Conversation about aspect ratios

[zehd]

Carried over from
http://forums.nextpvr.com/showthread.php?t=28289&page=4

Right, but I am not talking WSS, I am talking hard-coding a video output size on transcoded data. My preference is to let the mvp hardware control resolution and aspect ratio regardless of the dongle and let ffmpeg concentrate on optimizing the conversion saving a lot of CPU.

Martin

Of course I have been dealing with aspect switching mostly how it pertains to ZProcess. This is the way I understand it works...

AVI world

With MVP in 4x3 Mode, GB-PVR in 4x3 mode, 4x3 TV:
I have a letterbox AVI. Played with Hauppauge software, the ltterbox is zoomed in and sides cut off. With GB-PVR and ZProcess, the Letterbox is fit into a 4x3 rect, top bottom padded. The transcoded mpeg is stamped 4x3 and the MVP plays the 4x3 video (that is the letterbox plus top/bottom pad = 4x3)

With MVP in 16x9 mode, GB-PVR in 4x3, 4x3 TV
Same video automatically letterboxed when playing on Hauppauge software. With GB-PVR and ZProcess letterboxing still calculated in 4x3 rect but other positioning allowed. Seems that hauppauge 16x9 mode allows for more positioning. The 4x3 stamped mpg plays correctly on 4x3, displaying the top/bottom padding and leterbox

With MVP in 16x9 mode, GB-PVR in 16x9, 16x9 TV. Same 720x480 rect stretched out to fill wide screen. Wide AVI is calculated to have no padding, transcoded to fill 720x480 rectangle. TV stretches video to fill wide screen.

With a 4x3 AVI, ZProcess will add Left right padding, and when the finished 720x480 is unfolded to the wide screen, the 4x3 aspect ratio is maintained.

If the TV is set to autoswitch between apspect ratios, it would respond to the aspect switch encoded into the transcoded MPG. But in the above wide screen scenraios, the wide switch is always encoded, and it's ZProcess that decides Wide or Standard.

Question. Is it possible that ZProcess could transcode 4x3 avis with the 4x3 switch and 16x9 with the 16x9 switch, and the TV does the autoswitching? That way ZProcess would not be adding padding and leave it to the TV.

(I ask this because I was not able to test this on a switching TV)

MPG world
My feeling is that GB-PVR would have to send the Wide Screen or Standard switches to the MVP so the TV could switch automatically. And as I understand it, GB-PVR doesn't have any control of that swicth. It just passes the MPG stright over to the MVP