On 07/31/2014 09:16 PM, Andy Walls wrote: > 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). I knew that. Really :-) One of the rare (I think) cases where my native Dutch interfered with English. > > 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. Yeah, I had plans for that. There actually is a sine-table already in vivid-tpg.c since I'm using that to implement Hue support. Regards, Hans > > >> +- 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
