Mailing List Archive: MythTV: Dev

Record now?

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chuckw at quantumlinux

Jan 17, 2003, 2:32 AM

Post #26 of 42 (2029 views)
Permalink

RE: Record now? [In reply to]

> I guess the feasibility of this depends on how the ringbuffer works -
> can you tell just by examining the ringbuffer file where you started
> watching a particular channel? If you were surfing and stumbled on
> "Friends" and decided to tape it, you only want to copy the portion of
> the ringbuffer that is "Friends".

TiVo starts from where the program started. It can tell this simply by
the time and which program it senses that you are currently watching.

> If you change channels, does the ringbuffer start over from the begining
> of the file? If not, does it indicate that a channel change occured or
> does it just basically have a capture of what I've been watching (and,
> gosh, what are the privacy implications of that!:-)

Again, TiVo kills the ring buffer and starts over when you change
channels. In fact it kills the ring buffer a little too easily if you ask
me. I've lost more than a few programs I was intending to record.

-Chuck

--
Quantum Linux Laboratories - ACCELERATING Business with Linux Technology
* Education |
* Integration | http://www.quantumlinux.com
* Support | chuckw[at]quantumlinux.com

"Be liberal in what you accept, and conservative in what you send."
-- Jonathan B. Postel

wentz at gmx

Jan 17, 2003, 5:43 AM

Post #27 of 42 (2032 views)
Permalink

Re: Record now? [In reply to]

Am Freitag, 17. Januar 2003 10:10 schrieb Chuck Wolber:
> > a) should the backend provide an interface to the database or
> > b) should the frontend connect to the database directly
> >
> > Security wise, a makes more sense, but how secure do you want your
> > recordings of M*A*S*H to be???
> >
> > In most situations all connections would be behind a firewall hopefully,
> > and connecting to the db directly, and even through an api would be less
> > costly than asking for the info through the backend.
> >
> > Personally, I don't care who knows that I record junkyard wars, but
> > ymmv. ;-)
>
> From a programming standpoint, wouldn't it be better to hide the database
> behind an API anyway?

that's just my point.
maybe the backend can be seperated in serveral parts, like av-backend and
data-backend, every part does just what it's supposed to do. av-b could do
all the recording and streaming-stuff, and data-b could fire up the queries,
transmit data as needed, etc. in a prior post Mark Musone mentioned to have a
listening instance for changes of all kind, this could be done here, too

stephan

bjm at lvcm

Jan 17, 2003, 6:16 AM

Post #28 of 42 (2063 views)
Permalink

Re: Record now? [In reply to]

Chuck Wolber wrote:
>
>>I guess the feasibility of this depends on how the ringbuffer works -
>>can you tell just by examining the ringbuffer file where you started
>>watching a particular channel? If you were surfing and stumbled on
>>"Friends" and decided to tape it, you only want to copy the portion of
>>the ringbuffer that is "Friends".
>
>
> TiVo starts from where the program started. It can tell this simply by
> the time and which program it senses that you are currently watching.

That's an interesting way to think of it but, of course, TiVo
has no way to sense what the viewer is doing. It does, however,
know what channel it is tuned to and when the ringbuffer was
restarted. If you choose to record the current show, you are
given the choice of continuing to record at "Best" quality
saving the previous portion or to change quality starting
from the current time.

To continue at "Best", it appears it is simply renaming the
ringbuffer to the filename for the show. This works because
the open filehandle is unaffected by the fact that the inode
number is associated with a different directory entry. In
Unix, you can open any file for writing, rename it, and
continue to write (but you cannot move it to another
partition and continue writing to it unless you reopen ;-).

So, if you change channel at 7:05 then decide at 7:10 to
record this half hour show, the result is 7:05-7:30. However,
this gives unexpected results if you were on the channel
before the show started. If you changed channel at 6:55 then
choose to record at 7:10, the result is 6:55-7:30 (try it ;-).

MythTV could do the same rename trick if there is nothing
special about the ringbuffer file format. However, cropping
a ringbuffer that started before the show's start time is
trickier.

>>If you change channels, does the ringbuffer start over from the begining
>>of the file? If not, does it indicate that a channel change occured or
>>does it just basically have a capture of what I've been watching (and,
>>gosh, what are the privacy implications of that!:-)
>
>
> Again, TiVo kills the ring buffer and starts over when you change
> channels. In fact it kills the ring buffer a little too easily if you ask
> me. I've lost more than a few programs I was intending to record.

