I would like to be able to play and record some VHS tapes that I have, so I
started researching this issue on TGB. As I read back through various threads
on this issue, I became rather intrigued by the complexity of this simple and
commonly requested capability, and I ended up reading a lot of threads to get
various folks' experiences and comments. After doing all this reading, I
thought it might be helpful to write up a summary of what I learned.
I'm sure I've either missed some important points, or I've gotten some of this
stuff wrong, so please set me straight.
------------------------------
There are a variety of external non-live-TV video signals or video sources which
many MCE users would like to play or record via their MCE systems. These sorts
of video signals/sources could include:
(1) VHS tapes. Many MCE users have VHS movie collections and/or sets of
noncommercial VHS tapes recorded via analog camcorders (home movies). The
question of how to play or record VHS tapes via MCE is, in fact, a very common
request in this forum.
(2) Camcorders holding recordings internally.
(3) Game machines.
(4) External DVR machines holding recorded shows.
(5) External Laser Disc players.
Unfortunately, the design of MCE with respect to the handling of external video
signals seems to have concentrated on providing a full-featured TV DVR facility.
There doesn't seem to have been any explicit provision in the MCE design for
playing or for recording any other kind of external video signal.
This concentration on the TV DVR functionality has led to MCE being implemented
with the following characteristics:
(1) Multiple TV tuner cards are supported in order to support useful features
like recording one TV show while watching another, or recording two or more
conflicting TV shows, etc., etc. However, to simplify what could quickly become
a very complex problem in handling the scheduling and allocation of the multiple
cards, MCE requires that each of the NTSC cards has the same capability in terms
of receiving TV stations, and that all of these cards use the same mode of TV
tuning/decoding (i.e. all use either input via RF or input via composite video
or input via svideo). In addition, this uniform tuning/decoding mode is not
simple to change, but is established as a part of the initial setup of the system.
(2) In order to support the ability to schedule TV recording for any hour of the
day, MCE uses some background recording/scheduling processes that are always on
(whether MCE is active or not) and that take and retain full control of all of
the TV cards.
(3) In order to support the ability to pause live TV, input video is always
constantly buffered via the HD, adding a delay of a second or so to the display
of the video.
(4) In order to implement DRM features and to implement quick skip forward and
backward, MS invented a new video file format that combines an mpeg-2 video
stream with suitable additional data. This file format uses extension "dvr-ms",
and is (so far) supported by only a few video processing programs (NOT including
Windows Movie Maker!).
(5) In order to support suitable user-friendly polices concerning the lifetime
of the recorded TV shows, MCE isolates the .dvr-ms files into their own pool
(folder) and implements various levels of user-controlled retention/non-
retention on the files in that pool. For example, .dvr-ms files cannot be moved
to "My Videos" and be played without conversion to another file format.
There are several possible work-arounds for this lack of direct MCE support for
external non-live-TV video signals, but they are "work-arounds", not solutions.
None of them are really clean or easy, and none of them are without
disadvantages.
The work-arounds seem to fall into one of the following four categories:
(A) Bypass the computer. Make a connection from the external signal source
directly to the display device, completely bypassing the computer. This might
be done by manually switching cables to make the connection or it might be done
by using a commercially available signal switch, or, if suitable additional
inputs are available, might be done by a permanent connection to an additional
input of the display.
(B) Fake it via an RF signal. Use a VCR or a separate modulator to create a
modulated RF signal which carries the external video signal on some specific TV
channel and which is input to the coax input (of all of) the NTSC TV cards in
the MCE system. Also, manually add an SD channel to the EPG that corresponds to
the channel the modulator is set to use.
(C) Fake it via a post-RF signal. Take a composite or svideo external signal
and feed it into the corresponding input on a TV card in the MCE system. This
might be done by manually switching cables to make the connection, or it might
be done by something like one of the commercially available signal switches.
(D) Use Windows. Shut down MCE and use straight Windows with some non-MCE
application to do the playing and/or recording.
Work-around (A) may or may not be easy to use, depending on the setup, but it is
certainly not integrated with MCE and it makes no provision for recording the
signal.
Work-around (B) has two variants, (B1) for users whose TV input is being done
via RF and (B2) for users whose TV input is being done via composite or svideo.
