AVCHD Solid-State Workflow
There are many advantages to shooting tapeless and working in a tape-free production environment, but there are a lot of people out there still shooting on tape, simply because they don’t understand how a tapeless workflow works. There are many tapeless acquisition formats currently on the market that have been around for several years now, including Sony’s professional XDCAM HD Optical Disc format and Panasonic’s professional P2 solid-state card format. Of course, these two options are professional formats and may be financially out of reach for many. More recently there is Sony’s SxS solid-state card format, which for me, is the very first step on the ladder for a system that touches broadcast quality. But even Sony’s SxS system can be costly for some, namely the price of the SxS cards themselves. But don’t despair; there is another format out there that is making some serious inroads in the consumer and prosumer market. Let me introduce you to AVCHD: the solid-state replacement for the ageing HDV tape-based format.
AVCHD (Advanced Video Codec High Definition) is a high-definition recording format for use in digital tapeless camcorders. In May 2006 Panasonic and Sony jointly announced AVCHD as a tapeless high-definition recording format. The format was based on existing Blu-ray Disc specification and allowed the recording of AVC-encoded video onto optical discs. Smaller 8cm DVD discs were chosen as the recording media, instead of the considerably more expensive Blu-ray discs. In July 2006 the format was amended to include other types of random-access media, like SD and SDHC memory cards, Memory Stick cards and hard disc drives. Today the most common recording media for AVCHD are SDHC solid-state memory cards.
AVCHD is kind of a ‘Super HDV’ if you like, only recording to solid-state SDHC cards instead of tape; it is the unofficial replacement for HDV. AVCHD is the most advanced video codec on the market right now. The AVCHD codec is loosely based on Panasonic’s superb AVC-Intra 10-bit intra-frame H.264/MPEG-4 codec. The AVCHD codec uses inter-frame long GOP compression and AC3 or PCM audio codecs. Both interlaced and progressive are supported in a wide range of frame sizes right up to full raster 1920x1080 at bit-rates of up to 24-Mbps variable. Compared to HDV tape-based camcorders, which are based on the MPEG-2 codec and record at 25Mbps constant bit-rate, AVCHD camcorders achieve higher compression and lower data rates with better image quality. Video compression is MPEG-4 AVC/H.264, colour is 4:2:0. at 8 bits.
THE SD & SDHC SOLID-STATE CARDS:
AVCHD camcorders record to 8cm DVD discs, internal hard drives and SD/SDHC cards; the latter being by far the most popular recording medium. The SD (Secure Digital) Memory Card has been around since 1999. It was developed by Panasonic, SandDisk and Toshiba and was designed to compete with Sony’s Memory Stick card, which was released the previous year. SD cards are now a firmly tried, tested and proven media. SD (Secure Digital) and SDHC Secure Digital High Capacity) cards have a ‘write-protect’ tab that can be slid back/forth to prevent accidental erasure of footage recorded to it, or to prevent further footage being recorded to it. With the write protect tab in the down position it is write-protected and read-only. SD cards are available in capacities of up to/including 4GB, while SDHC cards are available in up to 32GB.
It is worth noting that SDHC cards come in different ‘class’ forms. These are Class 2, 4 and 6. Although Class 2 cards are fine with digital stills cameras, you’ll need to use either Class 4 or 6 for use with AVCHD camcorders, as Class 2 won’t be able to handle the MB/s speed required for AVCHD camcorders recording at higher quality settings such as 24Mbps.
Here is a breakdown of the class-speeds:
Class 2 Card: A speed of 2 MB/s or higher is achieved.
Class 4 Card: A speed of 4 MB/s or higher is achieved.
Class 6 Card: A speed of 6 MB/s or higher is achieved.
By law, all SDHC cards 4GB and over must display the Class speed. This is easily identifiable by the symbol, which is basically a letter C with the number inside it.
Panasonic are pushing forward with the AVCHD format for some of their consumer and semi-professional camcorders, so it is no surprise that Panasonic have some super-fast and high capacity SDHC cards of 4, 6, 8, 12, 16 and 32GB capacity. These Panasonic cards also have a ‘Full HD Video’ logo on them; they are also faster. Speeds of up to 10MB/s data transfer speed is achievable with the Class 4 SDHC cards, while speeds of up to 20MB/s data transfer speed is achievable with the Class 6 SDHC cards.
