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hyperjm
11-13-2012, 11:50 PM
Hello all,

I would like to ask if it is possible to "compress" a tiny video feed with the Teensy 3.0, say 640x480 at <10 fps. Assuming that I somehow successfully obtain raw video data, would the teensy 3 be able to compress it AND transmit the compressed video over a 2Mb/s wireless link? Are there useable libraries out there for this(compression)?

Thanks in advance,
jeremy

hyperjm
11-14-2012, 12:29 AM
ah..while i'm on the topic I shall be shameless and ask a few more questions...

1. I understand the teensy 3.0 is a 3v3 device but obviously runs on 5V USB...similarly can I run it directly from a 3.7v LiPo battery without voltage regulators? Will clock speed be affected?
2. Can the USB port be used to host the camera? If so, can that camera also draw power(say, 2W) from the USB port?

Cheers

pixelk
11-14-2012, 11:23 AM
1) Yes, connect your lipo to vin and gnd, but DO NOT connect the USB on the same time.
2) no, not yet. The USB host library is not yet available (later in 2013).

TimO
11-15-2012, 10:39 AM
... but (and I'm fairly sure, but not certain of this), if you're powering the Teensy using a 3.7V supply, then you won't be able to use the USB to talk to a slave device unless you provide that device with +5V independently, since the Teensy won't have anywhere to source the 5V from.

Of course, it's possible that the USB device may work off of less than 5V, but you would be outside of the USB spec then, so I wouldn't rely on it.

JBeale
11-15-2012, 02:33 PM
I don't know what is possible, but I know the Raspberry Pi (at a clock speed from 700 MHz+) has trouble using USB webcams at that resolution and framerate. The Teensy 3 has a maximum clock speed of 96 MHz, so I'm not optimistic this would work.

hyperjm
11-18-2012, 12:19 AM
alright I guess I will take it a step at a time and see how it goes...thanks guys!

Dave X
11-18-2012, 01:35 AM
640x480*10fps at 8 bits/pixel = 3Mbyte/sec. To get it down to 2Mbit/sec, you'd have to compress it more than 12:1, so you'd have to do all your input, processing, compression, and transmission in less than 30 cycles/byte of raw input.

I think you'll need a tinier, or much slower video feed.