My first experience with a digital recorder was the ATI AIW
windoze software. You set the ringbuffer size (say, two or
three hours) and you could move back and forth to previous
shows on previous channels. This made perfect sense to me.
When I got a TiVo, I was shocked that it restarted the
buffer when you change channel (doh! =). I believe they only
do this for the sake of the record in progress feature starting
from the channel change without having to crop the buffer.

-- bjm

bjm at lvcm

Jan 17, 2003, 6:28 AM

Post #29 of 42 (2054 views)
Permalink

Re: Record now? [In reply to]

Stephan Wentz wrote:
...
> that's just my point.
> maybe the backend can be seperated in serveral parts, like av-backend and
> data-backend, every part does just what it's supposed to do. av-b could do
> all the recording and streaming-stuff, and data-b could fire up the queries,
> transmit data as needed, etc. in a prior post Mark Musone mentioned to have a
> listening instance for changes of all kind, this could be done here, too

*Sigh* av-b == mythbackend, data-b == mysqld .

-- bjm

erik_nospam.arendse at bigfoot

Jan 17, 2003, 6:45 AM

Post #30 of 42 (2042 views)
Permalink

Re: Record now? [In reply to]

At 17-1-03 14:16, Bruce Markey wrote:
>Chuck Wolber wrote:
>To continue at "Best", it appears it is simply renaming the
>ringbuffer to the filename for the show.
>....
>MythTV could do the same rename trick if there is nothing
>special about the ringbuffer file format. However, cropping
>a ringbuffer that started before the show's start time is
>trickier.
I was thinking along these lines a few months back, but a copy would be
best. That way you can put recorded files on a different disk/nfs/partition
whatever from your ringbuffer.

For me it should be possibel as well to search for the beginning of a show
in the ringbuffer by hand, start recording, and have the option to let the
show end ik scheduled or enter a manual endtime.
I need this for unexpected changes in programming, currently all depends on
a EPG which matches the actual programming. Come and live over here in
Europe, and see what you are missing...

If nobody else beats me to it I'll probably implement something like this
one day as an added option to the current instand recording from the EPG:
1) optional: pause live TV
2) optional: search in the buffer
3) start instant recording
4) get show end from EPG, show it and let the user correct it, if no EPG
available just suggest a fixed recordlength from starting time on.
5) display is locked with message "copying timeshift to new recording"
6) mythTV opens a new file, writes the header
7) while shifting is still going on, the copy routine copies all needed
data to the new file
8) when position of copying reaches the position where timeshifting
records, the timeshift output is send to the new file and shifting is stopped

This should be possible from what I looked into the source, similar to
transitions like "watching recording" to "recording only"

>>>If you change channels, does the ringbuffer start over from the begining
>>>of the file? If not, does it indicate that a channel change occured or
>>>does it just basically have a capture of what I've been watching (and,
>>>gosh, what are the privacy implications of that!:-)
>>Again, TiVo kills the ring buffer and starts over when you change
>>channels. In fact it kills the ring buffer a little too easily if you ask
>>me. I've lost more than a few programs I was intending to record.
>My first experience with a digital recorder was the ATI AIW
>windoze software. You set the ringbuffer size (say, two or
>three hours) and you could move back and forth to previous
>shows on previous channels. This made perfect sense to me.

Why not make a userselectable behaviour:
1) clean buffer whenever a channelchange (current implementation)
2) use all of the buffer
3) use all of the buffer without ever cleaning, keep buffer even in between
livetv sessions. Check what the kids viewed three days and five reboots ago
in your 120Gb ringbuffer-only drive. No privacy evermore... :-)
4) like (1), but let channelchange with its reset confirm on certain
userselectable conditions:
A) if shifting is used since last bufferclear on the current channel
B) if buffer contains the start of the current show accoring to
the EPG
C) ... whatever, think of your own tv-behaviour...

