Jean-Baptiste, thank you very much for this answer! "merging down" is a nice concept that is easy to explain to the ordinary Kdenlive user.
Beyond that there is still that nagging feeling that I would like to understand where this "merging down" can be seen and the b_track getting removed from the tractor list? Or does the particular track then produce no frame when it's covered by a b_track+in+out of a transitions? Best regards, Harald Am 26.07.2016 um 21:49 schrieb Jean-Baptiste Mardelle: > On Tuesday, July 26, 2016 9:41:26 PM CEST, Harald Albrecht wrote: >> I can't get my head around really understanding why MLT, taken >> the following example, uses video frames from track #1 (middle >> track) instead of from track #0 with track #2 composed onto it. >> Besides the overall documentation, I've also tried to read the >> core sources for tractor, multitrack, and transition, but I >> sadly notice I still lack a lot of understanding of the inner >> workings of the MLT framework... >> >> Let's assume a simple MLT setup, along the lines of this XML; >> hopefully this shows the gist: >> >> <mlt> >> ... <!-- some producers here --> >> <tractor> >> <multitrack> >> <track producer="playlist1"/> >> <track producer="playlist2"/> >> <track producer="playlist3"/> >> </multitrack> >> <transition id="transition1"> >> <property name="a_track">0</property> >> <property name="b_track">2</property> >> <property name="mlt_service">composite</property> >> </transition> >> </tractor> >> </mlt> >> >> Now let's also assume that all three playlists have video clips >> starting with the same in and out points. That is, all three >> clips overlap each other in my imaginary timeline. >> >> Without any transition, if I'm correct, I understand the >> tractor to work such that it takes always the "topmost" video >> frame from track #2, that is, from "playlist3". >> >> But with "transition1" in place, the tractor takes the frames >> from track #1, aka "playlist2". Can someone please explain to me >> simpleton why the tractor now "produces" video frames from track >> #1 instead of from the composition of track #2 onto track #0? > Quick answer: a transition merges the b_track onto the a_track. > So the track containing "playlist3" is merged into the track containing > "playlist1". The first visible track will now be "playlist2". > > regards > jb > > > ------------------------------------------------------------------------------ > What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic > patterns at an interface-level. Reveals which users, apps, and protocols are > consuming the most bandwidth. Provides multi-vendor support for NetFlow, > J-Flow, sFlow and other flows. Make informed decisions using capacity planning > reports.http://sdm.link/zohodev2dev > _______________________________________________ > Mlt-devel mailing list > Mlt-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/mlt-devel ------------------------------------------------------------------------------ What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports.http://sdm.link/zohodev2dev _______________________________________________ Mlt-devel mailing list Mlt-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mlt-devel
