cse Posted March 16, 2007 Posted March 16, 2007 Hello, I tried connecting my laptop to my new Epson TW700 using a digital DVI (male DVI-D dual link connector) to HDMI cable. When connected, the laptop's display properties identifies the projector as a 'Flat Panel Display' and says it is limited to 800x600 resolution. Is there a way to increase this resolution to at least 1024x768? I tried changing the laptop resolution to 1024x768 or higher but all that does is show a larger image behind a standard 800x600 size display window. The zoom/wide/squeeze options (aspect ratio alternations) are also disabled on the projector, which is a pain as I cant stretch the output image to watch a movie or something. Note that a standard DVI-A (analog) to VGA (PC) connection works fine (ie I could get higher resolutions). It also has most of the zoom/wide/squeeze options. Ive also tried the S-video output from my laptop and that works too although the output image is very blurry. My laptop's display card is a ATI 9700 equivalent so Im sure thats not a bottleneck.
sm0241 Posted March 16, 2007 Posted March 16, 2007 I've only ever used the d-sub 15 pin VGA to VGA connection with my old Epson EMP-S1H. I have a TW700 on the way but won't have it until late next week at the earliest. I'm interested to know why you are using the HDMI input as opposed to the standard VGA one, it is to gain an improvement with PQ ? I will drive my TW700 predominately with a PC which was the case with my old EMP-S1H (via standard VGA input), I never had a problem with it but being old it was not HDMI capable. There are several TW700 owners on this forum so they should be able to help. I asked the question about PQ differences using different inputs on this projector a few weeks back, people did not seem to think it would make a difference which was used. Thanks, Steve
The_Preacher1973 Posted March 16, 2007 Posted March 16, 2007 Hello,I tried connecting my laptop to my new Epson TW700 using a digital DVI (male DVI-D dual link connector) to HDMI cable. When connected, the laptop's display properties identifies the projector as a 'Flat Panel Display' and says it is limited to 800x600 resolution. Is there a way to increase this resolution to at least 1024x768? If you turn to the page of compatible signals in the manual you'll see that it does't support XGA via HDMI. XGA is only supported though the HD15 (VGA) port.
ocujos Posted March 17, 2007 Posted March 17, 2007 There is only one resolution you want to use on any digital display (including a projector): that digital display's native resolution. In the case of TW700 it's 1280x720. Set your laptop to output 1280x720 (also known as 720p) and all will be sweet. TW700 is a digital display and as such it works best with digital signals such as the one from your HTPC. If you use VGA out, two video signal conversions take place: on a PC digital > analogue and than analogue > digital on the projector. This is why it's best to use digital signals for digital displays.
The_Preacher1973 Posted March 17, 2007 Posted March 17, 2007 There is only one resolution you want to use on any digital display (including a projector): that digital display's native resolution.In the case of TW700 it's 1280x720. Set your laptop to output 1280x720 (also known as 720p) and all will be sweet. TW700 is a digital display and as such it works best with digital signals such as the one from your HTPC. If you use VGA out, two video signal conversions take place: on a PC digital > analogue and than analogue > digital on the projector. This is why it's best to use digital signals for digital displays. Um yeah. If you use a digital connection for playing DVD's from a PC then the digital signal only has to undergo the following conversion: 4:2:0 to 4:4:4 then back to 4:2:2 for internal processing than back to 4:4:4 for display. 3 conversions. But aside from that , yes you should definitely be trying to send it a 720P signal.
Tinsanta Posted March 17, 2007 Posted March 17, 2007 Um yeah. If you use a digital connection for playing DVD's from a PC then the digital signal only has to undergo the following conversion:4:2:0 to 4:4:4 then back to 4:2:2 for internal processing than back to 4:4:4 for display. 3 conversions. But aside from that , yes you should definitely be trying to send it a 720P signal. Sorry, so to get this stright, I have a htpc and want to hook it up to my Epson Tw700, what is better component or hdmi. Will i be able to run my projector on full resolution (720p) from the htpc if i connect via hdmi? ie the computer send 720p and the projector shows 720p.