SDHC cards cost approximately (street price) £45 for the 32GB Class 6 card, £20 for the 16GB Class 6 card, £12 for the 8GB Class 6 card. SDHC cards are made by companies such as Sandisk, Transcend, Fuji, Kinston, Lexar, Panasonic and many more.
Recording times vary according to the recording quality, but as a rough example, recording to a 16GB SDHC card at 21Mbps at full 1920x1080 you could expect approximately 80 minutes of full HD footage. At 13Mbps 1920x1080 this would increase to around 120 minutes. Double these times when using a 32GB SDHC card. For wedding videographers needing long record times for those boring speeches, you can reach massive record times of approximately 12 hours in one take with a 32GB SDHC card in economy recording mode.
WHO IS AVCHD FOR?
AVCHD camcorders are aimed at exactly the same market as HDV. Only AVCHD is for those who want to move over from tape to a solid-state workflow, with an added improvement in image quality. Due to the affordable price of AVCHD camcorders and solid-state SDHC cards, it will appeal to those who are currently shooting on the HDV tape format.
ADVANTAGES OVER TAPE:
Solid-state formats offer a fast and simple IT-compatible workflow with
ultra-reliable performance and resistance to shock, vibration, extreme temperatures, and weather. No more tape-jams or clogged heads, no more tedious logging-and-capturing of tapes, no more tape drop-outs, no more tape jams, instantly play back clips on the camcorders LCD screen using the thumbnails without breaking time code, delete shots instantly during acquisition to save time in post. This is just the beginning; read on.
There are loads of advantages to shooting solid-state over tape and when you learn what they are and have tried it out for yourself, you will never turn back. Here are a few of them:
Camcorders are more reliable as there are no moving parts or tape-transport mechanisms. There are no tape-heads to clog up, wear out or go wrong, so solid-state camcorders are cheaper to service and maintain. Shooting in extreme conditions such as extreme temperatures won’t bother solid-state; tape on the other hand can stick to the heads in these instances. Flicking an AVCHD solid-state camcorder into video playback mode allows you to instantly chose a thumbnail and play back any given clip right there in the field, something that would involve re-winding a tape to play back a clip, risking breaking time code, not to mention the time it takes. If you are not happy with your last shot, simply hit the ‘last clip delete’ button and it is gone in an instant. The advantage of deleting clips during acquisition stage is that it saves time at the editing stage because you know that all the clips on the card are good takes; no more tedious logging-and-capturing and marking in/out points. Also, with solid-state you simply drag-and-drop the clips into your edit system and they transfer across to your computer in a fraction of the time, because they are digital files; not tedious real time like tape. Because solid-state works like a digital stills camera, you can play back and show a clip to a client right there during the shooting stage. Clients are impressed with this and at least you know they are happy with the way things are going during the acquisition stage. There’s nothing worse than having to go back to a location to shoot a shot again because the client was not happy with it. Shooting on solid-state will reduce your overall production time from acquisition to the end of post-production by approximately 70%. It’s only when you move over to solid-state and use it for a while that you realise how slow and painful tape is as a workflow.
There are quite a few AVCHD models on the market right now, most of which are of the consumer ‘palmcorder’ type. However, Panasonic have just launched the all-new AG-HMC151 semi-professional camcorder at an amazingly low price of just £2,750 inc vat. The AG-HMC151 is just a little bit larger than Panasonic’s aging DVX100B, and a tad smaller than their HVX200 P2 model.
The AG-HMC151 has all the features you’d expect from a semi-professional camcorder including: 2 x professional XLR microphone inputs, built in stereo mic, a 28mm Leica Dicomar wide-angle zoom lens with an optical image stabilisation (OIS) system to ensure stable shooting when hand-held, extensive menu settings including various Cine modes, various shooting modes including 1080/25p, 1080/50i and 720/50p, 3-second picture record cache, SMPTE time-code generator/reader, focus assist options, 3 user buttons. The shutter speed can be selected from a minimum of 1/12-second to a maximum of 1/2000-second; the Synchro Scan is an ideal function for recording images from computer monitors. There is also a three position Gain selector switch, which is customizable via the menus. The 151 is also equipped with both composite (RCA) and component (Mini D4) video outputs, this allows HD to be down-converted and output as SD images.
