How to choose ffmepg codec on synfig command line, could you explain in documentation

Hello, I want to set the codec to H.264 in synfig command line.

I currently do:
synfig -t ffmpeg -Q 10 -o vid.mp4 --start-time 25f --end-time 75f anim.sifz

But as the quality is bad, I want to change the codec, I guess the default codec is not good.

I tryed:
synfig -t ffmpeg -Q 10 -o vid.mp4 --start-time 25f --end-time 75f anim.sifz --video-codec “mp4”

and
synfig -t ffmpeg -Q 10 -o vid.mp4 --start-time 25f --end-time 75f --video-codec “mp4” anim.sifz

Also with using “H.264” or “H.264 / AVC / MPEG4-AVC” at the place of mp4, but it doesn’t work.

Finally I half succed with:
synfig -t ffmpeg -Q 10 -o vid.mp4 --start-time 25f --end-time 75f --video-codec “mpeg4” --video-bitrate 2000 anim.sifz

But I would like to know all the supported codec on ffmpeg, and I don’t find a place for that. And I would like to set H.264 better than mpeg4.

For those who work on the synfig documentation, I believe that you should tell (in the documentation) that -vs and -vb commands no more work (apparently), and that one should use both --video-codec and --video-bitrate to export with specif ffmpeg codec, and give the list of accepted codec tag.

thank you very much.

My synfigstudio ubuntu package doesn’t export , I have to use synfig command line, is it normal?
Thanks

$ synfig --target-video-codecs

outputs

 flv:   	Flash Video (FLV) / Sorenson Spark / Sorenson H.263.
 h263p:   	H.263+ / H.263-1998 / H.263 version 2.
 huffyuv:   	Huffyuv / HuffYUV.
 libtheora:   	libtheora Theora.
 libx264:   	H.264 / AVC / MPEG-4 AVC.
 libx264-lossless:   	H.264 / AVC / MPEG-4 AVC (LossLess).
 mjpeg:   	MJPEG (Motion JPEG).
 mpeg1video:   	Raw MPEG-1 video.
 mpeg2video:   	Raw MPEG-2 video.
 mpeg4:   	MPEG-4 part 2 (XviD/DivX).
 msmpeg4:   	MPEG-4 part 2 Microsoft variant version 3.
 msmpeg4v1:   	MPEG-4 part 2 Microsoft variant version 1.
 msmpeg4v2:   	MPEG-4 part 2 Microsoft variant version 2.
 wmv1:   	Windows Media Video 7.
 wmv2:   	Windows Media Video 8.

So you should use libx264 as video codec.

Besides, quality 10 is the worse quality available; and 0 is the best. Some codecs have settings in this same twisted logic (like CRF). There is a reason: 0 means to do stuff as much is intended to. Other values are diferent levels of simplification that makes code faster (but, e.g., with some artifacts) - and you can create as many simplification levels as you need/want to. It would be ‘impossible’ to say a number for the best quality for every feature, as different features may have different number of levels.

Where did you see those options?
I can’t see them here Doc:Synfig CLI Syntax - Synfig Animation Studio

Lol, Indeed if q 10 is worst quality it s logical.

I saw VC and vb options here
https://wiki.synfig.org/Doc:Synfig_CLI_Syntax

I guess that I’m on the wrong web page
I found it by typing “synfig command line” on Google

Can you redirect me to a right documentation.

Thank you very much for your answer

Oh, now I saw them: they are mentioned only in the example, not in the table! lol
Well, I investigate the code and they seem to not be usable since (at least) 2012.