Simple Delay Checker

About Simple Delay Checker Android App

* How to Use
1. Connect the terminal and the LCD with an HDMI cable, and start app.
2. Shooting the screen of the LCD and the screen of terminal in the same photo by digital camera etc.
3. By counting the displacement of the frame on the image, you can estimate delay frame of the LCD.

* Required Equipment
- An Android terminal with HDMI output function.
- HDMI Cable.
- The LCD that you want to measure.
- Shooting devices such as digital cameras.

* Screen & Principle
[White Square Marker]
- 12 white square markers disposed around the screen, are displayed sequentially in a clockwise direction for each frame(5 laps at 60 frames).
- If delay is zero on the LCD, you will see a square marker in the same position as the screen of the terminal. If there is a delay, square marker will be displayed on the delayed position. Shooting the screen of the LCD and the screen of terminal in the same photo, and by counting the displacement of the frame on the image, you can estimate delay frame of the LCD.
- The number displayed in the square marker is an internal processing time. In fact, it is the blocking time of the multi-buffering. There is no less important.
[Frame Rate]
- Frame rate will be displayed in blue in the middle left side of the screen.
- Basically it works with the refresh rate of the terminal.
- Simply, the synchronization is performed, by utilizing the buffer blocking of SurfaceView.
- When the terminal can not update drawing in the refresh rate or returns wrong refresh rate value, app works with an guess mode. App shows "*" mark on fps, and works at the highest frame rate possible drawing. In this case, app might draw the same frame.
[Lost Frame Count]
- Lost frame count per 60 frames will be displayed in red in the middle right of the screen.
- Low spec terminal or GC causes Lost Frame. In that case, since the display position of the square marker is skipping, delay measurement may be affected in the image judgment.
[Display Text]
- Input text can be displayed in yellow in the center of the screen.
- By inputting the mode setting name etc of the monitor and displaying it, confusion can be prevented at the time of confirming the video later.
- The text can be entered from the setting item of the option menu.

* Points
- Higher performance terminal is recommended.
- Faster shutter speed shooting equipment is recommended.
- In principle, the delay time which can be read from one of the image will be an integral multiple of 1 frame. Therefore, in order to increase the accuracy of estimation of the delay, please statistical processing a large number of data. We will recommend the technique to investigate the video movie in the frame-by-frame.
ex) Please examine 10 shots captured video. If there are 7 shots of 1 frame delay , 2 shots of 2 frame delay, and 1 shot of 1 frame delay, delay is estimated to average 1.4 frame.
- Using the LCD in advance the exact delay time is known in order to investigate the conditions of the internal delay in the measurement environment using this app , the accuracy of the delay time estimated from the measurement data probably can be improved.

* Notes
This app is not intended to strictly measure the delay, it is an auxiliary tool for only estimate the extent of the simple delay.
This app is good at applications to estimate the relative delay.
ex1) Which monitor of the more delay?
ex2) When you change the display mode, or delay of the monitor to increase or decrease?
ex3) Whether the delay is caused by the use of the HDMI Switcher?

Due to the following factors, the measurement value that is estimated by this app might differ from the actual delay.
- Delay that occurs when the HDMI output signal generation in the terminal.
- Lost Frames that occurs when the HDMI output signal generation in the terminal.
- Deviation due to the difference of the refresh rate of the terminal and the LCD.
- Frame Repetition in Guess mode.

This app does not guarantee anything in your measurement at all.