Ahhhh ... since you've mentioned MLT_AVFORMAT_CACHE, I've searched the
mltframework GitHub repository for queries to getenv() and found
MLT_PIXBUF_PRODUCER_CACHE. Setting this to 100 now makes melt play the
project fine.
So this triggers two questions:
1. What are "sensible" values for MLT_PIXBUF_PRODUCER_CACHE? The number
of parallel tracks? Or much more?
2. Is it possible for applications that use MLT to control such settings
through API calls?
Thank you very much for getting me on the right track this time!
-- Harald
Am 21.01.2017 um 20:25 schrieb Dan Dennedy:
Regression from what version or time frame? Is it really a regression
or a long-standing problem?
From the sound of it, the automatic increment of avformat producer
cache size might not be working as expected. The automatic part of
this is in mlt_multitrack.c: when tracks are added the size is
increased too track count plus one. That will cause for each frame at
least one producer to release its avformat and avcodec contexts and
file handle and re-open this within another producer.
Try running it with melt command line with env
var MLT_AVFORMAT_CACHE=20 to see if it makes a difference. That will
set a minimum cache size whereas the default is 4. Obviously, I have
been talking about avformat producer primarily. If you are using
images that might be another matter.
On Sat, Jan 21, 2017 at 11:15 AM Harald Albrecht
<harald.albre...@gmx.net <mailto:harald.albre...@gmx.net>> wrote:
Hi,
over time I've seen strange performance breakdowns in my Kdenlive/MLT
projects, where sometimes playback and rendering of a multi-track
timeline breaks down to a crawl without a compelling reason (to
me, that
is). When six clips are composed of each other (using the Qt
composite &
transform transition), then rendering breaks down from around
15fps to a
single frame every three seconds or so. CPU load is negligible, around
16% on a Core i7, so most cores are idle.
I've finally isolated a minimal regression project, both as .mlt and
.kdenlive files with a few associated image files, ~400kb in total.
melt --version gives "6.5.0", it's from the Kdenlive git master ppa
which also has the recent git master MLT to offer.
If someone is willing to look into this issue then I'm happy to
send my
regression project. There is no private data included.
With best regards,
Harald
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, SlashDot.org! http://sdm.link/slashdot
_______________________________________________
Mlt-devel mailing list
Mlt-devel@lists.sourceforge.net
<mailto:Mlt-devel@lists.sourceforge.net>
https://lists.sourceforge.net/lists/listinfo/mlt-devel
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, SlashDot.org! http://sdm.link/slashdot
_______________________________________________
Mlt-devel mailing list
Mlt-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/mlt-devel
