Video ADC (2023 Update)

need:

second

Thats not entirely true. H264/MPEG based transmission systems like the ones used for DVB-T allow some errors without distorting the entire frame.

need:

second

You can connect the output of the TW9900 to a SoC (chip with ARM cpu and peripherals) and use that to encode the video stream into MPEG for transfer over a network or decode/scale it for displaying on a screen (direct LCD panel connection, RGB analog, VGA, composite or HDMI). Most SoCs have hardware accellerators to do this. You don't need a state of the art SoC to do this. It will require some software (Linux).

jpeg pictures)!

transmitted only very so often

For JPEG with 8x8 DCT block, a corrupted low order coefficient will corrupt the whole 8x8 block, with clear visual impact. A corrupted high order coefficient will have much less visual impact, since the error will appear as high frequency low amplitude noise across the 8x8 block.

On a sunny day (Sun, 16 Dec 2012 21:46:34 +0100) it happened h200 wrote in :

need:

second

?? If you want to do encoding to jpeg, mjpeg, do it yourself so to speak, then there was on www.opencores many years ago FPGA code for a JPEG encoder. Not sure that site still exists, and you would have to learn verilog or VHDL. That is the only way to get the speed *. As to the 'transfer', whatever modulation you want to use (QAM64??), you still need to add overhead for error correction 'FEC', so add an other 30 to 20% to the data rate.

• there are ASICS hat do it all.

Like I replied in my first reaction, get a PAL to MPEG2 USB stick and use a small computer, ethernet, or one with a WiFi. One of those netbooks would do. I have tried that, and it works, my eeepc (old one) has VGA out (there is your decoding.

But now I use WiFi cameras that have it all build in, the Chinese ones use a small ARM based board that does all that, display on a PC monitor and record to disk (you want that anyways).

On a sunny day (Mon, 17 Dec 2012 08:00:28 +0200) it happened snipped-for-privacy@downunder.com wrote in :

of jpeg pictures)!

transmitted only very so often

Yes, but you only lose one frame (1/25 second or whastever speed you use). In my other reply I mentioned the need for error correction in the transmission chain, FEC. That is how it is done, add an other 20 to 30% to the data rate, in whatever form (compressed or not comprerssed).

On a sunny day (Sun, 16 Dec 2012 21:02:08 GMT) it happened snipped-for-privacy@puntnl.niks (Nico Coesel) wrote in :

Right extra data is transmitted that allows 100% (in many cases) correction of errors. In the Netherlands transmission of DVB-T is QAM64 and a FEC of 1/2 (add 50% error correction data). FEC = Forward Error Correction

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fully

Have a link to a data sheet?

?-)

transfer

NOT

You can do that analog as well. OK, they were fiber optic. Want some old model numbers?

?-)

transfer

NOT

That will work, but for more free space applications i would put an FM modulated carrier to the laser. Several advantages. For that matter, even for FO connections.

?-)

There isn't much "decode" at that point; is nearly raw digitized SMPTE-170 at that point, shove it to an appropriate video DAC and it is analog again. Well there are some caveats here, but if you understand the tech it is nearly this simple.

MPEG-2 and MPEG-4 and h.264 IP cameras are readily available from a bunch of vendors, why deal with the compression in your own hardware except as a learning exercise?

?-)

deep, you need:

bits per second

Shalzbot.

Here is the datasheet such as it is:

The output is pretty much digitized full speed raw YUV 4:2:2 data. No MPEG or JPEG has been applied yet.

I certainly would NOT call that a decoder chip; even though it takes raw analog NTCP/PAL/SECAM input.

?-)

Is this an outdoor or indoor application ?

If outdoor condition and such short distance a simple analog system will do. Just get base band composite video and feed it to an FM-modulator. For reception get an old analog satellite-TV receiver.

However, if this is an indoor application, the reflections from the walls will cause a lot of multi path (ghosting),

With some primitive digital signal with much higher bit rates, the nultipath is going to be a severe issue. You might have to feed the digital data stream into a DVB-T modulator and receive it with a DVB-T tuner (available as USB sticks).

DVB-T with suitable parameters is very robust against multipath.

You are replying to a post from over 10 years ago!