[mythtvnz] OT: recording from VHS

[Nick Rout]

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:
>>> The best recording format may be H264 - at either 576i or possibly even de-interlaced to 576p but maybe no advantage in 576p as the
>>> de-interlace would do its stuff on playback in any event.?  (Reason - smaller files)
>>> I am not sure how we'd do that in H264 though and the kit would need to be up to SD H264.
>>> Has anyone tried this?
>>>
>>> ----- Original Message -----
>>> From: "Criggie" <criggie at criggie.dyndns.org>
>>> To: "MythTV in NZ" <mythtvnz at lists.linuxnut.co.nz>
>>> Sent: Saturday, July 18, 2009 6:45 PM
>>> Subject: Re: [mythtvnz] OT: recording from VHS
>>>
>>>
>>> Jim Cheetham wrote:
>>> > I'd like to increase the utility value of a stack of VHS cassette
>>> > tapes I have here, by digitising them so they can be played back by
>>> > Myth. I still have a working VHS player (with RF and RCA outputs).
>>> > What hardware would be good to get that would help me record from the
>>> > player? I only have DVB-S cards at the moment ...
>>>
>>> Video tapes are standard definition, so anything "high def" would be a waste.
>>>
>>> I use an old nicam recorder plugged into the RCA composite input of one of
>>> my PVR150 (the other one doesn't have these physical sockets)
>>>
>>> However the quality isn't great, and of course you can only watch at 1
>>> speed :)
>>>
>>>
>>> Others have recommended cat /dev/video0 > file.mpg
>>> but I run up mythfrontend and record closer to the desired position by
>>> simply pressing R while watching.  Be aware that the tape is running
>>> anything from 2-5 seconds ahead of what you see and hear on screen though.
>>>
>>> Then once the recording is done, you can edit the cutlist and transcode
>>> out adverts or any lead in/out.
>>
>>Try to stick with the quoting style, it's hard to follow the
>>conversation when it jumps all over the place.
>>
>>Any framegrabber card/device can do H264 if the host hardware is up to
>>it.
>>
>>hads
>
> Not really.  There are very few CPUs that might be able to encode to
> H.264 on the fly.  It is very CPU intensive.  And for the best results
> you normally want to do 2 pass encoding anyway, which is impossible on
> the fly.  One pass fixed bit rate encoding gives pretty bad results,
> and that is the only method that you have any hope of doing on a
> normal CPU without dropping frames.  One pass quanitzer encoding
> (fixed quality, variable bit rate) can give good results if you have
> enough CPU, but 2 pass encoding will still be a little better.
>
> The best results from tape capture are by capturing the raw video
> signal directly to hard disk (usually an AVI file).  This takes around
> 1.2 Gibytes of disk per minute of video.  You can reduce that to
> around 1 Gibyte per minute by using a lossless compression codec such
> as HuffyYUV.  Then once the capture is done, you use the normal tools
> to do a proper 2 pass encoding to H.264.  That will happen at well
> less than the frame rate of the capture - IIRC, my system can do about
> 5 frames per second on the second pass of an H.264 encoding, at "best"
> encoding settings.  So encoding a 90 minute VHS tape takes several
> hours - just leave your PC doing it overnight.
>
> 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.

> 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