, argv, "hs:", opts, NULL)) != -1) {
+	while ((c = getopt_long(argc, argv, "b:hs:", opts, NULL)) != -1) {
 		switch (c) {
+		case 'b':
+			buffers = atoi(optarg);
+			break;
 		case 'h':
 			usage(argv[0]);
 			return 0;
@@ -450,7 +455,7 @@ int main(int argc __attribute__((__unused__)), char *argv[] __attribute__((__unu
 		goto cleanup;
 	}
 
-	vo = vo_init(vo_devname, &vo_ops, rect.width, rect.height);
+	vo = vo_init(vo_devname, &vo_ops, buffers, rect.width, rect.height);
 	if (vo == NULL) {
 		printf("error: unable to initialize video output\n");
 		goto cleanup;
diff --git a/videoout.c b/videoout.c
index f6fbbe7..f8b6be2 100644
--- a/videoout.c
+++ b/videoout.c
@@ -37,7 +37,7 @@
 #include "isp/v4l2.h"
 #include "isp/v4l2-pool.h"
 
-#define NUM_BUFFERS 3
+#define MAX_BUFFERS	16
 
 struct videoout
 {
@@ -47,12 +47,13 @@ struct videoout
 
 	int streaming;
 
-	int queued[NUM_BUFFERS];
+	int queued[MAX_BUFFERS];
 	int num_queued;
 };
 
 struct videoout *vo_init(const char *devname,
 			 const struct video_out_operations *ops,
+			 unsigned int buffers,
 			 unsigned int width, unsigned int height)
 {
 	struct v4l2_pix_format pixfmt;
@@ -110,7 +111,10 @@ struct videoout *vo_init(const char *devname,
 	}
 
 	/* Allocate buffers. */
-	vo->pool = v4l2_buffers_pool_new(NUM_BUFFERS);
+	if (buffers > MAX_BUFFERS)
+		buffers = MAX_BUFFERS;
+
+	vo->pool = v4l2_buffers_pool_new(buffers);
 	if (vo->pool == NULL) {
 		printf("error: unable to allocate buffers pool for display.\n");
 		goto error;
diff --git a/videoout.h b/videoout.h
index 63309aa..3d459e2 100644
--- a/videoout.h
+++ b/videoout.h
@@ -34,6 +34,7 @@ struct video_out_operations {
 
 struct videoout *vo_init(const char *devname,
 			 const struct video_out_operations *ops,
+			 unsigned int buffers,
 			 unsigned int width, unsigned int height);
 void vo_cleanup(struct videoout *vo);
 int vo_enable_colorkey(struct videoout *vo, unsigned int val);