Top 5 reasons why DIY digital video conversion can look bad

By | 17th April 2017

There are lots of cheap DIY digital video conversion kits available online and in stores. The units themselves tend to be USB2.0 and contain a dedicated analogue to digital converter circuit. The bundled software is usually quite limited and main not include everything you need to make good quality files. The marketing material suggests the kit if fully featured but this may not be the case.

Shows USB stick in a Smart TV

In this article we will explain some of the common pitfalls of converting analogue videotapes to digital files and list the 5 most common reasons how it can go wrong. This is not intended as a complete how-to guide and we’re not offering free technical support but we do encourage feedback and will try to answer questions in the comments below.

1 – Fuzzy soft images with colour bleed

Most domestic VHS players and many camcorders relied upon composite video signals either from a yellow RCA connector or via a SCART lead. Composite signals contain all the picture information is mixed together – hence the name composite. On domestic equipment composite signals can be inherently poor – they simply aren’t that good at carrying a decent image.

Higher end players such as SVHS or Hi8 players had an S-Video connection which separates chrominance and luminance to give a better overall signal quality. Colour holds up a lot better and images are sharper compared to a typical domestic composite signal.

2 – Choppy, juddering or unstable recordings

Many of the cheaper conversion kits don’t have any kind of signal smoothing (timebase correction). The result can be that your computer is unable to lock onto a decent signal properly. The picture can drop out, skip frames or fail to record at all.

Timebase correction (TBC) is needed to stabilise analogue video signals. A TBC irons out any anomalies in the video allowing a clean smooth digital recording to be made. Some higher end players include basic timebase correction but experience tells us that a proper, external TBC is the only guaranteed method that works.

3 – Choppy, juddering or unstable recordings AGAIN!

Modern computers should have no trouble keeping up with recoding standard definition video but life isn’t always that simple. Software and hardware performance can be affected by many factors resulting in poor quality. Computers can get bogged down with too many tasks running at once, hard drives that are running too slowly because they’re full or fragmented etc.

The capture software may conflict with other software e.g. anti-virus or your hardware such as the computer graphics card. The supplied capture application may need to be updated – it’s not uncommon that you may have to pay extra for the ‘upgrade’ with no guarantee it will work any better.

In essence your computer needs to be in tip-top condition with few or no other software running when capturing video. Sometimes the only way to diagnose a persistent capturing problem is by substitution – that means swapping out the computer, capture card etc until you pinpoint the root cause of the fault.

4 – Converted video is jagged and doesn’t have smooth motion

Analogue video is made of 50 unique images per second (60 in the UK). However each of these 1/50th of a second images represents only half a full frame image. In simple terms a video frame is made up of horizontal and vertical dots in a grid pattern. Each sequential frame shows either the odd horizontal dots (lines) or the even dots (lines) of an image. This is known as field based interlaced video. By showing odd/even/odd/even fields fast enough you can achieve smooth looking motion fast enough to fool the human eye but only ever drawing half the image every 1/50th of a second.

Computer displays and modern televisions are not interlaced. They are what’s known as progressive scan. The entire image can be drawn in full for each and every frame. When we convert analogue video to a digital file such as an MP4 to show on a SmartTV we must convert the image from interlaced to progressive which is a process known as de-interlacing.

If de-interlacing isn’t done at all then the image will appear to have jagged edges and a ‘double image’ or ghosting appearance on horizontal motion. Basic de-interlacing throws away one field resulting in a reduced frame rate of 1/25th of a second. Field blending techniques attempt to overcome this but you’re still throwing information away which is why things don’t look as vivid and smooth as the original tape. The more advanced field-blending methods maintain the original frame rate and achieve much more vivid and smooth results. It takes considerably longer to achieve and is not a standard feature on all conversion software.

5- Videos don’t play on other devices such as your SmartTV

SmartTVs are quite forgiving and will play a range of files provided they meet one or two basic conditions. The footage must be made with a compatible compression CODEC. The industry standard is currently H.264 MP4. Secondly, the data rate must not be too high for either the television to decode or the storage device to keep up. Standard definition H.264 files can be encoded well below 10mbps and still look great. In fact half that data rate is still as good as the maximum theoretical rate for a DVD.

If you’re plugging a USB drive into a SmartTV then the file system must conform to something the TV will work with. In general this is FAT32. Most USB sticks are already formatted this way as standard but external hard drives may not be. There are serious limitations to FAT32 to be aware of. Some modern televisions and most computers are happy with ExFAT.

It’s easy when you have the right kit, knowledge and experience

Most of us like having a go at doing something ourselves. The Internet is a great source of information with help, advice and guidance available to enable us to try just about anything we put our minds to. However, there comes a point when we realise that some things are best left to the experts.

At Manchester Video Ltd we have many years of experience and the right equipment to consistently achieve excellent quality video conversions. We are friendly and approachable – if you’ve had a go and discovered your kit just isn’t good enough or perhaps just need the video capturing so you can edit the files yourself then we can help. Give us a call on 0800 228 9422 or click the contact us button on this website to get in touch.

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