Rewinding past beginning of current "event"

[jeffb]

Beyonwiz T4 - 1TB 25/08/2015

I downloaded and installed the latest firmware image this morning (25-08-2015) and was disappointed to discover that I still can't rewind live TV back past the beginning of the current "event" - or at least the time that the EPG believes the current "event" began. An issue which really highlights why basing recordings on inaccurate EPG "events" is not such a good idea.

From what I've read on this forum the issue relates to a bug where the rewind pointer (for want of better word) doesn't automatically skip back to the end of the preceding event's timeshift buffer when it reaches the beginning of the current buffer. I also read that this issue had been fixed, hence my disappointment.

Is there an ETA for when this fix will be included in a firmware upgrade?

I've done some further reading and come across a discussion describing the use of the PREV and NEXT buttons to move between event timeshift buffers. I'm yet to try this method out but it certainly sounds like a clumsy workaround for what is really basic PVR functionality. When will it be fixed?

[MrQuade]

No this hasn't been fixed, not sure where you read that. There are still a few outstanding things to iron out with timeshifting, but they have not been prioritised at the moment.

There is the one you mentioned. Namely being able to skip or trickplay between events.
Also, having thePVR unit drop back to LiveTV once the end of the timeshift buffer is reached.

And yes. you are correct, NEXT and PREV are configured to allow you to skip between events.

Do you often see the event boundaries not match up with the ends of shows? The start and end of events are signalled from your broadcaster at the times when shows start and finish, so they don't rely on the EPG, or pre-set times to determine with an event occurs.
I find they are usually pretty good.

[jeffb]

Hi MrQuade, thanks for replying.

No this hasn't been fixed, not sure where you read that. There are still a few outstanding things to iron out with timeshifting, but they have not been prioritised at the moment.

To be honest I'm not sure now either. I've just spent half an hour searching fruitlessly for the thread where I saw it. I'll keep looking, possibly I saw it somewhere else.

Do you often see the event boundaries not match up with the ends of shows? The start and end of events are signalled from your broadcaster at the times when shows start and finish, so they don't rely on the EPG, or pre-set times to determine with an event occurs.
I find they are usually pretty good.

I didn't know that it relied on signals sent by the broadcaster, I thought it relied on times provided by the EPG. But that raises another question for me. The first time I noticed the problem was when I left the room to do some things, came back and tried to rewind back to the point in the movie where I'd left. I was able to rewind back past the beginning of the program that had come on after the movie but then I could only rewind through the last ten minutes of the movie. If what you say is true then the network I was watching must have sent out the "event end" signal before the actual end of the event! Ten minutes before in that case.

If I'm honest I'm a bit disappointed with how "raw" the new T4's interface is. I do remember the earlier versions of the P1 firmware though and how much it improved over time. It does seem we've gone a fair way backward in functionality though.

Maybe we could request that liveTV just gets it's own buffer that doesn't rely on "event" timing at all and that, if the user requests to record a section of or all of the timeshift buffer, they can do that with a single simple query on screen. To be honest though I really don't see where the problem comes from. Streams get written to files, the files get recorded in a table with the necessary metadata. If necessary, extend the meta data to allow a simpler "chaining" of events but it should be possible to very quickly query that table to determine the previous event. I saw somewhere that the code is all on GIT. I might pull it down and have a browse through.

[prl]

Hi MrQuade, thanks for replying.

No this hasn't been fixed, not sure where you read that. There are still a few outstanding things to iron out with timeshifting, but they have not been prioritised at the moment.

To be honest I'm not sure now either. I've just spent half an hour searching fruitlessly for the thread where I saw it. I'll keep looking, possibly I saw it somewhere else.

IIRC, the only thing that's changed recently with rewind is that you can now use the rewind button to initiate timeshift.

Do you often see the event boundaries not match up with the ends of shows? The start and end of events are signalled from your broadcaster at the times when shows start and finish, so they don't rely on the EPG, or pre-set times to determine with an event occurs.
I find they are usually pretty good.

