Convert unsigned 8 to float 32 [-1 to +1], which is commonly
used format for baseband signals by SDR applications.
Some implementation changes done as suggested by Hans Verkuil,
Hans de Goede and Andy Walls.
Cc: Hans Verkuil <hverk...@xs4all.nl>
Cc: Hans de Goede <hdego...@redhat.com>
Cc: Andy Walls <awa...@md.metrocast.net>
Signed-off-by: Antti Palosaari <cr...@iki.fi>
---
contrib/freebsd/include/linux/videodev2.h | 4 ++
include/linux/videodev2.h | 4 ++
lib/libv4lconvert/libv4lconvert.c | 77 +++++++++++++++++++++++++++++++
3 files changed, 85 insertions(+)
diff --git a/contrib/freebsd/include/linux/videodev2.h
b/contrib/freebsd/include/linux/videodev2.h
index 1fcfaeb..05cc19b 100644
--- a/contrib/freebsd/include/linux/videodev2.h
+++ b/contrib/freebsd/include/linux/videodev2.h
@@ -465,6 +465,10 @@ struct v4l2_pix_format {
#define V4L2_PIX_FMT_SE401 v4l2_fourcc('S', '4', '0', '1') /* se401
janggu compressed rgb */
#define V4L2_PIX_FMT_S5C_UYVY_JPG v4l2_fourcc('S', '5', 'C', 'I') /* S5C73M3
interleaved UYVY/JPEG */
+/* SDR */
+#define V4L2_PIX_FMT_SDR_FLOAT v4l2_fourcc('D', 'F', '3', '2') /* float
32-bit */
+#define V4L2_PIX_FMT_SDR_U8 v4l2_fourcc('D', 'U', '0', '8') /* unsigned
8-bit */
+
/*
* F O R M A T E N U M E R A T I O N
*/
diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
index 437f1b0..ba2a173 100644
--- a/include/linux/videodev2.h
+++ b/include/linux/videodev2.h
@@ -431,6 +431,10 @@ struct v4l2_pix_format {
#define V4L2_PIX_FMT_SE401 v4l2_fourcc('S', '4', '0', '1') /* se401
janggu compressed rgb */
#define V4L2_PIX_FMT_S5C_UYVY_JPG v4l2_fourcc('S', '5', 'C', 'I') /* S5C73M3
interleaved UYVY/JPEG */
+/* SDR */
+#define V4L2_PIX_FMT_SDR_FLOAT v4l2_fourcc('D', 'F', '3', '2') /* float
32-bit */
+#define V4L2_PIX_FMT_SDR_U8 v4l2_fourcc('D', 'U', '0', '8') /* unsigned
8-bit */
+
/*
* F O R M A T E N U M E R A T I O N
*/
diff --git a/lib/libv4lconvert/libv4lconvert.c
b/lib/libv4lconvert/libv4lconvert.c
index e2afc27..b7cc0e1 100644
--- a/lib/libv4lconvert/libv4lconvert.c
+++ b/lib/libv4lconvert/libv4lconvert.c
@@ -266,6 +266,10 @@ int v4lconvert_supported_dst_format(unsigned int
pixelformat)
{
int i;
+ /* only supported SDR destination format */
+ if (pixelformat == V4L2_PIX_FMT_SDR_FLOAT)
+ return 1;
+
for (i = 0; i < ARRAY_SIZE(supported_dst_pixfmts); i++)
if (supported_dst_pixfmts[i].fmt == pixelformat)
break;
@@ -435,6 +439,32 @@ static int v4lconvert_do_try_format_uvc(struct
v4lconvert_data *data,
return 0;
}
+static int v4lconvert_do_try_format_sdr(struct v4lconvert_data *data,
+ struct v4l2_format *dest_fmt, struct v4l2_format *src_fmt)
+{
+ int i;
+ struct v4l2_format try_fmt;
+ static const unsigned int supported_src_pixfmts_sdr[] = {
+ V4L2_PIX_FMT_SDR_FLOAT,
+ V4L2_PIX_FMT_SDR_U8,
