Have tv plugged in on hdmi cable but picture only showing in 480i how do i change to 1080p

You don't. The TV has a resolution of 1920 x 1080 pixels; so it's already 1080p. The number of pixels can't be changed.

What you're probably getting mixed up with is the TV showing the resolution of the incoming signal when you change channels or go to a different source. Standard definition from cable might be flagged as 480i. DVD might show either as 480i, or 480p, or maybe 720p or 1080i or 1080p if you have a scaling DVD player and set it appropriately. HDTV on cable or satellite will show as 1080i or possibly 720p. Blu-rays and PS3/XBox 360 or PS4/Xbox One should show as 1080p when your TV is connected.

Whatever the source signal resolution, the TV will scale it up to fill the panel area of 1920x1080 pixels. So the TV is always using all the pixels, regardless of the resolution of the source signal.

AV inputs are for standard analog video which is 480i. HDMI and Component inputs are the high definition inputs that run at either 1080i or 1080p You won't ever get 1080i or p through AV inputs.

Roku only supports 720P and 1080P along with the Standard Definition. If your TV only supports 720i, then the Roku won't be able to display 720i but instead 480i which is the standard display that Roku can do on a TV that doesn't support 720p or 1080p

U can't just do it on ur own setting like 480i to 1080p when ever u want.No,u only get what ever the tv stations modes they set and send out only.Ur tv have the 1080p mode capability mean ur tv can pickup that 1080p mode.Dosen't mean u can change 480i to 1080p by ur self anytime u want,if the tv station is broadcating tv signal to u only in 480i u get only 480i.

The video source dictates what it will show on the screen, 480i video input = 480i display.
If the video source is not 1080p, it will not show 1080p. It works the same as your PC monitor, you adjust the resolution at the PC Video card setting not at the monitor.

Basic LCD monitor and TV troubleshooting guide:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide
http://www.fixya.com/support/r6150077-basic_lcd_monitors_troubleshooting
http://www.fixya.com/support/r7406380-tv_training_manuals
Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm
Learn about bad caps: http://en.wikipedia.org/wiki/Capacitor_plague

Video Output Settings Adjust the system's video output settings. Select the best output settings for the TV in use.
1.
Check the resolution supported by your TV.
Resolution (video mode) varies depending on the TV type. For details, refer to the instructions supplied with the TV.
2.
Select (Settings) > (Display Settings).
3.
Select [Video Output Settings].
4.
Select the connector type on your TV.
Resolution (video mode) varies depending on the type of connector used.
Input connector on the TV Supported video modes (NTSC region) *1 Supported video modes (PAL region) *1 HDMI 1080p / 1080i / 720p / 480p 1080p / 1080i / 720p / 576p Component / D-Terminal *2 1080p / 1080i / 720p / 480p / 480i 1080p / 1080i / 720p / 576p / 576i Composite / S Video *3 480i 576i AV MULTI / SCART *4 480p / 480i 576p / 576i *1 The video mode options vary depending on the region where the PS3™ system was purchased. In North America, Asia and other NTSC regions, 480i video mode is displayed as [Standard (NTSC)]. In Europe and other PAL regions, 576i video mode is displayed as [Standard (PAL)]. For details, refer to the instructions supplied with the product.
*2 D-terminal is a connector type used mainly in Japan. The resolutions supported by D1-D5 are as follows:
D5: 1080p / 720p / 1080i / 480p / 480i
D4: 1080i / 720p / 480p / 480i
D3: 1080i / 480p / 480i
D2: 480p / 480i
D1: 480i
*3 Composite is the connector used to connect the AV cable that is supplied with the PS3™ system. S VIDEO is a format mainly used in Japan.
*4 AV MULTI is a format mainly used in Japan. SCART is a format mainly used in Europe. If [AV MULTI / SCART] is selected, the screen allowing you to select the type of output signal will be displayed.
5.
Change video output settings.
Change the resolution for the video output. Depending on the connector type selected in step 4, this screen may not be displayed.
6.
Set the resolution.
Select all resolutions supported by the TV in use. Video will automatically be output at the highest resolution possible for the content you are playing from among the selected resolutions.*
* The video resolution is selected in order of priority as follows: 1080p > 1080i > 720p > 480p/576p > Standard (NTSC:480i/PAL:576i).

