First, let's understand the imager type that will have to feed an Android:
1. IP webcam: these are digital video format, further compressed down (usually severely) then packetized (into IP packets)
They usually use WiFI to connect to the Android. They are not really using USB interface thus not in-scope with your original question
BTW, their usage in asro applications are fairly limited due to lack of manual control and other limiting factors.
2. Videocam with an analog video output, which then feed into a video-to-USB dongle.
These USB dongles usually generate tremendous amount of traffic in USB 2.0 high-speed form and require isochronous transfer mode.
I have yet seen any Android can handle such type of load feeding into it.
3. Astro-imager with USB interface: these IMO really shouldn't be called webcams but "imager head".
These are hard nut to crack for an Android due to lack of device driver (which needs to be compiled into the Kernel), so many flavors,
and lack of downstream processing power in the Android itself.
4. USB webcam using UVC as its software interface protocol: many modern USB webcams took this common approach, since UVC is a common interface definition
thus less a need on proprietary driver need to be written.
However, IMO, the basic UVC spec is written mainly for a common video interface, it is less feature-rich for many still shoots in astro use cases.
Some vendors tried, however you know the "wall" is just a distance away.
In a way, it is the word "common" that kills the niche.
I will describe it in the next post.
5. USB webcam using proprietary interfaces. This is similar with (3) except that the webcams is more or less a commercial or consumer grade "webcam"
and the features are pretty limited. Due to garden variety, you usually will not find a device driver for Android.
6. Android's own built-in camera(s): these have special feed into Android Main processor's GPU section via CSI data highway.
The image processing algorithms are GPU proprietary in the firmware and some useful features are not directly exposed.
For Android, the main hope is (4), but subject to many limitations and set-backs described in the next post.
Edited by ccs_hello, 04 May 2015 - 05:15 PM.