One of our audio and video archive customers has a large collection of AVCHD video files that are stored in 1.9GB ‘chunks’ as xxxxx.MTS files. All these files are of 60 minute and longer duration and must be joined, deinterlaced, re encoded to a suitable size and bitrate then uploaded for online access.

This is quite a task in computer time and file handling. These small domestic cameras produce good HD movies for a low cost but the compression to achieve this is very high and does not give you a file that is easily edited. The .MTS files are MPEG transport stream containers for H264 encoded video.

There are some proprietary solutions for MacOS X and Windows that will repackage the .MTS files into .MOV Quicktime containers that can be accessed by MacOS X or re-encoded to a less compressed format for editing with Final Cut Pro or Premiere. We didn’t need this though, just a reliable and  quick open source workflow.

1. The first and most important issue is to rejoin the camera split files.
   These cameras use FAT32 file systems which cannot handle individual files larger than 2GB so they split the .MTS video file into chunks. As each chunk in a continuous sequence references the other chunks these must be joined in the correct order. This is easily achieved with the cat command.
2. The rejoined .MTS files can now be reencoded to a more manageable size using open source software such as Handbrake. We also needed to deinterlace our footage as it was shot interlaced and it would be accessed on progressive displays. This will increase the encoding time but without it any movement will look odd with visible artifacts.
3. Finding the ‘sweet spot’ for encoding can be time consuming but in this case was important as projected text needed to be legible but the file sizes kept manageable for reasonable upload times!

A documentary we transferred and created DVD access copies for its director recently. He only had a VHS copy of the 8mm original unfortunately but it’s still a great piece of history about St Pauls, the St Pauls Carnival and Bristol.

If anyone can recognise themselves or anyone else, please contact the director, Colin Thomas by email, ctbr...@blueyonder.co.uk

2 u-matic video tapes were discovered of a Black Roots live performance in Bristol in the 1980′s. We were able to restore, digitise and make the umatic transfer of this recording as a high quality, uncompressed Quicktime file then encode and author a DVD for future release by Bristol Archive Records.

Some information supplied by the label:

Black Roots were Bristol’s premier Reggae band throughout the eighties and having gone their separate ways in the nineties they reformed last year and will be rekindling the magic with an intimate hometown gig at the Fleece on Friday September 9th, the show coincides with the release of “Black Roots – The Reggae Singles Anthology”, released on Bristol Archive Records in collaboration with Nubian Records, this release showcases all of the band’s singles released during their first decade and as an extra bonus the CD issue comes coupled with a DVD of the band’s 1986 video release “Celebration” recorded at the long gone Studio nightclub in Bristol. This show will be something special and likely sell out so book your tickets early and don’t miss out.

www.thefleece.co.uk

We were very excited recently when Chris Bradfield from Soundscommercial uncovered a previously unseen batch of EIAJ half inch reel to reel video tapes. In the process of looking for 1976 footage for their event, Sprit of 76, we uncovered many other gems. One of these goals was the famous hat-trick scored by Kevin Mabbutt against Manchester United at Old Trafford in 1978. Mabbutt is one of only two players in Football League history even to have done this and this footage was never recorded anywhere else!

Unfortunately this large batch of valuable recordings had been stored in damp, unheated conditions and had suffered. The tape had deteriorated in several ways.

• Mould growth was evident on some tapes
• The oldest tapes from the early 1970′s were shedding oxide severely and had little lubrication left in the binder.
• Binder hydrolysis, often called sticky shed was evident on other tapes.

Each issue needed a different process to treat the tape. The common assumption that ‘tape baking‘ will restore all unplayable tape is not true. It is just one solution to one of these issues and can cause more problems if used incorrectly. Deteriorated video tape is much less forgiving than audio tape when attempting transfer and must always be handled and processed with extreme care. Crinkled, curled, edge damaged tapes are next to impossible to restore back to their original condition and it’s common that more damage can occur when owners are desperate to transfer footage.

We were able to restore all the tapes to a playable condition and make uncompressed quicktime files of these.

Below is a clip from a later recording. We are not able, unfortunately, to show the Kevin Mabbutt clip yet.

