What is AVCHD?
AVCHD is a highly compressed form of video stored in H.264 format. The sound can either be stereo or 5.1 surround sound depending on the camera. The picture is excellent given the amount of space it takes up but the heavy compression may lead to problems when editing. The footage is recorded in the camera to memory cards or a hard drive or in some cases onto a DVD-style disc. Once recorded you need to transfer the footage form the memory card etc onto your computer for editing. This is generally done by simply plugging in a USB cable and copying the footage across.
There are two main formats of AVCHD - AVCHD and AVCHD lite - the lite variation is practically the same as the full version but does not let you film in full HD and is restricted on size and datarate.
AVCHD can be recorded in various sizes and at various data rates -
The three main sizes would be 1280 x 720, 1440 x 1080 and 1920 x 1080. 1280 x 720 & 1440 x 1080 are exactly the same number of pixels as used in HDV cameras and you should get an equivalent picture. HDV cameras record in MPEG2, which is less advanced compression than MPEG4 as used by AVCHD, and so is easier edit.
1920 x 1080, or "full HD" means that you will be filming at the top quality of HD and theoretically better than HDV. Of course there are other considerations on how good the picture will be - if you buy a £300 AVCHD camera it will still give you a picture that looks like it came from a £300 camera even if it is saved at 1920 x 1080. There are some excellent professional AVCHD cameras now available from both Panasonic and Sony which make stunning pictures.
1280 x 720 footage is always recorded as progressive - this means every picture is recorded as a whole frame. 1440 & 1920 footage can be recorded either progressive or interlace - with interlace footage each frame is split into two "fields" so that you can have more pictures per second, meaning smoother footage. If filming at 25 fps progressive you can sometimes have problems with fast moving objects or pans - this is because the human eye really needs to see 50 pictures per second for smooth movement. This is why some cameras will film in an interlace mode - because even thought you are filming 25 pictures per second as they are split into two "fields" you end up with 50 half pictures per second which means better movement. Some cameras will film at 720P at 25 fps and 50 fps progressive, or at 1440/1920 25fps interlace, or 1440/1920 25fps progressive. There are even some AVCHD cameras that film at 1920 50fps progressive which should give the best quality, such as the Panasonic HDC-HS700, a "domestic" camcorder which is about £800 but is the hardest to make. This does deliver stunning pictures, although as 1920 50P is not officially part of the Blu-ray specification, it is not something you can put onto a Blu-ray disc! A
The frames rates etc at which cameras film vary a lot - whatever the setting though you have the same issues when it comes to editing.
Which programs support it directly?
Ideally you just want to copy the footage off your camera, put it in your editing program and use it (called using the "native" footage). You can do this with many of the programs available today. Grass Valley EDIUS 5 and upwards, Sony Vegasand Adobe Premiere Pro CS4 and later let you put AVCHD footage directly on the timeline. Initially Vegas would only deal with Sony AVCHD footage but it will now also load Panasonic. How well it plays back is dependant on how good your computer is, and does vary from one program to another. If trying to edit native then we would recommend using the latest type of i7 system.
Why is it hard work for the computer to edit the native footage?
AVCHD is a great filming format, creates an excellent picture in a very small space and is one of the formats you can use to make Blu-ray discs. It is so flexible because the way the video is stored is pretty complicated. Just like with a video DVD the footage is not stored as whole frames but instead as bits of frames. To see one frame you need to look at several, which means the computer needs to be doing all this work just to try and play the footage back, let alone try to add effects.
Why do cameras use this format if it is so hard to edit?
To be able to use relatively cheap cards, like HD SD cards used in Panasonic cameras, the video cannot take up too much space or use too much data per second. If it was less compressed and used up more data then the cards would not be fast enough to keep up. Therefore you would have to need to buy much faster and more expensive cards. This is one of the reasons that formats like XDCAM-EX, which are less compressed, film on to SxS cards - SxS cards are considerably faster than SD cards. They are also a lot more expensive! So AVCHD is a compromise - a way to get a really good picture on to media that is easily affordable.
How well can you edit native footage in the various programs?
In Vegas you can play the footage at full quality quite happily. Editing and trimming is smooth as well. If you start add effects Vegas will not be able to play it back properly but instead will drop the quality so it will always show you something. You can always render to see it properly. On our i7 system we can manage a clip with a cross-dissolve before Vegas needs to render. However, the footage is usable. Preferably use the 64bit version of Vegas as this can use more processing power on a modern computer.
Adobe Premiere can play the footage back very well, with the 64bit CS5 (and later versions) working a lot better than the older CS4. On our i7 system we can manage a 3-4 layers of picture in picture (assuming we are using the right graphic card and the MERCURY PLAYBACK ENGINE) as well, so quite a bit better than Vegas. Like Vegas trimming is fine.
