Hello,
I’m beginning a new project.
I have to display a pal/ntsc signal on a 2.8" LCD.
I tought to use an ARM mcu but i dont know how to decode video …
Anyone can give me some tips ?
Thanks
Why not just use a composite video input monitor? This will be a lot easier. ARM probably won’t be quite fast enough.
Hello KoV,
First the good news: You’re famous! Just google “arm ntsc decoder project” to see what I mean.
I’m quite a newbie to this forum, but it seems to me the focus is more on the “and LPC” part of the title than the “Everything ARM” part. Possibly a consequence of Sparkfun doing such a good job catering to the needs of the severely budget-limited amongst us. Mike is unquestionably right about that segment of the ARM market. No hope of video processing.
But, even a low end arm might be able to supervise a video decoder chip and an LCD controller chip. OTOH, you still might need substantial glue functions, perhaps a PLD or FPGA.
I’m assuming your lcd is something like 320x240 resolution. Just thinking out loud here. The simplest approach is to throw away 3/4 of the pixels to get to that resolution. Maybe you could store each even line of YcBcR in a one line buffer, then spend two lines playing it back, leaving out half the luminance samples. And leaving out the odd lines completely.
[As I re-read what I’ve just written, it doesn’t look like a trivial task.]
Your post prompted me to do quite a bit of searching, but I don’t have many results to report.
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I thought the ADV7180 looked like an interesting possibility as an input device.
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TI, NXP, and ST all have somewhat similar offerings.
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If I had to start a project capturing and actually processing the video, I think I’d look at the TI OMAP product line first. But, just getting “hello LED” up and running on an OMAP platform looks like an expensive and time-consuming task to me. No personal experience so I could be wrong.
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I ran out of steam before looking at LCD controllers much at all. (maybe yours is already selected) But I did notice there is a controller available on opencores.
-Hugh
You might want to look at the “Propeller” chip from Parallax http://www.parallax.com/tabid/407/Default.aspx. Not sure if it’s up to your task, but it’s has a lot of built-in support for video.
First of all, thanks for the answers.
@mikeselectricstuff : I cant use other video than NTSC or PAL, I get it from a video RF module.
@hsutherl : ye ive just noticed it at the moment, google loves me 
I’m beginning architecture design and i’m a newbie with video decoding.
I know very well MSP430, but it seems I need a faster proc.
Ive made somes search, I found media processors, NTSC decoders … but its very new to me, ive no experience.
I’m very interested by this kit http://www.sparkfun.com/commerce/produc … ts_id=8858 to build a functional demonstrator.
I need to add the decode module and the ADV7180 seems interesting thanks.
But this µc seems to slow (72MHz maximum), isnt it ?
Thanks for your help.
@Gsm Man : I will study your solution after a good night.
Somehow I failed to mention the Freescale i.MX (dragonball) series. Something there might be your best approach. Some of them have video decoders and LCD controllers built in. You’d probably have to start by coughing up the $$ for a development board. It appears there are a few third parties.
Freescale is apparently in some sort of packaging patent dispute that may affect availablity of the i.MX chips in the US. I don’t know the details.
I recently looked at the Propeller datasheet myself. Intriguing concept (especially if you’re wrestling with the “to nest or not to nest” issue as your ISR’s grow like weeds). And the built-in video generators look very handy. Nothing there to help you with decoding though, as far as I can tell.
I think you’re right about the LPC2378. Great (or at least adequate) for a nice GUI. Not fast enough for live video.
I also failed to mention Conexant and Empia, who seem to be a couple of the major suppliers for consumer grade video interface chipsets (like the Hauppauge HVR-950 USB tuner that I own). But I have no idea where to get technical documents on their chipsets. It is a mystery to me how the video4linux people got enough information to create driver software for so many of their devices.
Perhaps a propeller and a parallel flash ADC? Start with the video-overlay design at http://www.hittconsulting.com/hcosd.htm to sync with the video signal, and use a flash ADC to read the analog data. Since the video output on the propeller is twice the instruction rate, you can use the waitcnt instruction to cause four cogs to perfectly interleave their work, allowing you to get a 40mhz sampling rate (exactly what the bt878 has).
Good luck.
Quick digikey search turned up an ADC08060 which might be fast enough to decode video for you.
Also, you said NTSC/PAL. Are you getting composite video, or do you get S-Video/SCART?