Unseen to 32 years, although there could possibly be other tapes in the vaults at Abbey Road.
This ntsc umatic transfer to uncompressed quicktime files was a damaged tape that at some point in it’s life had been ‘eaten’ by a greedy u-matic machine! The tape shell also had some plastic debris inside that needed removing before it was safe to attempt loading and migration.

We’re very happy to be working with Mike Wright and the Archive for Mathematical Sciences and Philosophy on a large scale and ongoing transfer, restoration and online management programme.

akloster tape 2a Download whole video to your computer

We have several time base correctors and frame synchronisers at our disposal. One recent addition is a new old stock (NOS) CEL Tetra. This is an early 1990′s motion adaptive Standards Converter for PAL, SECAM, NTSC 3.58 and NTSC 4.43 systems. A very flexible unit with composite, Y/C (S-Video), umatic DUB High Band/Low Band and component inputs and outputs.

Out unit still has it’s shipping caps over the BNC sockets and looks unused but after 5 minutes of power a cloud of white smoke billowed out of the cooling fan accompanied by a pungent smell. The Shaffner EMI mains filter had a nasty, sticky brown residue leaky out and all around the back of it. This is the second TBC that I’ve had this happen to. I’d assumed these units get left on for long periods when used in broadcast applications which would hasten their demise. According to their website, the mean time between failures (MTBF) of their recent products is around 2,000,000 hours! Our CEL TBC doesn’t look like it’s done more than 30 minutes so maybe there’s been some dodgy electrolytic fluid in these units just like the motherboard capacitor problems between 2000 and 2003.

We use time base correctors and frame synchronizers all the time in the transfer and digitising of analogue video tape.

One of our more flexible and high quality units had recently developed an annoying and very obvious fault on it’s video outputs. While the unit was working there were faint but distinct horizontal lines on the video. This phenomenon is often called a hum bar and can be caused by ground loops.

In this case we isolated the unit from the rest of our installation and using a separate power point the problem was still there. Looking at the unit itself it is a very deep and heavy 1U case with two 40mm cooling fans at the rear corners. It is quite old too and being designed for continuous studio use is likely to get hot and have been on for very long periods.

The video fault appeared to be AC ripple ‘riding’ on the DC power. It was time to look at the electrolytic capacitors in the power supply.

Although I could have tested each one, all these caps were old and only rated for 3000 hrs at 85 celcius so they all had to go! Here’s a list of them:

The only one hard to find was the large 400v dump one. Most units now are thinner and taller but eBay came to rescue here.

This shotgun approach worked beautifully and the fault had gone. While tracing the exact fault is always the best way, capacitor often get a hard life and will not last indefinitely, especially in switch mode power supplies.

High resolution audio and video digital tape conversions can use large amounts of computer storage. 8 bit uncompressed Standard Definition (SD) PAL video runs at 70 GB per hour and 24 bit 96 kHz audio files at 2 GB per hour.

As a result of this many of our analogue to digital tape transfers require the use of external storage, usually USB 2.0 portable hard drives, to supply the copied digital transfers back to the customer. Some drives supplied by customers have not been of great quality and not designed to be sent about in the post. One such drive we had recently, a Sony Vaio branded 2.5″ USB drive wouldn’t copy certain directories of important files with the Mac OS Finder or the Windows Explorer. While most of the drive copied this certain folder always resulted in a crashed computer!

Thanks to GNU/Linux we have a bit more power and information at our disposal about hard drives and IDE or USB interfaces. It’s always best practice to copy as much information from the drive or mirror it before attempting any other types of data recovery or file system repair. Using the standard dd

A recent addition to our video arsenal is this rare 1976 vintage 1/2″ colour reel to reel machine.

This has needed some work to get it functioning well such as new belts, hardened grease cleaned off the mechanism, etc but is now able to transfer colour recordings made in this format of reel to reel video.

A more detailed article on the repair of this will appear soon as will information about our other reel to reel video machines, the Hitachi / Shibaden EIAJ machine, the Sony CV-2100 skip field VTR and the enormous Ampex VPR-2B 1″ video machine… and we’ve got two of these!

Thanks to Rich at www.labguysworld.com for the JVC service manuals.