Erik

erik_nospam.arendse at bigfoot

Jan 17, 2003, 6:48 AM

Post #31 of 42 (2015 views)
Permalink

Re: Record now? [In reply to]

At 17-1-03 14:28, Bruce Markey wrote:
> av-b == mythbackend, data-b == mysqld

That's the most elegant compact argument I've seen in a long time.
For what it's worth: I agree :-)

Erik

hpoley at dds

Jan 17, 2003, 7:45 AM

Post #32 of 42 (2050 views)
Permalink

Re: Record now? [In reply to]

> Van: Bruce Markey <bjm[at]lvcm.com>
>
> Also, there is the possibility of having more than one machine
> with a tuner care on your network. So, for example, the frontend
> should be able to check the database for the list of recorded
> shows. If you pick a show to watch, it should then connect to
> the backend on the machine where the file is stored.

Uhm, I don't think that MythTV is already up to multiple tv-cards scattered
across the network...

Henk Poley <><

ijr at po

Jan 17, 2003, 8:58 AM

Post #33 of 42 (2021 views)
Permalink

Re: Record now? [In reply to]

On Friday 17 January 2003 09:45 am, Henk Poley wrote:
> > Van: Bruce Markey <bjm[at]lvcm.com>
> >
> > Also, there is the possibility of having more than one machine
> > with a tuner care on your network. So, for example, the frontend
> > should be able to check the database for the list of recorded
> > shows. If you pick a show to watch, it should then connect to
> > the backend on the machine where the file is stored.
>
> Uhm, I don't think that MythTV is already up to multiple tv-cards scattered
> across the network...

Actually, it will be next week, if I have enough time.

Isaac

tony at blight

Jan 17, 2003, 1:20 PM

Post #34 of 42 (2066 views)
Permalink

Re: Record now? [In reply to]

On Fri, Jan 17, 2003 at 02:45:49PM +0100, Erik Arendse wrote:
> If nobody else beats me to it I'll probably implement something like this
> one day as an added option to the current instand recording from the EPG:
> 1) optional: pause live TV
> 2) optional: search in the buffer
> 3) start instant recording
> 4) get show end from EPG, show it and let the user correct it, if no EPG
> available just suggest a fixed recordlength from starting time on.
> 5) display is locked with message "copying timeshift to new recording"
> 6) mythTV opens a new file, writes the header
> 7) while shifting is still going on, the copy routine copies all needed
> data to the new file
> 8) when position of copying reaches the position where timeshifting
> records, the timeshift output is send to the new file and shifting is
> stopped

I haven't actually looked at the code to see how things really work.
However, at step 5, instead of hanging while the new file is getting
caught up with the ringbuffer, why not something like this so the
user can continue to watch the show:
5) mythTV opens a new file and instantly does a seek() forward the
size of the ringbuffer. Playback starts from this point.
6) start up a background "thread" that copies data from the ringbuffer
into the empty space at the start of the new file.

If you copy the data in reverse-order (from the moment the user said to
record back in time to the oldest time in the ringbuffer), then the user
could even rewind back toward the beginning while it's still recording.

It might be more trouble than it's worth, though. Especially if steps
5-8 are fast and dosen't appear "hung" for very long.

-- Tony tony[at]blight.com

risto at elkhornbanff

Jan 17, 2003, 5:39 PM

Post #35 of 42 (2061 views)
Permalink

Re: Record now? [In reply to]

> Why not make a userselectable behaviour:
> 1) clean buffer whenever a channelchange (current implementation)
> 2) use all of the buffer
> 3) use all of the buffer without ever cleaning, keep buffer even in between
> livetv sessions. Check what the kids viewed three days and five reboots ago
> in your 120Gb ringbuffer-only drive. No privacy evermore... :-)
> 4) like (1), but let channelchange with its reset confirm on certain
> userselectable conditions:
> A) if shifting is used since last bufferclear on the current
> channel B) if buffer contains the start of the current show accoring to the
> EPG
> C) ... whatever, think of your own tv-behaviour...
>
> Erik

I think that user selectable behaviour of the ringbuffer would definitely be
an improvement.

The bottom line of course is that when you are watching a program and go to
the EPG and press record the user wold get a choice to
-record current program from current time onward only(default)
-record current program from the point I started watching.
("point i started watching" would be "from start of program"
if the whole show is in the buffer-easily detected)

There should also be an easy way to "STOP rcording now"!!!
or maybe there already is

This would all be useful for recording music videos and such,
as well as, recording whole episodes you already are watching and not
recording.

risto at elkhornbanff

Jan 17, 2003, 5:58 PM

Post #36 of 42 (2064 views)
Permalink

Re: Record now? [In reply to]

> If you choose to record the current show, you are
> given the choice of continuing to record at "Best" quality
> saving the previous portion or to change quality starting
> from the current time.