+ };
+
+ for (i = 0; i < ARRAY_SIZE(supported_src_pixfmts_sdr); i++) {
+ try_fmt = *dest_fmt;
+ try_fmt.fmt.pix.pixelformat = supported_src_pixfmts_sdr[i];
+ if (data->dev_ops->ioctl(data->dev_ops_priv, data->fd,
+ VIDIOC_TRY_FMT, &try_fmt))
+ continue;
+
+ if (try_fmt.fmt.pix.pixelformat != supported_src_pixfmts_sdr[i])
+ continue;
+ }
+
+ *src_fmt = try_fmt;
+
+ return 0;
+}
+
static int v4lconvert_do_try_format(struct v4lconvert_data *data,
struct v4l2_format *dest_fmt, struct v4l2_format *src_fmt)
{
@@ -445,6 +475,8 @@ static int v4lconvert_do_try_format(struct v4lconvert_data
*data,
if (data->flags & V4LCONVERT_IS_UVC)
return v4lconvert_do_try_format_uvc(data, dest_fmt, src_fmt);
+ else if (dest_fmt->fmt.pix.pixelformat == V4L2_PIX_FMT_SDR_FLOAT)
+ return v4lconvert_do_try_format_sdr(data, dest_fmt, src_fmt);
for (i = 0; i < ARRAY_SIZE(supported_src_pixfmts); i++) {
/* is this format supported? */
@@ -1293,6 +1325,43 @@ static int v4lconvert_convert_pixfmt(struct
v4lconvert_data *data,
return result;
}
+/* SDR format conversions */
+static int v4lconvert_convert_sdr(struct v4lconvert_data *data,
+ unsigned char *src, int src_size,
+ unsigned char *dest, int dest_size,
+ struct v4l2_format *fmt, unsigned int dest_pix_fmt)
+{
+ int i, dest_needed;
+ unsigned int src_pix_fmt = fmt->fmt.pix.pixelformat;
+ float *fptr = (float *) dest;
+
+ switch (src_pix_fmt) {
+ case V4L2_PIX_FMT_SDR_U8:
+ /* 8-bit unsigned to 32-bit float */
+ dest_needed = src_size * sizeof(float);
+ if (dest_size < dest_needed)
+ goto err_buf_too_small;
+
+ for (i = 0; i < src_size; i++)
+ *fptr++ = (*src++ - 127.5f) / 127.5f;
+ break;
+ default:
+ V4LCONVERT_ERR("Unknown src format in conversion\n");
+ errno = EINVAL;
+ return -1;
+ }
+
+ fmt->fmt.pix.pixelformat = dest_pix_fmt;
+
+ return dest_needed;
+
+err_buf_too_small:
+ V4LCONVERT_ERR("destination buffer too small (%d < %d)\n",
+ dest_size, dest_needed);
+ errno = EFAULT;
+ return -1;
+}
+
int v4lconvert_convert(struct v4lconvert_data *data,
const struct v4l2_format *src_fmt, /* in */
const struct v4l2_format *dest_fmt, /* in */
@@ -1310,6 +1379,14 @@ int v4lconvert_convert(struct v4lconvert_data *data,
struct v4l2_format my_src_fmt = *src_fmt;
struct v4l2_format my_dest_fmt = *dest_fmt;
+ /* SDR */
+ switch (my_dest_fmt.fmt.pix.pixelformat) {
+ case V4L2_PIX_FMT_SDR_FLOAT:
+ return v4lconvert_convert_sdr(data, src, src_size,
+ convert2_dest, convert2_dest_size,
+ &my_src_fmt, my_dest_fmt.fmt.pix.pixelformat);
+ }
+
processing = v4lprocessing_pre_processing(data->processing);
rotate90 = data->control_flags & V4LCONTROL_ROTATED_90_JPEG;
hflip = v4lcontrol_get_ctrl(data->control, V4LCONTROL_HFLIP);
--
1.8.4.2
--
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