1080P/60fps

Application and feasibility of 1080P

Chipset is just like CPU of PC, which collects image data and compresses it, being the core part of a dash cam. Currently in the market there are six major solution providers: Ambarella), Zoran, Novatek, STK, SQ and Sunplus. Based on the criteria of recording resolution, dash cams can be categorize as: 1080P(1920x1080), 720P(1280x720) and VGA(640x480)

VGA(640x480) is used in early dash cams, and the solution used is STK, SQ and Sunplus, normally used for low end dash cams, very low cost.
At the moment, 720P is the most cost-efficient configuration, using Novatek and Zoran solution, to reach 720P. This is the medium and high end solution.
By using STK, SO and Sunplus solution, VGA(640x480) can be interpolated to 720P(1280x720), but this is not true hardware decoding. The actual visual effect of VGA(640x480) is not upgraded, but the recording has taken up more memory of the dash cam. After long time operation, the dash cam may be down frequently, with missing frames. For dash cam of 1080P with 30 FPS, only Ambarella and Zoran solution can support. Visual effect with Ambarella solution is better than Zoran, but the former is more expensive.
 

In the order of performance of chipset: Ambarella > Zoran > Novatek > STK, SQ > Sunplus
 

 

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60帧的应用范围及适用性

我们都知道,电影是依靠人类的视觉暂留现象而发展起来的艺术。以前的拉洋片就是让纸片上的渐变图案在你眼前快速掠过,你看起来就感觉画面动起来了。在电影里,一幅静止的图像被称做一“帧”(Frame),而研究表明,只要达到每秒24帧,人们的眼睛就会被欺骗,以为看到的是运动的画面。动态的画面则按每秒钟显示多少帧来衡量,这就是所谓的“每秒帧速率”(fps)。

人的眼睛视觉暂留现像的存在,使要看到感觉连续流畅的画面,最基本的要求是每秒录制画面的速度要在24帧以上,很多山寨产品的每秒录影的速度只有15帧,这种速度人眼感觉可能还不是很不明显,但是在播放重要时刻暂停时的画面就很差了。目前每秒30帧的速度必须是行车记录仪的标准配置,可以计算一下,高速行车时每秒可以跑多远的距离,再计算一下1/15和1/30分别行进了多少距离。目前凌度产品做到了每秒60帧的速度,这个数据就是运动摄像机级别的了。

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