Friday, July 8, 2016

Car Camcorder - DVR - Car Camera - Car Black Box for More Understand The Technical Specification

I saw one of my Facebook friend posted on a sale group to ask for standby time or operation time to recording video of a product selling by the group administrator. He not really understand what is Car Camera or he though Action Camera is same as Car Camera. To make clear, the main different of car camera and action camera is depend on size of battery then operation hours or standby hours will huge different on both. The software carry on the camera is also designate the main function of the device. Some people may use action camera as car camera. Actually it is working, but inconvenient. The action camera will not start function automatically when the car start because software is build-in to do so.

The car camera main specification is divide by battery size, angle of camera view, camera sensor, image process chipset, camera Megapixel, record-able resolution, frame rate per second of video, video format of recorded and supportable memory card size.

Battery size bigger is better, mean the operation time is longer. This is great when the car camera is stop getting input current from car battery, but is seldom happen in real situation. The reason of this is car camera normally programmed when car start then car camera start and in the reverse.

The camera view angle larger is better. Theoretically maximum is 180 degree, but most advance is 170 degree is good enough. larger angle of view gives video able record in more larger area in front of your car.

Camera sensor is a main point of choose car camera. Normally the budget car camera is not mention what the camera sensor is build-in. The common camera sensor used in the market is Sony, Samsung and OmniVison. The camera Megapixel can be very high, but not with a good camera sensor will the image or video quality to be good? Need a balance, a good camera sensor and high Megapixel to produce the best capture quality. Actually the camera just need a 2 Megapixel camera can record the full high definition video (1080p). Does the resolution is important?

I must say the record resolution and frame rate per second is together in recorded file. The high resolution is better, of course the frame rate per second must 60fps. There is a formula to calculate the size of video file: File size (bytes) = frame size (bytes) x frame rate (fps) x video time (s). The resolution of full high definition 1080p with frame rate 30fps still the lagging video with full HD screen size. So the frame rate is rather 60fps than screen size lower a bit in 720p. The frame rate is more important to record a smooth video.

The old school car camera will record into the video format of AVI. The MP4 format is much more better. Why? the MP4 format is smaller in size and support more high frequency sound format. Some technical specification may show the video format of recorded is H.264. Actually H264 is same as MP4 video format.

The supportable memory card size decides the video recording length in time.
Normally, suggest to record in full high definition video.

For 64GB memory card, can record
1080p 30fps 8hours 35minuts
1080p 60fps 6hours 25minuts

For 32GB memory card, can record
1080p 30fps 4hours 12minuts
1080p 60fps 3hours 12minuts

For 16GB memory card, can record
1080p 30fps 2hours 8minuts
1080p 60fps 1hours 36minuts

I suggest use Class 10 memory card for car camera because if you use lowe Class memory card will meet the lag video case.

The type or brand of microphone in car camera is an optional specification because many people is not care about the recorded sound quality. The main function of car camera is record the scene of emergence as the evidence for show to the police officer or self record to revise driving attitude.


Mediatek with Model Code "65XX" Common Problems

Mediatek chipset with model code 65XX is near to bottleneck because almost all current smartphone is not using this chipset anymore. Some budget and beginner level smart phone may still apply this chipset. The main reason is Mediatek is replaced the newer processor with model code start with "67XX". The still using 65XX chipset is "MTK6580". I still see new coming smart in very low budget and price using this. 

I have experienced with smartphone with Mediatek "65XX". There are few common problems occurred. First, I have very low output sound either on 3.5mm earphone plug or internal speaker. Of course, some developer may apply external sound chip to out perform better output sound, but does it make sense to increase cost. Rather than developer can choose better chipset of a bit higher in cost.

The GPS module of Mediatek can say it is working nor not. The GPS signal is too weak until get accuracy within 10 meter. It is 10 meter, can not imagine how you navigate your journal when your car show on the building on the navigation app. Obviously,  the possible locked satellites on my tested phone is around maximum is 7. Understand that locked 3 satellites is workable GPS, but I need more locked satellites in case of the car moves into some blind spot is too weak to received the GPS signal. At least, there is more optional choices to locked other satellites easily.

Why Mediatek is used to choose to multiple the processor cores only within Cortex-A7 for more advance model 65XX? In some old school chipset may use Cortex-A9, especially the MTK6575 and MTK6577. The bigger brother in this field, Qualcomm is using Cortex-A17 more powerful core for the performance. In that century, still happened some other chipset maker such as Ericsson, Texas Instruments, and Broadcom in the game. They are using Cortex-A7 for more cores processor.

Something is hidden from user - Cache memory. Cache memory is important to store commands to execute by processor in queue of task. Mediatek is cut of the Cache memory size in the technical specification. There is not so obvious normal user can realize this problem. Other chipset competitor may not cut cost in this.