RE: Interlaced video
I guess it's going to be pretty random. Hmm interesting. If its interlace mode for normal broadcast telly works, (ie you always get ABABAB not BABABA) then it must be receiving some other signal to identify the A frames from the Bs. Does turning off the screen with an OUT 252,0 reset it? Howard -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dave Laundon Sent: 22 May 2008 20:56 To: sam-users@nvg.ntnu.no Subject: Re: Interlaced video 2008/5/22 Colin Piggot [EMAIL PROTECTED]: Now the question is, depending how the TV is interlacing the frames, and how many frames there's been since the SAM was powered up - when the 'Interlaced Pictures' from FRED are loaded the frames might show with the intended 'interlacing', or be reversed - if 'A' is the frame with the top row, 'B' is the frame with the row to be shown below, your telly could interlace correctly so the TV displays with the lines ordered ABABAB, or could be out of order and display BABABA (hope that makes sense!) Hmm, I hadn't thought of that. I guess it's going to be pretty random. I'll type that ROLL test in again and keep running it and see if the orientation changes. Kind of makes any applications difficult without a calibration option! I seem to remember there was a cover tape on one of the magazines that had a new display mode that swapped between two screens at 50Hz or something. Can't remember if it was interlacing or some method of increasing colours. My memory is vague... Makes me want to dig out those Fred issues with interlaced images on them to see how they look. If only my drive worked... (Colin, do you still have spare belts? :-) Should do, I'll drop you an email in a bit once i've checked :) Thanks. Must get him up and running again :-) Dave. No virus found in this incoming message. Checked by AVG. Version: 7.5.524 / Virus Database: 269.24.1/1463 - Release Date: 23/05/2008 15:36 No virus found in this outgoing message. Checked by AVG. Version: 7.5.524 / Virus Database: 269.24.1/1463 - Release Date: 23/05/2008 15:36
Re: Interlaced video
There's a timing difference between even frames and odd fields in the syncs generated at the field end. Non-interlaced video essentially sends only even fields. That said, I'm not sure if non-interlaced video was ever an official part of the PAL spec, so perhaps this TV is justified in its implementation. Though it seems odd, as even technology as recent as the Playstation 2 uses non-interlaced video modes for some games. On 24 May 2008, at 11:20, Tobermory wrote: I guess it's going to be pretty random. Hmm interesting. If its interlace mode for normal broadcast telly works, (ie you always get ABABAB not BABABA) then it must be receiving some other signal to identify the A frames from the Bs. Does turning off the screen with an OUT 252,0 reset it? Howard -Original Message- From: [EMAIL PROTECTED] [mailto:owner-sam- [EMAIL PROTECTED] On Behalf Of Dave Laundon Sent: 22 May 2008 20:56 To: sam-users@nvg.ntnu.no Subject: Re: Interlaced video 2008/5/22 Colin Piggot [EMAIL PROTECTED]: Now the question is, depending how the TV is interlacing the frames, and how many frames there's been since the SAM was powered up - when the 'Interlaced Pictures' from FRED are loaded the frames might show with the intended 'interlacing', or be reversed - if 'A' is the frame with the top row, 'B' is the frame with the row to be shown below, your telly could interlace correctly so the TV displays with the lines ordered ABABAB, or could be out of order and display BABABA (hope that makes sense!) Hmm, I hadn't thought of that. I guess it's going to be pretty random. I'll type that ROLL test in again and keep running it and see if the orientation changes. Kind of makes any applications difficult without a calibration option! I seem to remember there was a cover tape on one of the magazines that had a new display mode that swapped between two screens at 50Hz or something. Can't remember if it was interlacing or some method of increasing colours. My memory is vague... Makes me want to dig out those Fred issues with interlaced images on them to see how they look. If only my drive worked... (Colin, do you still have spare belts? :-) Should do, I'll drop you an email in a bit once i've checked :) Thanks. Must get him up and running again :-) Dave. No virus found in this incoming message. Checked by AVG. Version: 7.5.524 / Virus Database: 269.24.1/1463 - Release Date: 23/05/2008 15:36 No virus found in this outgoing message. Checked by AVG. Version: 7.5.524 / Virus Database: 269.24.1/1463 - Release Date: 23/05/2008 15:36
Re: Interlaced video
Thomas wrote: There's a timing difference between even frames and odd fields in the syncs generated at the field end. Non-interlaced video essentially sends only even fields. Was about to say the same thing. The standard 625 line frame (consisting of one odd and one even field) has several sync pulse bursts (taking up 15 of the 625 lines) to mark the start of the odd and even fields within. Non interlaced PAL is only sending single 312 line fields which always have the same sync pulses so there is no way a TV would be able to know which is meant to be an odd or even field because they aren't marked differently. Dave's TV must just be alternating between displaying it as an odd or even field itself. Colin = Quazar : Hardware, Software, Spares and Repairs for the SAM Coupe 1995-2008 - Celebrating 14 Years of developing for the SAM Coupe Website: http://www.samcoupe.com/
