On 22 October 2017 at 00:36, Moritz Barsnick <[email protected]> wrote:
> On Sat, Oct 21, 2017 at 23:32:15 +0200, Szucsik György wrote: > > This is rather odd, since vpxenc has had this feature already for some > > time. > > Well, not in the libvpx code I could find. Which vpxenc were/are you > using? What is its version, what is the option called? > I grabbed the official source from here https://www.webmproject.org/code/ cloned https://chromium.googlesource.com/webm/libwebp the compiled code corresponds to vpxenc v1.6.1-1338-gb58259ab5 the option is in help --row-mt=<arg> Enable row based non-deterministic multi-threading in VP9 it's even in the Windows build v1.6.1-1258-gc8f6e7b99 I was using and I can confirm it's working as advertised binaries from here https://forum.doom9.org/showthread.php?p=1820572#post1820572 > > In the libvpx source code, the option was at one time originally called > "new-mt", for a short while, and renamed to "row-mt" with the commit I > quoted. > > > Looks like there is a miscommunication here, unfortunately. > > Between whom? > Between ffmpeg and libvpx devs? > > You're obviously the libvpx/vpxenc expert, not me. I'm not. > I can only interpret > the sources and their changes. ffmpeg looks at a libvpx source define > " > > > VPX_CTRL_VP9E_SET_ROW_MT" to see whether the feature is available. > This source define was added in the named commit. ffmpeg *could* also > check for the old name "VPX_CTRL_VP9E_SET_NEW_MT", but that was also > never available in a libvpx release, and only available for a short > term, in other words experimental / not final. > So it must have changed then, I don't know. Does not explicitly say it's experimental https://groups.google.com/a/webmproject.org/forum/#!topic/codec-devel/oiHjgEdii2U > > > I was referring to this line (please note my C skills are very basic) > > https://github.com/FFmpeg/FFmpeg/blob/master/libavcodec/ > libvpxenc.c#L1159 > > > > The option that needs to be passed is row-mt but the variable that's > > responsible for controlling this behavior is called row_mt. A bit of > > inconsistency but if it works, it works. > > An option is a command line option for the shell (or for libavcodec's > API). Its name "row-mt" was chosen, corresponding to vpxenc's > "--row-mt". > > The variable name is only internal to ffmpeg's source code. It could just > as well be named "foobla". Indeed it's called "row_mt" for convenience. > ;-) C (the language) doesn't allow it to be named "row-mt", if that's > what you mean. (In libvpx's source code, the same "inconsistency" > exists, of course.) > Now that you mention it, it's indeed like that. Oh well. Regards, George _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
