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uman
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Reged: 04/15/12
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Re: Question about ALG driver status
07/18/17 12:23 PM Attachment: 20136348_10209925983488974_2020747436_n.png 644 KB (0 downloads)


> Could you expand on this please? As I understand it, part of the issue with laser
> disc support is the ongoing discussion of accuracy.
>
> Disclaimer: I'm not presuming to question MAME design decisions, I'm just wondering
> about a different path.
>
> What caught my attention is this: What you're proposing sounds to me like you're
> discussing the capture of the parts of the "frame" that are relevant to the game and
> disregarding the parts of the "frame" that are present only because of the
> requirements of the co-opted technology (Laserdisc).
>
> I'm wondering if that is an interesting discussion point as MAME doesn't attempt to
> emulate all of the intricacies of the underlying technology (Not counting discrete
> circuits). MAME isn't attempting to emulate any frequencies outside of the human
> range of hearing for example, so I'm wondering if not grabbing unused frame
> information might be similar?

I also dont want to question MAME design decisions, but in this case i would just like to know more about, how and why the tools for LD games work that way.

With my bad english, i will still try to describe my concerns with the current approach of MAME (and the LDverify tool in general), of capturing the whole frame (525 lines).

I attached screenshots from (LDverify tool approved) capturings that SailorSat did on some games. If you take a close look at the first 20 or so lines, you will see a lot color noise and distortion, but normally the VBI range has no color subcarrier, this only happened because the capture card was forced to grab the whole frame. In practice this is not how professional equipment is working. In practice the card would capture seperately the relevant VBI data and put that on top of the capture, resulting in a clean (from distortion and color) frame, at least for the VBI data.

So the downsides of the LDverify tool are:

- forcing/hacking a capture card to capture the whole frame.
- by this method also driving a cheap card to the absolute limits, resulting in more poor capturing.
- predetermined errors while in verify-process, because of distortion and colornoise and you will often need to capture a source like 3-4 times and make a single working capture of it, that is finally approved by LDverify tool.
- capturing the whole frame, introduce a high risk that you destroy/break the fields. Remember that just one shifted scanline can make the capture useless.

I dont write this to bitch on the MAMEdevs or the tools, i just want to show why the approach is not the best. VBI data was initially introduced for subtitles in broadcast stations, however LD games abused this technique for their own purpose. Only three lines are relevant to get this working (the 4th line is just a copy for safety). A good card just needs to know, which lines needs to be captured. Different manufacturers, used different techniques, that resulted in different lines that are needed.

So the initial approach of the LDverify tool is perfect, if you have no clue, which lines are important, to make the game work properly.

