On 18.08.2010 11:13, jori.hamalainen@xxxxxxxxxxxxxxx wrote:
I also would like to remind the framerate issues. Naturally you decide
what
is enough precision and quality for you.
Computer hardware usually cannot provide 50.000Hz, 59.940Hz or 23.976Hz
outputs to your TV/Monitor. This will cause some judder on display output
as MPEG/AVC input-stream is not synchronized to output framerate.
I have got "good enough" 50 Hz output to HDMI from Nvidia GS8400 DVI
output with VDPAU. Typically there is small jump about every 10s with
DVB SDTV content but it is visible only with graphic news scrollers. It
is not annoying me that much. That is of course a very subjective matter.
For example dedicated blu-ray player Philips BDP3000 had a 24.000Hz output
(before firmware fix) which resulted a jumped frame every 42 seconds as
real input stream is 23.976Hz. It was annoying after you noticed it. But
luckily now it is fixed to real 23.976 output.
With this bridge we come to VGA-hardware which might have 50.01Hz closest to
50Hz signal. So every 100 frames we get a jump in picture synch. Ever seen
jumping camera panning while watching a film and got annoyed by it?
Yes -- I have tried VGA but my one TV has only 60 Hz VGA mode that
produces bad juddering picture. Then my other TV does not accept full HD
modes via VGA. I also prefer the brighter colors and perfect pixels I
get over HDMI. Subjective things again ...
For ATI cards there is a dynamic framerate fix, unfortunately there is not
one
for Nvidia cards. Nvidia has good HW acceleration but potentially bad
output.
With ATI vice versa.
This ATI fix fixes 50.01 by dynamically reprogramming VGA timers so real
output
is 50.000Hz. (General description, the author can describe more if needed).
I tried two years ago a motherboard with integrated AMD graphics with
HDMI but bought soon the cheap NVidia GS8400 card because of problems:
poor stability/wife acceptance factor, tearing, blurry scaling etc. I
am still using AMD stuff at work for desktop usage so I have seen the
improvement in the open source drivers but I still feel I get better
value for the money with NVidia stuff.
So if you aim to HD with full HD quality I'd be carefull with computer
outputs.
My answer was to setup Popcorn hour to output 50.000Hz with TV-stuff.
Unfortunately
you lose some easy-of-use with VDR as you need to have separate layer to set
up etc.
I have also a PS3 and tweaked Mediatomb to serve the VDR recordings and
some live TV channels over UPnP. It is slightly better with 576i50 ->
1080p50 conversion than my HTPC but the difference is quite small. I
guess that is "perfect" and comparable to the picture you get with
Popcorn Hour.
The usability with PS3 is poor for Live TV because the channels are made
to look like recordings and there is no p+ / p- channel surfing. The
hack is not supporting DVB subtitles and sometimes I hear a non-prefferd
sound track (the speech synth on the Dutch track). My family has learnt
to use the hack while the HTPC is out of order but it is far from ideal
solution. The fatty PS3 is also a bit noisy and consumes more power than
a typical HTPC. I suppose the usability issues are not a problem with
Popcorn if there is VDR usage dedicated firmware available?
Also as original question came from Finland and if you use commercial HD
channels
they are (or at least should be) paired to your receiver.
I see only some HD from DVB-S/S2. Fortunately the kids channels that I
subscribe do not require the pairing
Cheers,
Seppo
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