Live TV playback interruptions in between shows

[jamesnw]

I am using the latest beta V6.0.13 and have noticed a problem that occurs when the timeslot ends for a show in the Program Guide. Whenever the timeslot for a show ends, the UI pops up with the new show's information as if you had clicked the left mouse button once. This works correctly, but the problem I am experiencing is that the screen turns black and the audio stops for a period of approximately 2 seconds before the UI appears. This occurs for analog TV and digital HDTV. This is normally not an issue because it is in between shows, but for certain live events such as sports they often run past the programmed timeslot. This causes a distraction that I would like to resolve.

Here is some information about my system which may help diagnose this issue:

Processor: Pentium D - 2.8GHz
Memory: 1GB, 800MHz FSB
Video: ATI X300SE w/128MB video memory, latest stable drivers
Hard Disk: Seagate Barracuda 7200.10 ST3320620AS 320GB 7200 RPM SATA 3.0Gb/s (Dedicated recording drive)
Sound card: M-Audio Revolution 7.1 using latest stable drivers
Analog TV Tuner: Hauppauge PVR-500MCE
Digital TV Tuner: Vbox Cat's Eye DTA-150 ATSC
Video decoders: NVIDIA PureVideo v1.02-233
Audio decoders: NVIDIA PureVideo v1.02-233 (S/PDIF Passthrough)

If you need any further information such as log files or configuration files I can provide them.

-james

[Mark SS]

Its caused by Sage stopping the recording for the previous show and starting a new one for the next. It may be a shorter delay if you turn off the "always tune channel at start of recording" option but i don't believe it can be made seamless.

[jamesnw]

I turned off that option and experience the same length of ceased video and audio output when the current show's timeslot ends. This probably is not a bug but I do not think the playback should be interrupted when the channel is not being changed. Fixing this would be more of a functional enhancement per se.

[GKusnick]

It's not just a matter of changing channels or not. The capture device has to be told to stop recording to file A and start recording to file B. Similarly, SageTV itself has to close file A and then wait for enough data to appear in file B to allow playback to begin. That's an unavoidable consequence of the fact that Live TV is treated the same as recorded TV, with each program recording to a different file.

If that's not what you want, your options are either to set padding on the recording to make sure it gets the whole program, or else use timed recordings to record an uninterrupted block of time to a single file without regard to program boundaries.

[jamesnw]

Originally Posted by GKusnick

The capture device has to be told to stop recording to file A and start recording to file B. Similarly, SageTV itself has to close file A and then wait for enough data to appear in file B to allow playback to begin. That's an unavoidable consequence of the fact that Live TV is treated the same as recorded TV, with each program recording to a different file.

The interruption is definitely caused due to the fact that SageTV plays directly from the recorded file rather than from the stream coming from the tuners. This makes me wonder if there is a possible solution to my problem. Is there a way to increase padding on live TV playback (without manually recording them) so the new file starts being recorded for a few seconds prior to the timeslot ending, yet continue playing from the current timeslot's file. This would allow SageTV to begin buffering input from the new file while still playing from the previous file and more seamlessly switch over to the new file without losing more than a couple frames. This may be possible because SageTV already has the ability to write to multiple files at once.

Your suggestion to increase the recording timeslot manually is a good workaround until I find a more permanent solution. This will prevent interruptions if the live events run past their allotted time. Thanks!

-james

[jkohn]

I understand why this happens, but I still don't think it should happen. None of the satellite DVR's I've used behave this way even though they play everything from disk. The problem is recording a file for each show, there's no need to do that. It shouldn't start a new file unless I change the channel or otherwise interrupt the current broadcast. It should just keep spooling to the same file as long as I'm on the same channel, up until it hits some limit on disk space used (which could be user-configurable).

[gplasky]

Originally Posted by jkohn

I understand why this happens, but I still don't think it should happen. None of the satellite DVR's I've used behave this way even though they play everything from disk. The problem is recording a file for each show, there's no need to do that. It shouldn't start a new file unless I change the channel or otherwise interrupt the current broadcast. It should just keep spooling to the same file as long as I'm on the same channel, up until it hits some limit on disk space used (which could be user-configurable).

