Movies with variable frame rate can cause mismatch of displayed frame
when proxies are used. Since proxies are not used for rendering, this
means, that output may be different than expected. This problem can be
avoided when timecodes are used.
Set used timecode to Record Run. Timecodes are built with proxies at
the same time, therefore if proxies are built and used this will
resolve possible mismatch of output.
Record run is chosen, because it will show frames based on time they
were encoded by encoder and should match behavior as if movie was
played back at normal speed. This change is done only for new strips
in order to not overwrite user defined settings.
Other minor changes:
- When proxies are enabled, size 25% is no longer set by default. It was mostly annoying anyway.
- Silence warning when timecode file is not present. This was introduced in 4adbe31e2fc98f982aed3d97505513750ec348d4. Previously use of timecodes was hard-coded in sequencer and this error would spam console if timecodes would be enabled by default and proxies would be never built.
ref: T95093