There are a wide range of data and signal interfaces including HDMI out, USB 2.0, component out, composite out and RCA audio out jacks. Other features include white balance with presets and two manual settings as well as auto tracking, zebra settings where you can select two levels, centre markers to provide an accurate numeric display of the brightness of the screen centre, tally lamps on both the front and rear, remote LANC socket for controlling zoom, record, focus and aperture. Buy any lanc unit that is compatible with the DVX100B or HVX200.
The AG-HMC151 is an AVCHD solid-state-only camcorder aimed at the semi-professional market; the same market that HDV is aimed at. Although the AG-HMC151 uses solid-state media, it takes the much cheaper SDHC cards. This is obviously a huge advantage for the budget conscious corporate videographer, wedding videographer or low-budget independent filmmaker, as SDHC cards are dirt-cheap; around £20 for a 16GB class 6 SDHC card; that’s 80-minutes at full 23Mbps 1920x1080 HD quality. The Panasonic AG-HMC151 strikes a very reasonable balance between cost, image quality, versatility, portability and ease of use, with image quality that beats Sony’s A1 and Z1 HDVmodels.
PLAYING BACK FROM SDHC CARDS:
With simple playback on many consumer devices and players, from computers and video game consoles such as the Sony PS3 to Blu-ray players and flat panel displays with SD card slots, with AVCHD it is easier and quicker to view your footage on other devices without having to edit, burn, or plug your camcorder into the HDMI socket of your TV. Sony’s PS3 for example has an SD or USB card slot right on the front, simply remove the card from your camcorder and stick it right in. I tried this with my Sony PS3 and 46” Bravia TV and the images produced from the Panasonic AG-HMC151 were pretty amazing considering the camcorder cost less than £3,000. Once the card is in the SD slot (or USB via USB/SD card reader) on the PS3, you simply select ‘SD Slot’ from the PS3’s menu and hit play. You can then flick through clips and play them as you would a DVD. In this instance, the PS3 is acting like a regular solid-state playback deck. You can play back AVCHD footage off SDHC cards on many other regular games consoles and domestic Blu-Ray players that have the SD card slot.
In this section I’m going to go into the entire solid-state workflow from acquisition right through to postproduction and archiving. This section will be especially helpful to those who are used to shooting on tape-based formats such as HDV. This solid-state workflow is approximately 70% faster than a tape-based workflow. I’m going to use the Panasonic AG-HMC151 camcorder as the acquisition example. I’ll be using Apple’s iMovie and Final Cut Pro for editing examples. However, I’ll be mentioning PC editing solutions also.
SHOOTING AVCHD TO SDHC CARDS:
If you’ve never filmed anything with a solid-state camcorder before you’re in for a very pleasant surprise. Using the Panasonic HMC151 is not too dissimilar to using a digital stills camera like a Canon EOS for example; the main difference being, one takes stills pictures and the other shoots video footage. Just like a digital stills camera, with the HMC151 you simply insert an SDHC card into the slot on the back of the camcorder. That’s it; you’re now ready to start filming. The recording time you have remaining appears in the top left corner of the LCD screen and in the viewfinder. Once you press record a red arrow flashes on and off next to the time remaining indicator as a visual confirmation that the camera is recording. Time code (if you have set it up this way in the menus) also starts to run, and is displayed in the top left corner of the LCD screen. When you press the record button the second time, recording stops. At this stage, if you are not happy with the shot, you can instantly delete it by pressing the USER 1 button (this function must be set up in the menus beforehand). Deleting unwanted or bad clips during the filming stage will save you loads of time when it comes to the editing stage, as the only clips you’ll have on the card will be good ones.