That is a a good choice and mythTV should also offer that choice.
Bothering the user with the details about quality is a little unnecessary
though

just
if <time of last channel change> is b4 <the start of the show>
give the choice of
- record starting from <the start of show>
- record starting from the current time.
else
give the choice of
- record starting form <time of last channel change>
- record starting from the current time.

>
> To continue at "Best", it appears it is simply renaming the
> ringbuffer to the filename for the show. This works because
> the open filehandle is unaffected by the fact that the inode
> number is associated with a different directory entry. In
> Unix, you can open any file for writing, rename it, and
> continue to write (but you cannot move it to another
> partition and continue writing to it unless you reopen ;-).
>
> So, if you change channel at 7:05 then decide at 7:10 to
> record this half hour show, the result is 7:05-7:30. However,
> this gives unexpected results if you were on the channel
> before the show started. If you changed channel at 6:55 then
> choose to record at 7:10, the result is 6:55-7:30 (try it ;-).
>
> MythTV could do the same rename trick if there is nothing
> special about the ringbuffer file format. However, cropping
> a ringbuffer that started before the show's start time is
> trickier.

why not automatically crop the resulting file down to 30 minutes AFTER
the program has finished recording.
As I understand it video editing capabilities are at least in the works.

so the result is still 6:55-7:30
but THEN it gets cropped, no need to crop the ringbuffer on the fly

>
> >>If you change channels, does the ringbuffer start over from the begining
> >>of the file? If not, does it indicate that a channel change occured or
> >>does it just basically have a capture of what I've been watching (and,
> >>gosh, what are the privacy implications of that!:-)

having one long ringbuffer might be useful as an option,
but only if it marked when channel changes occurred

> >
> > Again, TiVo kills the ring buffer and starts over when you change
> > channels. In fact it kills the ring buffer a little too easily if you ask
> > me. I've lost more than a few programs I was intending to record.
>
> My first experience with a digital recorder was the ATI AIW
> windoze software. You set the ringbuffer size (say, two or
> three hours) and you could move back and forth to previous
> shows on previous channels. This made perfect sense to me.
> When I got a TiVo, I was shocked that it restarted the
> buffer when you change channel (doh! =). I believe they only
> do this for the sake of the record in progress feature starting
> from the channel change without having to crop the buffer.
>
> -- bjm
>
>
> _______________________________________________
> mythtv-dev mailing list
> mythtv-dev[at]snowman.net
> http://www.snowman.net/mailman/listinfo/mythtv-dev

bjm at lvcm

Jan 17, 2003, 6:39 PM

Post #37 of 42 (2051 views)
Permalink

Re: Record now? [In reply to]

Risto Treksler wrote:
...
> The bottom line of course is that when you are watching a program and go to
> the EPG and press record the user wold get a choice to
> -record current program from current time onward only(default)
> -record current program from the point I started watching.
> ("point i started watching" would be "from start of program"
> if the whole show is in the buffer-easily detected)

If the channel change (restart buffer) is after the beginning
of the show, "point i started watching" is simply using the
whole buffer. It's "from start of program" if the buffer
started before the the program that is the tricker porblem.
You'd have to find that point in the buffer and rewrite the
file starting from that point.

> There should also be an easy way to "STOP rcording now"!!!
> or maybe there already is

Not in 0.7 but in CVS the current recording appears in red
in the "Watch a Recording" and "Delete Recordings" lists.
If you choose to delete ("d") it will stop recording and
delete the file. There could be a feature to stop recording
and keep the recorded portion but there are losts of little
extras like this that haven't been implemented yet.

-- bjm

bjm at lvcm

Jan 17, 2003, 7:10 PM

Post #38 of 42 (2064 views)
Permalink

Re: Record now? [In reply to]

Fisrt, I want to be clear that was describing how an
existing commercial product works rather than saying that
myth should do the same ;-)...