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Subject Posted by Posted on
* Question about ALG driver status DarkMoe 06/22/17 10:47 PM
. * Re: Question about ALG driver status TrevEB  06/26/17 08:20 AM
. * Re: Question about ALG driver status Haze  06/28/17 02:13 PM
. * Re: Question about ALG driver status uman  07/15/17 08:39 PM
. * Re: Question about ALG driver status casm  07/16/17 01:21 AM
. * Re: Question about ALG driver status uman  07/16/17 09:09 PM
. * Re: Question about ALG driver status casm  07/17/17 03:20 PM
. * Re: Question about ALG driver status John Doe  07/18/17 08:58 PM
. * Re: Question about ALG driver status casm  07/19/17 03:31 PM
. * Re: Question about ALG driver status John Doe  07/22/17 07:47 AM
. * Re: Question about ALG driver status anikom15  07/22/17 08:23 AM
. * Re: Question about ALG driver status casm  07/22/17 05:40 PM
. * Re: Question about ALG driver status anikom15  07/22/17 06:07 PM
. * Re: Question about ALG driver status John Doe  08/06/17 02:55 PM
. * Re: Question about ALG driver status uman  07/22/17 06:31 PM
. * Re: Question about ALG driver status DarkMoe  08/01/17 04:23 PM
. * Re: Question about ALG driver status StilettoAdministrator  07/19/17 06:07 PM
. * Re: Question about ALG driver status Vas Crabb  07/19/17 06:10 PM
. * Re: Question about ALG driver status Pernod  07/19/17 07:15 PM
. * Re: Question about ALG driver status StilettoAdministrator  07/19/17 07:50 PM
. * Re: Question about ALG driver status Pernod  07/19/17 09:11 PM
. * Re: Question about ALG driver status casm  07/19/17 08:45 PM
. * Re: Question about ALG driver status StilettoAdministrator  07/19/17 06:36 PM
. * Re: Question about ALG driver status casm  07/19/17 08:05 PM
. * Re: Question about ALG driver status BIOS-D  07/19/17 08:53 PM
. * Re: Question about ALG driver status casm  07/19/17 09:27 PM
. * Re: Question about ALG driver status BIOS-D  07/20/17 01:42 AM
. * Re: Question about ALG driver status casm  07/20/17 03:14 PM
. * Re: Question about ALG driver status anikom15  07/15/17 08:56 PM
. * Re: Question about ALG driver status uman  07/15/17 09:34 PM
. * Re: Question about ALG driver status anikom15  07/18/17 07:41 AM
. * Re: Question about ALG driver status John Doe  07/17/17 08:30 AM
. * Re: Question about ALG driver status uman  07/17/17 01:46 PM
. * Re: Question about ALG driver status John Doe  07/18/17 10:48 PM
. * Re: Question about ALG driver status anikom15  07/19/17 04:31 AM
. * Re: Question about ALG driver status casm  07/17/17 04:16 PM
. * Re: Question about ALG driver status uman  07/17/17 06:11 PM
. * Re: Question about ALG driver status casm  07/19/17 04:08 PM
. * Re: Question about ALG driver status Rygar9  07/18/17 01:57 AM
. * Re: Question about ALG driver status uman  07/18/17 12:23 PM
. * Re: Question about ALG driver status SmitdoggAdministrator  07/18/17 07:36 PM
. * Re: Question about ALG driver status uman  07/18/17 11:08 PM
. * Re: Question about ALG driver status anikom15  07/19/17 05:09 AM
. * Re: Question about ALG driver status casm  07/19/17 04:22 PM
. * Re: Question about ALG driver status Vas Crabb  07/19/17 04:33 PM
. * Re: Question about ALG driver status Rygar9  07/20/17 12:21 AM
. * Re: Question about ALG driver status R. Belmont  07/20/17 08:54 PM
. * Re: Question about ALG driver status anikom15  07/20/17 04:02 AM
. * Re: Question about ALG driver status redk9258Moderator  07/20/17 01:12 AM
. * Re: Question about ALG driver status StilettoAdministrator  07/19/17 05:53 PM
. * Re: Question about ALG driver status casm  07/19/17 08:12 PM
. * Re: Question about ALG driver status uman  07/20/17 11:56 AM
. * Re: Question about ALG driver status anikom15  07/20/17 08:45 PM
. * Re: Question about ALG driver status casm  07/20/17 04:02 PM
. * Re: Question about ALG driver status uman  07/20/17 05:21 PM
. * Re: Question about ALG driver status casm  07/21/17 12:44 AM
. * Re: Question about ALG driver status anikom15  07/20/17 09:06 PM
. * Re: Question about ALG driver status uman  07/20/17 11:05 PM
. * Re: Question about ALG driver status anikom15  07/21/17 02:15 AM
. * Re: Question about ALG driver status uman  07/21/17 10:15 AM
. * Re: Question about ALG driver status anikom15  07/22/17 04:18 AM
. * Re: Question about ALG driver status uman  07/22/17 01:17 PM
. * Re: Question about ALG driver status MooglyGuy  07/22/17 10:15 AM
. * Re: Question about ALG driver status uman  07/19/17 07:30 PM
. * Re: Question about ALG driver status anikom15  07/19/17 08:24 PM
