Aspect Ratio in Live and Recorded TV

[lard4304]

First post so I'm a total GBPVR dummy as you might expect. Excellent application so far, I'm loving it. I've searched for the answer to this question but no luck. Received my Nova TD 500 earlier, installed it, installed drivers, installed GBPVR and eventually got it recording two things at once (in fact four things at once!). Latest version of everything, XP, Intel CPU etc.

However, I can't get it to show 4:3 broadcasts in 4:3. It shows 16:9 broadcasts in 16:9 just fine (in fact the picture is excellent). I know what I've recorded is 4:3 because I played the .ts in VLC outside of GBPVR. Inside GBPVR, live 4:3 broadcasts play slightly stretched in width and recorded 4:3 programs play totally stretched to 16:9. I havent worked out how to fix this so I thought I'd ask.

Thanks.

[whurlston]

Press "F7" to cycle through aspect ratios.

[lard4304]

Ha! That's great.

So, my next question is is there a way (a plugin maybe?) to auto-switch between 4:3 and 16:9 depending on the aspect ratio of the signal? It's a common feature on TV's etc these days...

Cheers

[sub]

If you have your video decoder set to something other than 'system default', then you can F7 to the 'auto' aspect ratio mode and leave it there.

[lard4304]

Thanks. I have it running on the Nvidia decoder and it auto-swaps between 16:9 and 'other' quite nicely. I say other because no matter how much I tweak the settings, I can't seem to get a proper 4:3 aspect ratio. It's always slightly wider than proper 4:3 making people look somewhat fatter than they really are! Does anyone have any ideas on how to cure this?

I have tried other decoders but the Nvidia one seems to have the most options available for tweaking etc.

Cheers

[fuzzweed]

What are you viewing it on? Is your TV or monitor applying a stretch or zoom mode? Also the nVidia control panel (if you're using an Nvidia card of course) applies a default stretch that you might need to play around with.

[sub]

Make sure you have your TV Shape setting set correctly.

[lard4304]

I'm viewing on a Sony TV at 1360x768. I really dont think my TV is applying any stretch or zoom. I make sure I view everything on my HTPC in the native resolution of the TV as it looks the best it can. The machine has a Nvidia graphics card which I dont think is applying any stretch or zoom modes in any way.

I'm using the Nvidia MPEG decoder though I have tried others too. I havent seen all that much difference between the various decoders so I'm wondering if I've implemented them properly. Also, the control panel for the Nvidia decoder has some options for 'display type' which looked promising for forcing it to display pure 4:3 aspect ratio but didnt seem to change anything.

It's a good thing that most channels in the UK are transmitting in 16:9 these days. It would be more of a problem otherwise.

I have set the TV shape correctly. Any help or ideas will be appreciated.

Cheers

[crlorentzen]

lard, you can check the pvrx2.exe-native.log file and see what resolution GBPVR is selecting

e.g.

Code:

(My Digital Tuner)
2008-11-05 08:10:41.734    VERBOSE    video resolution is 853 x 480
2008-11-05 08:10:41.734    VERBOSE    source is 16:9
...
2008-11-05 08:10:42.328    VERBOSE    Creating video texture: 1280x720

or
(My Analog Tuner)
2008-11-05 08:11:04.203    VERBOSE    video resolution is 720 x 540 (This is exactly 4:3)
2008-11-05 08:11:04.218    VERBOSE    source is 4:3

It has been my experience that GBPVR displays a true 4:3 where as many SD TVs have a ratio closure to 1:1 (4:4) and show a full frame.

I might also recommend, to further prove it, download a screen ruler tool like JR Screen Ruler, and take a measurement of the width of the video vs the height of the video and i bet you will see it is 4:3.

Of course final resort is to provide a screenshot and the logs so that we can see what GBPVR is doing.

EDIT: Hmm...you may be right actually...I thought I had fully tested this in 1.2.13, but 1.3.7 seems to provide something closer to 3:2. Attached is my images showing PVRX providing a 1.539:1 output for a 4:3 stream. Playing the same TV recording in any other program provides a true 4:3 (Same Decoder, Either MPV or Dscaler 5).

[lard4304]

Your post had me a little paranoid so I got out a tape measure and measured the actual size of the image on the TV. It's showing 60cm by 40cm which is 3:2 aspect ratio which isnt right IMO.

I had a look at the logs (attached) and it seems to be struggling to find the proper aspect ratios. The log shows it tuning to BBC news and then playing a recorded show (Just Shoot Me, sigh!). I'm really not sure if it's doing what it should because it complains of 'unknown source aspect ratio' repeatedly.

It seems to select 720x480 in the end, which is 3:2 (confirmed by physical measurements). I think I'm doing something wrong but I can't see what it is! Anyone fancy parsing my logs?

Thanks.