The (B1) approach, when used for just VHS sources, should work reasonably well,
at least for displaying the signal. A VCR can be used to do "pass-thru"
modulation, i.e. connect the TV RF signal to the VCR and connect the VCR RF
output to the TV card(s) and add a suitable SD channel to the EPG and things
should be stable. Watch TV normally and when you want to watch a VHS tape,
switch to the added channel and pop in the tape. This can also be used for
recording, but the resulting file will be in .dvr-ms format and a conversion
process will be required to get it into another format or onto a DVD. Also,
some caution is required in how any recording is done. MCE might have program
data for the added channel and might therefore stop recording at the end of what
it thinks of as the end of a show. Thus any recording should be non-Guide manual
recording with a specified duration. If more than one TV card is in use, the RF
signal splitting or chaining needs to occur AFTER the VCR. Because of the
additional modulation step, it is probable that there will be some amount of
signal quality degradation for (B) compared to other work-arounds.
The (B2) approach is quite awkward, since it requires re-doing the TV channel
setup to switch to RF input, and re-doing it again to switch to live TV, and
information such as hand modifications to the channel list or the scheduled
recordings list or any recordings in progress are lost in this process.
Also, either of the (B) approaches are probably out of the question for games
because of the video delay.
Work-around (C) also has two variants, (C1) for users whose TV input is being
done via RF and (C2) for users whose TV input is being done via composite or
svideo.
With the (C1) approach, all the disadvantages of the (B2) approach apply, since
the TV channel setup needs to be switched to use the external signal and then
switched back again to use live TV.
The (C2) approach can be made easy to use by employing a signal switch. It has
basically the same disadvantages as the (B1) approach except that it will
probably deliver a better signal because it doesn't use RF modulation.
With each of the (C) approaches there were reports of a problem with the audio
part of the signal. The cause of this is not clear (at least to me).
Also, either of the (C) approaches are probably out of the question for games
because of the video delay.
Work-around (D) has two variants. In (D1), the external video connection is made
to one of the MCE TV cards. In (D2), the external video connection is made to a
video capture card not seen by MCE.
The (D1) variant might be awkward or easy connection-wise depending on how the
connection is made. If, say, the live TV connection is via svideo and the
external signal is an RF signal from a VCR, then no switching of cables is
needed. In other cases, some cable switching, either by hand or via a switch
might be needed. Most importantly, the (D1) variant stumbles over the fact that
the MCE background recording processes continue to own the MCE TV cards even
when MCE is dropped, and so they must be stopped prior to starting up any
non-MCE application for displaying or recording the signal, and then they must
be restarted when MCE is resumed. (All "eh*" processes need to be stopped.)
The (D2) variant has no connection difficulties, since the external signal goes
to a separate card from the MCE TV cards. It also has no interference with MCE's
capture of the MCE TV cards, since the separate card is not captured by MCE.
Both the (D) variants have the advantages of no video delay and no entanglement
with the .dvr-ms format.
The (D2) variant would appear to be the one with the most overall advantages,
and it seems to be the one advocated most frequently by the senior members of
this forum. Its only disadvantages are the need to go outside MCE to use the
external signal and the need to buy and install the non-MCE card (and maybe its
matching application). One piece of sage advice was to use (A) for games and (D2)
for signals you want to record.
Notice that essentially all of the above discussion applies only to NTSC (analog
SD) TV signals.
There were several references in the threads to using USB tuners to ease
connection difficulties.
There was also mention in the threads of lip-sync problems in recording VHS if a
time-base correction device is not used, and mention that Macrovision copy
protection interferes with recording commercial VHS movies in some (all?)
circumstances.
There was LOTS of comment in the threads that MS had missed a pretty fundamental
capability by not providing easy-to-use direct support for external video
signals. The lack seems to violate one of the basic premises of the MCE idea.
One possible interface for providing direct support would be to provide
dedicated TV channels, but there were other suggestions. It is almost comical
how many users of HP MCE machines have hooked up their VCRs to the video inputs
on the front of the machine and tried to get it to work.
I did not come across any plugins that address this problem, but I did come
across an interesting hack that lets the user use approach (D1) but pretty much
stay within the MCE interface. (How this works wrt the background processes is
not clear to me.) The hack is at:
http://www.thegreenbutton.com/community/shwmessage.aspx?ForumID=27&MessageID=156445
My preference would be that comments on this thread concentrate on the issue of
giving good advice to folks who want to process external video signals through
their MCE systems, and not to wander very far from this topic, so that the thread
winds up containing the collected wisdom of the TGB experts on this issue.
Thanks.
--Milt--
Cellar Cinemas HTPC-595, Sanyo PLV-Z2000