TVHeadend Raspberry Pi and Transcoding

lord slash · 2014-11-04T22:19:08+00:00

Hi guys, I've setup a TVHeadend back end with my raspberry pi and raspbian, where I stream the italian tv to my home in Germany. The system works perfectly d...

Kris Van Bruwaene

Aren't all these problems with mpeg2 transcoding due to the fact that the RPI needs a payed key to decode (so presumably transcode as well) mpeg2?

renne -

You need the MPEG2 license for MPEG2 hardware-decoding, of course. What we want to do is h.264-encoding in hardware. The RPi(2) is shipped with a h.264 hardware-decoder AND encoder including the license. The one and only problem is to interface an application like TVHeadend with the OpenMax hardware stack. It seems GSTreamer can do this.

TVHeadend uses FFMPEG for transcoding, not GSTreamer.

SD: MPEG2 Transport Stream -> OpenMax MPEG2 decoder -> RAW Frames -> OpenMax h.264 encoder

HD: h.264 Transport Stream -> OpenMax h.264 decoder -> RAW Frames -> OpenMax h.264 encoder with lower bitrate

Maury Markowitz

Realistically, if we have hardware decode/encode working properly, is a realtime, on-the-fly transcode of an ATSC stream from MPEG2 to h.264 something the RPi2 could handle? I'm talking about live streams of HD television, not offline recodes for DVR.

renne -

According to
https://blankstechblog.wordpress.com/2015/01/25/hardware-video-encoding-progess-with-the-raspberry-pi/
GSTreamer needed about 160% runtime to recode 720p60 from MPEG2 to h.264. The question for live-streaming would be if GSTreamer/the GST-OpenMax-Plugin can be optimized enough for live-streaming.

It's definitely an option for non-realtime re-coding as h.264-re-coding would allow to watch non-h.264 videos in browsers like the video window of TVHeadend.

Maury Markowitz

Most excellent Redmine. This suggest my goal of realtime transcoding to iOS devices is not realistic (for now).

So... has anyone used TVH with one of the transcoding hardware solutions like the SiliconDust EXTEND? I suspect that will work fine, although it would up the price of my system (I need two).

Tony Brook

So, I have this successfully set up and itseems to run OK. I've only been running it for a few hours, so time will tell.
I'm using a Pi3 though. I've compiled from source and this seemed to work. I've attached the debs.
Install using

sudo dpkg -i tvheadend_4.1-2116~gf59669c_armhf.deb && sudo dpkg -i tvheadend-dbg_4.1-2116~gf59669c_armhf.deb

Mihai P

no debs attached, at least, i don't know how to get them, thanks!

Anonymous

What does work? Live transcoding with the PI? Software or Hardware transcoding?

Tony Brook

Just software transcoding. Both live TV and recorded programs.
There are still a couple of things I'm trying to get working;
Sending to Chromecast using TVHClient fails "Failed to load video", maybe a codec thing. The web-player is unwatchable due to long pauses. Smooth video though on Android phone and the Desktop through VLC. This is even for HD channels on DVB-T2. I've even set up a VPN server and I can connect and watch on external WiFi & 4G.
I've tried re-attaching the debs - hopefully it'll work this time.
I haven't tried this on my Pi2, so your millage may vary. Pi3 is definitely seems powerful enough.

Nikolay P

Hi Tony,

I have tried your dep files, but unfortunately live SD channel transcoding does not work well for me. The pictures disappears and so on, with VLC. I have tried all build-in transcoding profiles with different results, but non of them are good enough on a Pi3. Could you please let me know what profile works for you?

I can see from top that the pi3 only uses less then ~160% cpu, perhaps there is a way to tell tvheadend to use all the cores while transcoding?

Pablo Alone

HI there,

I would also like to see this working. Very encouraging that the Pi3 can handle it, although the post above me seems to have issues with it. I am currently running on Pi2, but plan to get a pi3 in the next few weeks.

@Tony Brook, please give us details of the transcoding profile you are using...

