Raspberry Pi - HDMI / LCD TV configuration & setup (Part 2)

The current version used in consumer electronic gear for the HDMI interface is Enhanced EDID (E-EDID) 1.3 which is based on CEA-861E and incorporated into the HDMI 1.4 specification. The EDID 1.3 specification was released in 2000. The current version used for PCs with the DisplayPort interface is EDID 1.4, released in March 2007.

Here is a description lifted from Open Tech Guides.

Picture doesn't fill the entire size of the screen and you can see black borders on left, right, top, bottom or all sides.

This is possibly because Pi is adding overscan to the signal. Modern TVs and monitors don't need overscan and hence disabling overscan altogether can make the Pi graphics fill the entire screen.

Check the settings on the TV or monitor first. Eg: On a Sony Bravia TV these settings are under Screen Format (Normal, Zoom, Wide Zoom etc.,). If this doesn't remove the black borders, then try disabling overscan on the Pi. This can be done by setting the parameter disable_overscan to 1 in /boot/config.txt and commenting other parameters related to overscan.

1. Take a backup of /boot/config.txt

   sudo cp /boot/config.txt /boot/config.txt.backup
   

2. Open config.txt for editing

   sudo nano /boot/config.txt
   

3. Uncomment the #disable_overscan=1 (Remove the #)
4. Comment all other overscan parameters

   #overscan_left=10
   #overscan_right=10
   #overscan_top=15
   #overscan_bottom=15
   

5. Save and exit. ( CTRL+X followed by Y to save)
6. Reboot

   sudo reboot
   

On most monitors / TVs this would remove the black borders and make the desktop fill the whole screen. However, if your display still has some overscan you may need to keep the overscan parameters in config.txt file but adjust the values:

overscan_left=-10
overscan_right=-10
overscan_top=-30
overscan_bottom=-30

More negative values mean less black borders. Centre the display by trying different values for left, right, top, bottom.

Picture spills off the size of the screen and some parts of the picture are outside the screen

This means you need positive overscan values.

overscan_left=10
overscan_right=10
overscan_top=30
overscan_bottom=30

The resolution and HDMI modes are not the best values for your screen

Try to change monitor settings from Preferences → Monitor settings

However, if it says "Unable to get monitor information", find out the modes supported by your monitor by running tvservice command and set the correct mode in /boot/config.txt as below

1. Run the tvservice command to output the result to a file.

   $ tvservice -d edid.dat
   Written 256 bytes to edid.dat
   

2. Pipe the file to edidparser to generate a readable text file.

   $ edidparser edid.dat > edid.txt
   

3. Grep the desired resolution to check if it is available. For example if you are checking for 1080p resolution

   $ cat edid.txt | grep 1080p
     HDMI:EDID found preferred CEA detail timing format: 1920x1080p @ 60 Hz (16)
     HDMI:EDID found CEA detail timing format: 1920x1080p @ 50 Hz (31)
     HDMI:EDID found CEA format: code 31, 1920x1080p @ 50Hz 
     HDMI:EDID found CEA format: code 16, 1920x1080p @ 60Hz 
     HDMI:EDID found CEA format: code 32, 1920x1080p @ 24Hz 
     HDMI:EDID found CEA format: code 34, 1920x1080p @ 30Hz 
     HDMI:EDID best score mode is now CEA (16) 1920x1080p @ 60 Hz with pixel clock 148 MHz (score 5398248)
     HDMI:EDID CEA mode (31) 1920x1080p @ 50 Hz with pixel clock 148 MHz has a score of 4232360
     HDMI:EDID CEA mode (32) 1920x1080p @ 24 Hz with pixel clock 74 MHz has a score of 124532
     HDMI:EDID CEA mode (34) 1920x1080p @ 30 Hz with pixel clock 74 MHz has a score of 149416
     HDMI:EDID preferred mode remained as CEA (16) 1920x1080p @ 60 Hz with pixel clock 148 MHz
   
     HDMI:EDID best score mode is now CEA (16) 1920x1080p @ 60 Hz with pixel clock 148 MHz (score 5398248)

   "CEA" corresponds to hdmi_group=1
   "DMT" corresponds to hdmi_group=2
   The value inside () corresponds to hdmi_mode.
   From the above result:
   hdmi_group=1
   hdmi_mode=16
4. Take a backup of /boot/config.txt

    sudo cp /boot/config.txt /boot/config.txt.backup

5. Edit /boot/config.txt

    sudo nano /boot/config.txt 

6. Uncomment hdmi_group and hdmi_mode and set the right values

    hdmi_group=1
    hdmi_mode=16 

7. Save and exit; Ctrl+X followed by Y to save
8. Reboot

   $ sudo reboot 

You can find more information at eLinux.org.

