[pvrusb2] pvrusb2-mci-20070114 radio support - stereo?

Andreas Beck becka-ilist-pvrusb2 at bedatec.de
Sat Jan 27 07:05:22 CST 2007

Pantelis <pakt223 at freemail.gr> wrote:
> now, play it like this:
> mplayer -vo null -ao alsa -af pan=2:1:1:-1:-1 test.mpg

You can just use that while streaming from the device as well.
I tune down video bitrate to 100kbit, which stops mplayer telling me the
system is too slow to play. Maybe I should tune down video size as well.

> notice the added -af pan ...  This subtracts the right channel from the left.

Yes - I (24xxx device, Germany, some stations should be good enough, but 
got to use a good arial first, before I can say for sure) hear squeaking 
noises like from a tape bewing in extremely fast forwind most of the time.

However this is heavily influenced by the setting of the
ctl_mpeg_audio_mode control. Mono completely mutes the channel (no
surprise), but Dual, Stereo and Joint Stereo already give a very audible 
difference - not only from mono, but also from each other.

So I suppose there might be an extra issue with the MPEG encoding
distorting phase differences.

So according to my tests, I do get Stereo, but the differences are
rather weak. I should try to locate a classic or 60ies station that will
play stuff with pronounced stereo effects often.

If someone has one of those little FM transmitters they now sell for
attaching your MP3-Player to your car stereo (a few microwatts output,
so they only work at very close proximity), they could as well use it to
send a defined stereo signal and do further testing.

BTW: It is rather strange, that Kradio starts up in "power off" mode,
but with controls working and display reacting to them. I expected the 
power button to quit kradio, so I didn't touch it. 
So if someone else wonders why he can't tune with kradio, this might be

CU, Andy

= Andreas Beck                    |  Email :  <becka-sig at bedatec.de>         =

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