Hi Hans! On 12.12.2013 09:55, Hans Verkuil wrote:
On 12/12/2013 12:54 AM, Antti Palosaari wrote:Add V4L2_TUNER_CAP_1HZ for 1 Hz resolution. Signed-off-by: Antti Palosaari <crope@xxxxxx> --- include/uapi/linux/videodev2.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h index 6c6a601..1bac6c4 100644 --- a/include/uapi/linux/videodev2.h +++ b/include/uapi/linux/videodev2.h @@ -1349,6 +1349,7 @@ struct v4l2_modulator { #define V4L2_TUNER_CAP_RDS_CONTROLS 0x0200 #define V4L2_TUNER_CAP_FREQ_BANDS 0x0400 #define V4L2_TUNER_CAP_HWSEEK_PROG_LIM 0x0800 +#define V4L2_TUNER_CAP_1HZ 0x1000 /* Flags for the 'rxsubchans' field */ #define V4L2_TUNER_SUB_MONO 0x0001I was wondering, do the band modulation systems (V4L2_BAND_MODULATION_VSB etc.) cover SDR?
There is no such modulations defined for SDR hardware level. SDR demodulation is done by software called DSP (digital signal processing) in host computer.
In ideal case, SDR receiver has only 1 property: ADC (analog to digital converter) sampling rate.
But as digital signal processing is very CPU intensive when sampling rates are increased, there is very often RF tuner used to down-convert actual radio frequency to low-IF / BB. Then ADC is used to sample that baseband / low-IF signal and only small sampling rate is needed => stream is smaller => DSP does not need so much CPU.
Anyway, I'm happy with this patch series. As far as I am concerned, the next step would be to add documention and I would also recommend updating v4l2-compliance. Writing docs and adding compliance tests has proven useful in the past to discover ambiguous API specs.
I will do these at finally when I drivers and applications are tested to be working.
regards Antti -- http://palosaari.fi/ -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
