[MPlayer-users] question concerning DAR and PAR

[Steven Miller]

You hit the nail on the head. I have to create video to be streamed from a
Darwin streaming server to quicktime clients. I'm only shooting for 'good'
quality as streaming via 'wireless' is another requirement. 

I'm still not sure about,
	704x480 (DAR 1.74) scaling to 836x480 on playback. Does this
resizing 
	Keep the 1.74 ratio or is it resizing to a resolution that provides
square pixels? Maybe both?

I know I can look up the PAR for common dvd's
"http://en.wikipedia.org/wiki/Pixel_aspect_ratio" easily enough.

How would I find the PAR for my 704x480 with a DAR of 1.74:1?

Thanks for your help with this. I'm under the gun to get this going. Once I
get el capitan off my back, I'll be able to take the time to learn without
annoying people ;-)

Steve


-----Original Message-----
From: mplayer-users-bounces at mplayerhq.hu
[mailto:mplayer-users-bounces at mplayerhq.hu] On Behalf Of belcampo
Sent: Wednesday, November 25, 2009 7:03 AM
To: MPlayer usage questions, feature requests,bug reports
Subject: Re: [MPlayer-users] question concerning DAR and PAR

belcampo wrote:
> Steven Miller wrote:
>> I have a dvd (ntsc 740x480) that crops to 704x480 (704:480:8:0) which
>> changes the DAR from 1.78:1 to 1.74:1. The resulting resolution (on
>> playback) ends up being 836x480. Before anyone asks, I have been reading,
>> but it's lot to absorb! If I understand correctly, 836x480 maintains the
>> 1.74:1 ratio?  Another question is, 1.74 indicates a non square pixel,
>> doesn't your typical monitor use square pixels? I'm confused as to what's
>> happening here.
>>
>> If I wanted square pixels, would using the 'dsize' filter with a 
>> resolution
>> that is divisible by 16 (scale=-1:-10,dsize=704:400 (this ends up with a
>> resolution of 704x400 and a 1.76:1 ratio)) give me square pixels, while
>> maintaining a mathematically and visually correct encode?
> dsize=704:400 will do this.
> Almost all video-sources were/are meant to play on TV, where AFAIK NEVER 
> square pixels are used, as in your DVD-example. Square pixels will 
> result in more pixels without ANY benefit.
Another point, if square-pixels is needed, and 400 is not a limit 
somehow, is that reducing vertical pixels reduces percepted quality more 
then horizontal. So for max square-pixel quality you would use the full 
836:480 values
> Only if you need to play on devices that don't accept, iPod and others, 
> non-square pixels it's usefull/necessary to use square-pixels.
>>
>>  
>>
>> Thanks in advance!
>>
>>  
>>
>> _______________________________________________
>> MPlayer-users mailing list
>> MPlayer-users at mplayerhq.hu
>> https://lists.mplayerhq.hu/mailman/listinfo/mplayer-users
> 
> _______________________________________________
> MPlayer-users mailing list
> MPlayer-users at mplayerhq.hu
> https://lists.mplayerhq.hu/mailman/listinfo/mplayer-users

_______________________________________________
MPlayer-users mailing list
MPlayer-users at mplayerhq.hu
https://lists.mplayerhq.hu/mailman/listinfo/mplayer-users