15 January 2015, 11:25 | #41 |
Registered User
Join Date: May 2006
Location: France
Age: 48
Posts: 211
|
Tearing is a consequence of the 50Hz to 60Hz frame rate conversion like the telecine method where additional frames are created to match the input 50Hz rate to the output 60Hz. Perhaps simply duplicating frames may avoid the tearing but don't know which visual consequences it would have.
There may be good reasons why it was not implemented in the Indivision AGA... The problem of solution 1 is that it requires 2 times the memory of solution 2. Additionally, Solution 1 will delay video from sound of 1/25 s in laced mode. Don't know if it can be noticed by humans. I will try to implement solution 1 to see how it performs... |
15 January 2015, 13:54 | #42 |
Registered User
Join Date: Mar 2012
Location: Norfolk, UK
Posts: 1,153
|
Solution 1 will still create combing. Even if it takes 1/25 of a second to output a full interlaced frame, the display is not guaranteed to be static for that 1/25th of a second - objects such as the mouse pointer can move between the two fields, so any solution which mixes lines from alternate fields to make a single progressive VGA field will produce combing.
|
15 January 2015, 14:22 | #43 | |
Registered User
Join Date: May 2006
Location: France
Age: 48
Posts: 211
|
Quote:
So why don't we see combing on the original amiga laced picture? Mixing alternate fields is exactly what interlaced video does. So combing would be seen also on the RGB or PAL ourput. And that would mean Amiga updates objects at 50fps regardless of the laced/non-laced mode... |
|
15 January 2015, 14:54 | #44 | |||
Registered User
Join Date: Mar 2012
Location: Norfolk, UK
Posts: 1,153
|
Quote:
Quote:
Quote:
|
|||
15 January 2015, 15:03 | #45 |
Unregistered User
Join Date: Sep 2012
Location: Copenhagen / DK
Age: 43
Posts: 4,190
|
The only way to get 50 fps without combing effects is to apply some smoothing around the area where things are moving fast (like the mouse cursor). This is how many deinterlacing algorithms work. It is not a very good solution (also it needs some DSP), but there is no perfect solution when it comes to deinterlacing a signal like this. Either you will lose fps (mix fields), lose resolution (show fields on top of each other, so 1/2 as many lines), get flicker (show every 2nd line as black, alternating) or get combing effects if you show two fields at the same time.
|
15 January 2015, 15:06 | #46 | ||
Registered User
Join Date: May 2006
Location: France
Age: 48
Posts: 211
|
Quote:
Quote:
According to your answer, solution 1 has no advantages over solution 2. |
||
15 January 2015, 15:19 | #47 | |
Unregistered User
Join Date: Sep 2012
Location: Copenhagen / DK
Age: 43
Posts: 4,190
|
Quote:
Like this: 0 sec: Frame 1, even field 100% 0.02 sec: Frame 1, even field 50%, Frame 1, odd field 100% 0.04 sec: Frame 2, even field 100%, Frame 1, odd field 50% 0.06 sec: Frame 2, even field 50%, Frame 2, odd field 100% 0.08 sec: Frame 3, even field 100%, Frame 2, odd field 50% 0.10 sec: Frame 3, even field 50%, Frame 3, odd field 100% etc.. |
|
15 January 2015, 15:49 | #48 |
Registered User
Join Date: May 2006
Location: France
Age: 48
Posts: 211
|
Your solution is interesting and may be easily implemented on analog VGA output where intensity can be adjusted with R, G, B gain for example. But when outputing digitally like DVI, it's more difficult because the color code have to be alterated in realtime to half them when intensity has to be made 50%.
|
15 January 2015, 15:53 | #49 |
Unregistered User
Join Date: Sep 2012
Location: Copenhagen / DK
Age: 43
Posts: 4,190
|
If you have the digital video data on a parallel connection somewhere, you can simply use a mux to switch the bits between two positions, so bit 1->0, bit 2->1 etc. every second frame. On a serial connection, you need to introduce one sample delay (and discard LSB).
|
16 January 2015, 09:32 | #50 |
Registered User
Join Date: May 2006
Location: France
Age: 48
Posts: 211
|
This seems to be good solution to me and easy to implement. Thanks.
|
19 August 2015, 17:03 | #51 |
Registered User
Join Date: Jun 2012
Location: Portugal
Posts: 105
|
I know this is a bit old, but I have one question.