I didn't know that it relied on signals sent by the broadcaster, I thought it relied on times provided by the EPG. But that raises another question for me. The first time I noticed the problem was when I left the room to do some things, came back and tried to rewind back to the point in the movie where I'd left. I was able to rewind back past the beginning of the program that had come on after the movie but then I could only rewind through the last ten minutes of the movie. If what you say is true then the network I was watching must have sent out the "event end" signal before the actual end of the event! Ten minutes before in that case.

It uses the Now/Next transitions in the broadcast data to indicate the start/end of programs (the same as is used to put the start/end markers in recordings). These are supposed to be accurate so that parental lock works properly. The details are in the ACMA EPG Principles:

The present/following section of the EPG must contain accurate and useful parental guidance rating information that meets Australian standards.

The ‘following program’ field in the EPG must immediately transition to the ‘present program’ field as program content changes on air.

However, this is all regulation by wishful thinking:

Do broadcasters have to comply with the EPG principles?

No – there is no formal requirement for broadcasters to comply with the EPG principles.

The principles provide broadcasters with an opportunity to meet agreed EPG service standards without the introduction of regulations.

The ACMA will consider broadcaster performance against the principles when deciding to exercise its regulatory powers in relation to EPGs.

If I'm honest I'm a bit disappointed with how "raw" the new T4's interface is. I do remember the earlier versions of the P1 firmware though and how much it improved over time. It does seem we've gone a fair way backward in functionality though.

Maybe we could request that liveTV just gets it's own buffer that doesn't rely on "event" timing at all and that, if the user requests to record a section of or all of the timeshift buffer, they can do that with a single simple query on screen. To be honest though I really don't see where the problem comes from. Streams get written to files, the files get recorded in a table with the necessary metadata. If necessary, extend the meta data to allow a simpler "chaining" of events but it should be possible to very quickly query that table to determine the previous event. I saw somewhere that the code is all on GIT. I might pull it down and have a browse through.

Go for it: https://bitbucket.org/beyonwiz/easy-ui-4/overview

But there's about 140000 lines each of C++ and Python code. Clearly not all of it relevant to the timeshift function.

However, consider that there also some good things about the way it's done now, in particular it has a fairly efficient way of converting any program in the timeshift buffer into a recording (without any copying if the recordings directory is on the same volume as the timeshift directory).

A problem with the "single recording" approach to the timeshift buffer is that unlike the DP series, a T series recording is a single file, and data can't be efficiently trimmed from the start of the file, which will simply grow without limit while the PVR remains running.

IMO, being able to REW/FF/skip across the event boundaries in the timeshift buffer would be a good thing, though, and perhaps easier to implement than completely restructuring the way timeshift is done. It would give the appearance of continuity without losing the advantages of the present structure.

[jeffb]

Go for it: https://bitbucket.org/beyonwiz/easy-ui-4/overview

I did - Ha! Oh my God! 140000 lines is a little conservative I think.
I'll have a hunt around though and see if I can contribute.

Is there a sticky somewhere with the list of what's actually being worked on?

It uses the Now/Next transitions in the broadcast data to indicate the start/end of programs (the same as is used to put the start/end markers in recordings). These are supposed to be accurate so that parental lock works properly. The details are in the ACMA EPG Principles:
...
However, this is all regulation by wishful thinking:
Do broadcasters have to comply with the EPG principles?
No – there is no formal requirement for broadcasters to comply with the EPG principles.
The principles provide broadcasters with an opportunity to meet agreed EPG service standards without the introduction of regulations.

Ah, self-regulation. The regulation you demand when you don't want to be regulated at all. The principles sound good in theory but you know what the broadcasters are like here in Australia, they think the programs are just buffers for the ads.

IMO, being able to REW/FF/skip across the event boundaries in the timeshift buffer would be a good thing, though, and perhaps easier to implement than completely restructuring the way timeshift is done. It would give the appearance of continuity without losing the advantages of the present structure.

Agreed. Logically you should be able to rewind through channel changes as well. Might be interesting.

Thanks for the replies guys.

[MrQuade]

Agreed. Logically you should be able to rewind through channel changes as well. Might be interesting.
Thanks for the replies guys.

Not unless you also change the timeshift code to retain the timeshift buffer when you change channels. I don't know of another PVR that does that when you change channels (Though the T series can be configured to save the current event automatically, and the TiVo can apparently timeshift on two services at once as long as you do a "tuner swap" as was pointed out in another thread recently).

