[mythtv-users] getting video decode errors on ATSC subchannels

[Klaas de Waal]

On Fri, 17 Feb 2023 at 05:31, Ian Evans <dheianevans at gmail.com> wrote:

> On Thu, Feb 16, 2023 at 10:57 PM Ian Evans <dheianevans at gmail.com> wrote:
> >
> > On Thu, Feb 16, 2023 at 10:16 PM Gary Buhrmaster
> > <gary.buhrmaster at gmail.com> wrote:
> > >
> > > On Fri, Feb 17, 2023 at 1:10 AM Ian Evans <dheianevans at gmail.com>
> wrote:
> > >
> > > > Any idea what I should be looking at?
> > >
> > > WAG's follows:
> >
> > That took me a second. LOL.
> >
> > >
> > > What does mediainfo indicate about the recording?
> > > There are a few locations where the non-primary
> > > subchannel(s) is in a non-mpeg2 format[0] that one
> > > may need different decoders (or hardware) to
> > > decode.
> >
> > Even though there was a 300 MB .ts file, mediainfo wasn't able to read
> it.
> >
> > To clarify, this was just a test on a clean system, so completely new
> > installation, nothing to upgrade. When I was testing jellyfin, their
> > DVR was able to record them fine. But wow, did I miss the
> > functionality of MythTV for TV. So I nuked all that. Looking at the
> > logs, I do see a ton of lines about "Malformed NAL units" right after
> > the subchannel recording started:
> >
> > Feb 16 22:27:31 bhmf mythbackend: mythbackend[19718]: I CoreContext
> > scheduler.cpp:717 (UpdateRecStatus) Updating status for Posse on
> > cardid [3] (Tuning => Recording)
> > Feb 16 22:27:31 bhmf mythbackend: mythbackend[19718]: I TVRecEvent
> > tv_rec.cpp:4146 (TuningNewRecorder) TVRec[3]: rec->GetPathname():
> > '/media/disk2/15103_20230217032800.ts'
> > Feb 16 22:27:31 bhmf mythbackend: mythbackend[19718]: I TVRecEvent
> > tv_rec.cpp:4179 (TuningNewRecorder) TVRec[3]: TuningNewRecorder -
> > CreateRecorder()
> > Feb 16 22:27:31 bhmf mythbackend: mythbackend[19718]: E
> > HDHRStreamHandler mpeg/AVCParser.cpp:410 (addBytes)
> > AVCParser::addbytes: malformed NAL units
> > Feb 16 22:27:31 bhmf mythbackend: mythbackend[19718]: I TVRecEvent
> > tv_rec.cpp:1648 (HandlePendingRecordings) TVRec[4]: ASK_RECORDING 4 0
> > 0 0
> > Feb 16 22:27:31 bhmf mythbackend: mythbackend[19718]: E
> > HDHRStreamHandler mpeg/AVCParser.cpp:410 (addBytes)
> > AVCParser::addbytes: malformed NAL units
> > Feb 16 22:27:31 bhmf mythbackend: mythbackend[19718]: I TVRecEvent
> > tv_rec.cpp:1648 (HandlePendingRecordings) TVRec[1]: ASK_RECORDING 1 0
> > 0 0
> > Feb 16 22:27:31 bhmf mythbackend: mythbackend[19718]: I TVRecEvent
> > tv_rec.cpp:1648 (HandlePendingRecordings) TVRec[5]: ASK_RECORDING 5 0
> > 0 0
>
> [snip]
>
> UPDATE: Ok, so it's not the subchannel, it's the multirec.
>
> I went into program guide and started recording 7.2. That recorded
> fine. A minute later I started recording 7.1. That exhibited the same
> issue as before. I have two  tuners setup for the homerun and both are
> set to eight max recordings. 32 has a different HDHomerun setup than I
> had back in .27 so I'm not sure which other settings I need to look
> at. Heading to bed, but can answer questions about the config on
> Friday. Thanks!
>
> MythTV 27 uses static tuner assignment and that means the HDHR cannot be
shared with other devices.
MythTV 32 (30+ IIRC) uses a dynamic allocation scheme that allows sharing
the HDHR with other devices that have implemented the dynamic allocation
scheme.
So if you want to use the new version 32 system make sure the old version
27 system is disconnected. Note that "not recording" can mean it is still
doing EIT.

You might want to check the software version of the HDHR and possibly do an
update of the software. This can be done with the hdhomerun-config or the
hdhomerun-config-gui app. The source code of this can be downloaded from
the Silicon Dust website.
It could be that the software in the HDHR is too old and that it does not
yet (or does not properly) implement the dynamic allocation.

Everything you always wanted to know about tuner configuration and channel
scanning can be found here https://www.mythtv.org/wiki/Channel_Scanning and
especially for the HDHR there is this paragraph
https://www.mythtv.org/wiki/Channel_Scanning#Scanning_with_HDHomeRun_tuners

Klaas.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mythtv.org/pipermail/mythtv-users/attachments/20230217/e291123f/attachment.htm>