Editing AVCHD
 

Is the challenge of editing AVCHD material present when you only wish to edit as SD rather than HD?

No, the problem lies in the compression that is AVCHD, no matter the resolution or definition. AVCHD almost seems engineered to personally offend any computer processor.

Good luck my friend.

been discussed before
 

Curt,

The challenges of AVCHD has been discussed before. Just do a search and see the responses. As Clint pointed out, it is pretty cpu intensive. It does not matter if your final output is SD. AVCHD is a tough codec that isn't really conducive to editing (at this time).

But in a nutshell, the two main "solutions" you can opt to are:

- get a powerful quad or more cpu and an NLE that can edit AVCHD natively
- transcode first then edit that material.

There's probably other sub-variants in there, but these are basically the two options one can really look up to.

For me its not the fact my pc is not pwerful enough but unless i convert the footage any avchd film refuses to add titles music dissolves etc, the only 1920x1080 blu rays i can make are basic rough edited files ie deleting and chopping,
But if only sd editing is required converting the footage is the easy answer.

Martyn, what editing software are you using ?

If you downconvert the AVCHD footage (HD>SD) before editing, you're talking about reducing the pixel load about 75%, so that should help a lot!

That said, I prefer to stay at the highest possible rez until the latest possible processing point... to achieve that with AVCHD takes a fast computer and a fair amount of patience.

Dave,

Are you talking about proxies? I used proxies about 4 times already on long projects. I would convert the HDV files into 2-3mpbs SD mpeg2 files and edit those. Easier on the cpu. Come time to render, I use the HDV files not the proxy files. Is this what you mean?

Will this also work with HD or AVCHD files? In theory it should. I just don't have enough long material to see if it syncs well for long footages. My hf-100 is relatively new and I haven't done a project with it.

What I did yesteraday, by coincidence to your post, is I have unpacked and tried cineform, and then tried rendering a proxy using Sony Vegas 8.0c on my avchd file. Basically, they give me 1:0.5 render ratio. It means a 30 min AVCHD file will transcode in about 15 min. I tried using vegas also to make an 3mpbs mpeg2 file from the avchd file and I get about the same time. The difference is that the neo scene file is about 6x as big as the avchd files. Of course, with neo scene, I can edit that file directly and render off it. But I was thinking, will proxing also work? I edit the mpeg2 file and then, like what I did in the past, I render the AVCHD instead when it's time to create the final output. The advantage of the mpeg2 files is that they are small and not big like the neo scene files.

Have you tried using proxies? Will it work? I use Sony vegas.

Any special reason for that approach Dave?

My final output resolutions are 1280 x720p, and I've been converting my AVCHD from 1920 x1080i to 1280 x720p Canopus HQ intermediate format, before editing.

Would I be better off editing as 1080i, and then resizing and de-interlacing as part of the final rendering process, rather than before the edit?

The rule of thumb in any editing process is to make all the cuts, titles, effects, color correction and only in the end convert and/or downgrade the footage.

Keep it pristine until the very end. You can always downgrade the quality of good footage if need be, but you can't improve an already pixelated or artifacted (is that a word?) footage.

Higher bit rate and higher resolution footage can withstand more color corrections and manipulation.

You might want to consider using Cineform which is an intermediate codec that is specifically designed to be editor friendly. It will convert AVCHD to the Cineform codec for editing purposes. It is much less of a burden on the CPU to edit using Cineform. It is also a very low loss codec which minimizes degrading the video when reencoding. The Cineform file sizes are pretty big but that's a small price to pay when you consider the benefits of using it.

Hi Dave, I think Mel has the best solution, one way I have read about is to set up 2 folders one with the original AVCHD and the other the low res copy which you edit then substitute the AVCHD for the low res and relink the files, I use Corel ProX2 and that uses what they call smart proxy and does all the low res files in the background for you, it then uses the AVCHD for the final render. I always do a AVCHD 1920x1080i edited video first and then use that to produce the 1280x720P for Vimeo, and re-encode it with SuperC (freeware) into MOV or mp4 using it's h264/AVC codec
Bryan

Sorry i missed you Ron i use pinnacle ultimate but have tried Adobe and a few others, having to down convert is one of the reasons i have gone back to hdv for now ,editing is so much easier with it.

Bryan,

When I was still using core 2 duo in my dell notebook, sometimes, I use proxies for the HDV files. I'd lay down the HDV track on the Vegas timeline, render it to a 3mpbs or so mpeg2 file. That's what I edit. Come render time, I use the HDV file to get the best quality. I've used this method for 4 full projects in the past without problems. The cuts were where I cut them. And there was no audio syncing problems. But this was with HDV files, not AVCHD.

In theory, the avchd file should be the same. I haven't tried it yet with a true project, so I can't really say if it will work. I can go for neo scene workflow and have tried it. But the file size it produces is horrendous. I've tried a 5 min avchd file and it takes about 2:40 to make a 2.1mbps bitrate mpeg2 file w/c are also small to convert in vegas 8.0c.

So, has anybody tried it with longer files or with a true project?

If you are using Vegas there is no need to use proxies. I use Vegas 8 to edit AVCHD from my SR11 and XR500 native on the timeline. Playback in the preview monitor is set to so that frame rate is normal and resolution is about the same as SD. For multi track editing in Edius I convert to Canopus HQ. File sizes increase just like Cineform to about 4 times the AVCHD file sizes depending on the conversion settings.

