[MPlayer-users] question concerning DAR and PAR

[belcampo]

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