video cameras

[Tom Honeyman]

I just want to point out a tricky problem with miniDV versus flash/HD  
based recorders, which is (if you want to skip the long-winded bit  
below): DV is a compressed format that doesn't automatically trump  
compression used in modern recorders. It isn't the best. In fact it's  
a pain in the neck.

(before I begin, I am always talking about lossy compression here, not  
lossless compression)

The video that is transferred from MiniDV cassettes is often called  
raw. But actually dv is a compressed format, using a  discrete cosine  
transform algorithm, with a ratio of 5:1 (or higher). There are other  
aspects of the format (as it is stored on a tape, not on the computer)  
that relate to the fact that it is stored on fallible magnetic media,  
but I won't go into that. When using DV as a format you are using a  
degraded form. "Digitising" (or transferring to your computer) may or  
may not also re-compress the original compressed DV stream. But in  
transferring a recording to your computer, you receive an already  
compressed file, not an uncompressed file.

I admit I'm being a little pedantic, but I simply want to point out  
that when you copy a compressed AVI file (or any of the many other  
formats out there) off of the flash card or HD drive, you are  
similarly making a "raw" copy of that file. Really, with digital  
video, the debate is about the subjective quality of one compression  
algorithm over another. Unless you are using truly high end gear, no  
one is using uncompressed video. Lets face it, if you did, it would be  
completely unmanageable with current tech. Imagine working with a real  
raw video file. With a frame size of 640x480 (not HD), an hour of  
footage would be 82.8GB! That's a fair bit more than a DV file.

Because storage is cheap with magnetic media (but more fallible), and  
we are now approaching a point where solid state storage is becoming  
cheaper, there has been a transitional trade off. DV uses a lower  
compression ratio than most modern consumer and "prosumer" level  
recorders, but modern formats in modern devices use compression  
algorithms that produce subjectively better results at much higher  
compression ratios. Basically, it was cheaper to use worse compression  
at a lower ratio with cheaper storage (that was more fallible). But DV  
is a pain in the neck. So we had these transitional forms of storage  
with DVD based recorders, and Hard Disk recorders, which allowed  
cheaper storage of larger amounts of data (but both of which are power  
hungry, produce noise, and are still fallible - but less so than  
tape). Meanwhile, we're sitting around waiting for Flash based Storage  
to get cheaper... and now it is. As a side point, the computing power  
in these devices has also increased, allowing us to apply  
computationally more complex algorithms.

What I really like about these newer removable flash-based devices is  
that they have low power consumption, are less fallible (if you buy  
good flash cards), and I copy the file off of the card and start using  
it in ELAN within minutes. Another great thing that all new formats  
have over DV is that many/most of them can record for more than an  
hour! I carry two wafer thin flash cards and transfer my data to  
alternate storage in the field. Perfect but...

The main problems then are the proliferation of a variety of file  
formats, the fact that many of them are proprietary and the difficult  
question of subjective quality of the video compression - which is an  
equally valid question to pose about DV formatted video.

So yes,

> It has also been sometime since we have revisited what the  
> manufacturers are doing in regards to recording formats.

that's the tricky bit...

-tom

On 26/03/2010, at 12:06 PM, Daryn McKenny wrote:

