[mythtvnz] OT: recording from VHS

[Stephen Worthington]

On Sat, 18 Jul 2009 20:43:25 +1200, you wrote:

>On Sat, Jul 18, 2009 at 8:20 PM, Stephen
>Worthington<stephen_agent at jsw.gen.nz> wrote:
>> On Sat, 18 Jul 2009 19:45:04 +1200, you wrote:
>>
>>>On Sat, 2009-07-18 at 19:22 +1200, Tortise wrote:

>> If you have something like a PVR150 that does hardware compression to
>> MPEG-2, and you capture that and then convert to, say, H.264, you are
>> doing two compressions, and you lose quality by doing that.  So you
>> are still better off using the PVR150 to capture to a raw AVI file and
>> then do just one compression from that.  I have not tried it with my
>> PVR500, but most cards with builtin compression can also do raw
>> capture.
>>
>
>no the pvr 150/500 cannot do that afaik.

Pity - it is a useful thing to be able to do.

>> Of course, all of the above assumes that your VHS tapes are good
>> quality.  If they are not, then the hardware compression to MPEG-2
>> will likely not produce a result that is much different from playing
>> the tape.  And it is *much* easier to do.
>>
>> Also, if you have access to an S-VHS video, that is a better tool for
>> capturing old tapes.  S-Video has much wider bandwidth and the S-VHS
>> videos
>
>you confuse s-vhs (a recording format) and s-video (an encoding on an
>analogue pair of wires), although I accept that s-vhs devices usually
>featured a s-video connector to take advantage of the increased
>quality. Logically the two standards are unrelated.
>
>"It is not unusual to see the term S-VHS incorrectly used to refer to
>S-Video connectors (also called "Y/C connectors"), even in printed
>material. This may be due to S-VHS being one of the more common
>consumer video products equipped with the s-video connector"
>
>from http://en.wikipedia.org/wiki/S-VHS

No confusion on my part whatsoever.  S-VHS videos (tape
playing/recording machines) output S-Video.  S-VHS tapes, S-VHS videos
and S-Video signals have much higher bandwidth than is needed for a
VHS tape.  VHS videos frequently have lower bandwidth than the tapes
they are playing and degrade the signal.  Hence playing back a VHS
tape on an S-VHS is the best idea as playing it back on a VHS video
usually results in a degraded signal.  And yes, that does mean that
VHS videos often have better bandwidth on recording than on playback.