HDMI

This document provides detailed instructions on the Quectel-Pi-H1 single-board computer's HDMI display interface identification, display connection methods, system configuration, and troubleshooting solutions, using an 11.6-inch HDMI display as an example.

HDMI Display Connection

Follow the diagram below for connection:

11.6-inch HDMI Display

QuecPi with Connected HDMI Display

After connecting the HDMI display and powering on, start the display service, select default user: pi, password: quecpi, and the HDMI screen will display the Gnome desktop.

Display effect as shown below:

Screen Display Effect

Function Usage

Adjusting Screen Brightness and Volume

Note: After connecting an HDMI display, the resolution is adaptive and cannot be changed. Currently supported HDMI resolutions are 3840 × 2160, 1920 × 1080, 1280 × 720, 720 × 480

After connecting the HDMI display and powering on, enter the Gnome desktop, click the battery icon in the upper right corner, and slide the volume bar and brightness bar to adjust volume and brightness.

The following is the operation diagram for adjusting screen brightness and volume:

Brightness and Volume Adjustment Operation

Touch Function Usage

After connecting the HDMI display and powering on, you need to connect the USB port to the HDMI screen.
Note: This function requires an HDMI screen with touch functionality.

Follow the diagram below for connection:

Touch Function Connection Effect

Video Playback Function Usage

Visual Interface Video Playback: Open the Gnome desktop, find the video file in the Gnome desktop's File Manager, and click the video file to play it.
Note: Double-click the frame to play the video in fullscreen.

Desktop Operation Steps

Video Playback Display Effect

VLC Command Line Video Playback: When playing via command line, follow these steps to enter the corresponding commands.

export LIBGL_ALWAYS_SOFTWARE=1 #Modify this window's environment variable to switch to CPU rendering when playing video
VLC test.mp4                   #Play video

The following is the video playback effect diagram:

Video Playback Display Effect

GST Command Line Video Playback Function: When playing via command line, you need to enter the following corresponding command.

gst-launch-1.0 filesrc location=/home/pi/test.mp4 ! qtdemux ! h264parse ! avdec_h264 ! autovideosink    ## The parameter after "location" should be modified according to the actual video file path

Command parameter description:

• gst-launch-1.0: This is GStreamer's command-line tool for building and running a GStreamer pipeline.
• filesrc location=/home/pi/test.mp4: Uses the filesrc element to read video files from the specified path /home/pi/test.mp4.
• ! qtdemux: Through the ! symbol, connects the output of the previous element to the input of the next element. qtdemux is responsible for demultiplexing the MP4 container format, separating the audio and video streams within it.
• ! h264parse: Parses the separated H.264 video stream, reorganizing it into a format suitable for decoder processing.
• ! avdec_h264: Uses the software decoder avdec_h264 to decode the H.264 video stream. This is a GStreamer plugin element based on FFmpeg.
• ! autovideosink: Automatically selects an appropriate video output component to display video content. Depending on the system environment, it will choose the most suitable sink, such as waylandsink under Wayland environment or ximagesink under X11.

The following is the video playback effect diagram:

Video Playback Display Effect

Audio Playback Function Usage

Visual Interface Audio Playback: Open the Gnome desktop, find the audio file in the Gnome desktop's File Manager, and click the audio file to play it.
Note: To play audio, connect speakers to the SG565D single-board computer.

Desktop Operation Steps

Audio Playback Display Effect

VLC Command Line Audio Playback Function: When playing via command line, follow these steps to enter the corresponding commands.

export LIBGL_ALWAYS_SOFTWARE=1 #Modify this window's environment variable to switch to CPU rendering when playing audio
VLC 1.mp3                      #Play audio

The following is the audio playback effect diagram:

Audio Playback Display Effect

GST Command Line Audio Playback Function: When playing via command line, you need to follow the steps below to enter the corresponding commands.
Note: After entering the corresponding command, the audio playback progress will be displayed in the terminal.

