Page 1 of The way EP & LP implemented on stand-alone recorders - does it differ?

Do all stand-alone DVD recorders handle LP and EP recordings in the same way ??

My understanding is that recordings at these speeds have only half the number of horizontal lines ie. are similar to `VCD` Question is, is the horzontal resolution reduced as well ?
I believe that some machines behave differently and maintain the same line numbers as a DVD but reduce the data rate. This would seem to have advantages if there is no fast action.
I currently use a Mico 311i and whilst the degradation is decernable ( as an increse in background noise ) the difference is not as marked as running the same comparison on a Cyberhome 1600

Can anyone advise please

Images

DVD is a standard and for players to be able to play home recorded discs, they have to be compliant with the specifications laid out by the DVD Forum (of manufacturers of DVD kit).

Full DVD resolution is 720x576 pixels, known as full D1. This can be sampled at various compressions and recorded to disc at bitrates between 9.72Mbps and 4.06Mbps, giving recording times on a single layer disc of between 60 and 150 minutes.

Contrary to popular belief, the number of horizontal lines stay absolutely the same for the lower half D1 resolution. However the horizontal resolution (or number of vertical lines) halves to 360x576 pixels. This gives you 3,4 and 6 hour recording speeds at bitrates between 3.38Mbps and 1.70Mbps.

Some manufacturers may push the bitrate envelope for three hour recording by staying at full D1 but reducing the bitrate to the minimum 3.5Mbps allowable. This would give a sharper image but with more compression artefacts than dropping to half D1.

There are some machines which can pack eight hours of recording on to a single layer disc, but they do this by dropping the resolution to the SIF standard of 352x288 pixels and a bitrate of 1.27Mbps.

The main reason you see a lot of difference between the standards on one machine is that the build quality of the Mico is better than the Cyberhome. You also have to consider the media you`re using. A lower bitrate will inevitably show up any shortcomings in the media the programme is recorded on.

Speaking from personal experience, I wouldn`t use LP (let alone EP) mode to record anything important. If you have two machines (as you appear to have), I`d record half of whatever it was that lasted more than two hours on one machine and the rest on the other, giving me two discs and a programme recorded at a decent bitrate. :)

J Mark Oates

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Wishing you the Compliments of the Season.
May you have a very Merry Christmastime
Whatever your Beliefs or Sentiments
And Hoping that 2006 will be a very Happy New Year.

My Column Isn`t Dead, It`s In Hiding Here

Mark have you seen the `4 hour` recordings on the new Panasonics. The quality is extremely good. Whether you `Archive` at this speed is another thing, but some shows I`d keep in this quality.

Mark, Many thanks for your prompt and informative reply.

One point however, you comment on `the build quality; of the two machines, I always took this to mean the physical construction. In this case however `the hard work ` is done by the respective chipsets. Since these are LSI and probably common to several machine manufacturers does the difference in result lie in the chipsets themselves or is there much scope for different manufacturers to utilise them in different ways resulting in differing quality ?

I am currently transferring some Betamax tapes recorded twenty years ago to DVD for convenience and had forgotten just how good the quality of the system was. My only gripe is the absence of a linear `clock` on the Sony machine, a feature one has since come to take for granted.

Images

I`m sure the latest Panasonic does produce nice pictures, Paull. But is that on DVD-RAM discs, and can you watch them on the usual sort of range of players or are you stuck watching the discs on the recorder that produced them?

Images asked how Mico and Cyberhome machines handled video encoding, and I restricted my reply to the standard formats. DVD-RAM may be the Betamax of the standard-def DVD world, but with its premium on media prices and the fact you`re locked into a small handful of Name-makers, it is in danger of being sidelined by the wider-supported formats.

As for both the Cyberhome and Mico having the LSI chipset, that is an eye-opener and all I can think is there must be a wide variation of implementation of these encoding chipsets which affects results. I suspect data buffering may be the big issue and that it`s handled off-chip, although more technically oriented minds may have more of a clue than me.

J Mark Oates

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Wishing you the Compliments of the Season.
May you have a very Merry Christmastime
Whatever your Beliefs or Sentiments
And Hoping that 2006 will be a very Happy New Year.

My Column Isn`t Dead, It`s In Hiding Here

No, it`s nothing to do with DVD-RAM. The 4 hour mode is twice the resolution of other recorders.

Ste

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We will pay the price but we will not count the cost..

Mark,
To avoid confusion the LSI referred not to the manufacturer but rather that most of the processing was done in one `large scale integration` chip. As far as I know the Cyberhome sold in Europe ( with ME before the serial number on the box ) uses a Mediatec chipset.
The USA version I believe is different, ? a Zoran chip.
Haven`t looked inside the Mico yet but that may use a Cirrus chip.

BTW my preliminary tests done after reading your reply confirms that EP & LP have a resolution of 352 x 576 as reported by ` Bitrate` which also correctly reports a VCD as 352 x 288

Images