Quote:
Originally Posted by Robert M Wright
(Post 1480665)
I'm a bit disappointed Canon chose to go with MPEG-2 compression in their new cam. That choice seems a little short-sighted (to me), when you consider that this cam (and siblings) is likely to constitute Canon's pro camcorder offering for the next half decade.
It won't be long until AVC is just as easy to edit (give it a year or two) as MPEG-2 is today, and editing AVC is quite reasonably manageable currently.
With AVC encoding at 32Mbps, Canon could have offered very close to the same image quality (or better), with some very nice side benefits.
At 32Mbps, recording to low cost media reliably is much easier than at 50Mbps. Even just decent class-6 SDHC is adequate for recording at 32Mbps,.....
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Most engineering decisions involve compromises, and you have to weigh up pros and cons.
On the side of 50Mbs is that it is a relatively tried and tested solution. It's already well supported by NLEs, etc. Coders are relatively easy to make, and relatively cheap therefore. It meets oft-quoted minimum recommended spec requirements, no arguments. Yet at the same time, it's low enough to be easily recorded onto fairly basic consumer media - class 6 SDHC of a decent brand should be OK, the EX/SDHC limitation has more to do with the adaptor and interface than the media itself.
So why move to AVC-HD? (Or a form of long-GOP AVC that is outside the AVC-HD spec to enable 4:2:2.) The ONLY advantage I can think of is a lower bitrate, so more minutes can be recorded per GB. But is it worth it?
Against that, moving outside AVC-HD specs begs the question of what NLE support will be like, certainly for the first year or two. Even if supported, performance is likely to be down compared to working with MPEG2. Coders will have to be complex to code in real time and get anything like equivalence at the 32Mbs you mention - and that likely means much more expensive and power hungry. Or they could be simpler and less powerful and get equivalence at (say) 40Mbs maybe - but is the 20% saving then really worth it?
An analogy may be the differences between engineering decisions for a basic family car and a high performance racing car. For the latter, it may be necessary (if expensive) to use lightweight alloys to reduce weight to get the performance, for the former, it's unlikely the gains would justify the cost. In this respect, the complexity of AVC-HD may be well worthwhile when coding for transmission (and bitrate= big money), but much less so if all it does is save a few GB of fairly cheap memory.
As far as the longer future goes, then my expectation would be that memory will come down further in price, and bitrate reduction for acquisition become even less of an issue. Yes, computing power will likely increase, but it seems far more sensible to use this to enable wavelet codecs such as JPEG2000.
In the meantime, MPEG2 seems a good compromise for this level of acquisition recording, H264 for transmission and squeezing content on to such as Blu-Ray. (In the latter case, it's much easier - the coding doesn't need to be real time.)
What the chip size will be remains to be seen. My feeling is that it SHOULD be 1/2" to really give Canon the edge, when they could claim to meet all the desired broadcast recommendations. If they do go for 1/3", my vote would remain with the EX - you can always add a nanoFlash to a 1/2" camera, you can't add 1/2" chips to a camera with a 422 codec!!
The announcement also must be a wake up call for Sony. I've made no secret that I like a lot about the PMW350, but think it should have the 50Mbs codec. Now that Canon have included that in a far, far cheaper camera, what do you think it's going to be like for a Sony salesman? How many times is he going to have to put up with hearing "but why doesn't it have the 50Mbs codec?" at a tradeshow?