Dear all,
I have lurked a while on this list but until now have not had reason to post.
I am unable to configure xineliboutput to my liking. I don't imagine I am the only one with this issue, but I have not been able to find a solution, either by trial and error or by googling. I would appreciate to hear how other people configure their vdr boxes.
My output device is a 4:3 analog TV. Watching a 4:3 stream is fine in the sense that the full real estate of the TV is used. Watching a 16:9 stream results in (depending on various settings I have tried) either the stream 'compressed' vertically to maintain the 16:9 ratio (with black bars top and bottom), or a vertically 'stretched' image that loses the 16:9 ratio but fills the entire TV screen.
What I would like is to maintain the stream 16:9 ratio but by by cropping the left and right sections of the stream that fall 'outside' the TV, so the full real estate of the TV is used, at the expense of losing some stream information.
I have played with various xineliboutput settings, all through the OSD plugin setup menu. My current settings are roughly:
LOCAL FRONTEND: Using Xv and set to fullscreen and stretched-to-window video. Aspect ratio set to 4:3 (although Pan&Scan and CenterCutOut looked promising but don't do what I thought they might).
VIDEO: aspect ratio set to automatic. Anything else seems to force the aspect ratio to that value. Software scaling does not seem to be the route to follow either. Autocrop 4:3 letterbox to 16:9 is disabled, but also looked promising, but I could not obtain the bahaviour I desire.
So (finally) a direct question: how do people with 4:3 output devices and vdr with xineliboutput configure their boxes?
Some brief details of my system:
I am using vdr 1.6.0, a recent-ish (last few days) xineliboutput CVS version running under X (i.e. vdr-sxfe) on a NVIDIA 6150 device with the binary NVIDIA module (TV-out at 720x576) watching DVB-S streams (thanks to a NOVA-S-Plus and a HVR4000 with multiproto, for what that is worth), all connected to a 4:3 aspect ratio TV.
I thought this would be a quick question but I have managed to write an epic! Sorry about that.
Best wishes,
Ian.
Thank you Torgeir for you response. Now I know the correct terminology!
Back to general comments.
I have had a look at the xineliboutput source code, and it appears that 'centercutout' and 'pan&scan', features which I think are the ones I want, are at best work in progress:
xine_frontend.c: around and after line 145:
/* Pan&Scan */ case 5: { double aspect_diff /*= video_pixel_aspect - 1.0*/; /* TODO */ /* does not work (?) */ aspect_diff=(video_pixel_aspect*(double)video_width/(double)video_height) - 4.0 / 3.0; if ((aspect_diff < 0.05) && (aspect_diff > -0.05)) { result = (4.0/3.0 * (double)this->height/(double)this->width); /*LOGDBG("diff: %f", aspect_diff);*/ /*new_cropping = 1;*/ } else { result = (16.0/9.0 * (double)this->height/(double)this->width); } /*result = (4.0/3.0 * (double)this->height/(double)this->width);*/ break; } /* center cut-out */ case 6: { /*#warning center cut-out mode not implemented*/ break;
'TODO', 'does not work (?)' and 'not implemented' are the points of interest. Maybe time to contact the xineliboutput author for further info.
One more remark, if as I believe from the comments in the code above, that the '16:9 crop to 4:3' behaviour is not implemented in xineliboutput, am I the only one suffering from the lack of this feature? Am I the only one still using a 4:3 TV? I don't think so, what do other people do when viewing 16:9 material on a 4:3 device, other than put up with the black bars?
Regards,
Ian.
Hi,
On Tue, 8 Apr 2008, Ian Bates wrote:
This is exactly what I'm doing - I'm accepting the black bars at the bottom and the top, dreaming about the screen I'm going to buy at some point in the future, along with being happy for other xineliboutput-users having already a 16:9 screen.
Patrick.
Patrick Boettcher wrote:
I would say the correct term is not accepting but acknowledging... Makes no sense to me why someone would like to cut 25% from the picture. And what about programmes in 2.39:1 aspect ratio? Should those be cut too so that they fit to 4:3 ratio and lose 44% of the image in the process?
Anyway, mplayer can do that, try something like "mplayer -vf crop=507:544,scale=720:544 http://<your_server>:37890". Although that will cut also programmes sent in 4:3 aspect ratio.
-Petri
Ian Bates wrote:
I also use a 21" 4:3 old CRT TV for all DVD and TV. And I want to see the whole picture, as the others who have responded.
There is another reason, in addition to the "real estate" reason of throwing away a lot of paid content (how wasteful!). Namely, the composition of the images is designed for the format they are shown in, at least in quality material. So, filling the whole screen means you do not see the material's photographic value.
I hope some day I'm able to bite the bullet and move to the Full HD panel TV world, but so far the old faithful has served well.
Nevertheless, although probably most techies feel the crop mode is not interesting, perhaps you'll be able to find one that is willing to implement it - or perhaps you can DIY and share the code.
Good luck.
yours, Jouni
On Wed, Apr 9, 2008 at 9:43 AM, Jouni Karvo Jouni.Karvo@iki.fi wrote:
I think the idea of cropping material from aspect ratios 16:9 or 2.39:1 to 4:3 is not worth putting attention, because it will often result in quite awkward image. When done properly with technique called pan&scan (http://en.wikipedia.org/wiki/Pan_and_scan) where the cropped selection can reside at any part of the original image, the result is bearable. But think about a movie shot and broadcasted in 2.39 and crudely cropped so that the 4:3 part in the middle is shown... You will see half heads, people talking to people not included in the picture and so on. Or think about a football match in 16:9 cropped to 4:3... with the ball in the portion left out.
-Petri
On Wed, 2008-04-09 at 13:43 +0300, Petri Helin wrote:
However, often things just work out: the camera operators are sometimes directed to shoot the full 16:9 frame but keep the action in a 4:3 frame. This does happen, and IMHO makes for shots that seem too wide on a 16:9 screen. Production companies do this to maximise the market potential for their material. To use the football case: the international feeds still need to deliver 4:3 images. So the host broadcaster who wants both a 16:9 version and a 4:3 version can either employ twice as many camera operators and have twice as many cameras etc etc OR shoot 16:9 but keep the action in the 4:3 frame.
Then there is 14:9 material. This is shown on a 4:3 image with smaller black bars, or cropped less (than 16:9) and shown full screen on a 4:3.
(I myself prefer the black bars on top and on bottom and view all 16:9 programmes that way on my 4:3 set)
(For movies the transfer to video can take more time: there pan&scan is used, but so are other techniques including letterbox, image distortion etc. It is particularly noticeable at the end of a movie with credits that use the whole 16:9 width)
I demand that Ian Bates may or may not have written...
I have lurked a while on this list but until now have not had reason to post.
I am unable to configure xineliboutput to my liking.
[snip]
Freeview STBs will use 4:3 or letterboxing, either 14:9 or 16:9, as indicated by the AFD setting embedded in the MPEG stream. xine-lib has no support for this wrt picture shape, though it does report its presence and value; there's a patch which improves this. I've observed problems with it, though, when the setting is changed.
http://xine-lib.alioth.debian.org/patches-1.1/AFD_support.patch
[snip]
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Darren Salt -
Ian Bates -
Jouni Karvo -
Malcolm Caldwell -
Patrick Boettcher -
Petri Helin