Extras and IR Blasters

[TheCompWiz]

I have an Hauppauge HDPVR2 that has given me endless headaches, and am about to try replacing it with a simple IP Capture device, but I have a few questions that I can't seem to find answers to.  I am already aware of the "Extras" option to specify a command to produce a video stream, but this also raises some additional questions.

1) With Extras, what are the requirements for the video stream? the example shows ffmpeg using http to pull from a m3u8 playlist, which I'm pretty sure just provides a list of URIs for ffmpeg to consume, output a MPEGTS stream, and outputs it to STDOUT.  
2) Does NextPVR have enough smarts to dynamically transcode/scale streams based on network congestion/configured preferences?  Is there documentation on this? I can't seem to find it anywhere.
3) I want to use a IR blaster for channel-changing & such... I know I could use a wrapper around ffmpeg to send the IR-Blaster commands and then call ffmpeg, but is there a different/better way to do this?  I'm open to suggestions.

[mvallevand]

Typically HDMI IP encoders already give you the option to stream in ts format and they can be in h264/aac 2 channel that NextPVR prefers. What this means is you don't need ffmpeg you can just use curl and stream URL that you'd like.

The extra just needs to call the script file and the script can call the blaster command. I use a URay device and the extra is like this

Code:

<extras>
  <channel name="{channel-name}">
    <command>cmd</command>
    <args>/c c:/users/public/npvr-data/scripts/uray.bat {channel}</args>
  </channel>
</extras>

and the script file is like this (I don't help on scripts beyond this) You can also use channel digits.

Code:

@echo off
blaster.bat %1
curl -s http://172.16.3.60/1.ts

Question #2 seem out of place, but NextPVR dropped video quality setting a long time ago. You can have multiple extras that use the same device with the different quality streams but NextPVR will see them as different devices. If you must have lower bit rate use one of the clients that allows you to set the streaming bit rate and not the recording bit rate.

Martin

[TheCompWiz]

Does NextPVR do any transcoding? If my video source is MPEG2, HEVC (h265) or VP8 and the device doesn't support it, could it transcode to H264? I also was asking about transcoding and scaling because frequently, bandwidth restrictions become an issue. I guess I was hoping for the ability to have rate-adaptation for those situations.

[mvallevand]

Could you clarify what you mean? Capturing HDMI it won't matter what the original video or audio format was. If it is a non-standard IPTV source, NextPVR will transcode that to NextPVR's standard.

The client requested transcoding will be done be NextPVR itself As an example for the web player, look at the Settings Transcoder profiles for resolutions and the gear has bitrates. Kodi has similar options as does sub's Android client.

Martin

[TheCompWiz]

If the input format is 4k HEVC encoded video with AAC audio (in an mpeg TS format) and a mobile device is on a 2mb Internet connection, that's just not going to fly. I know that I can setup the "preferred streaming profile" but isn't that more of a "master" setting that would affect all clients connecting to it? For example, if I set it to 720p, and my AndroidTV box requested 1080p from that server, it would end up with the 720p that was defined on the server, wouldn't it? It wouldn't upscale it.. or re-negotiate the bitrate/resolution. Also, is there an option to switch to HEVC or a more efficient codec instead of relying on H264, or whatever is hard-coded in the software? ... also I happened to notice that there appears to be no 4k option (in both the server, and the android app, and I'm assuming the apple-device apps as well. Is that a reason that isn't an option?

[mvallevand]

The profile used is client specific, but the bitrate for the profile might be fixed, I can't remember. You can have multiple profiles streaming at the same time from the web browser Kodi and some other clients. Why not try before expressing all your concerns?

HEVC doesn't work in browsers, but currently you can use user defined transcoding setting if you want and use more portable AV1 (and even HEVC) if you want.

Ultimately NextPVR is personal use only so the number of concurrent options isn't really that critical. Primary use will be direct play which isn't impacted be transcoding settings and there shouldn't be that many active mobile or internet users in a single household. Currently NextPVR doesn't negotiate the a/v settings or containers like Plex, Emby or Jellyfin but it is on sub's radar.

Martin

[TheCompWiz]

Thanks Martin for answering my questions, you really have been extremely helpful. I hope you'll tolerate just a few more.

You are correct, that my concerns are unverified. I have not in-fact yet tested the bitrate/resolution stuff, but will be putting it to the test this week. I was indeed making some assumptions. Where do I setup the "user defined transcoding" settings? Direct in the config? Is that documented somewhere?

As far as your "primary use will be direct play" statement, that doesn't seem accurate, as on the website directly, recommending native NextPVR clients on iphone/ipad/android. None of them I would consider a "direct-play" client, unless I am misunderstanding something. I admit, that in most cases people will use this within a home network, but more & more users are likely to want to have access to their content while traveling (like in my case).

I also noticed that you didn't mention anything about 4k. Was that deliberate?

[mvallevand]

Direct play means playing without transcoding. I don't know about iOS clients but all the other platforms have direct play clients tvOS, Roku, Android, Android TV, Windows, macOS. Plus there is Kodi that is direct play on Linux platforms like LibreElec and CoreElec. Browser technology is really the only limiting factor.

Not mentioning 4K wasn't deliberate, direct play client do support it but you are correct some older clients might not support it. Spending $20 to get a better direct play client seems like a better solution then taxing the server.

Sub doesn't do a lot of of documentation and only a hand full of users have helped on the wiki, but I think I posted how to change the default somewhere on the forum.

Martin

[TheCompWiz]

Is the code repo open to the public? ... might make figuring out the config options easier.

[sub]

No, it's closed source.