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Texas Instruments

The powerhouse inside my PVR is a TMS320DM320. This part contains within its tiny size an ARM926 processor and a C5409 DSP. This, however, leaves many questions. Image buffering? Overlay? How are the two joined - is the DSP autonymous in shared memory? Is it a co-processor? I know also that it is a chip that seems designed for digital cameras, hence it will have on-board CCD interfacing capabilities. How does this work when it comes to recording baseband video? Is the input split into chroma/luma and sampled? Is it something else that does the video digitising?

I wrote to Texas technical support asking about a datasheet for this part.
The response I received is copied verbatim:

Dear Sir,
Thank you for contacting the European Customer Support Center. In compliance with U.S Export Laws and Regulations, Texas Instruments is required to know to whom they are providing information or services
In your case we have no information about you or about your company as you are a private customer and our services are addressed just for Companies and universities there for I am please to inform you that we are unable to process you inquiry.
Wish you good luck.
Best Regards,
<name omitted>

Let's pick some holes in this, shall we?

  • Firstly, a European support centre is worried about US Export gumph. Lovely.
  • Secondly, this - I take it - would not apply to all of the more modern products with datasheets on their website?
    ARM is pretty open with its datasheets, and if you look around TI you can find the DSP datasheet.
  • Thirdly, if TI employed a native English speaker, they might point out how utterly rude it comes across to say "I am please to inform you that we are unable to process you inquiry.". No, you are not pleased. You are sorry. Learn the difference.
In reality, this sort of stuff probably needs a stack of NDAs and other legal nonsense. I'd happily sign an NDA if I could get access to some developer tools. But hey, they won't sell a million units to me, so why bother? I'm just a bedroom hacker wasting their time.

Thank you for wishing me good luck. I really didn't fancy taking apart one of the Linux-alikes to try to figure out how the chip works. So the search was on. Hardcore Googlage!


Well, China is in the news right now for the (alleged) attacks on Google and such. But China does offer a few useful things. By way of extensive cut'n'paste in Google Translate, I registered with a techie forum and found the TMS320DM320 datasheet.
Because this seems to be extraordinarily difficult to find, I will place a copy here. If you're doing any work on/with/for the TMS320DM320 (your PVR/camera uses it, the Cowon A2, one or other of the Creative Zen range, Rockbox?, et al), then grab a copy and you can make sure your code is bang on the money!

There now, you don't have to email TI just to get told "thanks, now go away please".

Perhaps one day companies will see us lone hackers as useful? I doubt it - their bottom line is capital. Produce something then move on. There is so much technology around that is half finished it is utterly depressing. This isn't to accuse TI of anything, but why should anybody bother updating the bugs in the PVR when something newer and more exciting has come along?

In a way, this is the problem with the Neuros OSD. Another (much better) PVR that has pretty much fallen by the wayside because now there's an HD version. Everybody say "whooo!". The big difference, however, is that Neuros have made their system as open-source as they were able so everybody with some techie skills can patch up the firmware. It is a little quiet on the forums, but already there are two official firmware types plus a third party one. The OSD uses a TMS320DM320, but a later version than my PVR it's the same hardware!.
My PVR. Closed source, no firmware updates, still plenty of questions now regarding the other hardware... and a company (Unisen) that never got back in touch regarding the firmware.

Some questions recently answered:

  • 640×480 30fps is a doddle.
    It ought to be able to manage 720×576 (D1), but there may not be sufficient bandwidth in the chip to do that and run the OS.
  • If the video processor is a TVP5150 (later: yes, it is), then not only should it be capable of PAL at 50Hz (it is), but it ought to be able to cater for teletext as well! Wouldn't it be something to capture the subtitling and save it as a caption stream in the MP4 file?
    There is also control over brightness, contrast, and sharpness (as well as saturation and - for NTSC - hue). Remember I commented on the recorded video being a bit "fuzzy"? A sharpness tweak would probably fix this.
  • The DM320 can output PAL and NTSC. Unless the output hardware is locked to NTSC by component choices, there's no reason why it shouldn't be capable of outputting a PAL picture. (no, PAL is possible, it's just crap&lazy programming)
  • Codec "quality", could have been a possibility? Sacrifice filesize for better quality?
I probably won't ever get around to writing firmware for my PVR, doing such a thing from the ground up with no codecs or libraries would surely be an exercise in pain... however that said as an educational exercise, today was a giant leap forward. With this information I may well be unable to rewrite the PVR firmware, but I bet I could have a decent go at getting a RISC OS kernel running! ☺

LATER: I have all but stopped using this PVR, for the OSD sings and dances and is pretty cool. Initial info here, or use the search box on the right and look for "OSD"...


Better looking Japanese

If you have to do any Japanese stuff, you'll know MS Gothic. Now it looks okay in large size, and it prints okay, but being an older TrueType font, it will revert to icky bitmaps for smaller sizes. Unfortunately one such smaller size is the standard display size.

For ages MS Gothic was the reference font for Japanese.
Now you can forget it ever existed.

Enter Meiryo (or, correctly, Meiryō). Based upon newer OpenType technologies, it works with ClearType for a much more pleasing experience. Don't take my word for it, here's a picture:

Meiryo, a better looking Japanese font

Here you can see Meiryō compared with MS Gothic. Worth the download, isn't it?

For Windows XP, you can download Meiryō here. It is a self-installing archive called VistaFont_JPN.EXE that contains the font files.

For Windows Vista, this should be the right download.

For Windows 7 - you'll already have it.

For fruity versions (Server, x64, etc) you will need to look around Microsoft's website.

By the way, if you are one of the dishonest types using a ripped-off version of Windows, give up now for you need to be validated as having a genuine version of Windows prior to downloading the file.


Hot damn!

Our local supermarket reduced the George Foreman grill to €20,30 (annoying price!) to shift them to make space for some other product. As I had two €10 gift tokens...

What can I say? It is lovely. I got a pack of beef and onion burgers, some pitta bread, and a Seriously Strong Cheddar. Oh, and a pepper sauce in a plastic squirty bottle (like ketchup).

Cooking on the grill is really zippy. The top and bottom heat up and close over the food. It said for a 100g burger that it might want around 5 minutes, with a further 3 or so if frozen. Well, from frozen it cooked the thing in under five minutes. Juicy like you wouldn't believe. I wiped the hot grill down with a paper towel (carefully!) and arranged my burger on half a pitta bread (and why not?) with (sorry Mick) cheddar on top, and the other pitta-bit on that. Back in the grill, forty-odd seconds it was hot and melty and ooooooohhhhhhh....
....sod writing this, I'm gonna go make another.


The George Foreman grill


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