Clarification on configuration options and transcoding library

Antonio S

Hi all
I'm happly using tvheadend on my banana pi, great piece of SW indeed. However, I'm looking for adding a real time transcoding to h264 in my setup. I still want to stay with a single board computer low power and I know that banana pi is not an option due to lack of working hardware encoder (for the moment).
From my research it seems that a good option could be raspberry pi, since ffmpeg now support OpenMax IL accelerated encoder wia omx_enc profile.

But here I'm getting a little bit confused. Let mi attach a picture from my tvheadend installation:

https://s19.postimg.org/69w8e9usj/transcoding.png

As you can see apparently my setup doesn't use ffmpeg (which I believe it should mean libavcodec) for transcondig, rather it uses libx264 for h264 encoding.

I have built my tvheadend with the following command:

AUTOBUILD_CONFIGURE_EXTRA="--disable-libvpx --prefix=/usr --disable-libvpx_static --disable-bintray_cache --enable-hdhomerun_client" ./Autobuild.sh

from the configure options I see:

--disable-libav Disable libav
--enable-libav Enable libav
--disable-ffmpeg_static Disable ffmpeg_static
--disable-libx264 Disable libx264
--disable-libx264_static Disable libx264_static
--disable-libx265 Disable libx265
--disable-libx265_static Disable libx265_static
--disable-libvpx Disable libvpx
--disable-libvpx_static Disable libvpx_static
--disable-libtheora Disable libtheora
--disable-libtheora_static Disable libtheora_static
--disable-libvorbis Disable libvorbis
--disable-libvorbis_static Disable libvorbis_static
--disable-libfdkaac Disable libfdkaac

--disable-libfdkaac_static Disable libfdkaac_static

So, does it means that I don't see the ffmpeg (and/or libavcodec) option because it is disabled by default? But I don't see any enable-ffmpeg option. What's the static vs no static option? Maybe static use some compiled version of the library built during the tvheadend compilation?
Thanks for the support

Bye

Antonio S

Hi
No one can help on this topic please?
Bye

mpmc

Antonio S wrote:
> Hi
> No one can help on this topic please?

> Bye

There has been work to overhaul the transcoding support in tvheadend but at the moment support for hardware transcoding is lacking. I believe it's only really possible with x32/x64 machines right now, and even then you have to install a special kernel (Intel SDK).

There is workaround that should allow you to transcode using ffmpeg externally though. https://tvheadend.org/projects/tvheadend/wiki/Custom_MPEG-TS_Input

Basically, you'd have to pipe & return the transcoded stream back into tvheadend.

Antonio S

Hello Mark, thanks for the answer. But it is still not clear to me why it is requested to use an external ffmpeg via pipe for transcoding. I mean, openmax encoding it is just a normal profile in ffmpeg (if compiled with mmal and openmax option), so then it comes to my question: doesn tvheadend use ffmpeg for transcoding, since I see several compilation options for it, or not?

mpmc

Antonio S wrote:

> Hello Mark, thanks for the answer. But it is still not clear to me why it is requested to use an external ffmpeg via pipe for transcoding. I mean, openmax encoding it is just a normal profile in ffmpeg (if compiled with mmal and openmax option), so then it comes to my question: doesn tvheadend use ffmpeg for transcoding, since I see several compilation options for it, or not?

I'm not sure why it's not included to be honest (I'm no dev), I actually tried to help lekma (on IRC) get transcoding working with tvh on the Pi, you can see the IRC logs "here" If you want to try lekma's source see "here"

Antonio S

Hi
Do you have any contact of Lekma?
I am a dev (not exactly in the Linux video world, but in Linux embedded), so maybe we can help each other.
Bye

mpmc

Antonio S wrote:
> Hi
> Do you have any contact of Lekma?
> I am a dev (not exactly in the Linux video world, but in Linux embedded), so maybe we can help each other.

> Bye

I don't unfortunately, but if you think you can help him out, just fork his code & give it a go, no harm in trying!