On 11.11.2013 15:14, Hans Verkuil wrote:
On 11/10/2013 06:16 PM, Antti Palosaari wrote:Convert unsigned 8 to float 32 [-1 to +1], which is commonly used format for baseband signals. Signed-off-by: Antti Palosaari <crope@xxxxxx> --- contrib/freebsd/include/linux/videodev2.h | 4 ++++ include/linux/videodev2.h | 4 ++++ lib/libv4lconvert/libv4lconvert.c | 29 ++++++++++++++++++++++++++++- 3 files changed, 36 insertions(+), 1 deletion(-) diff --git a/contrib/freebsd/include/linux/videodev2.h b/contrib/freebsd/include/linux/videodev2.h index 1fcfaeb..8829400 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_FLOAT v4l2_fourcc('D', 'F', '3', '2') /* float 32-bit */ +#define V4L2_PIX_FMT_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..14299a6 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_FLOAT v4l2_fourcc('D', 'F', '3', '2') /* float 32-bit */ +#define V4L2_PIX_FMT_U8 v4l2_fourcc('D', 'U', '0', '8') /* unsigned 8-bit */I would prefer V4L2_PIX_FMT_SDR_FLOAT and _FMT_SDR_U8. That way it is clear that this format refers to - and should be interpreted as - an SDR format. Otherwise it looks fine to me (but it needs to be documented as well, of course).
Thanks for the comments!What do you think is it OK to abuse/reuse pixelformat for radio signals? Basically the only one field needed is just that, whilst those image only fields (width/height) are not needed at all. Good point to reuse existing things as much as possible is that it does not bloat Kernel data structures etc.
I am also going to make some tests to find out if actual float conversion is faster against pre-calculated LUT, in Kernel or in libv4lconvert and so. Worst scenario I have currently is Mirics ADC with 14-bit resolution => 16384 quantization levels => 32-bit float LUT will be 16384 * 4 = 65536 bytes. Wonder if that much big LUT is allowed to library - but maybe you could alloc() and populate LUT on the fly if needed. Or maybe native conversion is fast enough.
regards Antti
Regards, Hans+ /* * 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..38c9125 100644 --- a/lib/libv4lconvert/libv4lconvert.c +++ b/lib/libv4lconvert/libv4lconvert.c @@ -78,7 +78,8 @@ static void v4lconvert_get_framesizes(struct v4lconvert_data *data, { V4L2_PIX_FMT_RGB24, 24, 1, 5, 0 }, \ { V4L2_PIX_FMT_BGR24, 24, 1, 5, 0 }, \ { V4L2_PIX_FMT_YUV420, 12, 6, 1, 0 }, \ - { V4L2_PIX_FMT_YVU420, 12, 6, 1, 0 } + { V4L2_PIX_FMT_YVU420, 12, 6, 1, 0 }, \ + { V4L2_PIX_FMT_FLOAT, 0, 0, 0, 0 } static const struct v4lconvert_pixfmt supported_src_pixfmts[] = { SUPPORTED_DST_PIXFMTS, @@ -131,6 +132,8 @@ static const struct v4lconvert_pixfmt supported_src_pixfmts[] = { { V4L2_PIX_FMT_Y6, 8, 20, 20, 0 }, { V4L2_PIX_FMT_Y10BPACK, 10, 20, 20, 0 }, { V4L2_PIX_FMT_Y16, 16, 20, 20, 0 }, + /* SDR formats */ + { V4L2_PIX_FMT_U8, 0, 0, 0, 0 }, }; static const struct v4lconvert_pixfmt supported_dst_pixfmts[] = { @@ -1281,6 +1284,25 @@ static int v4lconvert_convert_pixfmt(struct v4lconvert_data *data, } break; + /* SDR */ + case V4L2_PIX_FMT_U8: + switch (dest_pix_fmt) { + case V4L2_PIX_FMT_FLOAT: + { + /* 8-bit unsigned to 32-bit float */ + unsigned int i; + float ftmp; + for (i = 0; i < src_size; i++) { + ftmp = *src++; + ftmp -= 127.5; + ftmp /= 127.5; + memcpy(dest, &ftmp, 4); + dest += 4; + } + } + } + break; + default: V4LCONVERT_ERR("Unknown src format in conversion\n"); errno = EINVAL; @@ -1349,6 +1371,11 @@ int v4lconvert_convert(struct v4lconvert_data *data, temp_needed = my_src_fmt.fmt.pix.width * my_src_fmt.fmt.pix.height * 3 / 2; break; + /* SDR */ + case V4L2_PIX_FMT_FLOAT: + dest_needed = src_size * 4; /* 8-bit to 32-bit */ + temp_needed = dest_needed; + break; default: V4LCONVERT_ERR("Unknown dest format in conversion\n"); errno = EINVAL;
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