Ron Evans

I know
 

Ron,

I am aware of that. But on multicam editing, it does bog down even for a Quad core. I am even talking of hdv files here, not yet avchd. Mostly, it's the poor preview implementation of vegas, plus the need to access the HD constantly as you play back. If a proxy can be used, created easily and whose file size is small, that can be a way to edit with less pain, or at least less time waiting for the NLE to load the files, and "render" it to preview.

I've noticed that 2 multicams is not much of a problem. But once you hit 4, it becomes dicey. Without a doubt, I'll save myself a lot of extra work by not using proxies with avchd files, but I'll stick with 2 files on multicam editing. I don't know how it will go with 3.

I need to experiment though. We'll see :-)

I don't use the multicam in Vegas as Edius is so much better at multicam though it will not use AVCHD native at all. So for me its Vegas for single track and Edius for multitrack but with AVCHD converted to Canopus HQ. I then go back to Vegas for final audio and to render for Bluray authored with DVD Architect.

Ron Evans

Hi Ron, Just curious, if you use Edius for your multicam work, why do you use Vegas for single cam?

Hi Ron. I am still worrying through the whole issue of whether I want to edit AVCHD (from my SR11) at all because of the need to upgrade my current computer and because the whole matter of NLE editing of AVCHD footage seems unusally complex in support of a hobbyist level of video activity. One thing I still dont get (among many others) is how you go from the edited transcoded footage to rendering the AVCHD original footage. What is the process that finds the correct sections of AVCHD footage to use in the final rendering. Of course in film days you simply read the edge numbers off the final edited workprint and found the same numbers on the original film footage and cut the original accordingly to make the final print and end up with the exact same edit as that original footage. Is it all automatic in digital NLE editing? Fred

I am sure I posted a reply but its not here now so will answer again. Vegas will edit AVCHD native so it saves a lot of time and hard drive space to edit native. With multicam I edit with HDV native in Edius but have to convert the AVCHD files as Edius will not edit AVCHD native and certainly not in multicam with 2 tracks of native HDV as well.

Ron Evans

Fred, NLE is not really like editing film with a work print. You have two options if you want simple editing of your SR11 video.
1 Use the Sony Motion Browser software that came with the camera and transfer to the PC. This will log and backup your video in a nice calendar view on the PC and will allow you to quickly back these files up to other media if you wish( I advise you to do this as hard drives in camera or PC are not the most reliable pieces of hardware).
2 After you have done the above. Learn to edit in camera, its in the manual how to split, delete clips and add clips) and create playlists. That way you can show people video directly from your camera as a playlist( you can only have one playlist in the SR11 I think?).

For more complications use the simple editor in Motion Browser, it does much the same(divide, add, delete etc) and then will make a SD DVD for you to show others or an AVCHD disc that can only be played in a Bluray player ( don't put it in a normal SD DVD) It is slow but does work.
IF you want to get more capability than this you will need a real NLE of some sort.
AVCHD is no different than any of the other video formats to edit it just takes more CPU power to do the same thing or more time. Unlike film or even video tape AVCHD needs to be backed up to some other media for safe keeping. This is the number one thing to remember. A NLE will take files that you place on the timeline and allow you to edit out pieces or transition from one clip to another with effects if you want. Add titles etc. When this is done one renders from this timeline to whatever format of output is desired( could be back to AVCHD or more likely MPEG2 for SD DVD or for shorter programs MPEG2 HD as this is a lot quicker than re-encoding to AVCHD) The NLE uses the original file as source but doesn't alter it in any way in producing the output. It's a bit like using the original film in film editing and when done you still have the original film and your edited master!!!! Clearly there are potential losses when transcoding from one format to another but some NLE's will try and not transcode if this is not needed for colour correction or effects.
There are lots of NLE's to try.

Ron Evans

Edius can edit AVCHD natively.

Technically that is true. You can put AVCHD on the timeline and it will not crash and can be edited. However unless you have a supercomputer it will not play on the timeline at anything like realtime. Edius is my main editor and I have Q9450, 8G RAM, Vista 64 optimized with most of the Vista stuff turned off. Edius will not play AVCHD realtime on my system. Vegas plays realtime but only by reducing the resolution of the preview monitor. So its not an apples and apples comparison. The whole premise of Edius is WYSIWYG so reducing resolution is not part of the deal. There is some talk of the Firecoder Blu card being used to assist playback but as far as I know that is not the case yet.

Ron Evans

Specifically what are the settings for the preview window? I've been recording a bunch of stuff with my new HF-S100, and will start editing them soon.

Thank you!

There is no one setting as it will depend on your own PC. In vegas there are many choices for preview playback just start at draft and work up until the playback is less than realtime and choose the best for your viewing.

Ron Evans

I'm not sure why Edius and Vegas don't take advantage of AVC playback acceleration available with most mainstream ATI and NVIDIA graphics adapters nowadays, for preview.

Thanks Ron for all this. Very useful indeed. I shall go the simpler routes you have outlined at least for the medium term...until I get my computer seriously upgraded.

Fred Phillips