On Wed, 2014-07-30 at 16:23 +0200, Hans Verkuil wrote: > From: Hans Verkuil <hans.verkuil@xxxxxxxxx> > > The vivid Virtual Video Test Driver helps testing V4L2 applications > and can emulate V4L2 hardware. Add the documentation for this driver > first. > > Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> > --- > Documentation/video4linux/vivid.txt | 1108 +++++++++++++++++++++++++++++++++++ > 1 file changed, 1108 insertions(+) > create mode 100644 Documentation/video4linux/vivid.txt > > diff --git a/Documentation/video4linux/vivid.txt b/Documentation/video4linux/vivid.txt > new file mode 100644 > index 0000000..2dc7354 > --- /dev/null > +++ b/Documentation/video4linux/vivid.txt > @@ -0,0 +1,1108 @@ > +vivid: Virtual Video Test Driver > +================================ > + > +Section 8: Software Defined Radio Receiver > +------------------------------------------ > + > +The SDR receiver has three frequency bands for the ADC tuner: > + > + - 300 kHz > + - 900 kHz - 2800 kHz > + - 3200 kHz > + > +The RF tuner supports 50 MHz - 2000 MHz. > + > +The generated data contains sinus and cosinus signals. > + In (American) English the names are "sine" and "cosine" for sin(x) and cos(x). Maybe say: "The generated data contains the In-phase and Quadrature components of a 1 kHz tone that has an amplitude of sqrt(2)." FWIW, the signals are the In-phase and Quadrature components of the signal A*cos(2*pi*f + phi), where f = 1 kHz, A = sqrt(2), and phi = -pi/4 > + > +Section 15: Some Future Improvements > +------------------------------------ > + > +Just as a reminder and in no particular order: > + > +- Add a virtual alsa driver to test audio > +- Add virtual sub-devices and media controller support > +- Some support for testing compressed video > +- Add support to loop raw VBI output to raw VBI input > +- Fix sequence/field numbering when looping of video with alternate fields > +- Add support for V4L2_CID_BG_COLOR for video outputs > +- Add ARGB888 overlay support: better testing of the alpha channel > +- Add custom DV timings support > +- Add support for V4L2_DV_FL_REDUCED_FPS > +- Improve pixel aspect support in the tpg code by passing a real v4l2_fract > +- Use per-queue locks and/or per-device locks to improve throughput > +- Add support to loop from a specific output to a specific input across > + vivid instances > +- Add support for VIDIOC_EXPBUF once support for that has been added to vb2 > +- The SDR radio should use the same 'frequencies' for stations as the normal > + radio receiver, and give back noise if the frequency doesn't match up with > + a station frequency > +- Improve the sinus generation of the SDR radio. Maybe a lookup table, containing the first quarter wave of cos() from 0 to pi/2 in pi/200 steps, and then linear interpolation for cos() of angles in between those steps. You could go with a larger lookup table with finer grained steps to reduce the approximation errors. A lookup table with linear interpolation, I would think, requires fewer mutliplies and divides than the current Taylor expansion computation. > +- Make a thread for the RDS generation, that would help in particular for the > + "Controls" RDS Rx I/O Mode as the read-only RDS controls could be updated > + in real-time. Regards, Andy -- 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
