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Posted by Spex on 05/21/07 15:53
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?
>
> 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. We should be seeing the
introduction of the 72 Mbps and 100 Mbps systems now. 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...
>
> 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. 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.
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