lavf/concatdec: add timestamp log

Help debugging timestamp conversion issues.
ffmpeg: fix printed timestamp for droped frames

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/truemotion2: Use av_freep() to avoid leaving stale pointers in memory

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/tta: Use av_freep() to avoid leaving stale pointers in memory

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/twinvq: Use av_freep() to avoid leaving stale pointers in memory

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
ffmpeg: Use input packet duration in vfr/cfr code if available and valid

Fixes Ticket3052
ffmpeg: Check duration for overlap and clip in fps cfr/vfr code

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
doc/writing_filters: use ffmpeg.org instead of wikimedia.org for lena image

Less likely to change, and under our control.

Thanks-to: Michael Niedermayer