Here is a description lifted from Raspberry Pi.org.

CEA (Consumer Electronics Association) and DMT (Display Monitor Timings) are two logical groups of configuration settings. Here follows a list of all CEA and DMT formats (as of CEA-861 E and DMT V1 r12 respectively). If you want to use any of these modes explicitly, set hdmi_group and hdmi_mode to the correct values in the config file. Note that not all modes are supported by the Raspberry Pi hardware (mainly the high resolution / high frame rate modes) and all explicit modes are subject to EDID support from the monitor / TV you are using.


CEA (hdmi_group = 1)

HDMI_CEA_VGA = 1
HDMI_CEA_480p60 = 2
HDMI_CEA_480p60H = 3
HDMI_CEA_720p60 = 4
HDMI_CEA_1080i60 = 5
HDMI_CEA_480i60 = 6
HDMI_CEA_480i60H = 7
HDMI_CEA_240p60 = 8
HDMI_CEA_240p60H = 9
HDMI_CEA_480i60_4x = 10
HDMI_CEA_480i60_4xH = 11
HDMI_CEA_240p60_4x = 12
HDMI_CEA_240p60_4xH = 13
HDMI_CEA_480p60_2x = 14
HDMI_CEA_480p60_2xH = 15
HDMI_CEA_1080p60 = 16
HDMI_CEA_576p50 = 17
HDMI_CEA_576p50H = 18
HDMI_CEA_720p50 = 19
HDMI_CEA_1080i50 = 20
HDMI_CEA_576i50 = 21
HDMI_CEA_576i50H = 22
HDMI_CEA_288p50 = 23
HDMI_CEA_288p50H = 24
HDMI_CEA_576i50_4x = 25
HDMI_CEA_576i50_4xH = 26
HDMI_CEA_288p50_4x = 27
HDMI_CEA_288p50_4xH = 28
HDMI_CEA_576p50_2x = 29
HDMI_CEA_576p50_2xH = 30
HDMI_CEA_1080p50 = 31
HDMI_CEA_1080p24 = 32
HDMI_CEA_1080p25 = 33
HDMI_CEA_1080p30 = 34
HDMI_CEA_480p60_4x = 35
HDMI_CEA_480p60_4xH = 36
HDMI_CEA_576p50_4x = 37
HDMI_CEA_576p50_4xH = 38
HDMI_CEA_1080i50_rb = 39
HDMI_CEA_1080i100 = 40
HDMI_CEA_720p100 = 41
HDMI_CEA_576p100 = 42
HDMI_CEA_576p100H = 43
HDMI_CEA_576i100 = 44
HDMI_CEA_576i100H = 45
HDMI_CEA_1080i120 = 46
HDMI_CEA_720p120 = 47
HDMI_CEA_480p120 = 48
HDMI_CEA_480p120H = 49
HDMI_CEA_480i120 = 50
HDMI_CEA_480i120H = 51
HDMI_CEA_576p200 = 52
HDMI_CEA_576p200H = 53
HDMI_CEA_576i200 = 54
HDMI_CEA_576i200H = 55
HDMI_CEA_480p240 = 56
HDMI_CEA_480p240H = 57
HDMI_CEA_480i240 = 58
HDMI_CEA_480i240H = 59
HDMI_CEA_720p24 = 60
HDMI_CEA_720p25 = 61
HDMI_CEA_720p30 = 62
HDMI_CEA_1080p120 = 63
HDMI_CEA_1080p100 = 64

DMT (hdmi_group = 2)

