[mythtv-users] FE Stop/Restart for Smooth Playback

[jim]

On 03/28/2015 11:51 AM, Mike Perkins wrote:
> On 28/03/15 14:41, jim wrote:
>>
>>
>> On 03/28/2015 08:48 AM, Mark Perkins wrote:
>>>
>>>> On 28 Mar 2015, at 11:03 pm, "jim" <jim_32766 at hotmail.com> wrote:
>>>>
>>>>
>>>>
>>>>> On 03/27/2015 10:21 AM, jim wrote:
>>>>> Occasionally, usually after the system has been running 24/7 for a 
>>>>> few days,
>>>>> playback of recorded television shows is no longer smooth, with 
>>>>> visible
>>>>> stutter where there should be smooth panning motion. Stopping and 
>>>>> restarting
>>>>> the FE returns the playback to smooth operation. Has anyone else 
>>>>> experienced
>>>>> this scenario?
>>>>> I have experimented with sync, cache drop, and swap stop/restart 
>>>>> to achieve
>>>>> smooth playback without the FE stop/restart, but only the FE 
>>>>> stop/restart
>>>>> seems to work. Any ideas or suggestions would be greatly 
>>>>> appreciated. Thanks.
>>>>>
>>>>> System Info:
>>>>> 4 GB Ram
>>>>> i3 4330 CPU
>>>>> MythTV Version : v0.27.4-41-gf1115fc
>>>>> MythTV Branch : fixes/0.27
>>>>> Network Protocol : 77
>>>>> Library API : 0.27.20141016-1
>>>>> QT Version : 4.8.6
>>>> Based on receiving no answers it may be that nobody else 
>>>> experiences this
>>>> problem. Please confirm if you do not.
>>>> My system is very modern, and has plenty of RAM. I wonder what 
>>>> causes this
>>>> issue?
>>>>
>>>> _______________________________________________
>>> I do not have this problem, my FE can be on for weeks or months at a 
>>> time. But
>>> I have nvidia graphics, where I assume you use VAAPI.
>>>
>>> I would recommend starting by comparing the log file for a recording 
>>> that
>>> plays fine with that of one that does not to see what the 
>>> differences are.
>>>
>> If the difference were vaapi wouldn't the problem be present all the 
>> time? I
>> wonder if something else running on my system contributes, or if the 
>> OS (Mint
>> 17.1) is involved. What OS are you running?
>> I will also check the log file for a recording playback pre/post FE 
>> start/stop.
>>
> Any problem like this doesn't automatically have to be continuous. For 
> example, different programs may have different bit rates/frame 
> rates/screen formats. These can impose differing demands on the video 
> driver and hardware.
>
> The same also goes for audio, incidentally. If the audio encoding 
> changes mid transmission - say for a commercial break - then that 
> might cause buffering problems which could affect the vodeo.
>
> As Mark wrote above, your best bet is to look at the logs, a segment 
> which works and a segment which is bad.
>
I use recorded Jeopardy! episodes for testing as the panning of 
categories in Jeopardy! makes for a great test of smooth motion in 
playback. When I test I use the same exact recording, pre and post FE 
stop/start. The FE stop/start completely fixes the problem for some 
inexact period of time. I've not done a good log comparison between a 
smooth playback and a jerky one, and will do so as soon as the problems 
appears again.

I've never noticed a situation wherein the smoothness is better/worse 
before/after a commercial break. I've experimented with SD and HD and 
the full range of standard frame rates. None of that seems to stress the 
system. If the FE has been recently stopped/started all combinations are 
good. The problem behaves more like a buffer/cache issue that builds 
over time and eventually causes a problem. Why FE stop/start helps I do 
not know.

I really appreciate the time people contribute on this mail list 
answering questions. It really helps. Thanks.