Some of Aiptek's line of dirty cheap SD-card digital camcorders use H264 
(some of their others use MPEG4).
I used one.  H264 has VERY low bandwidth requirements, but the file has 
major hardware requirements to play back with software on another machine.

There's a bunch of buzz on the amateur tech forums.  Aiptek made 1080i 
HD versions under $200.  It's amazing at first but 1) it's a CMOS imager 
with "rolling shutter", which distorts anything moving quickly in the 
image field or anytime during quick panning, and 2) it has totally 
useless audio!  They put the mike facing upward and screwed up the 
preamp so badly it's all distorted.  It picks up lots of ambient noise 
and very little in the target zone.

I know there's a cost thing and all, but it's so weird they made such a 
spectacular cutting-edge video encoder and screwed up everything else.

Danny

M. Adam Davis wrote:
> On Wed, Dec 10, 2008 at 8:32 AM, Alan B. Pearce
> <Alan.B.Pearce@stfc.ac.uk> wrote:
>   
>>> This makes the CF cards viable BUT the
>>> class 6 SDHC rates are as I sated and are far too slow.
>>>       
>> And yet SDHC cards are used in current model Digital Video Cameras AIUI, as
>> per the recent discussion of the Canon one. Just how much preprocessing is
>> done on the video, to be able to record video?
>>     
>
> A lot.  The low end cameras compress with MPEG2 or similar, while
> newer cameras are compessing with MPEG4.  A typical stream at 640x480
> might be a few megabits per second.
>
> The high end consumer camcorders (1080p) compress to AVCHD (MPEG4,
> essentially, over an MPEG2 transport stream) at 24mbits/s, or about
> 3-4mbytes/s.  These require the class 6 SDHC cards.  The camcorder I
> have (Canon HF100) only encodes to 17mbits/s, which works well on a
> class 4 or higher.
>
> But the processing is not cheap - h.263, h.264, mp4, etc encoder chips
> are special purpose built around the algorithm, you wouldn't run this
> in a general purpose processor in real time at the higher resolutions,
> and if you could you'd be sucking 100+W in a typical quad core design
> trying to keep up with the stream and encoding requirements.  Just as
> with mpeg2, we're going to see a lot of add-in cards and USB devices
> that encode this until the processors catch up and it's all done in
> software again.
>
> The chips aren't expensive, though.  You can get a USB component 1080i
> AVCHD encoder from HAUPPAGE for $150, so a chipset should be on the
> order of $20 or so, and eats less than 2.5W.
>
> -Adam
>
>   

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist