ffmpeg drop-frame

[theiviaxx]

Hello, is the --drop-frame option enabled in libvpx for ffmpeg.
Nothing I try seems to be recognized. How do you disable drop-frame
using ffmpeg?

Thanks

[James Zern]

This was mapped to -skip_threshold in r23522, which defaults to 0
(disabled). Prior versions of libvpxenc in the ffmpeg tree did not map
this parameter, so the library default would be used.

[theiviaxx]

hmmm, im using that one and setting to 0, i guess i can just opt out
of it. Still getting dropped frames though. Not to go into too much
detail but there is an object sliding across the screen in the
source. however in the webm version its a chunky movement, like it
skips instead of sliding.

Are there some other settings i should be tweaking? I think lowering
the GOP size is helping.

On Aug 16, 2:30 pm, James Zern <jz...@google.com> wrote:

[James Zern]

On Mon, Aug 16, 2010 at 18:06, theiviaxx <thei...@gmail.com> wrote:
> hmmm, im using that one and setting to 0, i guess i can just opt out
> of it.  Still getting dropped frames though.  Not to go into too much
> detail but there is an object sliding across the screen in the
> source.  however in the webm version its a chunky movement, like it
> skips instead of sliding.
>

Are other codecs not showing the same behavior with this clip? The
first thing to determine for this material is whether libvpx or ffmpeg
is dropping the frames. If the first and -skip_threshold is 0 then it
would be a bug. If neither one are then it may be a performance issue
on the decode side.

[theiviaxx]

i'll give some other codecs a shot and see. Also, if i use the
default GOP size, 12 i think, it gets better. Would reducing it to
say 3 be a bad thing? It may also be the browsers. chrome 6 beta was
not playing sound sometimes and minefield had some issues as well. is
the tech too new?

On Aug 18, 7:31 am, James Zern <jz...@google.com> wrote:

[James Zern]

On Thu, Aug 19, 2010 at 00:05, theiviaxx <thei...@gmail.com> wrote:
> i'll give some other codecs a shot and see.  Also, if i use the
> default GOP size, 12 i think, it gets better.  Would reducing it to
> say 3 be a bad thing?
>

This will most definitely impact quality, even 12 is quite low.

>  It may also be the browsers.  chrome 6 beta was
> not playing sound sometimes and minefield had some issues as well.
>

I don't think we have enough information yet to place blame. Without
knowing the details of the source material, encoding settings used and
information on the playback machine it's hard to give guidance at this
point. Another check that you could make would be to use a gstreamer
based player or mplayer to rule out a problem with the browsers
themselves.

[cpetig]

>> Hello, is the --drop-frame option enabled in libvpx for ffmpeg.
>> Nothing I try seems to be recognized. How do you disable drop-frame
>> using ffmpeg?
> This was mapped to -skip_threshold in r23522, which defaults to 0
> (disabled). Prior versions of libvpxenc in the ffmpeg tree did not map
> this parameter, so the library default would be used.

unfortunately the mentioned patch did not make it into the ffmpeg
release. So it is quite likely that ffmpeg will drop frames for a lot
of people (including debian and ubuntu).

I filed an ubuntu bugreport at https://bugs.launchpad.net/bugs/622895
and will continue at other places.

[cpetig]

On 23 Aug., 20:49, cpetig wrote:
> I filed an ubuntu bugreport at https://bugs.launchpad.net/bugs/622895
> and will continue at other places.

Added an upstream bug report / release request as https://roundup.ffmpeg.org/issue2182

[John Koleszar]

Hi,

Thanks for pushing this issue. Distros can also package the new v0.9.2
which doesn't default to this behavior. There are other useful updates
for libvpx in/near that ffmpeg revision, so it's still worth pursuing
that angle, IMO.

John