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Posted by Frank on 05/21/07 11:14
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.
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.
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.
--
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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