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

[Dan Dennedy]

On Sat, Oct 29, 2011 at 2:02 PM, Johannes Bauer <dfnsonfsduifb at gmx.de> wrote:
> Am 29.10.2011 22:34, schrieb Johannes Bauer:
>
>> You mean the half second is incredible? I tried this out today and it I
>> am 100% certain. Actually I just removed the Gentoo-version of kdenlive
>> (my locally built GIT version conflicts with some audio plugins
>> apparently), but I'll happily reemerge the version and reproduce this.
>>
>> However, even if I report this, I do not know how to increase my
>> credibility. Are there any performance debug outputs that I could enable
>> to make you believe me?
>
> Okay, I just did the following: reemerge the Gentoo package. Then I set
> a camcorder up to record my PC monitor.
>
> I could reproduce the fast seeking. However, upon closer looking, it
> appears that it does not seek correctly (i.e. not to the desired
> position). As such, this is also useless. With the video I played around
> first this was not notable as the camera was statically mounted and the
> object in question only changed its shape, but didn't move.
>
> When trying this with a video with much motion, I get lots of
> encoding/decoding artifacts and have to seek three to four times to get
> a "correct" picture (it seems indeterministic). I can still record it if

OK, I believe this explains the situation. In version 0.4.6 of MLT, a
new form of seeking was added for AVCHD to make it clean and accurate.
Before this, using AVCHD was as you describe: fast but crappy and
therefore unusable. For some reason, even though you are using MLT
0.5.10, it appears to be slipping into that old mode.

> you wish, so you don't believe I just made that up.

No, its ok.

> Seems I'm stuck with the 4 seconds then... this at least works reliably.
> Do you have any pointers to transcoding into formats which give a decent
> seeking-time-to-disk-space ratio?

re-wrap them:
ffmpeg -i avchd.mts -vcodec copy -acodec copy -sn avchd.mkv

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