Hi, Riccardo
rghetta wrote:
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
cards.
...
I think that removing some sample formats tout-court is a bad idea,
because
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
formats
only when a dvb capture is running the situation would be more
reasonable;
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.
...
Aggreed
Yv12 is a planar format. Thats another argument why i originally
didn't do
this...
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
formats
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
format.
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,
Riccardo
Some more thinking necessary?
HArtmut
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