detail information

Technical audio-visual characteristics of the DVD recording modes

We made some test recordings on the DVDR3480 to analyse the actual quality of the audio and video parts of the recordings. These were made from the analogue aerial input and consisted of ten-minute recordings at the six quality settings of the BBC sports coverage of a rugby match. We deliberately chose this fast motion material as a test of the variable bitrate strategy in order to maximise the differences between modes. The individual titles were ripped using DVD Decrypter in IFO mode and analysed using GSpot 2.7.0.1.

Note the change in bitrate as the recording quality drops, but the recorder still keeps a picture at full D1 resolution (720 x 576 PAL) even when recording at the 4 hour EP mode. This is a great improvement on recording quality normally found on most recorders, and highly unusual to find in a budget-priced recorder; certainly rivalling much more expensive machines such as Panasonic and Sony, and much better than older Philips machines where full D1 was maintained only as far as the SPP mode.

The shaded row at the bottom is to highlight that the SLP quality uses the MPEG1 standard rather than MPEG2, and the number of horizontal and vertical pixels are approximately each halved. The audio bitrate also drops.

Viewing comparison of recording modes

Tables and numbers are all very well, but what do these different recording modes actually look like to the viewer? To find out we made a series of short recordings at the different quality settings, of the same piece of high quality video fed in through the DVDR3480’s EXT2 input. The DVD player was connected to the recorder with a fully wired and insulated RGB SCART lead, and an original commercial pressed DVD-Video of ‘Cars’ used to generate a consistent picture quality for assessing the different recording characteristics.

The pictures produced by the various recording modes, starting with a screen shot of the original DVD-Video quality, are shown below for comparison. Areas to keep an eye on for MPEG compression artefacts are the right-hand side edges of the car (ghosting), the wire fencing links in front of the rear spoiler and later the windscreen (edge-effects), and the tuft of grass between the rear-right of the car and the tyre leaning to one side (loss of detail).

We can see a small drop in quality from the original DVD when HQ mode is used; mainly in the slight colour desaturation, some loss of detail with the grass behind the car, and the small gaps where the fence wires loop round each other. However there are hardly any noticeable compression artefacts such as blocking around the edges of objects, and the diagonal sections of the wire fence are not showing any jagged edges. Moving to SP mode shows the appearance of some artefacts around the fence wires with the car roof behind, but not significant loss of detail from HQ. At SPP mode there are now more compression effects appearing around the wire fencing in front of the car’s rear spoiler, and indeed these become quite obvious at LP mode. In EP mode the compression artefacts are stronger and more widespread; now clearly over the wire fencing across the car’s front window. At SLP mode there is a considerable change in quality, particularly resolution of detail: but remember this mode uses MPEG1 encoding and half D1 resolution (352 x 288) so that is to be expected. The static picture looks a mess but a moving image looks much better and may be quite acceptable for some purposes; for example viewing on a small screen such as a portable DVD player.

Naturally some of these differences will appear to be slight on a computer monitor, especially with the graphic constraints of this review; and a larger TV display will make them more obvious. Nevertheless our opinion is that the picture quality is still going to be very good at the lower recording quality settings, simply because the DVDR3480 maintains a screen resolution of 720 x 576 (PAL) all the way down to EP mode.

Mini-verdict

Overall we found the array of recording qualities available on the DVDR3480, and their recording quality, to be simply excellent for a budget DVD recorder.

DVD burn quality

Editing recordings