[mythtv] Android playback synchronization (was Re: mythfrontend-20210221-arm-v32-Pre-2365-gb6e2003f64)

John Pilkington johnpilk222 at gmail.com
Thu Feb 25 10:04:49 UTC 2021


On 25/02/2021 02:12, David Hampton via mythtv-dev wrote:
> On Wed, 2021-02-24 at 21:22 +0000, John Pilkington wrote:
>> On 23/02/2021 18:12, Peter Bennett wrote:
>>>
>>> On 2/23/21 11:23 AM, Peter Bennett wrote:
>>>>
>>>> On 2/23/21 9:34 AM, Peter Bennett wrote:
>>>>>
>>>>> On 2/23/21 8:43 AM, John wrote:
>>>>>> Playback is very jerky with  the latest android build but
>>>>>> fine with
>>>>>> the same release on Intel hardware.
>>>>>>
>>>>>> Tested on F4K & Shield TV.
>>>>>>
>>>>>> I cannot say whether the issue is UK specific, tested with
>>>>>> 1920*1080 at 25fps.
>>>>>>
>>>>>> H264 vaapi is good.
>>>>>>
>>>>>> Mediacodec and opengl on android poor.
>>>>>>
>>>>>> Apologies as I can't compile for android I cannot bisect the
>>>>>> issue.
>>>>>>
>>>>>> FWIW mythfrontend-20201222-arm-v32-Pre-1870-g283caa7b84 is
>>>>>> fine.
>>>>>>
>>>>>>
>>>>>>
>>>>> Have you tried the various options in the playback profile? I
>>>>> believe
>>>>> the default playback profile for Mediacodec may have two
>>>>> entries, the
>>>>> first one being for "Standard" decoding. If you have that it
>>>>> will use
>>>>> "Standard" Entry if you have one and look at the Mediacodec
>>>>> entry.
>>>>> There are options for Mediacodec and Mediacodec(decode only).
>>>>> Try
>>>>> various options here to see if the problem is resolved.
>>>>>
>>>>> You may have already done this. I will try it out later myself
>>>>> to see
>>>>> if I have the same issues and respond.
>>>>>
>>>>> At this point I am not working on the mythfrontend playback,
>>>>> Mark
>>>>> Kendall is doing all of the work. I am just doing the packages.
>>>>> If
>>>>> the problem persists, please create a ticket in github and Mark
>>>>> can
>>>>> take a look at it.
>>>>>
>>>>> Peter
>>>>>
>>>> I tried it and I agree that playback is awful. There seems to be
>>>> no
>>>> synchronization of audio and video. The video shoots ahead at
>>>> high
>>>> speed and then slows to a crawl, then repeats that again.
>>>>
>>>> Possibly caused by chrono changes or playback changes.
>>>>
>>>> Peter
>>>>
>>>>
>>>>
>>> Just checked and it is only the 32bit build of Android mythfrontend
>>> that
>>> has the problem. On the shield you can run the 64bit version and
>>> that
>>> works fine. The fire stick will not support 64 bit and needs the
>>> 32bit
>>> build.
>>>
>>> Peter
>>
>> I have several times watched good continuous playback of mpeg2 video
>> for
>> 30 minutes or so - and then quite suddenly erratic speed changes and
>> loss of sync start and look likely to the end.  On the recording I
>> have
>> playing now it's OK for 36 minutes.  Firestick 4K, Peter's build at
>> 2365, 32 bit, MPEG-2 ffmpeg, Deint 4xCPU 2x CPU Onefield
> 
> I just committed a change that should fix the playback problem on 32-
> bit android. Please try again after Peter updates his builds.
> 
> David

I suppose it's obvious, but my observation of limited-duration good 
playback was with post-processed recordings with timestamps starting 
from zero.    ISTR the clock rate is 900 Khz, and 36 x 60 x 900000 > 
1.944G while 2 ** 31 > 2.1G

John


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