Does 24Mb/s AVCHD have a future

[Mark Stavar]

Interested in opinions:

Does 24Mb/s AVCHD have a future as a capture/editing format?

All thoughts/feedback appreciated.

Thanks,

marks

[Jay West]

Could you be clearer about what you are asking? Future for whom to do what and in what time frame?

Are you asking about buying an NX5 now versus waiting for the eventual NX 6 which may have full 60p (NTSC) or 50p (PAL)? Full "p" is a non-avchd format. It has been available in some Panasonic cameras for a while and is now available in some of Sony's CX700/560 and new NX70. (The full "p" formats are 28 mbps Mpeg 2 and are in addition to the 24Mbps AVCHD formats these cameras also offer.) Those few cams are a pretty limited selection. Before the recent earthquake, there were rumours and speculation about a full 60/50p NX6 being shown sometime next fall. Just when we will see the new camera is anybody's guess at this point.

The full "p" formats use a 28 Mbps Mpeg2. The image quality might not be as high (in theory) as the more efficient encoding of 24 Mbps AVCHD but this is largely theoretical. In practice, I am hard put to tell the difference even between AVCHD from my NX5 and HDV from the otherwise similar Z5/FX1000 cams. About all I've noticed in that comparison is that the NX5 seems slightly better with capturing high contrast-high motion. For me, the attraction of a full 60p or 50p would be the higher frame rate yielding another improvement in motion capture. Until I actually see a comparion, however, I'm not sure it will make much of a difference. I suspect that it will be a subtle improvement over interlaced 1080 footage.

Are you asking for any rumours anybody may have heard about the possibility that Adobe, Avid, etc. might someday eliminate support for AVCHD? Well, that is going to happen someday just as it happens with everything else in this business. Even so, it will not be any time soon. The very latest NLEs still have firwwire support and still ingest and edit miniDV video. Despite the advent of Blu-ray disks and HD shooting formats, many event videographers will still be delivering DVDs and shooting interlaced video. Some are still shooting SD, too. AVCHD will be with us for a long time.

Are you thinking that the availability of 50 Mbps Mpeg2 cameras "destroys" 24Mbps AVCHD because it has "twice the data rate"? It is nowhere near that much better. AVCHD is so much more efficient in coding that opinions vary over the extent to which high-mbps Mpeg2 images differ from 24 mbps AVCHD, just as there are arguments over how 35 Mpbps mpeg2 (Sony Ex cams) compares to 50 Mbps meg2 (Canon XF cams) and how much the bit rate differences actually mean to what viewers actually see on their tvs or computer screens.

The big attraction of 24 Mbps AVCHD is budgetary. It is a more bang for the proverbial buck in the mid-range price for prosumer and lower-end pro cameras. This is a price range where very high-bit rate Mpeg2 cameras do not compete. (The Canon XF300 and a Sony EX1r are $2500 more than an NX5).

My own take on all this is that I would like to have a full 60p camera for the dance programs I shoot, where the higher progressive frame rate may make for smoother shots, but it will not make any practical difference for the weddings I am shooting in interlaced AVCHD and HDV formats. I am not going to be junking my AVCHD cams nor buying new gear for a while.

So, if needed a new camera soon, and needed the array of functions the NX5 offers, I would not hesitate to buy it now. If I could use a lesser array of functions, I might well wait for the NX70 which was supposed to ship next month.

But, as noted in my question at the outset, the future of 24Mpbs AVCHD depends on who is asking about what they plan to do and what the time frame is.

[Mark Stavar]

HI Jay,

Thanks for the very comprehensive answer.

Guess what I have been wondering is whether AVCHD can be considered a long term acquisition and editing format for pro/sumer shooting and post-production - or will Sony et. al. move on to something else. (I still wonder why they wouldn't choose EX/MXF for this camera.)

It would seem that it (AVCHD) gets the big tick for acquisition, particularly given what you have said, but it seems generally accepted that it is not favoured editing format, given the highly compressed nature of the data and the horse-powered required.

Still, as I have read elsewhere, that was the same with DV when it first came to the desktop and now it it editable on even a low-end system.

For me, I am keen on the NX5, but I am still a bit hesitant on the recording format. Guess I'll just have to harden up and take the plunge.

Thanks again for the feedback.

marks

[Dan Asseff]

Mark, I love this camera. You didn't say what kind of shooting you are doing. I do weddings and some freelance work for a local PBS channel. I came from a PD170 that could see in the dark. The NX5 was kinda a disappointment in the low light department, I had to use more on camera light than I was used to. That is the only think I don't like about it. The rest of the features of this camera are awesome. I am adding the NX-FS100 to my arsenal for the low light and the DOF all the DSLR lovers talk about. It is not a run and gun camera though. The AVCHD is going to be around for a while. Buy the way it shoots 1920 x 1080 60p at 28mbs AVCHD.

Dan

[Jay West]

Dan:
I had thought that Sony was using an MPEG format for the 1080/60p, but I was distracted by the specs which described the format as "MPEG AVC/H.264." And, of course, that is AVCHD. Thanks for pointing out that Sony's 1080/60p formats are indeed AVCHD.