Risto Treksler wrote:
>>If you choose to record the current show, you are
>>given the choice of continuing to record at "Best" quality
>>saving the previous portion or to change quality starting
>>from the current time.
>
>
> That is a a good choice and mythTV should also offer that choice.
> Bothering the user with the details about quality is a little unnecessary
> though

But the quality is the only issue. TiVo's live recording
is always "Best". If the user wants to save disk space,
they need to restart recording "now" with the new parameters.
If there is no change in parameters, there is no reason not
to save the previous portion.

> why not automatically crop the resulting file down to 30 minutes AFTER
> the program has finished recording.

Corpping ain't automatic which is the issue ;-). But I
absolutely agree with you. When record in progress is
chosen, rename the ring buffer to, say, tmp.nvu. Stop
recording at the endtime then copy out the starttime to
endtime and remove the tmp file (or something like that).

> As I understand it video editing capabilities are at least in the works.
>
> so the result is still 6:55-7:30
> but THEN it gets cropped, no need to crop the ringbuffer on the fly

Exactly. It's just fun to see how TiVo mishandles this case.

>>>>If you change channels, does the ringbuffer start over from the begining
>>>>of the file? If not, does it indicate that a channel change occured or
>>>>does it just basically have a capture of what I've been watching (and,
>>>>gosh, what are the privacy implications of that!:-)
>>>
>
> having one long ringbuffer might be useful as an option,
> but only if it marked when channel changes occurred

Agreed.

I was using the ATI software when Barry Bonds set the home
run record. They had a feature where you could set the
start and end times to save as a file. I'd buffer the whole
game then select the portions around the home runs. I still
have these MPEG2 clips of his 70th thru 73rd. So choosing
the start and end times from the listing is useful and
choosing the start and end times that you want to keep can
be useful too.

-- bjm

technix at writeme

Jan 17, 2003, 7:26 PM

Post #39 of 42 (2052 views)
Permalink

Re: Record now? [In reply to]

why not use a button to hit record from any time and stop it at any time,
forget about the size of the recording and stuff if you wanted to do that
then go through a schedule recording aspect, Dish PVR does this you can
pause, record, stop , rewind (3 different speeds), fast forward (3 different
speeds), skip 30 seconds at a time forward or backwards. This is all
convenient just hit record and boom its going then stop it when you want or
it runs out of disk space

----- Original Message -----
From: "Risto Treksler" <risto[at]elkhornbanff.ca>
To: "Development of mythtv" <mythtv-dev[at]snowman.net>
Sent: Friday, January 17, 2003 7:58 PM
Subject: Re: [mythtv] Record now?

> > If you choose to record the current show, you are
> > given the choice of continuing to record at "Best" quality
> > saving the previous portion or to change quality starting
> > from the current time.
>
> That is a a good choice and mythTV should also offer that choice.
> Bothering the user with the details about quality is a little unnecessary
> though
>
> just
> if <time of last channel change> is b4 <the start of the show>
> give the choice of
> - record starting from <the start of show>
> - record starting from the current time.
> else
> give the choice of
> - record starting form <time of last channel change>
> - record starting from the current time.
>
> >
> > To continue at "Best", it appears it is simply renaming the
> > ringbuffer to the filename for the show. This works because
> > the open filehandle is unaffected by the fact that the inode
> > number is associated with a different directory entry. In
> > Unix, you can open any file for writing, rename it, and
> > continue to write (but you cannot move it to another
> > partition and continue writing to it unless you reopen ;-).
> >
> > So, if you change channel at 7:05 then decide at 7:10 to
> > record this half hour show, the result is 7:05-7:30. However,
> > this gives unexpected results if you were on the channel
> > before the show started. If you changed channel at 6:55 then
> > choose to record at 7:10, the result is 6:55-7:30 (try it ;-).
> >
> > MythTV could do the same rename trick if there is nothing
> > special about the ringbuffer file format. However, cropping
> > a ringbuffer that started before the show's start time is
> > trickier.
>
> why not automatically crop the resulting file down to 30 minutes AFTER
> the program has finished recording.
> As I understand it video editing capabilities are at least in the works.
>
> so the result is still 6:55-7:30
> but THEN it gets cropped, no need to crop the ringbuffer on the fly
>
> >
> > >>If you change channels, does the ringbuffer start over from the
begining
> > >>of the file? If not, does it indicate that a channel change occured
or
> > >>does it just basically have a capture of what I've been watching (and,
> > >>gosh, what are the privacy implications of that!:-)
>
> having one long ringbuffer might be useful as an option,
> but only if it marked when channel changes occurred
>
> > >
> > > Again, TiVo kills the ring buffer and starts over when you change
> > > channels. In fact it kills the ring buffer a little too easily if you
ask
> > > me. I've lost more than a few programs I was intending to record.
> >
> > My first experience with a digital recorder was the ATI AIW
> > windoze software. You set the ringbuffer size (say, two or
> > three hours) and you could move back and forth to previous
> > shows on previous channels. This made perfect sense to me.
> > When I got a TiVo, I was shocked that it restarted the
> > buffer when you change channel (doh! =). I believe they only
> > do this for the sake of the record in progress feature starting
> > from the channel change without having to crop the buffer.
> >
> > -- bjm
> >
> >
> > _______________________________________________
> > mythtv-dev mailing list
> > mythtv-dev[at]snowman.net
> > http://www.snowman.net/mailman/listinfo/mythtv-dev
>
>
> _______________________________________________
> mythtv-dev mailing list
> mythtv-dev[at]snowman.net
> http://www.snowman.net/mailman/listinfo/mythtv-dev

