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Posted by Ken Maltby on 05/21/07 17:00
"Spex" <No.spam@ta.com> wrote in message
news:4651c094$0$8744$ed2619ec@ptn-nntp-reader02.plus.net...
> 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.
>
Now this aspect of this thread seems more to the real issue.
The potential is there for an AVC HD camera, that could
provide excellent service for the Home User/consumer, where
there is an image of the highest quality. Even then it will have
less attraction to a professional community with a considerable
investment in editing tools that are not geared to that format.
I have some interest and appreciation for HD and AVC/H.264,
it is fine with me if some find the artificially crippled AVCHD
format useful, but I would not recommend the format, in its current
state. If/or when the format is released at its full potential it could
provide "professional" quality video imagery for the consumer, with
a limited editing capability, or requirement. This will become
more apparent when/if recordable HD-DVDs can be made from
AVCHD without transcoding.
Luck;
Ken
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