720p and Aspect Ratio Question

Cyberquark · 10-02-2004, 10:53 AM

I am trying to receive OTA digital stations using an LG LST-3510 off-air terrestrial receiver, connected to my Toshiba 43H70 digital monitor's component HD ColorStream input.

With the LG in native mode, my Toshiba TV gets 480p and 1080i signals just fine, but the 720p signals pass no video (black screen) although the digital audio is received. By switching the LG receiver to a mode where it converts 720p to 1080i, I get the video image in a vertical aspect ratio with vertically stretched distortion and gray bars on both sides, not very pleasant. I presume this means my Toshiba TV does not decode 720p signals. I would have expected the LG to correct the aspect ratio distortion when it converted 720p to 1080i. Since my TV lacks a DVI connector, I don't know if the LG would handle the conversion differently using DVI output instead of component output. Is this common for HD-ready digital monitor TVs to not support both 720p and 1080i?

Lanny · 10-02-2004, 03:00 PM

IAW your TV's owners manual, note on page #9, your TV doesn't do 720p. It may not have even been a consideration for a 4:3 TV from the year 2000.

However, if your OTA tuner is set to convert 720p to 1080i, and you have selected 1080i, see page #34 of your manual, I don't see why the picture wouldn't have the right letter-box format.

Your owner's manual

I'm not sure that your set is actually an HDTV ready TV. If it were, it would have to at least accept both 720p and 1080i signals.

**rbinck** · 10-03-2004, 09:58 AM

Many HD ready RPTVs that are crt based will not receive a 720p input signal and the trend is more toward the models that will not handle the 720p signals. That said, most sources (satellite receivers, cable boxes, OTA receivers) can be set to output 1080i when other formats are received.

The reason is cost. By cutting out the converters, they save quite a bit of cost. I have a last generation Zenith that will handle 720p input, but my current generation Zenith has a DVI input, but will not handle 720p.

10-02-2004, 10:53 AM	#1
Cyberquark What is HD? Join Date: Oct 2004 Posts: 2	720p and Aspect Ratio Question I am trying to receive OTA digital stations using an LG LST-3510 off-air terrestrial receiver, connected to my Toshiba 43H70 digital monitor's component HD ColorStream input. With the LG in native mode, my Toshiba TV gets 480p and 1080i signals just fine, but the 720p signals pass no video (black screen) although the digital audio is received. By switching the LG receiver to a mode where it converts 720p to 1080i, I get the video image in a vertical aspect ratio with vertically stretched distortion and gray bars on both sides, not very pleasant. I presume this means my Toshiba TV does not decode 720p signals. I would have expected the LG to correct the aspect ratio distortion when it converted 720p to 1080i. Since my TV lacks a DVI connector, I don't know if the LG would handle the conversion differently using DVI output instead of component output. Is this common for HD-ready digital monitor TVs to not support both 720p and 1080i?

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10-02-2004, 03:00 PM	#2
Lanny High Definition is the definition of life. Join Date: Sep 2004 Location: Winthrop, MA Posts: 421	IAW your TV's owners manual, note on page #9, your TV doesn't do 720p. It may not have even been a consideration for a 4:3 TV from the year 2000. However, if your OTA tuner is set to convert 720p to 1080i, and you have selected 1080i, see page #34 of your manual, I don't see why the picture wouldn't have the right letter-box format. Your owner's manual I'm not sure that your set is actually an HDTV ready TV. If it were, it would have to at least accept both 720p and 1080i signals.

10-03-2004, 09:58 AM	#3
rbinck Administrator Join Date: Apr 2004 Location: Katy, Texas Posts: 12,983	Many HD ready RPTVs that are crt based will not receive a 720p input signal and the trend is more toward the models that will not handle the 720p signals. That said, most sources (satellite receivers, cable boxes, OTA receivers) can be set to output 1080i when other formats are received. The reason is cost. By cutting out the converters, they save quite a bit of cost. I have a last generation Zenith that will handle 720p input, but my current generation Zenith has a DVI input, but will not handle 720p.