Re: DVD and *.flv playback is jerky on VLC
On 04/04/12 01:19, AG wrote:
> On 28/03/12 13:25, Celejar wrote:
>> On Wed, 28 Mar 2012 21:43:19 +1100 Scott
>> Ferguson<scott.ferguson.debian.user@gmail.com> wrote:
>>
>>> On 28/03/12 21:11, AG wrote:
>>>> Hi
>>>>
>>>> I've noticed, using Debian stable, that DVD and *.flv
>>> flv in unindexed, so can be a problem in itself.
>>>
>>>> playback tends to be jerky. That is, the motion of the
>>>> actors, etc., seems to jump in short but noticeable ways, as if
>>>> the playback is dropping several frames and picking it up
>>>> again. The sound track is fine, no jumps, but the movement on
>>>> screen does seem to be a little jerky. It doesn't seem to
>>>> happen on other media players, or at least isn't as
>>>> noticeable.
>>>>
>>>> As a VLC novice, how do I address this? Any pointers for me to
>>>> look at, and if so, what *should* I be paying attention to?
>>> Could be that your dropping frames for some reason. Start the
>>> movie with VLC then press Ctrl+M to bring up the Messages dialog.
>>> Also check dmesg | tail. The info from those should help the list
>>> diagnose the problem.
>>>
>>> Also some box specs will be useful.
And they'd *still* be useful.
eg.:-
what Debian release are you running?
what video card do you have?
what video output module are you using with VLC?
shared memory enabled?
which version of VLC are you running?
is that from Debian (or debian-multimedia?)
>>>
>>> You can of course rule out the DVD read by copying one of the
>>> VOBs to the hard drive and viewing it from there with VLC.
>> You can also try playback using a different application, such as
>> mplayer, to see if your problem is VLC specific.
Any additional isolation testing is good.
>> Mplayer gives a big fat warning when it thinks your hardware isn't
>> up to the task of playing a given media file.
>>
>> Celejar
>>
>>
> Sorry for the delay in responding.
>
> I've done a few tests now and this is what I've found:
>
> (1) As far as I can make out, only VLC seems to have this problem
Which other players did you try?
eg. Kaffeine, Mplayer, Dragonplayer, Miro (you haven't told us much
about your system).
> (2) Opening VLC and running ctrl+m as suggested yields the following
> output with verbosity level set at 2 (this is just a small sample):
>
> xcb_xvdebug: display is visible
>
> mainwarning: late picture skipped (27445 > -45)
>
> xcb_xvdebug: display is visible
>
> mainwarning: late picture skipped (87793 > -44)
>
> mainwarning: late picture skipped (53793 > -44)
>
> mainwarning: late picture skipped (20793 > -44)
>
> mainwarning: late picture skipped (61865 > -41)
>
> mainwarning: late picture skipped (28865 > -41)
>
> xcb_xvdebug: display is visible
>
> mainwarning: late picture skipped (54076 > -56)
>
> mainwarning: late picture skipped (20076 > -56)
>
> mainwarning: late picture skipped (87076 > -56)
>
> mainwarning: resampling stopped after 14417235 usec (drift: 37)
>
>
> (3) This problem seems to occur for all DVDs and downloaded *.flv
> videos
It's likely that both problems have the same cause - but it'd be nice to
rule the DVD/DVD player out (hint).
How are you "downloading" flvs? ie. are you using a browser plugin? does
it use ffmpeg/transcode? where did you get those "things"?
>
> So, does this help debug the issue?
A little - it tells me that VLC is dropping frames, and that you are
using either X11, GLI, or XVideo (they're all "XCB").
What it doesn't tell me is whether your DVD is damaged, the drive has
read errors, or whether it's a problem elsewhere. dmesg and /var/log/*
will tell you more.
> What settings am I looking at tweaking?
None until the cause of the problem is identified (and proven). So far
you've simply confirmed a symptom (frame skipping).
You can isolate the DVD/DVD player from the equation by:-
;identifying a VOB file that "skips" in VLC when played on the DVD
;copying that VOB file to the hdd (use a terminal to see output from cpio)
;play the hdd copy of the VOB file and compare the VLC debug output.
You can isolate the problem if the same file played from the hdd does
*not* have identical frames skipped when played multiple times.
>
> Thanks for any help.
>
> AG
>
>
Kind regards
--
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