The_Preacher1973 Posted March 17, 2007 Posted March 17, 2007 Sorry, so to get this stright, I have a htpc and want to hook it up to my Epson Tw700, what is better component or hdmi. Will i be able to run my projector on full resolution (720p) from the htpc if i connect via hdmi? ie the computer send 720p and the projector shows 720p. With a HTPC you will be able to send it a 720P signal either by DVI-HDMI or via RGBHV (VGA). And as Ocujos stated generally the best way to do this would be via the HDMI connection. It's just not always the case though and I was just pointing out that the signal is not a "pure" connection as many assume. It still goes though many conversions before it;s dispkayed on the screen. Digital is usually the best connection to use. But depending on your equipment analogue can sometimes give a better result for a variety of reasons. Here's a summary of my current thoughts on the whole analogue versus digital connection: What’s the better connection - Analogue or digital? There's two parts to this equation - transmission and transcoding. Firstly, if the component connection and the digital connection are both doing what they are supposed to do, there will be no difference between the two. Regardless of whether we're talking about digital or component, they're both carrying the same information. It's just that with digital it's carrying it as a series of 0's and 1's (on/off only) whereas with component it's carrying it as a voltage. For example ,as far as "brightness" goes, 0 IRE represents 0 volts and 100 ire is 700 mili volts. (Assuming a 0 pedestal for black level like we have in PAL land. NTSC in the US use an offset of 7.5 IRE but that's a whole other kettle of confusion). So as you can see, if all the 1's and 0's of the digital connection are getting through correctly and all of the voltage differences are being decoded correctly, there will be no difference. Both cables are passing "digital" information, they're just doing it in a different manner. Where this changes is when the signals aren’t getting through correctly. With a digital connection, it "fails". You'll get a blank screen, green screen or sparklies. You know there's a problem with your cable/signal. Thus with digital, you've either got a clear picture or no picture at all. It's not so simple with the analogue signal. If it starts to degrade, you will simply get ghosting, loss of detail and all the other things we have come to know and love about analogue TV transmission. Once again once a signal is this bad, it's pretty obvious, but it might be only slightly off thus causing you to think that the digital signal is clearer than the analogue. In short, it's possible to get slight degradation of PQ with component, whereas with digital it either works or it doesn't. In summary, an analogue signal can match a digital signal if all's going well. It will however never be a better signal than digital. It can't be. (Unless of course the digital has failed in the manner described above and is not producing a picture at all). So are all these people claiming that component is better than HDMI ful of it? No. Because there's the other part of the process to take into account: transcoding. Video information on a DVD (mpeg2) is encoded using a colour space of 4:2:0. In order for most display devices to display a picture this needs to be transcoded into RGB (4:4:4). Now if you use the component connection, the mpeg decoder in your source will transcode the data to 4:2:2 and transmit it in this format. Your display will then transcode the information to RGB (4:4:4) ready for display. If however you're using HDMI, your player will have an option of setting it to RGB 4:4:4 to transmit the information (a DVI connection on a HTPC will be RGB 4:4:4). Therefore your player will be transcoding the information before sending it to you player. So if the player is not doing as good a job of transcoding as your display, then the component picture will look better. Now you may have noticed a "component" option under the HDMI menu of your DVD player as well, and think that if you use that then you'll get the best of both worlds - digital transmission and the transcoding being done in your display. Well, not necessarily. If you use 480P/576P then you should be OK. If you "upscale" however, it can all turn to puss. When your display transcodes a signal from component 4:2:0 colour space to RGB, it has to apply a matrix. But the matrix that it uses for SD material is different to the one it uses for HD material. So if you've taken SD material and simply upscaled it, then the display will think it's receiving HD encoded material and employ the HD matrix to transcode the signal. This will result in a degradation of picture quality. In order for this to work, the DVD player must transocde the material as well as scale it. Not all players do this. Now just to complicate matters further, I found out in the course of the JVC HD1 thread that although a projector requires 4:4:4 information to display a picture, many displays can only do their internal processing at the component 4:2:2 (level). Therefore it needs to transcode the 4:4:4 information into 4:2:2, process it and then transcode it back to 4:4:4. So as you can see, there's no simple answer as to whether HDMI is better than component. It will depend on whether the transcoder in your display is better than the one in your DVD player as well as whether or not your component cable and connections are any good. As in anything, your mileage may vary and you owe it to yourself to see which connection works best with your equipment. You just can’t categorically state that "HDMI is better because it offers a pure digital connection between the source and the display" because as you can see, there's nothing "pure" about it. It's got to be transcoded somewhere and it's the quality of this transcoding process that's going to have the biggest effect on PQ (assuming your cables and connections are OK).
cse Posted March 18, 2007 Author Posted March 18, 2007 Thanks for the responses guys. My reasons for trying a pure digital signal as opposed to analogue VGA signal was in the hope that I would get the best possible PQ. The problem is my laptop detects the TW700 as being able to handle only 800x600 maximum resolution. If I force a higher resolution, the output only shows an 800x600 frame but the image behind that frame is larger than 800x600. Below is a picture to explain it: http://home.exetel.com.au/kb/misc/rez.jpg Like many of you have mentioned, the problem is probably because Im not setting the laptop to the projector's native resolution of 1280x720 but unfortunately my laptop doesnt support that resolution. It does however support 1920x1080 (which I think is another widescreen resolution?), but this also exhibits the above problem. I think the issue is that my laptop is detecting the Epson incorrectly (by restricting the output to 800x600), or the Epson has some issue with showing greater than 800x600 resolution when using DVI-to-HDMI. Whats worse is the PJ controls wont let me change aspect ratio via the 'aspect' button to at least scale the 800x600 image to fit the screen. Using an analog VGA cable (with dvi-to-vga adapter), everything works fine at 1024x768 and higher.
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