Record to something other than mpg, OR post transcode to mp4 on a Mac?


#1

Greetings.

I’m using the Channels server app on a Mac. Works great, but I’m hitting a wee snag. HD mpg files are rather cumbersome, so I’m wondering if there’s a config I’ve missed to record to, say, mp4?

If there isn’t, do any Mac users know of a way of automatically feeding the recorded file into Handbrake? I’m assuming some sort of Watch Folder, but I’m not sure if it would work with the TV folder due to the sub-folder nature of it (if that makes sense).

Many thanks.

Edit: in case it matters, I’m using a HDHomerun Connect.


#2

The only officially supported option I am aware of at this time is to use the HDHomerun Extend which offers hardware transcoding to h264. I have two Extends and transcode all recordings which results in files that are approximately 1/2 the size as the original HD mpeg2 OTA files with similar quality picture. I use heavier transcoding on my iOS devices for live television as it reduces the wifi and decoding work on the portable devices which helps with battery usage while still maintaining a nice picture on the smaller screens.

The Channels developers have stated that they plan to incorporate an option on the DVR to transcode recordings in the future but is not available today. The performance of DVR transcoding will depend on the hardware used for DVR. Most current Macs should be OK there.


#3

Thanks for the info. I’ll have to look into setting up some sort of watch folder to send the completed files to Handbrake’s CLI version then.

I think the problem I have is that I’m storing the files on a Netgear ReadyNAS104 with Red drives - highly reliable, but not the fastest. Additionally, .mpg files aren’t the most efficient and I think the NAS can’t deliver them quickly enough. It has no issues with full-res Bluray rips encoded to h.265 mp4/m4v files.

Project for the weekend methinks.


#4

Let us know if you make any progress on that. It’s something I’m really looking for. Transcoding, moving to another folder, ftp, etc would be very helpful. Devs said it’s on the roadmap, but no news so far.


#5

Absolutely, but I can foresee one problem: I don’t think watch folders will detect changes in sub-folders contained within them.

So for instance, if I write a script that watches ‘/users/jim/Recordings/TV Shows/’ then I’m not sure it will see ‘’/users/jim/Recordings/TV Shows/Airwolf/Airwolf S01E01 - Pilot.mpg’ when it gets created, due to it being in a folder of its own. I’m speculating here though.

There’s also the issue that it needs to only start processing the file once it’s been fully written…some sort of periodic check on the file size (say every 10s) will be needed I think.

But it’s early days. If I have any success I’ll add to this thread.


#6

Ideally, the web server would just have to include the option of executing a post-processing script after all its tasks are completed (renaming, moving, comskip), and pass along the name of the file to whatever task you set up in that script.


#7

Have you seen this? https://github.com/karllmitchell/Channels-DVR-to-Plex

I used portions of this to create a simple script to rename the comskip files to the same name as the mpg and move the comskip file in to the recordings directory. This would have allowed playback on Kodi with automatic commercial skipping.
I ended up abandoning my script once I got my remote working correctly in the channels app on my Nvidia Shield.


#8

That looks rather interesting. Thank you.

If I may ask a numpty question…what are ‘comskip’ files?


#9

Comskip is the program that identifies the commercials in a tv recording. It creates several files which serve to identify where the commercials exist in the recordings. An edl file is one of the files created. This file allows some players, such as Kodi, to automatically skip the commercials. If you turn on commercial flagging in Channels DVR these files are created by the channels app. However, the files are not in the proper location for Kodi.


#10

Ah, thank you. That makes sense.

I’m using Plex (without Plex Pass) for my video serving needs. Mostly it works fine(ish!) but these huge mpg files are giving it conniptions. Well, in fairness it’s not Plex’s fault, since trying to play one on the Mac from the NAS via VLC also results in stuttery/laggy play (it sort of resembles a slideshow with audio). Similar stuff encoded with h.264/h.265 plays fine, so it’s an mpg issue.


#11

I think you mean that its a network issue, since other users with reliable network connections don’t have a problem.


#12

My network connection is perfectly reliable, thank you. As stated, the problem doesn’t exist with similarly resolution’d mp4/m4v files encoded with Handbrake into (formally) h.264 files, and latterly h.265 files.


#13

Well, I wouldn’t dismiss that out of hand. I did a little research and your NAS should be able to handle at least 35Mb/second writing and between 50 or 60 reading. Are you sure that your files aren’t corrupt from too slow write speed?

At least in the US over the air mpeg2 recordings average about 20 Mbit/s . The encoded h.264 files are probably less than half that data rate for the same resolution.

My crappy little wd mycloud has no problem recording and serving mpeg2 files.


#14

If you’re in the UK and recording HD channels then they should already be in H264.

MPEG2 files are 2-3x bigger, but even the slowest arm processors have no problem reading them from disk and sending over the network.

It definitely sounds like there’s some sort of bottleneck on your NAS, either in the CPU, Network or Disk.


#15

For the past year I have tried to use Plex as a media server, however, all attempts were disastrous, for mpegts files. Once I changed to Emby as a media server I have able been to playback on all clients without problems.

FYI, I have tried numerous times to notify Plex developers of this defiency…only to be met with resistance from Plex to resolving this issue. Even their own DVR recordings (mpegts) are unplayable on various clients.

I also understood that DVR recordings from UK sources were in h.264…but maybe we in the US are mistaken. However, even trying to play H.264 files on Plex is horrendous, at least in US, Emby is much bettter…even from a low powered NAS.

Edit: Just to add: IMO, Channels playback is the first/foremost solution of all. I only have to use Emby when I want to be able to view ALL of my recordings, no matter the source. Currently, I am trying to re-record all “old recordings” in Channels, so I can use solely Channels…rather than having to utilize a “full function” media server (like Emby or Plex).


#16

Is it plugged in? What kind of transfer rates do you get from a network computer to your DVR?


#17

ridiculous. A single WD Red will read/write significantly faster than the maximum speed of gigabit ethernet. Your drives are not your problem, unless they are defective/failing.


#18

Good to know, but that still brings us back to the fundamental issue - two files in the same location on the NAS (same share, same folder). One is mpg from Channels, one is the same file run through Handbrake and is now mp4

Playing both on the Mac locally (wired connection to the NAS, using VLC): the mpg is a slideshow with audio, the mp4 plays fine.

mpg does seem to be the defining factor.


#19

If you copy the mpg to your computer does it play correctly?


#20

That’s something I need to try. I’ll do so tonight. Gut feeling says it will, but we’ll see.