[MrQuade]

One other thing that you may or may not have discovered that is another departure from the DP series.

You can't change to a channel that is in the middle of a recording, and automatically timeshift back into the recording, the timeshift starts at the point at which you changed channels.
In order to to step back into a currently recording event past the time that you changed channel, you have to do it somewhat manually by opening the media player and then playing the recording that is in progress.

[jeffb]

You can't change to a channel that is in the middle of a recording, and automatically timeshift back into the recording, the timeshift starts at the point at which you changed channels.

Yes I had noticed that. Another gotcha stemming from the "event" based approach probably.

Not unless you also change the timeshift code to retain the timeshift buffer when you change channels.

You'd think you could just close one buffer/file, add it to the chain and start a new one. Which all sounds great in theory but...

[prl]

...
I did - Ha! Oh my God! 140000 lines is a little conservative I think.
...

I said "about 140000 lines each of C++ and Python code". I.e. 280000 lines altogether.

Code: Select all

Cambyses:enigma2 prl$ find easy-ui-4 \( -name \*.cpp -o -name \*.h \) -exec cat {} + | wc -l
  141799
Cambyses:enigma2 prl$ find easy-ui-4 -name \*.py -exec cat {} + | wc -l
  138935
Cambyses:enigma2 prl$

[nealc]

Hi there
Has this been implemented yet. I have seen lots of discussion from years gone back but not found any confirmation that the feature now exists.
Also where is a wish list that is visible to see?
Thanks

[MrQuade]

Has this been implemented yet. I have seen lots of discussion from years gone back but not found any confirmation that the feature now exists.

Which feature? A few were discussed.

The timeshift buffering feature on the T series stores each event in its own recording file, so you currently need to skip between them to access each event. You can timeshift back past the current event to the previous event by just pressing the PREV button to skip back. You can skip between events easily using PREV and NEXT in this fashion.

There is a feature request in place that is intended to make this a bit simpler and just allow you to navigate back to the previous event using the regular skip buttons when the beginning of the event is reached (although the T series DOES skip to the next event automatically when you reach the end of the event). This hasn't been done yet. Issue #393 in the bug tracker.

The other thing that was mentioned was being able to skip back into a recording in progress, This is something you can't currently do, and doing so would be a bit tricky to achieve given the way the T series works. Probably not impossible though, but it isnt on the cards AFAIK. You can easily just open the media player and play any recording that is currently in progress though.

Also where is a wish list that is visible to see?

All of the feature requests and issues usually get discussed in the Bug Reporting forum first. If the bug or feature is confirmed and the solution agreed upon, then someone will post it to the official bug tracker here.

You can also find all of the T series source code at the same location in case you are interested .

[tb123]

I just tried timeshifting back to watch the end of the cricket (I left the T4 running in 9 while I had tea) and realised that it only timeshifted the current event. Found this thread, tried the PREV button and got a list of channels that asume I had watched previously although none was the afternoon session of the cricket I had been watching. Anyway, how do you timeshift to a program once you press the PREV button? It just looked like a list of channels I'd been watching.

[MrQuade]

I just tried timeshifting back to watch the end of the cricket (I left the T4 running in 9 while I had tea) and realised that it only timeshifted the current event. Found this thread, tried the PREV button and got a list of channels that asume I had watched previously although none was the afternoon session of the cricket I had been watching. Anyway, how do you timeshift to a program once you press the PREV button? It just looked like a list of channels I'd been watching.

You must be in timeshift mode when you press the PREV/NEXT buttons to be able to skip between events that are in the timeshift buffer.

You must have exited timeshift mode by pressing STOP before you tried pressing NEXT/PREV. When you are in normal Live TV mode (which is where I suspect you were), NEXT/PREV buttons will access your service/channel history as you observed.

Remember, to go from Live TV mode to Timehift mode, you must either use one of the skip-back buttons, or press REW.

[tb123]

Thanks, I'll give that a try. By REW button do you mean the << button to the left of the stop button?

[MrQuade]

Thanks, I'll give that a try. By REW button do you mean the << button to the left of the stop button?

Yes, I was using the "legacy" terminology REW=Rewind.