bfoddy at visi

Jan 18, 2003, 11:28 PM

Post #40 of 42 (2053 views)
Permalink

Re: Record now? [In reply to]

On Friday 17 January 2003 06:39 pm, Risto Treksler wrote:
> I think that user selectable behaviour of the ringbuffer would definitely
> be an improvement.
>
> The bottom line of course is that when you are watching a program and go to
> the EPG and press record the user wold get a choice to
> -record current program from current time onward only(default)
> -record current program from the point I started watching.
> ("point i started watching" would be "from start of program"
> if the whole show is in the buffer-easily detected)
>
> There should also be an easy way to "STOP rcording now"!!!
> or maybe there already is
>
> This would all be useful for recording music videos and such,
> as well as, recording whole episodes you already are watching and not
> recording.
>
> _______________________________________________

I would add one more behavior similar...

If you are timeshifting by 15 minutes a show using the ringbuf, and want to
change channels without restarting the ring. Need something like
Control Up Arrow or something to keep the ring running while allowing
channels to change.

Just my $.02 from what I've seen so far.

Brian

mythtv at matter

Jan 19, 2003, 10:03 AM

Post #41 of 42 (2049 views)
Permalink

Re: Record now? [In reply to]

I thought of one more "nice to have" for us busy parents. It is a
completely normal occurance in my house to pause a movie a get back to it
hours later.

If I'm watching live TV, and pause to deal with a "crisis" and leave it
paused passed the end of a show, it would be nice to have the ring buffer
automatically be converted into a recording of that show. It could stop
recording (liveTV'ing) after the show is over; presumably I don't care
about shows after the one I'm watching. I know I could set the ring
buffer abnormally large but like I said it could be hours later, and
that's gigabytes of ring buffer.

Larry

bjm at lvcm

Jan 19, 2003, 4:32 PM

Post #42 of 42 (2022 views)
Permalink

Re: Record now? [In reply to]

Larry Matter wrote:
> I thought of one more "nice to have" for us busy parents. It is a
> completely normal occurance in my house to pause a movie a get back to it
> hours later.
>
> If I'm watching live TV, and pause to deal with a "crisis" and leave it
> paused passed the end of a show, it would be nice to have the ring buffer
> automatically be converted into a recording of that show. It could stop
> recording (liveTV'ing) after the show is over; presumably I don't care
> about shows after the one I'm watching. I know I could set the ring
> buffer abnormally large but like I said it could be hours later, and
> that's gigabytes of ring buffer.

The short answer is "m", "r" ;-).

Being a digital recorder convert, I almost never watch
live TV but I do know the situation you are talking about.
If you pause and are away for longer than the buffer or
if another recording starts, you will miss the remainder
of the show. Rather than pause, choose to record the show
in progress. You can then choose it from the recorded list
anytime later. "M" goes to the EPG focused on the current
show. "R" is a shortcut to record once.

If I do watch live TV and decide I want to watch to the
end, I automatically choose to record so the it won't
start recording something else on the next half-hour or
whatever.

-- bjm

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