Mac OS BigSur?

dbloom · November 18, 2020, 5:46pm

For what it's worth, I've been running Channels DVR on an M1 Mac Mini for the past day and it's been working great so far.

I haven't tried software transcoding yet but frankly I don't think there's any need for it -- hardware transcoding quality is great on the M1, even at low bitrates.

I'd imagine the lowest hanging fruit is comskip because that is both CPU-intensive and it's a separate binary... but despite running under Rosetta translation it still runs so fast (without any audible fan noise) that it's still fine as-is.

dbloom · November 18, 2020, 5:51pm

Just for fun I tried software transcoding.

Transcoding 1920x1080 60Hz (CBS TVE) using software transcoding at the "1080p @ 10mbps" preset under Rosetta translation...absolutely no drama at all:

tmm1 · November 18, 2020, 6:25pm

Color me shocked. Certainly encouraging. My mini gets here next week.

dbloom · November 18, 2020, 6:37pm

so far the only thing that's broken my workflow is that I no longer get notified that a recording has finished by the sound of fans spinning up for comskip

bigtrouble · November 18, 2020, 7:38pm

You went with 8GB RAM? Is this a temporary test or do you plan on running it permanently with 8GB?

dbloom · November 18, 2020, 7:46pm

I bought it with 8GB and am committed to it (the memory is built into the M1 SoC so it's not upgradeable).

The high RAM utilization that Channels indicates in my screenshot above is a little misleading -- almost all of that utilization is purgeable memory (mostly stuff paged-in from disk that's kept in memory just in case it's needed again) that can be quickly reclaimed if needed.

tmm1 · November 19, 2020, 5:59am

FYI it is possible your DVR may lock up under Rosetta 2: https://github.com/golang/go/issues/42700

dbloom · November 19, 2020, 6:04pm

Yep, I think I just ran into this while the DVR was fetching guide data:

2020/11/19 09:40:01.318393 [DVR] Fetching guide data for 117 stations in X-TVE @ 2020-11-19 9:30AM
2020/11/19 09:40:02.776301 [DVR]   indexed 836 airings (117 channels) [0s fetch, 0s index]
2020/11/19 09:40:03.288519 [DVR]   indexed 45 movies (15 channels) [0s fetch, 0s index]
2020/11/19 09:40:03.396700 [DVR]   pruned 32 replaced airings in 0s.
2020/11/19 09:40:03.420734 [DVR] Fetching guide data for 121 stations in USA-CA04487-X @ 2020-11-19 3:30PM
assertion failed [abi_info.kind == AbiKind::TranslatedCode]: emulated forward to an arm pc that isn't in translated code. arm_pc=0x10686e4d8 abi_kind=6 emulation_interval=[0x106ea790c,0x106ea7920) instruction_interval=[0x106ea78f8, 0x106ea7920) x86_rip=0x4bddb6d
(ThreadContextRegisterState.cpp:677 move_to_instruction_boundary)

Had to launchctl stop com.getchannels.dvr;launchctl start com.getchannels.dvr to get it running again.

dbloom · November 19, 2020, 6:07pm

Although a subsequent, manually initiated "Fetch Guide Updates" ran fine so it doesn't seem to be 100% reproducible.

dbloom · November 20, 2020, 3:54am

To try to work around the issue, I've added setenv GODEBUG asyncpreemptoff=1 to /etc/launchd.conf and also ran launchctl setenv GODEBUG "asyncpreemptoff=1". I'll report back if it crashes again!

Lvevan · November 20, 2020, 4:20am

How the the “iPad app” version of channels work on the new Mac? Or is it available there?

dbloom · November 20, 2020, 4:28am

Not available -- the developers have (understandably) opted out until they have had a chance to test it.

tmm1 · November 20, 2020, 10:09pm

I expect it should be just fine once that's set.

I'd like to make the DVR do this automatically, but it needs to be able to detect that it is inside Rosetta2 first. Do you mind submitting diagnostics from your DVR so I can see what kind of values are available for this check.

Palandrel · November 24, 2020, 4:33am

I concur, Channels DVR is freezing each 2 or 3 days on my 16 MB M1 MacMini.

tmm1 · November 24, 2020, 6:18am

Click and hold the check for update button

resjus30 · December 30, 2020, 11:53pm

Wow, 8 GB is awesome -- how much Swap memory is being used, and do you use your Mac mini M1 for anything else (Backblaze, Plex, etc.)?

dbloom · January 2, 2021, 8:44pm

No other services running on the Mac mini, other than the system content caching service.

Currently I have 6.5GB of RAM used, and 2.15GB of swap used. But only 1.7GB of memory use is wired... the rest can be paged out without swapping, so memory pressure is very low (most memory being 'used' here is just macOS speculatively keeping files paged in in case they are needed again, but those pages are immediately available for other uses if needed). I'm currently on a Zoom call and also have three fairly active Slack tabs open in Safari. My Mac is connected to a very high-resolution display running at a scaled resolution of 6016x2538.

resjus30 · January 2, 2021, 9:55pm

Thanks! So are you feeling good about 8GB? I was afraid it wouldn’t be enough, but I intend for M1 mini to only be used as a headless media server.

Screens,
SuperDuper!,
BackBlaze,
iCloud photo sync,
Channels,
Plex (when it’s native) and
Very occasionally: AirPlay video mirroring with Chrome and Netflix Party when I wanna chat while watching a Netflix show.

dbloom · January 2, 2021, 10:07pm

I have no regrets whatsoever about 8GB. I'd expect it to be far more than adequate for your needs as well.

Apple Stores (and the Apple online store) have a great return/exchange policy so you can always buy from there and send it back if you find that you need the 16GB.

resjus30 · January 2, 2021, 10:43pm

I’m mostly looking forward to lower power consumption (looks like I’ll save around $85 annually assuming peak power usage all year long for both machines)… and no fan noise — the faster comskip is a nice bonus.