If [Composite / S Video] is selected in step 4, the screen for selecting resolutions will not be displayed.
If [HDMI] is selected, you can also select to automatically adjust the resolution (the HDMI device must be turned on). In this case, the screen for selecting resolutions will not be displayed.
7.
Set the TV type.
Select the type of TV in use. Set when only SD resolution (NTSC:480p / 480i, PAL: 576p / 576i) is to be output such as when [Composite / S Video] or [AV MULTI / SCART] is selected in step 4.
8.
Check your settings.
Confirm that the image displayed is at the correct resolution for the TV. You can go back to a previous screen and revise the settings by pressing the button.
9.
Save your settings.
The video output settings are saved on the PS3™ system. You can continue on to set audio output settings. For details on audio output, see (Settings) > (Sound Settings) > [Audio Output Settings] in this guide.



Source: http://manuals.playstation.net/document/en/ps3/current/settings/videooutput.html

Most TVs choose the resolution based on the signal coming in. Be careful if you try and use 1080P. Not all TVs support it. 1080P is only on HDMI. set the playstation to 1080i before connection.
Some TVs and Playstation HDMI do not mix well due to software in the HDMI ports. Try RGB cables.

Adjust the system's video output settings. Select the best output settings for the TV in use.

1. Check the resolution supported by your TV.
Resolution (video mode) varies depending on the TV type. For details, refer to the instructions supplied with the TV.

2. Select (Display Settings) under (Settings) in the home menu.

3. Select [Video Output Settings].

4. Select the connector type on your TV.
Resolution (video mode) varies depending on the type of connector used.

Input connector on the TV Supported video modes (NTSC region) *1 Supported video modes (PAL region) *1
HDMI 1080p / 1080i / 720p / 480p 1080p / 1080i / 720p / 576p
Component / D-Terminal *2 1080p / 1080i / 720p / 480p / 480i 1080p / 1080i / 720p / 576p / 576i
Composite / S Video *3 480i 576i
AV MULTI / SCART *4 480p / 480i 576p / 576i
*1 The video mode options vary depending on the region where the PS3™ system was purchased. In North America, Asia and other NTSC regions, 480i video mode is displayed as [Standard (NTSC)]. In Europe and other PAL regions, 576i video mode is displayed as [Standard (PAL)]. For details, refer to the instructions supplied with the product.

*2 D-terminal is a connector type used mainly in Japan. The resolutions supported by D1-D5 are as follows:
D5: 1080p / 720p / 1080i / 480p / 480i
D4: 1080i / 720p / 480p / 480i
D3: 1080i / 480p / 480i
D2: 480p / 480i
D1: 480i

*3 Composite is the connector used to connect the AV cable that is supplied with the PS3™ system. S VIDEO is a format mainly used in Japan.

*4 AV MULTI is a format mainly used in Japan. SCART is a format mainly used in Europe. If [AV MULTI / SCART] is selected, the screen allowing you to select the type of output signal will be displayed.


5. Change video output settings.
Change the resolution for the video output. Depending on the connector type selected in step 4, this screen may not be displayed.

6. Set the resolution.
Select all resolutions supported by the TV in use. Video will automatically be output at the highest resolution possible for the content you are playing from among the selected resolutions.*
* The video resolution is selected in order of priority as follows: 1080p > 1080i > 720p > 480p/576p > Standard (NTSC:480i/PAL:576i).
If [Composite / S Video] is selected in step 4, the screen for selecting resolutions will not be displayed.
If [HDMI] is selected, you can also select to automatically adjust the resolution (the HDMI device must be turned on). In this case, the screen for selecting resolutions will not be displayed.

7. Set the TV type.
Select the type of TV in use. Set when only SD resolution (NTSC:480p / 480i, PAL: 576p / 576i) is to be output such as when [Composite / S Video] or [AV MULTI / SCART] is selected in step 4.

8. Check your settings.
Confirm that the image displayed is at the correct resolution for the TV. You can go back to a previous screen and revise the settings by pressing the button.

9. Save your settings.
The video output settings are saved on the PS3™ system. You can continue on to set audio output settings. For details on audio output, see (Settings) > (Sound Settings) > [Audio Output Settings] in this guide.

You Can Not Change. The TV Recognize the signal on the INPUT.
If the signal is 480i than the tv shows 480i
If the signal is 1080p than the tv shows 1080p (if supported)
If you try with your areal antenna (for now digital broadcast is maximum 1080i (in USA) The TV itself doesnt "upconvert" lower resolution signals.

so u must go n plug the hdmi cable in a tv dat support an hdmi feature so u can be able to fix the problem from the menu.....if it's not lkike that i think u can use the AV cable on a normal TV ....so u can fix it as well