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Jasper

DVR's for downlink and Helmetcam

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I posted this over in RC groups but perhaps it would be better suited here:

In my quest to develop a decent helmet camera system I am trying to find a solid state DVR unit that will record video from a bullet cam in a format suitable for converting to DVD. When not using the helmet camera I would also like to use the same recording unit to view and record my video downlink for AP.

I realise that this is not entirely an AP question but thought that since there are so many techno savy members here already using DVR's to record their video downlinks, someone might be able to give me some advise on the best possible recording option.

I currently use a DV camera to record my video downlinks and the quality is fantastic. However, this is not exactly a lightweight option and I can't just attach it to my TX to view while walking around. So, for now, the DV cam is out.

I figure that using solid state technology to record directly onto a multimedia media card (ie. SD/CF cards) I would not have to deal with the inherent problems faced when using a hard drive recorder in a high impact environment... such as head vibration leading to recording interuptions and eventually hard drive failure.

There seem to be a lot of options out there for solid state recorders, most of which record in Mpeg-4 (.AFF) format. My minimum requirement would be the ability to record in at least 640 x 480 @ 30fps.

Here are a few products that I've found could be viable options, both for helmet camera and video dorwnlink recording.

Mobibox Recorder

mp411-front.JPG

Positives:

Phyical Size (pack of cards) & 96grams with battery

Records 640x480 -AT-30fps

Records to SD card

Cheap at US$200

Negatives:

Suggestions that company is being liquidated – No warrantee

No remote

Image quality (bitrate) unknown

Archos Range

prod_a404.jpg

Positives:

High resolution (Full PAL) avaialble

Nice small footprint / Lightweight

Negatives:

No good: Hard drives – Not solid State (bad for shock resistance)

PV-500 Recorder

pv5a.jpg

Positives:

Small and lightweight

Records 720X480 @ 25 – 30fps

LCD display

Negatives:

Price: US$389

Aiptek R-MZDV

prod_MZDV_lg.jpg

Positives:

720x480 -AT-30fps

Cheap at only $189

Negatives:

Unknown battery life

Slightly larger than PV-500

Don’t need the cheap CMOS camera/lens

RC Tek's upcoming DVR

rct_dvr1a.jpg

Positives:

Full PAL in Mpeg 1/2/4!

Small/lightweight

Negatives:

No LCD

On the expensive side

Has anyone had experience with any of these products? Are there any others that I may have missed?

Edited by Jasper

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I've recently started using of a 'Mobibox' clone. Impressively diddy! Encodes @ 2MBPs (just under an hour per GB), so much the same as the PV500 only physically smaller. While 2MBps is poorer than one might wish, it's a rate many folk end up encoding at for a couple of minutes of flight video to post on the internet, so perhaps a good compromise.

In terms of image quality, I've tried a solid-state HD recorder that encoded to 4MBps, perhaps better treatement of shade gradation, not obviously more 'fluid' when things are changing fast. Note too my warning at the bottomabout recorders that lack a screen! I've also used a Sanyo VPC5 which encoded at 2MBps - again, the slight 'jerkiness' overall, but no blocking up when things change quickly (it seemed to me that peripheral details, especially blues and greens, just got a lot fuzzier: clever!). I've also used another solid state camcorder that compressed to 4MBps, actually seemed 'jerkier' than the Sanyo, so there's obviously a lot in exactly how things are compressed. MiniDV recorders (25MBps) are still a bit bulky/vulnerable - I've also briefly used a Sony Video Walkman which seemed far too big in comparison with many camcorders. It would be nice if someone put a miniDV recorder in a cigarette packet at a reasonable price. One tip, if you do want a small miniDV recorder, bear in mind that some camcorders (e.g. Samsung do a small, 'low end' model) offer "A/V IN" but don't advertise the fact - a good excuse to try out a few models at your local camera store - no, the store might not know unless you try it; something about double import tariffs if something is a camcorder AND a VCR, so they keep quiet about the A/V input...

Just one tip - born from painful experience - DON'T get a recorder without a screen!!! Most of these don't have a monitor output - and if they do there is often a lot of distracting OSD you won't want in your FPV goggles. The real risk here is that you will return from the flying site to find you've recorded, er nothing... I've concluded that flashing 'record' LEDs or whatever are no substitute for a moving picture with an incrementing counter!

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The 'Mobibox' clone is cool because it's very small and light.

However, if you want good quality and are pleased with a DV camcorder you should just keep that. No other recorder I know of apart from a PC and maybe those portable DVD burners, but both are even more bulky, will give you near comparable quality. Those are also the only ones to record interlaced video, keeping the original movement smoothness. If the intended target is the PC world it doesn't matter as you'll need to deinterlace anyway, but if you say you intend to make DVDs then that's a real plus.

I'd put the Archos in good place, it encodes in DivX at a decent bitrate and is good price/quality ratio.

The others should be pretty much the same, and they all save in ASF which is pretty average and annoying to edit unless you use windows movie maker.

I'm not talking about "RC Tek's upcoming DVR", as the first time I've read about it was like 1 year ago... and I tend not to trust things that are "announced" for ages with nothing coming.

Edited by Kilrah

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RC-Tech (rc-tech.ch). Although the one I ordered tends to record a bit bright (see the 'Too light' thread in this forum).

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(Check the update on 'Too bright' thread - even if you get one that records bright, there is a fix :)...)

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Hi Scroopy, that looks like a nice item, but according to the eBay spec it only has USB and TV out - are you saying it has A/V in as well (i.e. it can record from a separate video source)?

Also, does it provide live 'video out' to your goggles in PAL, or only when outputing NTSC video?

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