Compile Tvheadend with Transcoding Support and FFMpeg with OpenMAX on RPi 3

Kevan Brown · 2018-01-22T22:42:53+00:00

I've gone through a lot of threads on the forums here and found little bits of information here and there, but what I'm looking or is a true, quick, down and...

mpmc

There's a reason transcoding isn't included in the rpi builds, it's not supported. There's been work to get it to run directly within tvh but this hasn't (to my knowledge) been successful, at least not for me so far.

I'll give it a shot tomorrow & see what I can do.

Kevan Brown

Thank you very much for the reply and your willingness to assist. I'll eagerly await your results.

Kevan Brown

Mark Clarkstone wrote:
> There's a reason transcoding isn't included in the rpi builds, it's not supported. There's been work to get it to run directly within tvh but this hasn't (to my knowledge) been successful, at least not for me so far.
>

> I'll give it a shot tomorrow & see what I can do.

Any luck Mark?

mpmc

I tried but it's still broken :( see #4572 with the results.

Kevan Brown

Well thank you for trying. I appreciate your time.

mpmc

Kevan Brown wrote:

> Well thank you for trying. I appreciate your time.

You could still use transcoding on the Pi though using the transcode spawn option, I haven't tried it yet, I should do.

Kevan Brown

I'm afraid that without hardware acceleration (OpenMAX), the Pi just won't be able to keep up with the transcoding of MPEG-2 to H264, which is my primary use case as I'm looking to use TVHeadend with Plex to stream Live TV (which is encoded as MPEG-2 OTA).

Adam Rybak

Im able to live transcode with ffmpeg used as command line:

/usr/local/bin/ffmpeg -threads 4 -c:v h264_mmal -i http://192.168.XXX.XXX:9981/stream/channelid/1040644304 -c:v h264_omx -s 480x270 -b:v 768k -pix_fmt yuv420p -bufsize 3000k -c:a libmp3lame -ac 1 -ar 22050 -f mpegts -r 25 - 2>/tmp/ff.log

and passing to php script...

CPU usage is about 80-90% and works well.

My tweaks in /boot/config.txt for good perf (found in internet forums):

core_freq=580
arm_freq=1380
over_voltage=4
disable_splash=1
gpu_mem=320
temp_limit=75

sdram_freq=460

i think the transcoding can be done in tvheadend.

mpmc

Adam Rybak wrote:
> Im able to live transcode with ffmpeg used as command line:
>
> /usr/local/bin/ffmpeg -threads 4 -c:v h264_mmal -i http://192.168.XXX.XXX:9981/stream/channelid/1040644304 -c:v h264_omx -s 480x270 -b:v 768k -pix_fmt yuv420p -bufsize 3000k -c:a libmp3lame -ac 1 -ar 22050 -f mpegts -r 25 - 2>/tmp/ff.log
>
> and passing to php script...
>
> CPU usage is about 80-90% and works well.
>
> My tweaks in /boot/config.txt for good perf (found in internet forums):
>
> core_freq=580
> arm_freq=1380
> over_voltage=4
> disable_splash=1
> gpu_mem=320
> temp_limit=75
> sdram_freq=460
>

>i think the transcoding can be done in tvheadend.

It can, but not directly, you may want to consider using the transcode spawn option instead though.

Adam Rybak

Mark, Can you explain?

mpmc

Adam Rybak wrote:

> Mark, Can you explain?

It's basically the same as the pipe way (like above) except you use stdin/out.

It's only in 4.3. When I get chance I'll give it a try & report back.

Adam Rybak

How to use it? I can try ;-)

Jan g

Adam Rybak wrote:

Im able to live transcode with ffmpeg used as command line:

and passing to php script...

CPU usage is about 80-90% and works well.

My tweaks in /boot/config.txt for good perf (found in internet forums):

core_freq=580
arm_freq=1380
over_voltage=4
disable_splash=1
gpu_mem=320
temp_limit=75

sdram_freq=460

i think the transcoding can be done in tvheadend.

how are you doing this? 1080i only 18fps here. 576i 30fps but sometimes no picture. 720p 25fps but everytimes PES errors and other ffmpeg errors