gst-launch-1.0 uridecodebin uri=file:///home/pi/test.mp3 ! audioconvert ! audioresample ! autoaudiosink ## The parameter after "location" should be modified according to the actual video file path

Command parameter description:

• gst-launch-1.0: This is GStreamer's command-line tool for building and running a GStreamer pipeline.
• uridecodebin uri=file:///home/pi/test.mp3: Uses the uridecodebin element to read and automatically decode audio files from the specified URI path file:///home/pi/test.mp3. This is an advanced element that can automatically detect media types and select appropriate demuxers and decoders.
• ! audioconvert: Through the ! symbol, connects the output of the previous element to the input of the next element. audioconvert is used to convert audio formats, ensuring audio format compatibility between consecutive elements.
• ! audioresample: Resamples the audio, adjusting the audio sample rate to match the requirements of subsequent elements.
• ! autoaudiosink: Automatically selects an appropriate audio output component to play audio content. Depending on the system environment, it will choose the most suitable audio output device, such as ALSA, PulseAudio, or other available audio backends.

The following is the audio playback effect diagram:

Audio Playback Display Effect

Advanced Functions

HDMI Display Hot Plugging

HDMI displays support hot plugging functionality, allowing you to plug and unplug HDMI displays while the system is running, with the system automatically recognizing and displaying the image.

Hot Plugging Usage Method

1. While the system is running, directly insert the HDMI display into the single-board computer's HDMI port.
2. The system will automatically detect the HDMI device and start display output.
3. To disconnect the HDMI display, simply unplug the HDMI cable, and the system will automatically switch display output.

Hot Plugging Considerations

1. Hot plugging functionality only supports displays connected via HDMI interface.
2. Displays connected via DP to HDMI adapters may not properly support hot plugging.
3. Avoid frequent operations during plugging and unplugging, it is recommended to wait at least 5 seconds between each plug/unplug operation.

Application Scenarios

• Media Entertainment Terminal: Using the Quectel-Pi-H1 single-board computer as a media entertainment terminal, it can play movies and videos, music, view pictures, etc.
• Industrial Data Visualization Platform: Using the Quectel-Pi-H1 single-board computer as an industrial data visualization platform, it can display industrial data, monitor equipment operation status, and perform data processing, etc.
• Smart Interactive Terminal: Using the Quectel-Pi-H1 single-board computer as a smart interactive terminal, it can be used for various human-computer interaction applications.

Troubleshooting

How to View System Logs

To view system logs, you need to connect the serial cable to a computer and use a serial tool to view the logs.

Black Screen Issue

After properly connecting the device, if the display shows a black screen after powering on, it may be due to the following situations:

1. Power connection issue
   Check if the display's power supply interface is properly connected, confirm that at least one of the 4 power supply interfaces is correctly connected, ensure the power screws are tightened, and the pogo pins make good contact with the 40PIN.
2. Connection line issue
   Check if the MIPI cable is properly inserted and securely connected, confirm the cable direction is correct to avoid reverse insertion, check if the connector has physical damage.
3. System startup issue
   Confirm the system has started normally and loaded the display service, check if the login credentials are correct (default user: pi, password: quecpi), view system logs to confirm the display driver is loaded properly.

Screen Distortion Issue

After properly connecting the device, if the display shows screen distortion after powering on, it may be due to the following situations:

1. Signal interference
   Check if the MIPI cable is too long or of poor quality, confirm there are no strong electromagnetic interference sources around the cable, try replacing with a high-quality MIPI cable.
2. Hardware compatibility issue
   Confirm the display model used is fully compatible with Quectel-Pi-H1, check if the display firmware version is the latest version.

Touch Function Abnormality

Touch function abnormality may be due to the following situations:

1. Driver issue
   Confirm the system has loaded the touchscreen driver correctly, check if I2C communication is established properly.
2. Calibration issue
   If the touch position is inaccurate, you may need to recalibrate the touchscreen through the touchscreen calibration tool in system settings.