| ||Thread Tools|
|10th November 2014, 09:16||#1|
Join Date: May 2010
Android Camera2 and External ISPs
While we've written about Android's Camera2 API before, there was one notable aspect of the discussion that was missing. The missing piece was a discussion of the physical link needed to enable all of the controls that were previously discussed. This isn't necessarily complicated, but it does represent a potential pitfall for updates to current devices. In short, the current protocols for using an external ISP provide insufficient bandwidth to support the full feature set needed for the new camera API. This means that some of the interesting features, such as per-frame controls are impossible to enable. As a result, many devices that we've evaluated before such as the Galaxy S4, HTC One (M7) and One (M8) won't support per-frame controls and similarly bandwidth-heavy features. The Galaxy Note 3, S5, and Note 4 appear to only use the on-die Qualcomm ISP.
To understand why this is, we must understand the protocol that is used for communication. Today, the de facto standard for interfacing between the AP (application processor), ISP, and camera is MIPI's CSI protocol. By and large, CSI-1 and CSI-2 are the most common iterations of this protocol. While the transport protocol (D-PHY) that actually carries the images has immense amounts of bandwidth (up to 10 Gbps), the control protocol defined has almost no bandwidth in comparison. Instead, the control protocol relies on fast-mode i2c, which can only provide 400 kbit/s of bandwidth.
While this may be an issue now, it seems that in the future this won't be an issue. According to Arrow Devices, the MIPI CSI-3 protocol merges control and transport protocols into a single M-PHY bus for up to 18.6 Gbps of bandwidth. It's likely that the demand for 4K60 video and 20+ megapixel burst mode functionality will drive adoption of this newer protocol. However, even now the disclosure of such protocols is rare, so it's hard to say whether we'll see widespread adoption of CSI-3 any time soon.
|Thread||Thread Starter||Forum||Replies||Last Post|
|Hold ISPs Responsible For Facilitating Piracy||Stefan Mileschin||WebNews||0||27th December 2013 19:38|
|ISPs and telcos have to admit data stuff-ups||Stefan Mileschin||WebNews||0||26th June 2013 06:44|
|Why Do ISPs Change Your IP Address?||Stefan Mileschin||WebNews||0||5th June 2013 10:38|
|Mini MicroSD Reader adds external storage to your Android device||Stefan Mileschin||WebNews||0||9th April 2013 06:56|
|ISPs Cannot Be Forced To Store Data on File-Sharers||Stefan Mileschin||WebNews||0||27th March 2013 07:46|
|Legit Pirate Bay spin-off blocked by UK ISPs||Stefan Mileschin||WebNews||0||4th December 2012 07:20|
|New Data Exposes BitTorrent Throttling ISPs||Stefan Mileschin||WebNews||0||10th August 2012 08:38|
|Top ISPs snub net neutrality code of conduct||Stefan Mileschin||WebNews||0||26th July 2012 07:31|
|New Solution For ISPs Makes Home Wi-Fi Network Accessible From Anywhere||Stefan Mileschin||WebNews||0||3rd July 2012 07:29|
|EU sues Sweden, demands law requiring ISPs to retain data||jmke||WebNews||0||27th May 2009 17:22|