. * Re: Question about ALG driver status uman  07/19/17 10:05 PM
. * Re: Question about ALG driver status anikom15  07/20/17 04:06 AM
. * Re: Question about ALG driver status casm  07/19/17 04:44 PM
. * Re: Question about ALG driver status SmitdoggAdministrator  07/18/17 11:17 PM
. * Re: Question about ALG driver status uman  07/19/17 12:29 AM
. * Re: Question about ALG driver status casm  07/19/17 04:36 PM
. * Re: Question about ALG driver status SmitdoggAdministrator  07/19/17 12:38 AM
. * Re: Question about ALG driver status uman  07/19/17 01:45 AM
. * Re: Question about ALG driver status anikom15  07/18/17 08:03 AM
. * Re: Question about ALG driver status Vas Crabb  07/18/17 08:24 AM
. * Re: Question about ALG driver status anikom15  07/19/17 04:27 AM
. * Re: Question about ALG driver status uman  06/28/17 04:52 PM
. * Re: Question about ALG driver status SmitdoggAdministrator  06/23/17 06:13 PM
. * Finding real technical information of LaserDisc is hard work. taz-nz  06/25/17 08:17 AM
. * Re: Finding real technical information of LaserDisc is hard work. Olivier Galibert  06/25/17 11:37 AM
. * Re: Finding real technical information of LaserDisc is hard work. anikom15  06/25/17 06:19 PM
. * Re: Finding real technical information of LaserDisc is hard work. Olivier Galibert  06/25/17 11:15 PM
. * Re: Finding real technical information of LaserDisc is hard work. anikom15  06/26/17 12:44 AM
. * Re: Finding real technical information of LaserDisc is hard work. Vas Crabb  06/26/17 01:41 AM
. * Re: Finding real technical information of LaserDisc is hard work. anikom15  06/26/17 03:26 AM
. * Re: Finding real technical information of LaserDisc is hard work. taz-nz  06/26/17 12:48 PM
. * Re: Finding real technical information of LaserDisc is hard work. uman  06/26/17 01:11 PM
. * So are you volunteering to do the hardware side of things? MooglyGuy  06/26/17 11:40 AM
. * Re: So are you volunteering to do the hardware side of things? anikom15  06/26/17 11:50 AM
. * Re: So are you volunteering to do the hardware side of things? taz-nz  06/26/17 01:15 PM
. * Re: Finding real technical information of LaserDisc is hard work. Vas Crabb  06/26/17 07:52 AM
. * Re: Finding real technical information of LaserDisc is hard work. anikom15  06/26/17 11:47 AM
. * Re: Finding real technical information of LaserDisc is hard work. taz-nz  06/25/17 12:41 PM
. * Re: Finding real technical information of LaserDisc is hard work. CTOJAH  06/25/17 12:45 PM
. * Re: Finding real technical information of LaserDisc is hard work. anikom15  06/25/17 06:40 PM
. * Re: Question about ALG driver status DarkMoe  06/23/17 06:16 PM
. * Re: Question about ALG driver status SmitdoggAdministrator  06/23/17 06:19 PM
. * Re: Question about ALG driver status DarkMoe  06/23/17 06:23 PM
. * Re: Question about ALG driver status SmitdoggAdministrator  06/23/17 06:28 PM
. * Re: Question about ALG driver status uman  06/23/17 08:12 PM
. * Re: Question about ALG driver status R. Belmont  06/23/17 10:12 PM
. * Re: Question about ALG driver status casm  06/25/17 05:25 PM
. * Re: Question about ALG driver status uman  06/25/17 10:07 PM
. * Re: Question about ALG driver status casm  06/26/17 02:12 AM
. * Re: Question about ALG driver status anikom15  06/25/17 06:48 PM
. * Re: Question about ALG driver status casm  06/26/17 02:16 AM
. * Re: Question about ALG driver status uman  06/26/17 12:43 PM
. * Re: Question about ALG driver status casm  06/27/17 12:40 AM
. * Re: Question about ALG driver status anikom15  06/26/17 03:41 AM
. * Re: Question about ALG driver status uman  06/24/17 01:50 PM
. * Re: Question about ALG driver status Sune  06/24/17 07:53 PM
. * Re: Question about ALG driver status uman  06/24/17 09:22 PM
. * Re: Question about ALG driver status SmitdoggAdministrator  06/23/17 08:22 PM
. * Re: Question about ALG driver status DarkMoe  06/23/17 07:01 PM
. * Re: Question about ALG driver status CTOJAH  06/22/17 11:39 PM
. * Re: Question about ALG driver status uman  06/23/17 11:45 AM
. * Re: Question about ALG driver status John Doe  06/23/17 04:56 PM
. * Re: Question about ALG driver status CTOJAH  06/23/17 05:44 PM
. * Re: Question about ALG driver status John Doe  06/23/17 05:57 PM
. * Re: Question about ALG driver status R. Belmont  06/23/17 10:35 PM
. * Re: Question about ALG driver status DarkMoe  06/23/17 06:14 PM
. * Re: Question about ALG driver status SmitdoggAdministrator  06/23/17 06:16 PM
. * Re: Question about ALG driver status DarkMoe  06/22/17 11:42 PM

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