Grass Valley EDIUS is one of the best programs at handling AVCHD footage. You can play 8-9 layers of video on a standard system, it is reasonably quick to load and working with the footage is nearly like using DV footage.
If you computer is not powerful enough there are two ways of using AVHCD footage - you can either convert it to Grass Valley's own HQ format, using a free utility which can transcode a lot of clips very fast, or, with the full version of EDIUS, create PROXY files which are low resolution versions of the clips which are very easy to play back. Ideally buy a better computer and do not waste time transcoding.
EDIUS also has one of the best ways of importing AVCHD footage using their "source browser". Once you plug in the card of camera the footage pops up in the source browser, you choose the clips you want, and import them. EDIUS will copy the footage off the card and into the project folder for you - which it will even do "in the background". the latter means you should be able to carry on editing while footage is imported, although to be honest with most cards and cameras being connected by USB, the process normally slows down the editing program too much and you are better off to leave the program to import the footage and then start working.
With Media Composer 5 and later you can load AVCHD footage directly into Media Composer. It works very well natively with Media Composer 8 and a recent computer, although we would generally recommend that you use the "link" feature and then transcode the footage to Avid DNxHD format to make it more "usable". </p>
If AVCHD is hard work should I stick with HDV?
HDV is easier to edit than AVCHD so you do not need such a powerful computer to edit the footage, although this does depend a lot on which program you choose to edit footage. With any program you could always convert AVCHD footage as outlined and it would work fine anyway, it's just more hassle. Also the programs do a much better job of editing native footage if you buy a better (and more expensive) computer.
If you are going to buy a new computer and say to yourself "I am probably going to spend about £2,000-£3,000 on a new computer with software" you can then forget about the how to edit the stuff and concentrate on which type of camera will actually be better to use.
AVCHD cameras can film in 1920 x 1080 and film on cards or hard drives. This means the technically they are better quality than HDV (which is 1440 x 1080) and they are more convenient than using tape. Less moving parts also means a longer battery life and generally a lighter camera. It also means you can film for longer periods (tape is limited to 1 hour). Of course you can film HDV onto cards with some cameras, or add in device like a FireStore and film onto a hard drive instead, so you can get the convenience of not using tape with HDV, its just that most HDV cameras do not come with cards or hard drives and have to be added.
In terms of quality it is not as clear cut as that because how good the camera is does depend on other things - for example I have a £300 Panasonic camera that films at 1920 x 1080 and an £800 HDV camera (filming at 1440 x 1080). In good light the pictures from the Panasonic are better. In bad light the HDV camera wins every time. If I was to use one of the professional AVCHD cameras from Panasonic (see some info on them here: http://www.dvc.uk.com/acatalog/Panasonic_AVCHD_camcorders.html) then I would have better pictures in both good light and low light than my £800 HDV camera.
I should not buy an HDV camera because tape based stuff is dead isn't it?
This is not true. Card based formats are the future, in the same way that still photography has moved away from film and on to cards, so will video. However we are sure tape will be around for many years to come! The advantage of buying an HDV camera is that it films HD footage in exactly the same way as you will have been filming standard definition so you don't have to work out different ways of doing things.
If you go card based then you will have to use a slightly different work flow - however don't be put off, despite this rather long document on the pitfalls and problems of AVCHD it is really not that hard and with every new revision of software keeps getting better. We are heading towards a situation where all you will do is film the video, copy it on your computer, edit it and output and you wont really care where it came from. We are not there yet, but with the advent of faster computers and new software like EDIUS with its AVCHD booster pack, or Premiere Pro CS5 with its Mercury Playback Engine we are getting closer!
What potential problems are there?
None really - although if copying files off a hard drive or memory card will be as fast as the connection you have, with my own system I can copy 1 hour from a card in about 15 minutes. If capturing through HDMI or component then 1 hour footage would take 1 hour to capture.
The most commonly used cards, and the cheapest are from Blackmagic (an Intensity Pro 4K with HDMI is about £150). The formats into which these can capture does vary between different editing programs with Avid and EDIUS offering the best codec options.
Once captured in this way the footage is no longer AVCHD but something a lot more usable, and should look practically the same, if not indistinguishable, from the original.
So which is the best program to choose?
Based purely on which one has the best support for AVCHD then Grass Valley EDIUS would be our choice. However, that should not be your only consideration when deciding which program to use as there are many reasons why you should choose one program over another. Please read the various documents on our website for more information on why you would chose EDIUS, Media Composer, Vegas or Premiere as your preferred editing program.