As for low light, I'd say that the NX5 goes about as deep as my old VX2000 did but requires more tweaking. The HD format, with its much smaller pixels, is a lot more sensitive to grainy video noise in the shadowy areas. The Neat Video software can help, but I've found it better to layoff the gain and work with slower shutter speeds. I also picked up some advice on picture profiles which help. Can't lay hands on the recipes just now, but I got a good one from a posting here by Ron Evans. YMMV. Interestingly, the little CX550 cams seem to have better noise containment down in the deep end of dark recesses.


Mark:
AVCHD is regarded as "not favoured" for editing simply because of the decompression processing load. To make it editable, the NLE has to convert everything to I frames on the fly. Other formats, such as HDV, are handled similarly but there is less load simply because there is less intensive compression . AVCHD can be easier to edit and color correct if everything is converted to "I" frames with a software such as Cineform.

All the bellyaching about computer loads aside, it really isn't bad for a newish computer (I7 processor, 12 g RAM, nVidia CUDA card & hardware MPE for CS5). I've had a couple of short deadline projects --- too short to wait for Cineform conversions and where the camera streams did not require tweaking to match up --- where I've done multi-cam edits in PPro CS5 with 3 streams of AVCHD and 4 streams of HDV.

[John Wiley]

I think AVCHD will be around for a while yet. Though "a while" is not a very long time in the digital world. For example, DV was introduced in the mid 90's and lasted about 10 years before HDV started to become commonplace. HDV didn't last nearly as long before AVCHD surpassed it, although it was only ever intended as an intermediate format.

Now that AVCHD is firmly taking over the mantlepiece as the primary aquisition format (maybe not the best, but certainly the one with the most market saturation), I think it will be a while yet before something else overtakes it. Sure, there are better quality codecs, but with all the licensing and marketing thoroughly in place, it will take a lot to topple it.

[Michael Johnston]

Short answer is yes, AVCHD has a future and is here to stay. It's relatively new and not yet accepted as a pro format but that will change. The big hang up right now is that AVCHD is so hard on current CPU's that it's difficult to edit with. That will change. Also, with regard to broadcasters, the EX1 is the lowest acceptable camera on the totum pole because A) it captures at 35Mbs and B) it had 1/2" chips. Broadcasters are really hung up on bit rate even though 24Mbs AVCHD is essentially equal in quality to the EX's 35Mbs MPEG. Sony seems committed to AVCHD as a pro line so it's going to eventually take off on the "Big Stage". Given it's high quality compression characteristics at such a small bit rate, AVCHD has to potential to become the next standard format much like BetaSP was for decades.

[Marc M. Myers]

Bandwidth and storage grows cheaper by the day. My guess would be that we are headed for a future with much less compression. There are already a fair number of people bolting solid state recorders like nanoflash to their NX5U's and EX3's. That said, AVCHD works well in the present generation of cameras. The editing problems are less than they used to be. software and hardware have almost caught up.

On forums like this we have a tendency to get it backwards. Just why do I want to shoot with the latest and the best? Well, I either have to or can afford to. Afford to is in the eyes of the beholder. Have to includes video you know is going to be composited and manipulated. AVCHD video will fall apart in the processing. The other have to is when you are shooting for someone who has a standard you must meet. The BBC, for example or Discovery. If clients are willing to pay the extra freight, they should get what they pay for.

Otherwise, the NX5U is making great video. With some consumer cameras getting really, really good, I think a more compelling argument can be made for going cheap rather than cutting edge. Cheap puts more food on the table for the spouse and kids. Cutting edge gives moral satisfaction or something.

[David Heath]

Originally Posted by Michael Johnston

Also, with regard to broadcasters, the EX1 is the lowest acceptable camera on the totum pole because A) it captures at 35Mbs and B) it had 1/2" chips. Broadcasters are really hung up on bit rate even though 24Mbs AVCHD is essentially equal in quality to the EX's 35Mbs MPEG.

It's important to realise that a codec spec such as AVC-HD 24Mbs does not determine the coder or the quality - it determines the DECODER. What that means is that any individual coder may not use all the tools that it theoretically could, though obviously the more sophisticated it is, the better the results for a given bitrate.

It might be reasonable to say that in a best case AVC-HD at max bit rate may equal 35Mbs MPEG2 - but practically the real time encoders in prosumer spec cameras don't.

You have to ask why AVC-HD came about. The first reason I heard was to enable solid state recording at consumer memory prices, rather than P2 or SxS. But in a way a lot of the point of it got overtaken by advances in solid state technology - the first AVC-HD cameras were barely out by the time people were finding out they could use SD cards in an EX. And newer, better memory is making that reliable enough for such as broadcasters to be regularly using SD cards in place of SxS for a lot of applications.

For broadcasting, bitrate is highly important. The number of channels you can fit into a channel depends on how low you can get the bitrate - and that equates to real money. Enough money to make it well worthwhile spending thousands of dollars on each coder. For acquisition, the imperative is far less. It may mean you need less memory - but what's the point if you have to spend a fortune on a high quality coder?

Originally Posted by Marc M. Myers

Bandwidth and storage grows cheaper by the day. My guess would be that we are headed for a future with much less compression.

Which is very true. Why put a lot of effort into lowering the bitrate for acquisition when memory is becoming cheaper, at least for professional acquisition?

At the end of the day we use what the manufacturers give us, and I suspect that AVC-HD will remain the norm in the consumer/prosumer world - but I don't see it going into the pro domain to any great extent.