Your satellite DVR buffers-Sage doesn't. Sage goes directly to disk all the time. There are pros and cons for both methods. Sage chose not to buffer. It is what it is.

Gerry

[jkohn]

Originally Posted by gplasky

Your satellite DVR buffers-Sage doesn't. Sage goes directly to disk all the time. There are pros and cons for both methods. Sage chose not to buffer. It is what it is.

Gerry

I guess I don't see the distintion you're drawing between "buffers" and "going directly to disk". The satellite DVR's are always playing from disk, otherwise they wouldn't be able to pause/rewind/etc.

[Opus4]

A singular circular buffer that eventually overwrites itself as the recording continues is not the same as saving each entire recording to its own file.

- Andy

[GKusnick]

A satellite DVR is a closed box with just one playback client. SageTV is a networked system with potentially many playback clients. Somebody browsing SageTV Recordings from another client shouldn't have to care what time a program started or whether anybody else is currently watching it live. They just want to select a program and watch it. For that to work seamlessly, all programs (even Live TV programs that are still in the process of recording) have to be treated separately, recorded to separate files, and listed separately in SageTV Recordings. It's that multi-client seamlessness (among other things) that makes Sage better than a satellite DVR. The price you pay for that is those little one- or two-second hiccups at Live TV program boundaries.

[blade]

Originally Posted by jkohn

I guess I don't see the distintion you're drawing between "buffers" and "going directly to disk". The satellite DVR's are always playing from disk, otherwise they wouldn't be able to pause/rewind/etc.

Here is a very basic explanation. With buffers you have a fixed amount of space that is used for live TV so it's constantly overwriting itself. This limits how long you can pause a show and how far back you can rewind. Also if you get too far into a live show it would be impossible to change your mind and record the entire thing because the buffer will have overwritten itself. Also it is my understanding the buffer is cleared when you change channels.

Since Sage treats live TV the same as a recording you don't have these limitations.

[travisbell]

Thought I would chime in...

Coming from MCE (which uses the one singular buffer that overwrites itself... seems to me it holds the last 15 minutes at all times) and now using Sage, I see the benefits of both methods.

For example, about 2 weeks ago I was watching a hockey game. I had paused it on MCE 'cause the phone rang. Next thing you know an hour had passed before I could go back to watching it. Well, I only get a 15 minute buffer when watching live TV so guess what? I missed most of the game. Remember, if I was thinking that night though, I could have simply hit record... but I totally forgot this would happen.

With Sage, that would not have been a problem since it automatically just keeps the whole program recording.

Have I been *slightly* annoyed by the 2 sec pause between programs, certainly, but at the end of the day it's saving me from not seeing part of my program.

Cheers,

[polen]

You're thinking old school by watching live TV. I was once a SageTV noob and watched live TV , no offence, now all I watch is recorded shows and skip comms . Say there's a show that just comes on, well we wait 20 minutes for an hour show or 40 minutes for a 2 hour show, before watching it. And since I skip comms with the remote better than the wife, she lets me hold the remote. Thank you SageTV for putting th remote back in my hands.

Just start using that Favorite function and set favorites for anything you give even a thought about. I have about 70 favs set. I'm sure others have more.

Polen

[motobarsteward]

I'd say that this delay is a lot more prominient with 6.1.3 than 6.0.19.

[49studebaker]

Originally Posted by blade

Here is a very basic explanation. With buffers you have a fixed amount of space that is used for live TV so it's constantly overwriting itself. This limits how long you can pause a show and how far back you can rewind. Also if you get too far into a live show it would be impossible to change your mind and record the entire thing because the buffer will have overwritten itself. Also it is my understanding the buffer is cleared when you change channels.

Since Sage treats live TV the same as a recording you don't have these limitations.

Why not have a live buffer and also write the data to a file? For example, lets say the memory can only hold 10 minutes of video at a time, why not write the data out to a file every 5 minutes. This way the live stream is always buffered and never interrupted and since the data is written to the disk every 5 minutes the data is not lost when the buffer is overwritten.


Edit:

So if my understanding is correct Sage works like this:
Live stream -> file -> Sage

As someone stated the delay is cause by Sage closing the file of the previous recording and then opening a new file. Why not buffer the data only when Sage is closing/opening a file then write that buffer to the file.

Previous recording (buffer) Next recording