If at any point during the day’s shoot you want to review any of your clips, it’s simply a case of pressing the MODE button on the back of the camcorder; this switches the camcorder from record mode to playback mode. Once you press the MODE button your clips will appear as small thumbnail images on the LCD screen. You can then scroll through the individual chips by using the small joystick controller on the camcorder. As you move through the clips a yellow border highlights the clip that is selected. The shooting mode i.e. 1080/25p, and the clip’s duration are displayed along the bottom of the LCD screen. To play back a clip, simply select it and press the play button on the side of the camcorder. This is a great feature to have for many reasons. You can play back and check your footage to be sure you got the shot you want. Or more importantly, you can play back clips to your client to make sure they are happy with the way the production is going. Because of the solid-state tapeless format, you don’t have to worry about breaking time code, or parking the play head back in the correct place after playing back clips; which could lead to you accidentally recording over footage on tape-based formats. It’s impossible to accidentally record over a clip using this solid-state format. Even when the card is full the camcorder will not permit you to record any more footage to it. The only way to delete a clip is to set the camcorder into playback mode via the MODE button, then go into the menu, select OPERATION, then select DELETE, then select either ALL CLIPS or SELECT. ALL CLIPS will delete all the clips on the card, whilst SELECT will give you the option to select either one individual clip, or multiple clips. It’s also possible to protect all clips, or individual clips, or a selection of clips by using CLIP PROTECT in the OPERATION menu. When a clip is protected it is impossible to select it and delete it. The card itself also has a ‘write-protect’ tab on the top/left side, which can easily be flicked into the ‘write-protect’ mode to prevent anything else being written to the card.
Once the card is full, you’ll get a warning on the LCD screen and in the viewfinder. Then it’s simply a case of taking the card out and replacing it with a fresh one. Bearing in mind that you can get 80 minutes of full HD high-quality footage onto a 16GB card, you might want to take two or three 16GB SDHC cards with you for a day’s shoot; or one or two 32GB SDHC cards.
Editing AVCHD footage from a solid-state workflow is both fast and easy. AVCHD is currently supported by a variety of editing solutions including: Apple’s iMovie, Apple’s Final Cut Pro 6.0.1, Adobe Premiere CS4, Sony Vegas, Grass Valley Edius PRO v4.5, Pinnacle Studio Plus 11, Nero-7 Premium Reloaded, Ulead Video Studio 11 Plus and DVD Movie Factory 6 Plus, to name a few.
Shooting on solid-state is pure bliss. When it comes to the editing stage, it just keeps on getting better and better. It’s at the editing stage that you notice the sheer speed of a solid-state workflow. Unlike tape, you don’t have to spend tedious hours marking in/out points and logging and capturing from a tape. Your editing workflow time is reduced by a factor of three to one i.e. what used to take you three days in post-production with the tape-based workflow, will now only take you one day in your new solid-state workflow.
Importing AVCHD footage into your computer editing system from an SDHC card is easy. You can either use the camcorder itself by using the supplied USB lead, or choose the easiest way by far which is to remove the SDHC card from the camcorder and use a small USB SD card reader. These small card readers are very cheap, about £3.50; in fact Transcend often give them away free with 16GB SDHC cards.
Once you’ve removed the SDHC card from the camcorder and put it into a USB card reader, simply plug it into one of your spare USB sockets on your computer.
Then launch your editing application, in this example I’m using Apple’s iMovie & Final Cut Pro (most PC editing software packages work in the same way). When you launch iMovie everything is automated. A small window will open with ‘Camera Detected – Scanning Contents’ (although it says ‘Camera Detected’, what it means is ‘Card Detected’) and a small progress bar; this takes just a few seconds. Then another small window will open with ‘Generating Thumbnails’ and a small progress bar; this also takes just a few seconds. Then a larger window will open showing you all the thumbnail images of the clips on the card. Underneath each image is a small square checkbox, simply select the clips you want to import by clicking in the small checkbox, then click ‘Import Checked’. After a few minutes (depending on the length of the clips – import time takes approximately half real time depending on the speed of your computer) the import process will be complete and your newly imported clips will be sitting in your clip-bin waiting to be edited.
