[mythtv-users] Correctly behaving 576i (or 480i) from vdpau-capable chip?

Andre mythtv-list at dinkum.org.uk
Thu May 27 11:25:27 UTC 2010

On 27 May 2010, at 11:49, Paul Gardiner wrote:

> Andre wrote:
>> On 27 May 2010, at 11:05, Paul Gardiner wrote:
>>> Jean-Yves Avenard wrote:
>>>> Hi
>>>> On 24 May 2010 17:51, Paul Gardiner <lists at glidos.net> wrote:
>>>>> That's the thing, the TV is pretty high end. It has something called
>>>>> 600Hz intelligent frame creation, which makes motion smoother than
>>>>> I've ever seen before from a TV. (It also causes the odd artifact
>>>>> when it gets confused, but over all it's a definite win). That
>>>> is that the LG one? they are the only ones who dare to use the word
>>>> 600Hz TV AFAIK...
>>>> I would still use the Advanced 2X vdpau deinterlacers and see how it
>>>> looks for you.. I'm sure you will be surprised.
>>> Tried it now, and it's not as good. But I don't think this is because
>>> of vdpau doing any worse a job of deinterlacing than the TV. I think
>>> it's a UK specific problem. As I've mentioned before, our SD TV here,
>>> although it is supposed to be 50i, is effectively 25p because each
>> It does vary depending on content but 50i is rare on SD channels, they are so short of bandwidth that dropping almost everything to 25p helps a great deal! That's why everyone complains so much about the football it's often the only thing that's not 25p!
> Ah, that's why. I thought it was just somebody making a bad choice. I
> hadn't considered bandwidth. QI is true 50i and the initial credits
> are so smooth.

That also explains why it's so terrible on Dave, after it's been ARCed to 14:9 and sent down their dismal low bandwidth channel, if it was 25p it would survive the punishment better.

>> BBC HD did a little experiment recently with the Only Fools & Horses prequel drama "Rock & Chips" this was broadcast as 25p on BBC1 and 50i on BBC HD, (ok for the pedants 576i25psf and 1080i25) read the BBC blogs for the in depth discussion but the consensus was that this was one of the best broadcasts in some years for technical quality and realistic motion.
> Not sure what you are saying. Did they think that the 25p SD was good? I

Sorry, wasn't clear, the BBC HD 50i was considered to be much much better than the BBC 1 25p, motion wise. It was a very high quality production in every way, well worth recording if it comes up again.

> can immediately tell the difference. The true 50i stuff looks so much
> better to me. There's a thing with Jules Holland that I sometimes catch
> the end of that's 50i.
>> I have a recording of a Baseball game shot natively at 720p60 and although I can't stand Baseball it's great to watch due to the smooth motion. IMPO all broadcast HD should be 720p50/60 leave 1080p to bluray and 1080i should be shot at dawn, I have a 90" projector screen and would rather watch 720p50 than 1080i25, really you can't properly see the difference <50".

I was referring to 720 over 1080 here.

> You watch Baseball just for the smoothness?!  You are seriously as weird
> as I am - no sorry, I didn't mean that. That's a terrible thing to say
> :-)

Purely for professional reasons ;-)

I see so much badly mangled video that it's useful sometimes to "reset" and watch something that's not so mangled, just to confirm that I can still tell the difference!

It's a useful clip to show to clients who think their mangled stuff is great, "this is how it should look" sort of thing, it's much easier to see the problems once you've seen something that's right. Usually the only way to get people to shoot 720p50 or 720p60 (or sometimes 1080p60 :-)) is a "just humour me" clip, the film industry has everyone in TV thinking that 24p is the great holy grail, rather than the exercise in saving expensive film stock that it really is.


I'm with James Cameron on this one.


I was recently at an old Cinema in Amsterdam (no not that sort of Cinema) and they had some of the old 1920's projection instructions in the projection booth, back then the crank speed was varied for different scenes to save film, it varied from 12fps to 55fps in the instructions I saw, so even then the need for >25fps was fully understood.

> Cheers,
> 	Paul.
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