Tony Brook

OK after extensive testing, it still appears to be a little flakey. It definitely seems to work better for some channels than others.
I've used default settings for MKV, but as far as I can remember, the only thing I changed was I switched both audio and video codecs to Copy.
I think this may also depend a little on the source of your TV. In the UK, I'm using a DVB-T2 stick which, I believe, is already H264.
TBH, I haven't had a play with it in a while, so I'll try and do some more tweaking and get back to you all.

renne -

DVB-S = MPEG-2 (experimental H.264)
DVB-T = MPEG-2 (experimental H.264)
DVB-S2 = mostly H.264, sometimes MPEG-2
DVB-T2 Europe = H.264
DVB-T2 Germany = H.265

Tony Brook

These settings seem to work for me.
The picture's not the best, but it's OK for streaming across 4G or the internet.
I would recommend, you disable transcoding if you're on the local network to improve picture quality. Just change codec to Copy codec type.

Pablo Alone

thanks for this. Good to know that it works.

RPi 3 ordered and awaiting delivery. This will be handy for me as I am travelling down to south of France in our campervan and my intention is to access my home DVB-T/DVB-S tvheadend in a Pi2. I have it working fine for SDTV and tested over 4G, but my home uplink is limited to 5Mbps. Currently I can get 98% of my channels except for 2 DVB-T Irish main channels (RTÉ 1 & RTÉ 2) which are broadcast in HD only. It all depends on the French campsite wifi quality, but I can log in to my home system and adjust that bitrate if it is poor. I am hoping for somehting in the region of 4096 which is within the bounds of my very reliable uplink.

Robert Mast

I read about a vorbis stream of 800 kbps with 100% CPU at the beginning of this thread and the lack of support for the TV-Headend-client, so you will have to fiddle with streams anyway, so how about trying to stream through the hardware-codecs?

https://www.raspberrypi.org/forums/viewtopic.php?t=113052 promises a recoded 2000 kbps stream without much processor load.

I just ordered the MPEG2-license for my RPI3.

By the way, the matroska-aac-settings hardly reach 800 kbps, and the screen often inverses color in VLC. (I however use TVHeadend 4.09 as compiled with OSMC)

Robert Mast

I received my MPEG2-licence, but didn't see it work yet on my TV-Headend 4.09 as plugin available on OSMC 2016.06-2 as TVHeadend collapsed.

The 401-issues I get are somewhat like in this thread: https://tvheadend.org/d/2950-solved-descramble-fails-at-random-times

with strange workarounds like https://tvheadend.org/d/591-401-when-accessing-live-tv

In the log of OSMC, which isn't in /var/log/syslog anymore

https://discourse.osmc.tv/t/no-var-log-syslog/676/7

I found another issue, of which I don't know whether it is related:

https://discourse.osmc.tv/t/automatic-fsck-of-root-filesystem-on-start-stop/9163/4

Do you have a clue what version of TVHeadend on what OS is stable nowadays for the RPi3?

Robert Mast

I somewhat struggled further and found a version that's stable enough to be able to zap between channels without freezing: Openelec 6.0.3 with TVHeadend 4.0.8 and OSCam from the 'unofficial addons'.

It's the only version I tried that's actually able to start the VLC-stream clicking the links in TVHeadend.

I saw the Omx-hardware-decoder run in Kodi with my MPEG2-license. However, a HD-channel was still not showing completely fluent on a SDTV during a panning camera, which appeared to be the default NTSC setting of the RPi. When I altered it to SDTV_mode=2 the issue disappeared.

From this point we could look further for transcoding a channel.

Pablo Alone

Tony Brook wrote:
> These settings seem to work for me.
> The picture's not the best, but it's OK for streaming across 4G or the internet.

> I would recommend, you disable transcoding if you're on the local network to improve picture quality. Just change codec to Copy codec type.

This did not work for me at all. RPi 3 latest Raspbian. CPU running at 350%, picture falling to pieces on SD & HD, DVB-T/T2 & DVB-S/S2.

Robert Mast

To try this I had to build gstreamer and plugins. However, the standard case of the RPi3 appeared not to be sufficient for keeping out heat-issues and the RPi3 broke. I returned it and am now studying cross-compilation, as I think this 2000 kbit stream should even be possible on a RPi1 as it doesn't seem to take much processing power. But first: Let's try.

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