The VideoLAN Forums

Hi,
I wanted to try to use HEVC for a transcoding task.
I downloaded a nighlty build (vlc-2.2.0-git-20140430-0402)

To start from something simple, I used the built-in vlc functions and got those parameters: Then I got that error:

It seems your Libav/FFmpeg (libavcodec) installation lacks the following encoder:
MPEG-H Part2/HEVC (H.265).

I get the same error with any nightly I get, I tried multiple ones in the 2.1 and 2.2 branch. Well some builds do not even display the error, but the resulting file is only an audio extraction.

Searching on the forums, I maybe misinterpreted the fact that from 2.1 (and even more 2.2) the encoder was available.
But maybe I should use the command line and use other parameters?
If so, is there a help file with some parameters available somewhere?

I thank you for any useful help provided.

I've been trying to update to latest FFmpeg since the error message states it doesn't come from VLC.
But it seems I'm not skilled enough to understand what happens... and what to do to correct my problem.

Any help appreciated.

Thanks

So "vlc --list" shows x265 as an encoder.
But "vlc -p x265 --advanced" says there's no module by that name.

Can someone just drop a word to confirm there's no usable x265 encoder in vlc yet?

You cannot use x265 in flv!

You should share your logs.

Thanks for the reply.
Regarding the flv settings, well at the time I wanted to try realtime transcoding, and adjusting size/parameters if needed. I used the gui that got me those settings.
But even a file convert gives the same error.

Example: Short Log (verbose 1) Long log (verbose 2)

x265 error: Height (118) must be a multiple of 8

Set the height manually.

Ok thanks for the help.
So the error is "generic" unless you watch the logs. Clear them and then see what happens.
After setting height/width manually, the encoder started.

Now I will try different settings and see what happens.
Thanks a lot!

I wonder if I can speak my trial and errors here...

So, with a transcode command to only encode in hevc and resize the video so that the encoding time is not too long, I get files that can't be played with VLC itself. I'll post a log later. I wonder if I should start a new thread.

So far, the encoding works, with problems related to the encapsulation.
Avi: Works, image is fine, but no audio is muxed
MP4: it seems it works, but the file is not playable with either VLC or other HEVC compatible players.
MKV: Works, but video is sometimes garbled, like every 3 seconds. Audio is properly muxed.

6 months later, big update:
The computer I used for the transcoding has been replaced by an overkill machine with an i7-4790k enough ram and a SSD.
Thing is, the power reserve is so immense I can transcode 1080p to 720p25FPS HEVC with a 1mbps target in realtime and still only use 80% of the processing power.
Needless to say that at the other end the image is vastly different.
If i try to encode to DVD quality, I'm only at 30% power.

So now my goal is to fine tune the settings to prevent buffering that appears when I overshoot the 1mbps limit for too long.

For the record, I transcode a 5 mbps 1080p50 livestream and restream it in hevc with an upload limit around 1mbps (my ADSL/VDSL line can't give more than that)
Wit the old comp, I couldn't use HEVC, too power hungry. So I had to lower resolution a lot (390 horizontal lines at max) in x264 at 25 FPS to meet the power and bandwidth limits.

Now I can go all the way up to 720p25 in HEVC. And VLC latest x64 nighlty does the job. A little detail, for the mux choose TS, it works great.

I'm back playing with the parameters and see if I can find a set that works best against bandwidth overshoot.

Have you managed to manipulate the crf setting from the vlc commandline? If so could you give a sample commandline?

This is something I have consistently failed to do...