HDMI_DMT_640x350_85 = 0x1, /**<640x350 */
HDMI_DMT_640x400_85 = 0x2, /**<640x400 */
HDMI_DMT_IBM_VGA_85 = 0x3, /**<720x400 */
HDMI_DMT_VGA_60 = 0x4, /**<640x480 (60Hz is same as VGA in CEA above) */
HDMI_DMT_VGA_72 = 0x5
HDMI_DMT_VGA_75 = 0x6
HDMI_DMT_VGA_85 = 0x7
HDMI_DMT_SVGA_56 = 0x8, /**<800x600 */
HDMI_DMT_SVGA_60 = 0x9
HDMI_DMT_SVGA_72 = 0xA
HDMI_DMT_SVGA_75 = 0xB
HDMI_DMT_SVGA_85 = 0xC
HDMI_DMT_SVGA_120 = 0xD
HDMI_DMT_848x480_60 = 0xE, /**<848x480 */
HDMI_DMT_XGA_43 = 0xF, /**<1024x768 – interlaced, DO NOT USE */
HDMI_DMT_XGA_60 = 0x10, /**<1024x768 */
HDMI_DMT_XGA_70 = 0x11
HDMI_DMT_XGA_75 = 0x12
HDMI_DMT_XGA_85 = 0x13
HDMI_DMT_XGA_120 = 0x14
HDMI_DMT_XGAP_75 = 0x15, /**<1152x864 */
HDMI_DMT_WXGA_RB = 0x16, /**<1280x768 reduced blanking */
HDMI_DMT_WXGA_60 = 0x17
HDMI_DMT_WXGA_75 = 0x18
HDMI_DMT_WXGA_85 = 0x19
HDMI_DMT_WXGA_120 = 0x1A, /**<120Hz with reduced blanking */
HDMI_DMT_1280x800_RB = 0x1B, /**<1280x800 reduced blanking */
HDMI_DMT_1280x800_60 = 0x1C
HDMI_DMT_1280x800_75 = 0x1D
HDMI_DMT_1280x800_85 = 0x1E
HDMI_DMT_1280x800_120 = 0x1F, /** reduced blanking */
HDMI_DMT_1280x960_60 = 0x20, /**<1280x960 */
HDMI_DMT_1280x960_85 = 0x21
HDMI_DMT_1280x960_120 = 0x22, /** reduced blanking */
HDMI_DMT_SXGA_60 = 0x23, /**<1280x1024 */
HDMI_DMT_SXGA_75 = 0x24
HDMI_DMT_SXGA_85 = 0x25
HDMI_DMT_SXGA_120 = 0x26, /** reduced blanking */
HDMI_DMT_1360x768_60 = 0x27, /**<1360x768 */
HDMI_DMT_1360x768_120 = 0x28, /**<120 Hz with reduced blanking */
HDMI_DMT_SXGAP_RB = 0x29, /**<1400x1050 reduced blanking */
HDMI_DMT_SXGAP_60 = 0x2A
HDMI_DMT_SXGAP_75 = 0x2B
HDMI_DMT_SXGAP_85 = 0x2C
HDMI_DMT_SXGAP_120 = 0x2D, /** reduced blanking */
HDMI_DMT_1440x900_RB = 0x2E, /**<1440x900 reduced blanking */
HDMI_DMT_1440x900_60 = 0x2F
HDMI_DMT_1440x900_75 = 0x30
HDMI_DMT_1440x900_85 = 0x31
HDMI_DMT_1440x900_120 = 0x32, /** reduced blanking */
HDMI_DMT_UXGA_60 = 0x33, /**<1600x1200 60Hz */
HDMI_DMT_UXGA_65 = 0x34
HDMI_DMT_UXGA_70 = 0x35
HDMI_DMT_UXGA_75 = 0x36
HDMI_DMT_UXGA_85 = 0x37
HDMI_DMT_UXGA_120 = 0x38, /** reduced blanking */
HDMI_DMT_SWXGAP_RB = 0x39, /**<1680x1050 reduced blanking */
HDMI_DMT_SWXGAP_60 = 0x3A, /**<1680x1050 60Hz */
HDMI_DMT_SWXGAP_75 = 0x3B
HDMI_DMT_SWXGAP_85 = 0x3C
HDMI_DMT_SWXGAP_120 = 0x3D, /** reduced blanking */
HDMI_DMT_1792x1344_60 = 0x3E, /**<1792x1344 60Hz */
HDMI_DMT_1792x1344_75 = 0x3F, /**<1792x1344 75Hz */
HDMI_DMT_1792x1344_120 = 0x40, /** reduced blanking */
HDMI_DMT_1856x1392_60 = 0x41, /**<1856x1392 60Hz */
HDMI_DMT_1856x1392_75 = 0x42, /**<1856x1392 75Hz */
HDMI_DMT_1856x1392_120 = 0x43, /** reduced blanking */
HDMI_DMT_WUXGA_RB = 0x44, /**<1920x1200 reduced blanking */
HDMI_DMT_WUXGA_60 = 0x45, /**<1920x1200 60Hz */
HDMI_DMT_WUXGA_75 = 0x46, /**<1920x1200 75Hz */
HDMI_DMT_WUXGA_85 = 0x47, /**<1920x1200 85Hz */
HDMI_DMT_WUXGA_120 = 0x48, /** reduced blanking */
HDMI_DMT_1920x1440_60 = 0x49, /**<1920x1440 60Hz */
HDMI_DMT_1920x1440_75 = 0x4A, /**<1920x1440 75Hz */
HDMI_DMT_1920x1440_120 = 0x4B, /** reduced blanking */
HDMI_DMT_2560x1600_RB = 0x4C, /**<2560x1600 reduced blanking */
HDMI_DMT_2560x1600_60 = 0x4D, /**<2560x1600 60 Hz */
HDMI_DMT_2560x1600_75 = 0x4E, /**<2560x1600 75 Hz */
HDMI_DMT_2560x1600_85 = 0x4E, /**<2560x1600 85 Hz */
HDMI_DMT_2560x1600_120 = 0x50, /** reduced blanking */
HDMI_DMT_1366x768_60 = 0x51, /**<1366x768 60Hz */
HDMI_DMT_1080p_60 = 0x52, /**<Same as 1080p60 in CEA above */
HDMI_DMT_1600x900_RB = 0x53, /**<1600x900 reduced blanking */
HDMI_DMT_2048x1152_RB = 0x54, /**<2048x1152 reduced blanking */
HDMI_DMT_720p_60 = 0x55, /**<Same as 720p60 in CEA above */
HDMI_DMT_1366x768_RB = 0x56, /**<1366x768 reduced blanking */

