[FFmpeg-devel] [PATCH] lavfi: add inverse telecine filter

Michael Niedermayer michaelni at gmx.at
Mon Mar 23 02:56:51 CET 2015

On Mon, Mar 23, 2015 at 03:43:55AM +0530, Himangi Saraogi wrote:
> This is an exact inverse of the telecine filter unlike previously existing
> pullup and fieldmatch ones.
> Tested on few samples generated using the telecine filter. Documentation is
> yet to be added. Added an additional parameter "start_frame" to allow using
> the filter for a stream that was cut and improved pts handling.

why does the filter not use the input pts?

./ffplay -vf telecine,detelecine matrixbench_mpeg2.mpg
shows AV desync

so does
./ffplay -vf detelecine matrixbench_mpeg2.mpg

and even
./ffplay -vf telecine matrixbench_mpeg2.mpg

i think its maybe best to add to both detelecine and telecine a
ts_mode argument that allows the user to select between
using the first input timestamp and then calculating the rest from
that point on / passing all timestamps through /
droping all and recreating like is now done

> +
> +        frame->pts = outlink->frame_count * av_q2d(av_inv_q(av_mul_q(outlink->frame_rate, outlink->time_base)));

floating point values should be avoided as they can lead to rounding
differences between platforms and cause regression tests to produce
differnt output

the same is true for vf_telecine


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Observe your enemies, for they first find out your faults. -- Antisthenes
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