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MediaPortal 1
MediaPortal 1 Talk
How to improve TV-OUT quality
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<blockquote data-quote="AberDino" data-source="post: 23582" data-attributes="member: 11575"><p>The 'TV-Out' quality issue seems to come back every so often, and understandably so. I have a Philips 32PW9525 100Hz widescreen CRT television set, which is about 5 years old now. I'm using a dedicated HTPC with a Radeon card (initially 9200, now 9800 Pro) and I found the picture quality from the composite and s-video outputs very poor, so I started to look for alternatives.</p><p></p><p>Initially I made the cable as described on <a href="http://www.idiots.org.uk/vga_rgb_scart/" target="_blank">http://www.idiots.org.uk/vga_rgb_scart/</a>. I bought a VGA cable, cut it, with a multimeter found all the cores I needed to use, and soldered on the scart plug. Usually these VGA cables don't have a pin '9' (+5v) (as used on <a href="http://ryoandr.free.fr/english.html" target="_blank">http://ryoandr.free.fr/english.html</a>), so I took the voltage from the PC's power supply. Not using the +12v, as I'm switching the TV to widescreen mode using the +5v. Also, since I'm not using my TV for sound I didn't connect up any audio.</p><p></p><p>When I started using this I found that I had a lot of interference on the other scart inputs on my TV, so had to look a bit further. Then found out that the composite sync that comes from the Radeon card is a TTL level signal (+5V). This would be fine for a monitor, but not for a TV! So, I had to find a circuit that would convert a composite TTL level sync to a format the TV is used to handling...</p><p></p><p>Found this:</p><p><img src="http://www.tkk.fi/Misc/Electronics/circuits/vga2tv/vgascart.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p>You can forget about the first bit of the circuit, that's to go from separate horizontal and vertical sync signals to a composite sync (which we already have straight from the Radeon card). So, you would need the circuit from point '8' onwards. The shopping list would be:</p><p>- R3+R4: 1.8 kohm</p><p>- R5: 2.7 kohm</p><p>- R6+R7+R8: 47 ohm</p><p>- U1: 74LS86 or 74HCT86</p><p>- T1+T2: BC 547</p><p></p><p>Once I included that circuit my TV was a lot happier; no more interference. Using this VGA -> RGB scart approach you get the best possible picture quality from a 'modern' PC on an old-style television set. I am extremely happy with the end result:</p><p>- Much clearer picture, i.e. it's sharper but also the colours are much more vivid.</p><p>- Strict control over the screen resolution, no stretched faces etc. I'm using a custom 1024*576 resolution with the TV automatically switching to widescreen mode.</p><p></p><p>When playing with Powerstrip make sure you leave the ~5% overscan, that's how a CRT TV is supposed to work, makes the picture more 'stable'. This is not a problem in MP with the BlueTwo skin, as everything is based round the center of the screen, not the edges.</p><p></p><p>Word of warning: My 100Hz TV does quite a bit of digital processing, but I don't know how good it will be on a standard 50Hz set.</p><p></p><p>Enjoy the soldering!</p></blockquote><p></p>
[QUOTE="AberDino, post: 23582, member: 11575"] The 'TV-Out' quality issue seems to come back every so often, and understandably so. I have a Philips 32PW9525 100Hz widescreen CRT television set, which is about 5 years old now. I'm using a dedicated HTPC with a Radeon card (initially 9200, now 9800 Pro) and I found the picture quality from the composite and s-video outputs very poor, so I started to look for alternatives. Initially I made the cable as described on [url]http://www.idiots.org.uk/vga_rgb_scart/[/url]. I bought a VGA cable, cut it, with a multimeter found all the cores I needed to use, and soldered on the scart plug. Usually these VGA cables don't have a pin '9' (+5v) (as used on [url]http://ryoandr.free.fr/english.html[/url]), so I took the voltage from the PC's power supply. Not using the +12v, as I'm switching the TV to widescreen mode using the +5v. Also, since I'm not using my TV for sound I didn't connect up any audio. When I started using this I found that I had a lot of interference on the other scart inputs on my TV, so had to look a bit further. Then found out that the composite sync that comes from the Radeon card is a TTL level signal (+5V). This would be fine for a monitor, but not for a TV! So, I had to find a circuit that would convert a composite TTL level sync to a format the TV is used to handling... Found this: [img]http://www.tkk.fi/Misc/Electronics/circuits/vga2tv/vgascart.gif[/img] You can forget about the first bit of the circuit, that's to go from separate horizontal and vertical sync signals to a composite sync (which we already have straight from the Radeon card). So, you would need the circuit from point '8' onwards. The shopping list would be: - R3+R4: 1.8 kohm - R5: 2.7 kohm - R6+R7+R8: 47 ohm - U1: 74LS86 or 74HCT86 - T1+T2: BC 547 Once I included that circuit my TV was a lot happier; no more interference. Using this VGA -> RGB scart approach you get the best possible picture quality from a 'modern' PC on an old-style television set. I am extremely happy with the end result: - Much clearer picture, i.e. it's sharper but also the colours are much more vivid. - Strict control over the screen resolution, no stretched faces etc. I'm using a custom 1024*576 resolution with the TV automatically switching to widescreen mode. When playing with Powerstrip make sure you leave the ~5% overscan, that's how a CRT TV is supposed to work, makes the picture more 'stable'. This is not a problem in MP with the BlueTwo skin, as everything is based round the center of the screen, not the edges. Word of warning: My 100Hz TV does quite a bit of digital processing, but I don't know how good it will be on a standard 50Hz set. Enjoy the soldering! [/QUOTE]
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How to improve TV-OUT quality
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