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Posted by Frank on 05/21/07 19:05
On Mon, 21 May 2007 16:53:55 +0100, in 'rec.video.desktop',
in article <Re: Another nail in the coffin to HDV>,
Spex <No.spam@ta.com> wrote:
>Frank wrote:
>> On Mon, 21 May 2007 08:59:07 +0100, in 'rec.video.desktop',
>> in article <Re: Another nail in the coffin to HDV>,
>> Spex <No.spam@ta.com> wrote:
>>
>>> Maxwell wrote:
>>>> On May 14, 10:50 pm, Frank <f...@nojunkmail.humanvalues.net> wrote:
>>>>> Well, alright, let me say this: I do think that the subject line of
>>>>> this thread is a bit off-base. As things presently stand, the
>>>>> highest-priced AVCHD camcorder doesn't provide audio or video quality
>>>>> even matching, let alone exceeding, that of even the lowest-priced HDV
>>>>> camcorder.
>>>>>
>>>>
>>>> HDV is MPEG-2.
>>>>
>>>> AVCHD is a variation of MPEG-4 (H-264 actually).
>>>>
>>>> The benefit of MPEG-4 is that it reduces the dataflow considerably.
>>>> It does that by increasing compression. In my opinion, the more you
>>>> compress, the more you sacrifice. For me, MPEG-2 (HDV) is too
>>>> compressed. I wouldn't even touch MPEG-4. All my cameras are HDV.
>>>> AVCHD is for the family vacation.
>>>>
>>> All very true but the camera manufacturers have crippled AVCHD cameras
>>> by starving them of bandwidth. The max bit-rate for these cams is
>>> around half the bit-rate as HDV but as efficient as MPEG 4 is it cannot
>>> make up for the difference.
>>
>> 720p HDV is 19.7 Mbps CBR and 1080i HDV is 25 Mbps CBR. The highest
>> datarate on any available or announced AVCHD camcorder is 15 Mbps VBR.
>>
>>> It is a classic case of the camera manufacturers clubbing together and
>>> forming little cartels that protect their higher-end cameras. An AVCHD
>>> camera running at 25 Mbps would easily be more than a match for Sony's
>>> XDCAM HD format running at 35 Mbps MPEG-2 and destroy P2 overnight.
>>
>> The AVCHD spec goes up to 24 Mbps VBR.
>
>I know, but where are all the cameras?
I don't know, but I'm told that good things come to those who wait. :)
But seriously, I keep getting told by people who should know that
AVCHD is going to be positioned as a consumer-only format (the
Panasonic AG-HSC1U notwithstanding) for some time to come, and maybe
even forever, which just *might*, and I stress the word might, mean
that we'll never see 24 Mbps AVCHD products, at least not at
consumer-friendly prices.
I'm also told that due to the significantly increased computational
complexity of processing 24 Mbps VBR AVCHD (MPEG-4 Part 10 H.264 AVC)
in realtime, the processors that would be needed to handle it would
require fan cooling, something which I don't see happening in consumer
camcorders of the hand-held variety. Heck, I can picture some folks
putting tape over the ventilation holes.
>> Sony will be introducing a new generation of XDCAM HD products with a
>> 50 Mbps VBR datarate. This will happen in conjunction with the
>> availability of their new, bigger, and faster Professional Disc
>> blue-violet laser optical media.
>>
>> The existing PFD-23 Professional Disc has a storage capacity of 23.3
>> GB while the new PFD-50DLA dual-layer Professional Disc will store 50
>> GB and run at 2.4x speed.
>
>This was supposed to be with us the same time as the first XDCAM HD
>cameras. Originally there was supposed to be two levels in XDCAM a HDV+
>level @35 Mbps 420 and 50 Mbps 422.
The explanation from Sony is that it turned out to be more difficult,
from a purely technical viewpoint, to get dual-layer Professional Disc
working reliably and dependably than was originally envisioned.
Obviously, that's either true or not true, and if not true, than
perhaps what we're seeing is nothing more than marketing in action.
There is no doubt, however, that a fair amount of engineering, and
maybe even some good old basic R&D, went into moving Pro Disc from
single-layer to dual-layer, and those things do take time and cost
money. Also, don't forget the 2.4x speed increase, necessary if one is
going to be able to support higher bitrates.
>We should be seeing the
>introduction of the 72 Mbps and 100 Mbps systems now.
Do you really think that we need 100 Mbps XDCAM HD? Maybe if it was
4:2:2 with 59.94 full progressive 1920 by 1080 frames per second (50
frames in PAL areas). MPEG-2 422P@HL (4:2:2 Progressive Profile at
High Level) at 100 Mbps happens to meet this requirement.
>But hey that
>would reduce the need for HDCAM and seriously reduce the number of
>people using HDCAM SR. We know how much Sony charge for their HDCAM/SR
>decks don't we? Nice income if you can get it...
Yes, we do know what they cost, but I'm sure that owner's of an
SRW-5500 ($98k list) sleep better at night. And it does HDCAM and
HDCAM SR.
Besides, it surely *is* a nice deck (written with lust in my heart).
>> I haven't seen it yet, but I think that the 50 Mbps XDCAM HD video,
>> which will also be 4:2:2 instead of the existing 4:2:0, will look
>> quite good.
>>
>> With regard to P2 and DVCPRO HD, I expect to see a big push on
>> Panasonic's part of their new AVC Intra codec.
>>
>>> The biggest problem these consumer level cameras have is not the
>>> compression scheme they use but the cheapo CMOS chips and their inherent
>>> rolling shutter. Jelly vision! But they're cheap and the idiots will
>>> buy 'em...
>>
>> Some of those buyers love them. I am not one of them. I do look
>> forward to XDCAM EX, however, even of it's only 35 Mbps VBR 4:2:0 and
>> doesn't support the new 50 Mbps VBR 4:2:2 codec, although it would be
>> nice if it did.
>>
>
>That just highlights the ludicrous nature of current manufacturers
>thinking. Their consumer cameras get a more efficient codec but it's
>crippled and their mid-end gear gets a less efficient codec but plenty
>of bandwidth.
Makes sense to me. :)
>Nothing about this is designed to give the consumer or
>professional the best image at the current state of technical
>development. It is simply an effort to protect the margins on their
>higher end gear.
Marketing, marketing, marketing.
At least they don't use semi-naked women and freshly decapitated goats
to introduce new products at NAB and IBC. :)
Slaughter: Horror at Sony's depraved promotion stunt with decapitated
goat, by Glen Owen and Rhodri Phillips
http://www.dailymail.co.uk/pages/live/articles/news/news.html?in_article_id=451414&in_page_id=1770
--
Frank, Independent Consultant, New York, NY
[Please remove 'nojunkmail.' from address to reply via e-mail.]
Read Frank's thoughts on HDV at http://www.humanvalues.net/hdv/
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