[FFmpeg-devel] [PATCH 2/3] ffplay: remove early frame drop functionality

Michael Niedermayer michaelni at gmx.at
Sun Oct 16 23:36:22 CEST 2011

On Sun, Oct 16, 2011 at 08:11:19PM +0200, Marton Balint wrote:
> On Mon, 10 Oct 2011, Michael Niedermayer wrote:
> >On Mon, Oct 10, 2011 at 08:59:09PM +0200, Marton Balint wrote:
> >>The current impementation of early frame drops (dropping frames before adding
> >>them to the picture queue) has multiple problems:
> >>
> >>Even after gettin A-V sync, the frame droping continues until
> >>VideoState->skip_frames reaches 1, which can take a lot of time causing useless
> >>additional frame drops and bad AV-sync. This issue can be easily triggered with
> >>for example changing the audio stream.
> >>
> >>Also video_refresh currenly does not handle early skipped frames in every case,
> >>for example if we skip a frame, then the last frame duration calculation will
> >>compute the duration of the sum of the skipped frame and the duration of the
> >>frame before that, and in compute_target_delay we may multiply this unusually
> >>big delay.
> >
> >The current early frame drop code has 2 reasons for its existence.
> >if the filtering is very timeconsuming and cannot be performed
> >in realtime AV sync is not possible with droping after the filtering.
> >
> >and when realtime display of all frames is not possibly it is better
> >to drop a consistent and evenly distributed pattern of frames instead
> >of a inconsistent one like for example droping several consecutive
> >frames and then not droping several in a row
> >
> >do you see an alternative to droping it ?
> No, I already have an almost-working version of early frame dropping
> which is using a bit different approach, and does not suffer from
> the problems above. I will push it to testing in a couple of days.
> So the removal of the feature is only temporary.

temporary loss is not a problem for me.


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

There will always be a question for which you do not know the correct awnser.
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