universal htpc approach

[sash]

well I was at my usaual forum, and someone built a DVB program that would display osd on HPlus type card.. well with little testing I see it worked with all sigma cards.. (congrates to emes30 for some original thinking)

but the interesting thing is with experimenting this approach, things could be applied universally.. to all dvd codec ( Emes30 is limited to one particular dshow filter that exposed the subpicture pin)

basically all you do is build pass through dvd navigator filter..

source- V->| passthrough | -> Video input codec pin
...........A-> | "DVD NAV' .| -> Audio indut codec pin
.................|_._._._._._._| -> subpicture pin

basicall all the pass through "dvd Nav " does if say that the out put is dvd compliant ( so the subpicture would be enabled on all codec) also if there is no souces pressent an backgroud image is displayed or if there is an actual dvd present. and if an source is pressent it will display switch to displaying the source..... but with investigating it seems that you should be able to build menus the same as any DVD menu found on any dvd.. and that it would display universaly..

I know SUB is unlikely to adopt this method . but I thought I mention it just In case it gave him some Ideas..

[sub]

Are you able to supply me the source code for such a filter?

[sash]

hi there at the moment not.. but I trying to find compatible .. I found some that would do the job somewhat..

http://dsfilters.agava.com/products/dvd_corrector.html

dvd_corrector
from the readme one should be able to pass any mpeg data to it and it will marked as dvd content so it does work as a pass through.. (but no download)

http://www.authoringware.com/sp_sdk.htm

subpicture sdk
this is a demo subpicture sdk
it says that it handles bitmaps text and colour shading..

and appently there is some in dx8 sdk.. but I can not find sdk dx8 to confirm..

also I will see if the developer of the dvb program is will to release any info.. but will I hunt out more and pass them your way as I find them..

[sub]

The difficult bit is getting the picture of the menus into the stream. Nethier of the links above are free, or address the issue of full screen menuing. The subpicture sdk is really aimed at sub titles.

[sash]

but what I read is that subpicture and subtext is the same thing .. it just a difference in encoding.
here a link that gives a general description of how the DVD streams work.

http://www.uni-giessen.de/faq/archiv/rec...00000.html

for bitmap and menus insertion a run-length-compressed bitmaps is used.

quote from the above text doc:

A disc also can have up to 32 subpicture streams that overlay the video for subtitles, karaoke, menus, simple animation, etc. These are full-screen, run-length-encoded bitmaps limited to four contrast values and four colors per pixel (contrast and color are selected for a group of subpictures from palettes of 16). Subpicture includes built-in effects such as scroll, move, and fade. The maximum subpicture data rate is 3.36 Mbps, with a maximum size per frame of 52 k bytes.

so i think if you follow the above description it should be possible to do ..NO?

and from links on the web it seems that it can be done it seems that one would use push source through a filter that connects to this IKsPropertySet AM_KSPROPSETID_DvdSubPic I believe found in sdk 9 dvd sample app ( but not certian)..

[sub]

If you're will to do the leg work and can provide some sample source code that does it, I'll look to see if we can include it. I dont really have time to investigate this myself.

[sash]

no problem I will hunt it out.. I will try to get you a source.. of some form.. hopefully

right now I trying to see if I can find a run length bitmap encoder. and encode at the above specifications and see if it connect directly to the subpicture pin-- you never know it might.. and produce a menu..

[sash]

hi sub no source yet! but working on it..

but I found basically enough data that one could do it realitve easy enough.. I guess

http://dvd.sourceforge.net/spu_notes

explains the method. to how it is encoded . and source code for is there

http://www.mpeg.org/MPEG/DVD/Book_B/Subpic.html

explains the general layout.

I even contacted a small dvd authoring company and they pointed me towards some info

"Sub basically is a 'frame' encoded in RLC. It has 4 different pixel groups. Each one presents the color and contrast indices. During decoding, the sub codec will first read the color lookup table for matching each pixel index. The sub frame is not overlaid on the top of video frame. The sub is only inserted to screen during video blanking. The video shows in two fields and therefore the sub has to be coded in even fields and in odd fields. In other words, a sub packet always contains two data fields.

The most difficult part to understand sub unit (SPU) is the internal control sequence. Each control can have more than one sub control group. When the sub is being displayed, the control groups also take place in sequential order. This is why sub can be fade-in and fade-out or scrolling. This is also the basic control structure for lyric color change in Karaoke mode."

but this (internal control sequence) is explain in the top links..

but you know i was thinking ( oh oh ) as a company sigmadesign does not change much or add much ( that why all directshow filters work with all thier cards and why almost all thier driver are inter changeable). I bet you the osd that you see with the xcard (netstream) is actuall the subpicture. the only thing is they by passed the subpicture pin and went directly ( perhaps skipping the the encoding routine ) but that something you would know better then me - i never seen how osd is generated in xcard.. does the above descriptions sound remotely familiar...