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

[Ian Evans]

On Fri, Feb 17, 2023 at 2:40 AM Klaas de Waal <klaas.de.waal at gmail.com> wrote:
>
>
>
> 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
>

Just to further clarify further, this is a brand new install miles
away from my .27 system at home. So there is no conflict there. :-)
Just wanted to mess around with 32 while I was here and before I do it
at home. The hdhomerun firmware is from December 20221205.

I can record on both tuners. I just can't record additional channels
on the same frequencies . That is, I can record 7.1 and 2.1 at the
same time but cannot also record 2.4 and 7.2. Will mess around further
today.