Bttv strange problem

[MrZammler]

Hi,

I've got bttv set up for my tv card, and watch TV through tvtime.

This setup has worked for me for years, however I always had an annoying bug which is time to solve.

For some channels, even though they appear fine when first tuned in, they start to "break" after a while. The picture starts to increase in brightness, and after a while, the signal is lost. I can do a channel up/channel down to the same channel, and everything is back to normal, untill it starts the same thing again.

I've had this problem through out years with the same card, but with different kernel versions. Some channels behave ok, some others dont.

Could this be a card, or a driver problem (tvtime and xawtv both shown the problem).

The card is:

00:0e.0 Multimedia video controller: Brooktree Corporation Bt848 Video Capture (rev 12)
(Miro PCTV)

Connected to an aerial - PAL.

Thanks

[jorgepeixoto]

With what options do you modprobe the bttv module?

I have had problems with my TV card because I was modprobing bttv with the wrong options. I never suspected the options were wrong because I thought that if the bttv module was configured for the wrong card or the wrong tuner, it wouldn't work at all. I was wrong: if you specify the wrong tuner or card, the module can work but show slight problems.

[MrZammler]

Nothing special really, just:

options bttv card=1

Any tips on what parameters should I be looking for? I'll try a google search for any pointers too.

Thanks.

[jorgepeixoto]

Are you sure that card=1 is the right parameter?

in /usr/src/linux/drivers/media/video/bt8xx/bttv.h I see what card=1 means:
#define BTTV_BOARD_MIRO
then in /usr/src/linux/drivers/media/video/bt8xx/bttv-cards.c:

struct tvcard bttv_tvcards[] = {
/* ---- card 0x00 ---------------------------------- */
[BTTV_BOARD_UNKNOWN] = {
.name = " *** UNKNOWN/GENERIC *** ",
.video_inputs = 4,
.audio_inputs = 1,
.tuner = 0,
.svhs = 2,
.muxsel = { 2, 3, 1, 0 },
.tuner_type = -1,
.tuner_addr = ADDR_UNSET,
.radio_addr = ADDR_UNSET,
},
[BTTV_BOARD_MIRO] = {
.name = "MIRO PCTV",
.video_inputs = 4,
.audio_inputs = 1,
.tuner = 0,
.svhs = 2,
.gpiomask = 15,
.muxsel = { 2, 3, 1, 1 },
.gpiomux = { 2, 0, 0, 0 },
.gpiomute = 10,
.needs_tvaudio = 1,
.tuner_type = -1,
.tuner_addr = ADDR_UNSET,
.radio_addr = ADDR_UNSET,
},
(...)

Are you sure your card is this MIRO PCTV? How about "MIRO PCTV pro", which is card=11?

You can take a look at /usr/src/linux/Documentation/video4linux/bttv/Cards.

[MrZammler]

Not really.

It works, but it has the problem I mentioned above.

I found a script that helps pick up the right bttv parameters, so I'll check it out.

[jorgepeixoto]

The fact that it works does not mean that you have the card=# parameter right. I have experienced this: the wrong parameter can lead you to slight problems, but your card may still work