SparkFun Forums

[Vandermg]

I am trying to design and build a device that would allow someone to stream video from a person (small unit, battery operated) to a computer. I have tried a small 900MHz frequency transmitter and receiver but the quality of video is lacking. I am now looking into trying to connect the person to a wireless network and transmit the video that way, but finding a device capable is proving challenging. Does anyone know of any such device? Do I need to compress the video first? I realize it all comes down to the quality of video (720p would be great).

Thanks for any help...

[SgtJimmmy]

Depends on the distance, if you are looking short range you could modify a wifi router and use an IP camera or something like that. It would be hard / expensive to get a small device that can transmit the quality you are asking for over any decent distance. Just my $.02

[thebecwar]

720p (1280x720) @ TV's frame rate (60 FPS) and using 24bit color (24BPP) works out to approximately 158.2 MBps or 1.235 Gbps. (Big B for Bytes, little b for bits) 802.11 won't do that kind of throughput.

That said, you could transcode to MPEG compression, and save some space, or drop down to CIF or QCIF. TI has a complete line of DSP chips, that may fit the bill.

If you want to build something yourself, you couldn't to too badly with the Xilinx Spartan series of FPGA. An FPGA on either end (one to compress the stream, one to decompress it) could make the whole thing workable. You might be able to get an ARM7 or ARM9 to shovel data fast enough, but processors are not as good at repetetive time sensitive tasks.

[theras]

If you need a solution for compressing HD video, the ADV212 is very effective. It takes 2 chips to compress 720p60 HD video and generate a JPEG2000 codestream. If you're happy with SD you only need 1 chip. The chips take about 1W of power each, iirc.

The ADV212 includes memory and is relatively simple to interface to. Unfortunately it's only available in BGA packages, but that's also the case for most Spartan FPGAs and TI DSPs with enough performance for HD video processing.

Using JPEG2000 you can probably get the data rate down to 50MBit/s for "visually lossless", and lower if you're happy with some blurring. Latency through the ADV212 is also very low, as compression is purely intraframe.

[stevech]

I am trying to design and build a device that would allow someone to stream video from a person (small unit, battery operated) to a computer. I have tried a small 900MHz frequency transmitter and receiver but the quality of video is lacking. I am now looking into trying to connect the person to a wireless network and transmit the video that way, but finding a device capable is proving challenging. Does anyone know of any such device? Do I need to compress the video first? I realize it all comes down to the quality of video (720p would be great).

Thanks for any help...

By far, easiest way to send video is in analog form, much as inexpensive video-senders do. Usually in 2.4 GHz. Using 4MHz or more of bandwidth. Can clobber WiFi since analog video is not packetized digitall, so choose frequencies wisely. Products abound, such as the not soo good but cheap X10 cameras.

In 900MHz, FCC regulations make it difficult or impossible to do analog streaming, and digitized video needs to cram into a 2MHz digital channel with frequency hopping.

A low frame rate and reduced frame size are solutions if it must be digital. But coders and decoders for digital are complex.

[nickersonm]

It might be simplest to use a wireless IP video camera, if it's not too bulky. I believe Linksys and D-link both make wireless-b/g/n cameras with MPEG-4 compression for around $100. You'd probably have to modify the power source to run off a LiPo, but that shouldn't be very difficult, at least not compared to rolling your own encoder and transmitter.