How is detected the interlaced mode from the non interlaced mode on A2320 scandoubler? I am trying to reproduce the Multivision, and from what I see, there is detection from 2 modes. Here is the link for sch. http://eab.abime.net/showthread.php?t=79278 Thanks! |
19 August 2015, 20:07 | #52 |
-
Join Date: Jul 2003
Location: Helsinki / Finland
Age: 43
Posts: 9,861
|
Amiga progressive modes always output only even frames.. If the flifi never sees an odd frame, then it is safe to assume we're not in an interlaced mode.
|
19 August 2015, 20:21 | #53 |
WinUAE developer
Join Date: Aug 2001
Location: Hämeenlinna/Finland
Age: 49
Posts: 26,505
|
Both odd or even only non-interlaced mode is possible. (It is simply state of LOF bit in VPOSW)
|
19 August 2015, 21:19 | #54 |
Registered User
Join Date: Jun 2012
Location: Portugal
Posts: 105
|
Then what about making an open code for the multivision first, and then evolve to a more sofisticated hardware?
I can start making in wincupl, but my knowledge in image processing is not that good. From What I see on sch there are 10bits on the input of the 2 gals from 74f163. Making a freq divider up to 1024 times. It's dividing the 14mhz clock. we have hsync and vsync inputs also. We know that hsync needs to be doubled at some point and also needed to clock some of the memory . If I make code, does anyone is willing to contribute? I will after make a simpler design and also share as I did with this one. I would like to keep this one, so I can make tests, since I already have a multivision with me. |
19 August 2015, 21:31 | #55 |
-
Join Date: Jul 2003
Location: Helsinki / Finland
Age: 43
Posts: 9,861
|
|
19 August 2015, 21:40 | #56 |
Registered User
Join Date: Jun 2012
Location: Portugal
Posts: 105
|
So if there is even & odd we need to deinterlace?
Last edited by Marmes; 19 August 2015 at 22:13. |
20 August 2015, 00:48 | #57 |
Registered User
Join Date: Jun 2010
Location: PL?
Posts: 2,745
|
Luckily most of Amiga interlace application are not interlace at all - this is progressive video displayed in two passes. I can imagine video applications (subtitlers etc) where real interlace signal is produced but once again this is not problems as they are not designed for progressive display anyway and comb artifacts from interlace on progressive can be accepted (IMHO).
There are good application notes about various approaches for interlace to progressive conversion but this is usually not required for Amiga. http://www.nxp.com/documents/applica.../AN10233_1.pdf or Micronas VSP9407b datasheet |
11 November 2020, 17:31 | #58 |
Registered User
Join Date: May 2006
Location: France
Age: 48
Posts: 211
|
I am wondering how the indivision flicker fixers retrieve sync information as they don't get HSYNC and VSYNC from Alice... There is also a CSYNC signal but not available on Lisa.
|
11 November 2020, 17:51 | #59 |
WinUAE developer
Join Date: Aug 2001
Location: Hämeenlinna/Finland
Age: 49
Posts: 26,505
|
|
12 November 2020, 10:32 | #60 |
Registered User
Join Date: May 2006
Location: France
Age: 48
Posts: 211
|
Thanks. I guess they are the STREQU/STRVBL/STRHOR/STRLONG addresses?
|
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests) | |
Thread Tools | |
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Little bit of help needed please with .docx support theory | fishyfish | Coders. General | 6 | 07 September 2012 20:05 |
|
|