> Your spot on with what you say Aidan as characteristics and  
> challenges with using tape and transferring to hdd asap, we cured  
> our dropped frame scenario with Premiere by making sure our hardware  
> was up to scratch.
>
> We always carry at least 6 tapes in our camera bag so that when that  
> tape is full there is minimal disruption to continuing the  
> recording. I would presume that would be possible with the Dvd/SD  
> recorders as well but not with the hard drive recorders as you have  
> to empty the hard drive before recording once again.
>
> It has also been sometime since we have revisited what the  
> manufacturers are doing in regards to recording formats.
>
> Regards
>
> Daryn
>
> Arwarbukarl Cultural Resource Association Inc. Trading as:
> Miromaa Aboriginal Language and Technology Centre
>
>
>
> -----Original Message-----
> From: Aidan Wilson [mailto:aidan at usyd.edu.au]
> Sent: Friday, 26 March 2010 11:47 AM
> To: r-n-l-d
> Subject: RE: video cameras
>
> While it is certainly true that raw is best, DV tapes are also highly
> irritating to work with. I can't tell you the number of times final  
> cut
> pro has encountered a 'dropped frames' issue when re-digitising from  
> a DV
> tape. Also, some may be tempted to leave them as is for some time  
> before
> they digitise/transfer them to a machine, thinking the data is safely
> stored on a DV tape. The cassettes themselves are as fragile as any
> physical medium, and the magnetic tape can become affected, allowing  
> the
> signal to deteriorate. Granted though, it is much better then the
> deterioration of VHS.
>
> If you transfer from a HDD camera as soon as you can, then the file  
> will
> be in .mov format, which is about the best format around when it  
> comes to
> forward-compatibility and cross-platform-ness, and it will be an exact
> clone of what's on the camera.
>
> Both methods yield very good results when used properly (I should
> emphasise that last point), and it depends on the individual user or  
> group
> whether they go for tapes or for HD/solid state.
>
> -- 
> Aidan Wilson
>
> The University of Sydney
> +612 9036 9558
> +61428 458 969
> aidan.wilson at sydney.edu.au
>
> On Fri, 26 Mar 2010, Daryn McKenny wrote:
>
>> I would like to add to what we as an Aboriginal Language centre  
>> would want alongside of supporting what Felicity has said:
>>
>> We don't want just audio recordings, I cant emphasise enough how  
>> important video is for us when receiving language spoken evidence  
>> back to community.
>>
>> Ourselves only use quality (Sony/Canon) HDDV recorders recording to  
>> tape, we will not go to hard drive or any other format yet because  
>> of proprietary formats and compressions/codecs used, raw is best  
>> and that is what tapes give us.
>>
>> Regards
>>
>> Daryn
>>
>> Arwarbukarl Cultural Resource Association Inc. Trading as:
>> Miromaa Aboriginal Language and Technology Centre
>>
>> P | 02 4927 8222    F | 02 4925 2185    E | daryn at acra.org.au    W  
>> | www.acra.org.au<http://www.acra.org.au/> & www.miromaa.com.au<http://www.miromaa.com.au/ 
>> >
>>
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>>
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>>
>> From: Felicity Meakins [mailto:f.meakins at uq.edu.au]
>> Sent: Friday, 26 March 2010 9:33 AM
>> To: Laura Robinson; r-n-l-d
>> Subject: Re: video cameras
>>
>> I haven't been overly impressed with the quality of the hard drive  
>> cameras I've looked at. I have a Canon HV30 Black Progressive HDV  
>> which rates better than the Sony equivalent. The HDDV quality is  
>> infinitely better than the normal DV cameras and better than any of  
>> the hard drive cameras I've used. The digitised files require more  
>> hard drive space, but it is worth it for the image.
>>
>> I think that as linguists doing documentation we spend more time  
>> worrying about sound quality and good sound equipment and not  
>> enough about the quality of footage. We think of it as just adding  
>> a bit of context to our recordings rather than considering them as  
>> the primary recording that language communities are going to be  
>> interested in in decades to come.
>>
>>
>> On 26/3/10 6:57 AM, "Laura Robinson" <lcrobinson1 at gmail.com> wrote:
>> Hello all,
>>
>> I am looking to buy some video cameras for my fieldwork this  
>> summer.  I'm thinking to get a couple of the new tiny video  
>> cameras, plus something more mid-range, like a solid-state video  
>> recorder.  It would be nice to get away from miniDV if possible,  
>> and I was wondering what this list thought of the various kinds of  
>> new video cameras on the market?
>>
>> Thanks,
>> Laura
>> --
>> Laura C. Robinson
>> Postdoctoral Researcher
>> Department of Linguistics
>> University of Alaska, Fairbanks
>> http://go.alaska.edu/lcrobinson
>>
>>

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