[linux-dvb] problems capturing analog and digital at the same
time with lifeview trio
hartmut.hackmann at t-online.de
Thu Sep 7 22:39:28 CEST 2006
> Nico Sabbi and Hartmut Hackmann wrote:
>> So MythTV doesn't allow to choose the video format?
> Apparently not a non-planar one. I've only found a way to ask for yv12
> or 422p(lanar). But I'll ask on the mythtv mailing list, here is going
> too much off-topic :)
> Many, many thanks for you help.
That's a pity. It whould be nice if you could drive this a bit...
>>>> A solution might be to suppress the planar formats on hybrid and duo
>>> I think that removing some sample formats tout-court is a bad idea,
>>> resampling from yuy2 to yv12 for compressing to mpeg* is very likely
>>> to reduce
>>> quality and introduce slowdowns; if it were possible to remove planar
>>> only when a dvb capture is running the situation would be more
>>> anyway, training the user about what he can and should do is is best
>>> option IMO.
> I agree, but imho the current situation is a bit unpleasant because the
> user has no way to know what he can do. I fear that without some help by
> the driver *and* the applications, only a minority of users will get the
> most out of their hybrid cards.
>> Yv12 is a planar format. Thats another argument why i originally
>> didn't do
>> Its not so easy but possible to "block" the planar formats dynamically in
>> the driver but i am afraid this won't work in practice:
>> If i had to write a tv application, i would query the device capabilities
>> in the beginning of the session and assume these to be fixed afterwards.
>> A compromise might be a combination of the options: block the planar
>> by default but restore the current behaviour with an insmod option.
> Is detecting an over-4-DMA-channels situation and returning a specific
> error (perhaps "bandwidth exceeded" or something like that) a viable
> option ?
> This way only an illegal combination will be flagged and the application
> could have a chance to inform the user or revert to a more appropriate
This can be detected and would be far better than nothing. But this message
would go into the kernel log. Afaik, there is no way to get this on a display.
Its also dangerous to refuse the streaming. Some applications don't have
timouts and will simpy hang if a DMA streaimg doesn't happen...
> Greetings and thanks,
Some more thinking necessary?
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