If you’re using Apple’s Final Cut Pro, the import process is not too dissimilar; here’s how it works. After inserting the card reader with SDHC card into your computer’s USB socket, launch Final Cut Pro. Then go to File/Log & Transfer… The Log & Transfer window will open, and your thumbnail images will automatically load. Simply select the clips that you want to import by Command-Clicking on them, then drag them down into the media window. A progress bar indicator shows you how long the clips will take to import; in Final Cut Pro this is less than half real time, depending on the speed of your computer. Your newly imported clips will now be in the clip-bin waiting to be edited. Now you can go ahead and edit your programme in the usual manner. That’s it, fast simple and efficient.
Of course, once you’ve shot footage to your card, imported it into your editing system, and edited it, you’ll want to reuse your cards again and again. So you’ll need to archive/backup your footage somehow. This is probably the only advantage tape had to offer. You would shoot a tape, logging capture the footage, then store the tape away with all your footage on it, in a safe place. You would then take a new tape for your next shoot. Working in the solid state environment is a little bit different. Unless you want to use your SDHC cards as an archive/storage medium, you’re going to have to do something else.
HERE ARE SOME SOLUTIONS:
One solution is to archive your AVCHD footage onto standard 4.7GB DVDs. To do this simply insert your SDHC card into a USB card reader and plug it into one of the spare USB sockets on your computer. In this instance I’m using an Apple Macintosh computer (it works in a similar way on the PC). Your SDHC card will show up as an external hard drive on your desktop. Now insert a blank DVD into your computer’s DVD drive, this too will show up on your desktop. Next simply drag and drop the entire folder structure content from your SDHC card to your blank DVD. Now burn the DVD by dragging it to the ‘Burn Disc’ icon on the dock (trash can). It is always best to burn your DVDs at the slowest speed possible, this will eliminate the chances of errors and ensures compatibility with other computers that try to read it.
Once your DVD is burned, you can archive it away on the shelf for safe-keeping. If you need to import clips from your DVD in the future, simply insert it into your computer and use the import features of your editing software in exactly the same way you would when importing directly from an SDHC card. Apple’s iMovie and Final Cut Pro recognize the AVCHD clips on your DVD, in exactly the same way that they recognize clips on your SDHC card. Archiving in this way to DVD produces no loss in quality, it is simply digital data files (zeros and ones) that are being moved from one place to another. You can also put this DVD into a Sony PS3 (or similar games console) and play back the clips on your TV.
Another method of archiving your AVCHD clips is to use blank Blu-Ray DVDs. The method for doing this is exactly the same as with regular 4.7GB DVDs as outlined above. But the big advantage of using Blu-Ray DVDs is that their capacity is greater (25GB and 50GB) allowing you to put a lot more AVCHD clips onto them. Blu-Ray DVDs currently cost around £5.50 for a 25GB single layer one; and prices are continuing to drop all the time.
Archiving your AVCHD clips on to regular 4.7GB DVDs or Blu-Ray DVDs is one of the safest method for long-term archiving.
It’s also possible to archive your AVCHD clips onto regular computer hard drives. If you do choose to do this, I’d recommend using two hard drives with a RAID-1 configuration. This basically means archiving your footage onto two separate hard drives, in case one of them dies or packs up for some unknown reason. However, even a RAID-1 configuration does not mean 100% reliability, various phenomena can happen that would destroy the data on both hard drives at the same time. This is why I personally would not use regular computer hard drives for archiving anything important. I only recommend using computer hard drives in a RAID-1 configuration as a temporary storage medium, perhaps for a corporate video that you know you won’t need in three months.
There is also another way of archiving your AVCHD footage; this one might surprise you. You can simply buy an 16GB SDHC card, shoot your footage to it as usual, import the footage into your computer as you normally would, then treat the card just like you would a tape i.e. put it directly in a case and on the shelf and archive it away. Currently a 16GB Class 6 SDHC card from a high-quality and reputable company like Transcend costs just £18 if you shop around; prices for SDHC cards are dropping all the time. £18 to archive 90-minutes of full 1920x1080 high-quality HD footage is very good and is comparable to Sony’s XDCAM HD Professional Optical Disc system. Archiving using this system may seem strange, but the cards really are cheap enough to do it, and professional digital stills photographers have been doing this for a few years now; so why not us videographers too. This is a very safe method for long-term archiving and one that I personally am using right now.
©2009 Nigel Cooper