[Kdenlive-devel] kdenlive-HEAD very slow on timeline click in AVCHD videos

[Dan Dennedy]

On Sat, Oct 29, 2011 at 7:27 AM, Johannes Bauer <dfnsonfsduifb at gmx.de>wrote:

> Hi list,
>
> I have a problem with Kdenlive, both on a Gentoo and Ubuntu computer. It
> was built from head using the scripts from
> http://www.mltframework.org/twiki/bin/view/MLT/BuildScripts because with
> both the distribution version of Ubuntu 11.10 and Gentoo, I experienced
> severe A/V delays when editing/transcoding.
>
> Now earlier when I clicked in the "middle" of a video, it took on my
> Q9550 PC about half a seocond to update the picture (ffmpeg 0.7.6, melt
> 0.5.10, kdenlive 0.7.8).


It is well known that seeking on AVCHD is horribly slow. Is this version
combination something you tested today or are you basing this on on a
memory? I have a lot of trouble believing your above claim is possible.

Does the machine have NVIDIA GPU with NVIDIA binary X driver? Possibly that
build of ffmpeg and mlt supports VDPAU. Run 'melt -debug avchd.mts 2>&1 |
grep vpdau'
If it the console out contains many messages with 'vdpau' in them, it is
using VDPAU.

VDPAU does provide some speed benefit on systems with weak CPU, but I have
not seen it improve seeking much, and it causes much more instability, which
is why it is now disabled by default. Still, it would be interesting to see
if this combo is the reason.


> Now with the HEAD version (built 2011-10-29,
> ffmpeg git-2011-10-29-6faf0a2, melt 0.7.5, kdenlive 0.8.1 rev 5997), it
> takes about 4-5 seconds for the picture to update, once I clicked on the
> timeline.
>

This is what is expected.


> Videos are AVCHD ("MTS" extension) directly from the camcorder, example
> at https://spornkuller.de/00022.mts
>
> If there's anything I can do to debug this problem, please let me know!
>
> People are re-wrapping, transcoding, or using proxy clips for anything but
very light editing with AVCHD.

-- 
+-DRD-+
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