If the file config.txt is not present or the output format is not set explicitly, the default output format is chosen as follows:

1. If the preferred format in EDID is supported, this will be chosen.
2. If the preferred format is not supported, then all the formats supported will be ranked according to some heuristics. The format with the highest score will be chosen.

If the chosen format is a DMT format, the default driven mode will be DVI. The user will need to set driving mode to 2 explicitly if HDMI output is desired. In DVI mode there will be no sound!

This is how to override the default format in config.txt:
1. Set hdmi_group = 1 (for CEA formats) or hdmi_group = 2 (for DMT formats)
2. Set hdmi_mode = x (where x is the code of the format of the respective group; see the list of CEA/DMT formats for details.)
3. If the chosen format is DMT, set hdmi_drive = 2 to enable HDMI output. (CEA modes are output as HDMI by default).

If you are unsure what formats are supported, set the output format to VGA 60Hz and then follow the instructions below to parse the EDID to find out what formats are supported. All executables are found under /opt/vc/bin.

1. Run “tvservice –m CEA” to give a list of CEA supported modes.
2. Run “tvservice –m DMT” to give a list of DMT supported modes.
3. Run “tvservice -s” to give you the current state.

Alternatively you can do the following:
1. Run “tvservice –d <file>” to capture a monitor’s EDID.
2. Pass this file to edidparser. Run “edidparser <file>”.

At this point, edidparser outputs the list of formats supported in EDID including formats not supported in Raspberry Pi, and it will show you which formats are filtered out. At the end of the output it will show which format is chosen as default. Note that edidparser is the internal EDID parsing code of Raspberry Pi with a command line front end.

Users are encouraged to post the EDID of their monitors (and the output for the parser), if Raspberry Pi chooses a default resolution which is not expected (or strange). Please include make and model number when you post EDID online.

VideoCore is a low-power mobile multimedia processor architecture originally developed by Alphamosaic Ltd. and now owned by Broadcom. The main specification points for a fully configured system at 250 MHz are:

• 25M rendered triangles/s.
• 1G pixels/s with single bilinear texturing, simple shading, 4x multisampling.
• Supports 16x coverage mask antialiasing for 2D rendering at full pixel rate.
• 720p standard resolution with 4x multisampling.
• Supports 16-bit HDR rendering.
• Fully supports OpenGL-ES 1.1/2.0 and OpenVG 1.1.

The VideoCore IV 3D hardware is self-contained and highly automated, requiring little processing bandwidth or real-time intervention from software drivers.

On the 2nd anniversary (28 February 2014) of the Raspberry Pi, Broadcom and Raspberry Pi Foundation, announced the release of full documentation for the VideoCore IV's 3D subsystem and a release of the graphics stack under a 3-clause BSD license.

root@raspberrypi:~# vcgencmd commands 
commands="vcos, ap_output_control, ap_output_post_processing, vchi_test_init, vchi_test_exit,
pm_set_policy, pm_get_status, pm_show_stats, pm_start_logging, pm_stop_logging, version, commands, set_vll_dir, led_control, set_backlight, set_logging, get_lcd_info, set_bus_arbiter_mode,
cache_flush, otp_dump, codec_enabled, measure_clock, measure_volts, measure_temp, get_config,
hdmi_ntsc_freqs, render_bar, disk_notify, inuse_notify, sus_suspend, sus_status, sus_is_enabled,
sus_stop_test_thread, egl_platform_switch, mem_validate, mem_oom, mem_reloc_stats, file,
vctest_memmap, vctest_start, vctest_stop, vctest_set, vctest_get"

Happy try-out!  Hope you enjoy your Raspberry Pi experience!

CAUTION: Your circumstances, connections, interfaces, options and versions may differ and needs to be re-evaluated for your specific application.