Among 4000 films the Grenoble Open Air festival selects ninety short-form films per year.
They should be delivered as 'conform' to DCP rules but in practice, because of improper subtitles
or sync+level+dispatch audio problems, 20% of them must be corrected and re-encoded.
Dcp-o-matic is heavily used for these corrections, and the Sony 4K SRX-R320 projector of the Cinémathèque
is used for the realtime verifications.(kind of an overkill isn't?)
To avoid this I asked VLC (HandBrake wiil follow) if they can add a faster than realtime "DCP light playback"
option, by using two simple methods (A) lower temporal sampling, and (B) lower resolution,
to eliminate the looong j2k conversion which shokes slow-CPU laptops :
(A) convert only one frame every three and repeat it 3 times on the display side;
This makes for an 8 samples per sec film which projected at 24fps shows realtime movements
smooth enough** to allow the verification of audio/subtitle sync.
(B) do not convert the upper tiles of the jpg2000 images, only use the low level tiles, e.g. 0.5k,
to produce SD images with more than enough resolution for the 15" screens we use for DCP verification
(focus-puller swiftness and precision is not our job here...)
Would this 'light playback' be acceptable for those of you in charge of cinema festivals DCP control?
**In 1969 at Eclair Corp of America we made an experiment with non warned cinemagoers in LA.
We projected at 24fps three similar sequences of a film about Tango dance respectively shot
at 24, 12 and 8sps. Nobody could see any artifacts on the 12sps shots, only a few people felt something
weird on the 8sps shots. We had to show them the Oude-Delft modified 16mm projector
before a second passage to make them more scrutinizing... and amazed by the plasticity of their brain